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Title: Smithsonian Institution - United States National Museum - Bulletin 240

Author: Museum of History and Technology

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Most recently updated: October 23, 2024

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*** START OF THE PROJECT GUTENBERG EBOOK SMITHSONIAN INSTITUTION -
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Compiler's Notes
Bulletin 240 was compiled from individual Papers posted on Project Gutenberg and the
Index for this volume:

Paper 34
Paper 35
Paper 36
Paper 37
Paper 38

Paper 39
Paper 40
Paper 41
Paper 42
Paper 43
Paper 44

Transcriber's Notes for each Paper and the Index follows the text of that Paper/Index.

SMITHSONIAN INSTITUTION
UNITED STATES NATIONAL MUSEUM

BULLETIN 240

SMITHSONIAN PRESS

MUSEUM OF HISTORY AND TECHNOLOGY

Contributions
From the
Museum
of History and
Technology

Papers 34-44
On Science and Technology

SMITHSONIAN INSTITUTION · WASHINGTON, D.C. 1966

Publications of the United States National Museum
The scholarly and scientific publications of the United States National Museum include two
series, Proceedings of the United States National Museum and United States National Museum
Bulletin.
In these series, the Museum publishes original articles and monographs dealing with the
collections and work of its constituent museums—The Museum of Natural History and the
Museum of History and Technology—setting forth newly acquired facts in the fields of
anthropology, biology, history, geology, and technology. Copies of each publication are distributed

to libraries, to cultural and scientific organizations, and to specialists and others interested in the
different subjects.
The Proceedings, begun in 1878, are intended for the publication, in separate form, of shorter
papers from the Museum of Natural History. These are gathered in volumes, octavo in size, with
the publication date of each paper recorded in the table of contents of the volume.
In the Bulletin series, the first of which was issued in 1875, appear longer, separate
publications consisting of monographs (occasionally in several parts) and volumes in which are
collected works on related subjects. Bulletins are either octavo or quarto in size, depending on the
needs of the presentation. Since 1902 papers relating to the botanical collections of the Museum of
Natural History have been published in the Bulletin series under the heading Contributions from
the United States National Herbarium, and since 1959, in Bulletins titled “Contributions from the
Museum of History and Technology,” have been gathered shorter papers relating to the collections
and research of that Museum.
The present collection of Contributions, Papers 34-44, comprises Bulletin 240. Each of these
papers has been previously published in separate form. The year of publication is shown on the last
page of each paper.
Frank A. Taylor
Director, United States National Museum

Papers
Page
34. The 1893 Duryea Automobile 1
Don H. Berkebile
35. The Borghesi Astronomical Clock 29
Silvio A. Bedini
36. The Engineering Contributions of Wendel Bollman 77
Robert M. Vogel
37. Screw-Thread Cutting by the Master Screw Method Since 1480 105
Edwin A. Battison
38. The Earliest Electromagnetic Instruments 121
Robert A. Chipman
39. Fulton’s “Steam Battery”: Blockship and Catamaran 137
Howard I. Chapelle
40. History of Phosphorus 177
Eduard Farber
41. Tunnel Engineering—A Museum Treatment 201
Robert M. Vogel
42. The “Pioneer”: Light Passenger Locomotive of 1851 241
John H. White

43. History of the Division of Medical Sciences 269
Sami Hamarneh
44. Development of Gravity Pendulums in the 19th Century 301
Victor F. Lenzen and Robert P. Multhauf

Produced by Colin Bell, Joseph Cooper, Stephanie Eason, and the Online Distributed
Proofreading Team at http://www.pgdp.net.
[1]

Contributions from
The Museum of History and Technology:
Paper 34

The 1893 Duryea Automobile
In the Museum of History and Technology

Don H. Berkebile
EARLY AUTOMOTIVE EXPERIENCE 5

CONSTRUCTION BEGINS 6

DESCRIPTION OF THE AUTOMOBILE 16

INDEX

Figure 1.—Duryea automobile in the Museum of History
and Technology, from an 1897 photograph. The gear-
sprockets were already missing when this was taken, and
the chain lies loosely on the pinion. Shown at the right, the
Duryea vehicle following the recent restoration
(Smithsonian photo 34183).

Don H. Berkebile

THE 1893
DURYEA
AUTOMOBILE
In the Museum of History and Technology
During the last decade of the nineteenth century a number of American
engineers and mechanics were working diligently to develop a practical self-
propelled vehicle employing an internal-combustion engine as the motive
force. Among these men were Charles and Frank Duryea, who began work on
this type of vehicle about 1892. This carriage was operated on the streets of
Springfield, Massachusetts, in 1893, where its trials were noted in the

newspapers. Now preserved in the Museum of History and Technology, it is a
prized exhibit in the collection of early automobiles.
It is the purpose of this paper to present some of the facts discovered
during the restoration of the vehicle, to show the problems that faced its
builders, and to describe their solutions. An attempt also has been made to
correlate all this information with reports of the now almost legendary day-to-
day experiences of the Duryeas, as published by the brothers in various
booklets, and as related by Frank Duryea during two interviews, recorded on
tape in 1956 and 1957, while he was visiting the Smithsonian.
The Author: Don H. Berkebile is on the staff of the Museum of History and
Technology, in the Smithsonian Institution's United States National Museum.
f the numerous American automotive pioneers, perhaps among the best known are Charles

O and Frank Duryea. Beginning their work of automobile building in Springfield,
Massachusetts, and after much rebuilding, they constructed their first successful vehicle in
1892 and 1893. No sooner was this finished than Frank, working alone, began work on a second
vehicle having a two-cylinder engine. With this automobile, sufficient capital was attracted in 1895
to form the Duryea Motor Wagon Company in which both brothers were among the stockholders
and directors. A short time after the formation of the company this second automobile was entered
by the company in the Chicago Times-Herald automobile race on Thanksgiving Day, November
28, 1895, where Frank Duryea won a victory over the other five contestants—two electric
automobiles and three Benz machines imported from Germany.
In the year following this victory Frank, as engineer in charge of design and construction,
completed the plans begun earlier for a more powerful automobile. During 1896 the company
turned out thirteen identical automobiles, the first example of mass production in American
automotive history.[1] Even while these cars were under construction Frank was planning a lighter
vehicle, one of which was completed in October of 1896. This machine was driven to another
victory by Frank Duryea on November 14, 1896, when he competed once again with European-
built cars in the Liberty-Day Run from London to Brighton. The decision to race and demonstrate
their autos abroad was the result of the company's desire to interest foreign capital, yet Frank later
felt they might better have used their time and money by concentrating on building cars and selling
them to the local market. Subsequently, in the fall of 1898, Frank arranged for the sale of his and
Charles' interest in the company, and thereafter the brothers pursued separate careers.

Figure 2.—Workmen in the Duryea factory in Springfield, Mass.,
working on some of the thirteen 1896 motor wagons. (Smithsonian photo 44062.)

Frank, in 1901, entered into a contract with the J. Stevens Arms and Tool Company, of
Chicopee Falls, Massachusetts, which built automobiles under his supervision. This association led
in 1904 to the formation of the Stevens-Duryea Company, of which Irving Page was president and
Frank Duryea was vice president and chief engineer. This company produced during its 10-year
existence a number of popular and well-known models, among them a light six known as the
Model U, in 1907; a larger 4-cylinder called the Model X, in 1908; and a larger six, the Model Y,
in 1909. In 1914 when Stevens withdrew from the company, Frank obtained control. The
following year he sold the plants and machinery, liquidated the company, and, due to ill health,
retired.
Charles, in the meantime, located in Reading, Pennsylvania, where he built autos under the
name of the Duryea Power Company.[2] Here, and later in Philadelphia under the name of the
Duryea Motor Corporation and other corporate names, he continued for a number of years to build
automobiles, vacuum cleaners and other mechanical devices. Until the time of his death in 1938,
he practiced as a consulting engineer.

Figure 3.—Admittance card of C. E. Duryea to the U.S. Patent Office, 1887.
(Gift of Rhea Duryea Johnson.)

Early Automotive Experience
Born in 1861 near Canton, Illinois, Charles E.
Duryea had learned the trade of a mechanic
following his graduation from high school, and
subsequently turned his interests to bicycle repair.
He and his brother James Frank, eight years
younger, eventually left Illinois and moved to
Washington D.C., where they were employed in the
bicycle shop of H. S. Owen, one of that city's
leading bicycle dealers and importers. While in
Washington, Charles became a regular reader of the
Patent Office Gazette,[3] an act which undoubtedly
influenced his later work with automobiles. A short
time later, probably in 1889, Charles contracted
with a firm in Rockaway, New Jersey, to construct
bicycles for him, but their failure to make delivery
as promised caused him to go to Chicopee,
Massachusetts, where he contracted with the Ames
Manufacturing Company to do his work. Moving
Figure 4.—Charles E. Duryea, about 1894,
there in 1890, he obtained for his brother a position as drawn by George Giguere from a photograph.
as toolmaker with the Ames Company. Thus, Frank (Smithsonian photo 48335-A.)
Duryea, as he was later known, also became
located in Chicopee, a northern suburb of Springfield.
During the summer, 1891, Charles found the bicycle business left him some spare time, and the
gasoline-powered carriages he had read of earlier came constantly into his mind in these periods of
idleness.[4] He and Frank studied several books on gasoline engines, among them one by an

English writer (title and author now unknown);[5] this described the Otto 4-stroke cycle as now
used. Some engineers, however, were concerned because this engine, on the completion of the
exhaust stroke, had not entirely evacuated all of the products of combustion. The Atkinson engine,
patented in 1887, was one of the attempts to solve this as well as several other problems, thus
creating a more efficient cycle. This engine was designed so that the exhaust stroke carried the
piston all the way to the head of the engine, while the compression stroke only moved the piston
far enough to sufficiently compress the mixture. The unusual linkage necessary to create these
unequal strokes in the Atkinson engine made it seem impractical for a carriage engine, where
compactness was desired.

Figure 5.—Advertisement of Duryea bicycle company,
Scientific American, September 9, 1893.

Going to Hartford, Connecticut, possibly on business relating to his bicycle work, Charles
visited the Hartford Machine Screw Company where the Daimler-type engine was being produced,
[6]
but after examining it he felt it was too heavy and clumsy for his purpose. Also in Hartford he
talked over the problem of a satisfactory engine with C. E. Hawley, an employee of the Pope
Manufacturing Company, makers of the Columbia bicycle. Hawley, searching for a way to
construct an engine that would perform in a manner similar to the Atkinson, yet would have the
lightness and compactness necessary for a carriage engine, suggested an idea that Charles believed
had some merit. This idea, involving the use of what the Duryeas later called a "free piston," was
eventually to be incorporated in their first engine.[7]

Figure 6.—J. Frank Duryea, about 1894,
as drawn by George Giguere from a photograph.

(Smithsonian photo 48335.)

Construction Begins
Back in Chicopee again, Charles began planning his first horseless carriage. Frank later stated
that they leaned heavily on the Benz patents in their work;[8] but while the later engine and
transmission show evidence of this, only the Benz manner of placing the engine and the flywheel
seem to have been employed in the original Duryea plan. Charles reversed the engine so that the
flywheel was to the front, rather than to the rear as in the Benz patent, but made use of Benz'
vertical crankshaft so that the flywheel rotated in a horizontal plane. Previously most engines had
used vertical flywheels; Benz, believing that this practice would cause difficulty in steering a
propelled carriage, explained his reason for changing this feature in his U.S. patent 385087, issued
June 26, 1888:
In motors hitherto used the fly-wheels have been attached to a horizontal
shaft or axle, and have thus been made to revolve in a vertical plane, since the
horizontal shaft is best adapted to the transmission of power. If, however, in
this case we should use a heavy rotating mass, corresponding to the power
employed and revolving rapidly in a vertical plane, the power to manage the
vehicle or boat would become very much lessened, as the flywheel continues
to revolve in its plane. I therefore so design the apparatus that its crank shaft x
has a vertical position and its fly-wheel y revolves in a horizontal plane…. By
this means the vehicle is not only easily controlled, but also the greatest safety
is attained against capsizing.
To the Duryea plan, Benz may also have contributed the idea for positioning the countershaft,
though its location is sufficiently obvious that Charles may have had no need for copying Benz.
Charles wisely differed from Benz in placing the flywheel forward, thus eliminating the need for
the long driving belt of the Benz carriage. Yet he did reject the bevel gears used by Benz, which
might well have been retained, as Frank was later to prove by designing a workable transmission
that incorporated such bevel gears. The initial plan, as conceived by Charles, also included the
details of the axles, steering gear, countershaft with its friction-drum, the 2-piece angle-iron frame
upon which the countershaft bearings were mounted, and the free piston engine with its ignition
tube, since hot-tube ignition was to be employed. No provision was made, however, for a burner to
heat the tube; nor had a carburetor been designed, though it had been decided not to use a surface
tank carburetor. The plans called for no muffler or starting arrangement.[9] Many engines of the
period were started simply by turning the flywheel with the hands, and Charles felt this method
was sufficient for his carriage.

Figure 7.—Drawing showing principle of the Atkinson engine; this feature
is what the Duryeas were trying to achieve with their free-piston engine, by
substituting the free piston for the unusual linkage of the Atkinson.
(Smithsonian photo H3263-A.)

Figure 8.—Drawing of 1885 Benz engine, showing
similarity in general appearance to Duryea engine. From
Karl Benz und sein Lebenswerk, Stuttgart, 1953.
(Daimler-Benz Company publication.)

The Ames plant customarily had a summer shutdown during August; thus, during August of
1891 Charles and Frank had access to a nearly empty plant in which they could carry on
experiments and make up working drawings of the proposed vehicle. It cannot now be
conclusively stated whether any parts were made for the car during August or the remainder of the
year. It is more likely that the brothers attempted to complete a set of drawings. Frank Harrington,
chief draftsman at Ames, may have helped out at this time; from Charles' statement of April 14,
1937, it is learned that he did prepare drawings during 1892.
The first contemporary record of any work on vehicles is a bill, dated January 21, 1892, for a
drawing made by George W. Howard & Company. This drawing was made in the fall of 1891 by
Charles A. Bartlett, a member of the Howard firm and a neighbor of Charles Duryea, according to
a statement by Charles in the Automobile Trade Journal of Jan. 10, 1925. He was then also of the

opinion that this drawing may not have
had anything to do with the carriage they
were about to assemble, but a notation
found by Charles at a later date has led
him to believe that it possibly concerned a
business type vehicle he had discussed
with an unidentified Mr. Snow.
By early 1892 Charles needed capital
to finance his venture, an old carriage to
attach his inventions to, a place to work,
and a mechanic to do the work. On March
26, he stopped by the Smith Carriage
Company and looked over a selection of
used buggies and phaetons. He finally
decided on a rather well-used ladies'
phaeton which he purchased for $70. The
leather dash was in so deplorable a state it
would have to be recovered before the
carriage went onto the road, and the
leather fenders it once possessed had
previously been removed; yet the
upholstery appeared to be in satisfactory
condition, and the candle lamps were
intact.

Figure 9.—Illustration from U.S. patent 385087,
issued to Carl Benz, showing the horizontal plane
of the flywheel, a feature utilized by the Duryeas in their machine.

Figure 10.—Phantom illustration of Benz' first automobile.
(From Carl Benz, Father of the Automobile Industry, by L. M. Fanning, New York, 1955.)

Two days later, Charles was able to interest Erwin F. Markham, of Springfield, sufficiently to
obtain his financial aid in the project. A contract was drawn up between the two men, which stated
that Mr. Markham was to put up $1000 for which he received a five-tenths share of the venture.
When the $1000 had been used, he then had the option to continue his aid until the project had
been carried to a successful climax, and retain his half share, or to refuse further funds and
relinquish four of his five-tenths interest in the business.[10] Had he eventually chosen the latter,
Charles would obviously have had to seek assistance elsewhere.

Figure 11.—The Howard & Co. bill showing the first work performed
toward a motor vehicle. While this may not refer specifically
to the machine now in the museum, it is evidence of early work.

That same day, March 28, Charles found
working space and machinery available at John W.
Russell & Sons Company in Springfield.[11] The
Russells had recently completed a large
government order of shells for the famous
dynamite guns later used on board the cruiser
Vesuvius in the Spanish-American War, and this
left an entire second floor, approximately 35 × 85
feet, virtually unoccupied, according to an
affidavit of William J. Russell of April 30, 1926.
Now ready to begin the actual work, Charles hired
his brother Frank to start construction. Frank
started about the first of April, receiving a raise of
about 10 percent over the salary he had received at
Ames. Before the vehicle was completed a number
of other men performed work on some of the
parts, among them William Deats who had been
hired by Charles primarily to work on bicycles in
the same area, but who occasionally assisted on
the carriage. Russell Company records show time Figure 12.—The shop of John Russell & Sons.
charged against Charles Duryea by six other It was on the second floor of this building that
Russell employees: W. J. Russell, P. Colgan, C. E. Charles and Frank Duryea built their first motor vehicle.
(Courtesy of the Springfield Union.)
Merrick, T. Shea, L. J. Parmelee, and A. A.
Poissant.

Figure 13.—J. Frank Duryea looking over the Russell shop lathe
on which he turned parts for the first Duryea vehicle.
Photo taken about 1944. (Courtesy of the Springfield Union.)

It is Frank Duryea's remembrance that he started work on Monday, April 4. He first removed
the body, with its springs, and placed it on a pair of wooden horses where it remained until the
summer of the following year. The next step was to remove the rear axle and take it to a
blacksmith shop where the old axle spindles were cut off and welded to a new drop-center axle.
Following this the front axle spindles were removed, the ends of the axle slotted, and a webbed, C-
shaped piece carrying the kingpin bearings was fitted into each slot, braced from underneath by
short brackets which were riveted and brazed in place. The old spindles then were welded to the
center of offset kingpins which in turn were mounted in their bearings in a manner similar to that
in which the frame of the Columbia high-wheeled bicycle was mounted in its fork. Arms welded to
the lower end of the kingpins were connected by the tie rods to an arm on the lower end of the
vertical steering column, located on the center of the axle.
While work on the running gear advanced, some progress was made in the construction of the
engine. Patterns for the castings were fabricated, most of them by Charles Marshall on Taylor
Street,[12] and castings were poured. The body or main casting of the engine resembled a length of
cast-iron pipe: it had no bosses or lugs cast on, nor any water jacket, for they thought the engine
would be kept cool merely by being placed in the open air. The front end of the engine was
secured to the vehicle by four bolts which passed through the halves of the bearings and onto four
projections on the open end of the engine. As the crankshaft of this engine was retained in
constructing the present engine, it is logical to assume that the bearings were the same also. The
head was cast as a thick disc, with both intake and exhaust valves located therein, and was bolted
onto the flanged head end of the engine.

Inside the cylinder was the strange arrangement
previously suggested by C. E. Hawley. To the connecting
rod was attached a rather ordinary ringed piston, over
which was fitted a free, ringless piston, machined to fit
closely the cylinder bore. This floating piston could move
freely a distance equal to the compression space. The
intention was that on the intake stroke, suction would open
the intake valve, which had no positive opening
arrangement, and draw in the mixture which then was
compressed as in a regular Otto engine. Fired by the hot-
tube ignition system, the force of the explosion would
drive both pistons down, forcing the outer one tight against
the head of the smaller one, and at the end of the stroke the
longer wall of the outer piston would strike an arm
projecting into the cylinder near the open end, moving
forward the exhaust valve rod to which the arm was
attached, thus pushing open the valve in the head.[13] On
the exhaust stroke the unrestrained outer piston moved all
the way to the head, expelling all of the products of
combustion and pushing the exhaust valve shut again.
With a bore of four inches or less, this engine, Charles
believed, should develop about three horsepower and run
Figure 14.—A portion of the Russell shop at a speed between 350 to 400 revolutions per minute.[14]
records showing charges made against
Charles Duryea during 1893-1894.
As no ignition system had yet been provided, they
prepared a 4½-inch length of one-quarter inch iron pipe,
closed at one end, and screwed the open end into the head. Heating this tube with an alcohol
burner would cause ignition of the mixture when a portion of it was forced into the heated tube
toward the end of the compression stroke. No attempt was made at this time to use the electrical
make-and-break circuit used in their second engine, as the free piston would have wrecked the
igniter parts on the exhaust stroke, and the push rod located on the end of the piston would have
prevented the piston from closing the exhaust valve.
After keying the flywheel to the lower end of the crankshaft, Charles and Frank decided to
make an attempt to run the engine. Carrying it into a back room, probably during July or August,
1892, they blocked it up on horses. A carburetor had not yet been constructed, so they attempted to
start the engine by spinning the flywheel by hand, at the same time spraying gasoline through the
intake valve with a perfume atomizer previously purchased at a drugstore in the Massasoit House.
Repeated efforts of the two men to start the engine resulted in failure.

Figure 15.—Conjectural drawing of the free-piston engine used in the Museum vehicle prior to the present engine.
(Drawing by A. A. Balunek.)

In the belief that the defects, whatever they might be, could be remedied after the engine was
installed, the Duryeas went ahead and mounted the engine in the carriage. To do this they
shortened the original reach of the carriage, allowing the engine itself to become the rear
continuation of the reach. The four ears on the front, or open end of the engine, were bolted to the
centrally located frame, with the bearing blocks in between. This frame, the same one now in the
vehicle, was constructed of two pieces of angle iron, riveted and brazed together. Greater rigidity
was obtained by a number of half-inch iron rods running from the frame to both front and rear
axles. Because of the absence of any mounting brackets on the engine casting itself, a wooden
block with a trough on top to receive the body of the engine was fitted between the engine and the
axle, while two U-shaped rods secured it with clip bars and nuts underneath.
Beneath the flywheel was mounted the friction transmission of Charles' design. This consisted
of a large drum, perhaps 12 inches in diameter, equal in length to the diameter of the flywheel and
keyed to a shaft directly under the center of the crankshaft and parallel to the axles. (Diameter of
drum estimated by examination of existing features.) In view of the four projections of the frame
extending downward and just in front of the jackshaft position, it is likely that these supported the
four jackshaft bearings. Being a bicycle manufacturer, Charles saw the need for a differential or
balance gear. Accordingly, he purchased from the Pope Manufacturing Company a very light unit
of the type formerly used on Columbia tricycles, and installed it somewhere on the jackshaft. A
small sprocket on each end of the shaft carried a chain from the larger sprockets clamped to the
spokes of each rear wheel. The lower surface of the flywheel had been machined so as to form a
friction disc, with a one-quarter inch depression 3 inches in diameter turned in the center. The
drum was positioned so that its upper surface was one-quarter inch below the face of the flywheel.
Hanging loosely around the drum was an endless belt, one and one-half inches wide, first made of
rather soft rubber packing material. The belt lay on the drum surface between the fingers of a
shipper fork. While it lay under the 3-inch depression in the center of the flywheel, the belt and the
drum were at rest, but when it was moved away from that depression the belt wedged itself tightly
between the drum and flywheel, the resulting friction causing the drum to turn and setting the
vehicle into motion. The farther the belt was moved toward the outer edge of the wheel, the faster
the drum and the vehicle moved.
In September 1892, Charles, who had contracted with a Peoria, Illinois, firm to have bicycle
parts manufactured, decided to move to that city. Departing on the 22d of September, he did not
return to Springfield for over two years, and thus was not able to participate in the completion and

testing of the carriage. At the time of his departure several units on the carriage were incomplete. A
carburetor had not been built, nor had a satisfactory burner or belt-shifting device. Charles had
experimented with various shifting levers just before leaving Springfield: however, as he reported
later, he did not succeed in designing a workable mechanism.[15] Frank Duryea, now left to finish
the work unassisted, continued the experiments with the belt shifter. He finally worked out a fork
mounted on a carriage that was supported by two rods, each of which slid in two bearings.
Although the short distance between the two bearings caused the shifter carriage to bind
occasionally, the device was thought to be sufficient and was installed just in front of the frame.
Connected to a system of cables, arms, and rods, possibly similar to the present cam-bar shifter,
the shipper-fork carriage was moved from side to side by raising or lowering the tiller.

Figure 16.—Drawing of the carburetor used on both Duryea engines, 1893-1894,
showing sight feed on left and choke mechanism on right. (Smithsonian photo 13455.)

Turning now to an efficient burner for heating the ignition tube, Frank started with an ordinary
wick-type kerosene lamp with a small metal tank. Wishing to use gasoline in the lamp, he found it
necessary to fabricate a number of burner units before he found a type that gave him a clean blue
flame. He then found the flame to be very sensitive to drafts and easily extinguished, and devised a
small shield or chimney to afford it some protection.
Early in October, while still working with the burner, Frank developed a severe headache. He
felt the fumes of the lamp had probably caused it, and went to his room in the home of a Mr. and
Mrs. Patrick on Front Street in Chicopee. After he noticed no improvement, a doctor's examination
showed he had typhoid fever, and on October 5 he was admitted to the Springfield Hospital. Here
he remained for one month, being discharged on November 5. Returning to his room he was
informed that because of the fear that he might be a typhoid carrier, the Patricks preferred him to
find other lodgings. He readily accepted the invitation of Mr. and Mrs. D. H. Nesbitt of Chicopee
to take a room with them. After several weeks recuperation in their home, he left Springfield to
visit his mother in Wyoming, Illinois.
After a restful visit at home Frank Duryea returned to Springfield and finished the work on his
burner. Now only the lack of a carburetor prevented a trial of the vehicle. He recalls that he studied
several gasoline-engine catalogs and in one of them, a Fairbanks catalog he believes,[16] he saw a
design that seemed to suit his needs. He decided to simplify the construction and operation of his
carburetor and had a small bronze casting made to form the body of it. Inside was a gasoline
chamber with two tapped openings, one to receive a pipe from the 2-gallon gasoline tank mounted

above the engine, the other taking a pipe to the overflow tank underneath the engine, thus
maintaining the gasoline level without the use of a float valve. This latter tank had a hand pump on
one end so that the overflow gasoline could at times be pumped again into the main tank. Gasoline
passed from the carburetor chamber through a needle valve, adjusted by a knob on top, then
through a tiny tube that entered the pipe leading to the intake valve. It is not certain whether this
intake pipe was at first fitted with the choke arrangement later used with the second engine.
Frank, hoping at last to be rewarded for his efforts by the sound of explosions from the engine,
was ready to give the carriage an indoor trial. Standing astraddle of the reach and facing to the
rear, he spun the flywheel with both hands, taking care not to get his hands caught between the
wheel and the frame. His efforts were in vain, as there was complete failure to obtain ignition. He
then made a new ignition tube, nearly twice as long as the original 4-½-inch tube, and turned down
its wall as thin as he thought safety allowed. The thinner wall did not conduct the heat off so
rapidly and thus kept the tube hot enough to permit ignition. After this slight change, he was able
to get a few occasional explosions but he does not now believe that the engine ever operated
continuously. Each explosion was accompanied by a loud knock, due, undoubtedly, to the
movement of the free piston. Had the engine operated continuously, it is likely that the action of
the free piston would have shortly wrecked the engine. Further efforts appeared unwarranted until
alterations could be made.

Figure 17.—Letter explaining the circuit breaker spring and the brass projection on top of the
ignition chamber.
Mr. Mitman was, at the time, curator of engineering in the U.S. National Museum.
View Larger Image of Letter Text of Letter

The two pistons were first pinned together into a single unit which was probably ringless, since
it is believed the walls of the outer piston were too thin to admit rings. Because the piston no
longer struck the exhaust valve, a short rod had to be screwed into the pistonhead; this pushed the
valve shut at the completion of the exhaust stroke. The remaining problem, the opening of the
exhaust valve, was solved by screwing a device to the side of the cylinder which operated from the
sidewise motion of the connecting rod. This device shifted a small spacer between the piston and
the striker arm of the exhaust-valve rod, permitting the piston to push open the exhaust valve. On
alternating strokes the spacer shifted back out of the cylinder; therefore, no contact was made
between piston and striker arm. Sometime in February 1893, the altered engine was successfully
started.
At last the transmission could be tested. Will Russell had come upstairs to watch the trial, and
according to a statement by him, given April 30, 1926, Frank, standing to the right of the engine
and behind the rear axle, reached forward and with the combination tiller-belt-shifter, moved the
belt into driving position. The carriage started forward, but as it approached the wall of the
building Frank discovered that he could not get the belt back into the neutral position. In
desperation, he grasped the rear axle with both hands and was dragged a short distance, attempting
to stop the machine, before it struck the wall. He had, however, sufficiently retarded it so that no
damage was done.
This short trial demonstrated some of the weaknesses in the friction transmission. Since the
speed of the surface of the flywheel, in feet per second, increased in proportion to the distance of
the point of contact from the center, the outer edge of the belt attempted to run faster than the inner
edge. This conflict of forces not only put an undue load on the motor causing a great loss of power,
but it also created a tendency for the belt to work towards the outer edge of the flywheel.
Conversely, when the operator desired to return the belt to neutral, it strongly resisted any efforts
to slide it toward the center of the wheel, as Frank had learned from the wall-bumping incident.
Furthermore, the rubber belt on the friction drum had worn so badly that it had to be replaced at
least once during the brief experiments.
At this point, Frank and
Markham felt that the carriage
was anything but satisfactory.
While they were trying to decide
what steps should be taken next,
Frank added one last
improvement to the engine.
Fearing that the uncooled cylinder
might suffer damage from the
excessive heat, he constructed a
copper water jacket in two halves,
drew them together around the
cylinder with clamping rings and
soldered the seams. Asbestos
packing sealed the end joints
Figure 18.—Ignition chamber, switch,
where the jacket contacted the and breaker contacts of the present Duryea engine.
cylinder. Thinking back, Frank
does not recall that he ever used a

water tank with this engine, though he does remember adding water through the upper jacket
opening. The engine was run only for a few brief periods following this addition.
Obviously this collection of patchwork could not fulfill their needs for an engine. First, it
would be next to impossible to start if the body was placed on the running gear, as the flywheel
then would be practically inaccessible. The absence of rings on the piston caused a further loss of
power to the already overloaded engine. The flywheel was too light. The absence of any form of
governor left the operator with no control over the engine speed. Ignition was poor, partly owing to
the hot-tube arrangement, and partly to the excessive distance between the engine and the
carburetor. Frank wrote his brother Charles on February 6[17] that in his opinion the mixing
chamber was so far from the engine that the gasoline could not be drawn into the cylinder as
liquid, and it was too cold to vaporize and go in as gas. Thus he had difficulty in getting the engine
started. When it did start the explosions were unmuffled. Less important to him than these defects,
however, was the awkward and unsightly wooden engine mount.

Description of the Automobile
Sometime in the early part of March, Frank convinced Markham that he could construct a new
and practical engine, using only previously tried mechanical principles.[18] Drawing up new plans
for this engine, he took them to Charles Marshall who began work on the patterns for the new
engine castings. After the patterns had been delivered to the foundry, Frank left Springfield for a
short vacation in Groton, Connecticut, where he visited with his fiancée. On May 17, 1893, several
weeks after his return to Springfield, they were married.
The engine castings were undoubtedly received from the foundry prior to Frank Duryea's
marriage, and the work of machining and assembling the parts went on through the spring and
summer. This engine, still on the carriage in the Museum of History and Technology, is cased with
a water jacket, and has bases on top to support the front and rear bearings of the starting
crankshaft, and a base with port on the upper right side where the exhaust-valve housing was to be
bolted. On the underside are two flanges, forming a base for seating the engine on the axle. A
separate combustion chamber is cast and bolted to the head. Inside this chamber are located the
igniter parts of Frank's electric ignition system. The fixed part, an insulated electrode, is screwed
into the right side of the chamber and is connected with the ignition switch outside, to which one
of the ignition wires is attached. A breaker arm inside is pinned to a small shaft extending through
the top of the chamber. Around the breaker-arm shaft is a small coil spring (originally a spiral
spring, according to the letter of Charles Duryea shown in fig. 17), anchored below to a thin brass
finger extending toward the right side of the car, and above to a nut screwed tightly onto the shaft.
This nut is also the terminal for the other ignition wire. The action of the spring keeps the breaker
arm and the electrode in constant contact until the push rod on the end of the piston strikes the arm
and separates the two parts. Breaking contact then produces the ignition spark. Since the
mechanism would spark at the end of both the exhaust and compression strokes, the battery current
is conserved by a contact strip, on the underside of the larger exhaust-valve gear, by means of
which the flow of current is cut off during the greater part of the cycle.

On the left side of the combustion chamber is bolted the housing containing the tiny intake
valve. A comparatively weak spring seats this valve in order that the suction created by the piston
can easily pull it open. Clamped onto the valve housing is the intake pipe, enclosing the choke and
carrying the carburetor on its forward side. The choke consists of two discs which block the pipe,
each with four holes at the edges and one in the center. Turning one disc by means of a small
handle outside, so that the four outer holes cannot coincide with those in the other disc, decreases
the flow of air and causes all air to rush through the center hole, where the tiny carburetor tube
passes through. The present carburetor was transferred over from the first engine. When Frank
later installed the engine on the carriage he noticed the close proximity of the intake pipe to the
open end of the muffler. Believing that the fumes might choke the engine, he attached a long sheet-
metal tube to the intake pipe so that fresh air would be drawn in from a point farther forward on
the vehicle.
Moving to the right side of the engine brings the exhaust-valve assembly into view. This valve
is contained in a casting bolted over the exhaust port in the side of the cylinder, and from the
casting a pipe leads to the muffler underneath. The valve is pushed open by a rod connected to a
crank which is pinned to the lower end of a shaft carrying an iron gear on top. This gear is in mesh
with a fiber gear, keyed to the upper end of the crankshaft, with half the number of teeth. This ratio
permits the opening of the exhaust valve on every other revolution.
The crankshaft of the first engine was retained for the new engine, thus giving the two engines
the same stroke of 5-⅜ inches, but the bore was increased slightly to 4⅜ inches. With this larger
bore and with the engine speed increased to 500 rpm, Frank rated this engine at 4 hp.[19] A heavier
flywheel, with a governor resting in the upper recess, was pressed onto the crankshaft. As the
operator of the vehicle had no control over the carburetor once he climbed into the seat, this
governor was necessary to maintain regular engine speed. Its function was to move a slide on the
exhaust-valve unit to prevent the valve from closing. Thus the engine, with the suction broken,
could not draw a charge on the next revolution. During the recent restoration of this carriage it was
found that while most parts are still intact, nearly all of the governor parts are missing. A
description of them must therefore be based on the recollections of Frank Duryea, along with
certain evidences seen on the engine.

Figure 19.—Under side of exhaust valve mechanism showing electrical contacts that give spark only on every other
revolution.

Just on top of the flywheel, and surrounding the crankshaft, rest two rings, 3⅞ inches in
diameter. Into the opposing surfaces of these rings are cut a series of small inclined planes,
appertinent to each other. On the outer circumference of the upper ring two pins pass through a
pair of lugs mounted in the flywheel, causing the ring to rotate with the flywheel, yet permitting
vertical movement. Underneath, the other ring is allowed to turn slightly when, by means of two
connecting links, the arms of the governor push against them. These two arms, each constructed

like a right angle and pivoted at the apex, are arranged directly opposite each other far out in the
flywheel recess. As a weight on one angle of the arm presses outward by centrifugal force against
a spring, the other angle presses inward against the connecting link mentioned above. The turning
of the lower set of inclined planes against the fixed set above raises the upper ring and the fork
resting on it. The upward movement of this fork, which is a continuation of an arm pivoted to a
bracket midway between the crankshaft and the slide carrying the exhaust valve stop, causes the
other end of the arm to drop, pulling the slide down with it. In this manner the closing of the
exhaust valve is blocked, preventing the intake of the next charge, and therefore the engine misses
one or more explosions until it slows to its normal speed.
A starting shaft is mounted above the engine casting by a cast-iron bracket on either end. The
front end of the shaft has a bevel gear which is held by a coil spring behind the front bracket, just
out of contact with a bevel gear pressed onto the upper end of the crankshaft. The short rear
portion of the shaft is a tube which slides over the main shaft. Fitting the removable handcrank to
the squared end of the hollow shaft and turning the crank clockwise, will advance the forward
section of shaft through the medium of a pair of inclined collars. With the bevel gears now
engaged the engine may be cranked. When ignition begins, the inclined collars slide back down
each other's surfaces, the shaft is again shortened, and its bevel gear springs free of the one on the
crankshaft.

Figure 20.—Piston and connecting rod of second engine. Screw on rod is where oil is poured into connecting rod to
lubricate wrist pin and crankshaft.

While Frank worked on his engine, he realized that certain parts of the old running gear would
need to be altered or replaced. In view of the heavier and more powerful engine, he felt the old
wheels, probably having compressed band hubs, were inadequate. He procured a set of new,
heavier wheels[20] with Warner-type, cast-iron reinforced hubs. The angle iron frame, apparently
sturdy enough to carry the added weight, was retained, but it was decided to install a heavier rear
axle.[21] The front axle assembly was at first allowed to remain unchanged, as was the steering
apparatus. A short time later when the engine and friction transmission were bolted in place on the
running gear, Frank saw that the rigidity of the framework had an undesirable effect. When the
vehicle passed over any unevenness in the shop floor, the framework was distorted and caused the
jackshaft bearings to bind tightly enough on the shaft to prevent its being turned by hand. In order
to provide the 3-point suspension necessary to eliminate this distortion, Frank attached the forward
parts of the framework to an extra wooden spring bar, installing between this bar and the front axle
a vertical fifth wheel of the type ordinarily used in a horizontal position in any light carriage.
Frank next calculated that with the faster running engine the speed of the vehicle would be
about 15 miles an hour, too much for the heavily loaded wheels. As he intended to make use of the
original transmission, he decided to decrease the speed by increasing the size of the friction drum.
He accomplished this by sliding a heavy fiber tube over the original drum, bringing its diameter to
approximately 14 inches. The original shipper fork carriage was improved by separating the

original bearings to a greater distance, and eliminating one of the two bearings on one end. This
permitted a smooth and free operation of the small sliding carriage.
In August 1893, possibly as a result of indoor experiments, Frank discovered that the chains
running from the small 5-tooth[22] jackshaft sprockets to the large, bronze, wheel sprockets were
tight at some times and loose at others. This caused considerable unnecessary noise. The difficulty
apparently was the result of the sprockets being cast and not machined. The patternmaker had said
he believed he could make the pattern accurately enough so that no machining of the castings
would be necessary. Nice castings were produced, but "these sprockets were the reason why an
unusual construction was put on the crankshaft [meaning jackshaft]," explained Frank Duryea
during an interview at the National Museum on November 9, 1956. Elaborating further, in reply to
the queries of E. A. Battison, of the Museum's division of engineering, Duryea told of the problem
and the solution when he explained that the sprockets had places where the shrinkage was not
even. The hot metal, contracting as it cooled, did not seem to contract uniformly, creating slightly
unequal distances between teeth. This resulted in the chain hanging quite loose in some places and
in others the tightness prevented adjustment. He contacted Will Russell, foreman of the Russell
shop, where the automobile was made, and Russell showed him a device, built by George
Warwick, who had made the Warwick bicycle. It was an internal-cut gear, according to Duryea's
description, with sprocket teeth on its periphery. With sprockets outside and normal teeth inside,
the wheels were about 6 inches in diameter, externally.
These little internal-gear sprockets were hung on double-shrouded pinions secured to each end
of the jackshaft. A solid disc or housing fitted against both ends of the pinion to prevent the
internal gear from working off sideways. Duryea explained the function of these unique little parts:
"as soon as tension came on that ring gear that we talked about, it not only tightened the chain
hanging on this sprocket on the upper side, but it tightened it on both sides. [The sprocket] rocks
right out: both sides of the chain are tight."
This feature is one rarely encountered elsewhere, and Duryea, later in the interview said, "To
tell you the truth, I think I was just a little bit ashamed about the thing, because I had to pull it off.
I didn't like the looks of it after I got it on."
Two small tanks, each with a capacity of approximately two gallons, were mounted over the
engine in the positions they still occupy, the one on the left for gasoline,[23] the other for water. The
small fitting under the gasoline tank has a thumbscrew shutoff and a glass-sight feed tube, leading
to the carburetor. The water tank, an inch longer than the gasoline tank, communicates with the
water jacket of the engine through two pieces of half-inch pipe, entering the jacket from above and
below. The overflow tank, holding just over a gallon, is suspended between the rear axle and the
flywheel.

A number of mufflers were constructed for the engine.[24] The first experimental one was built
of wood, being a box 6 × 6 × 15 inches with a hole for the exhaust pipe in one end and a series of
small holes in the opposite end. Inside, Frank arranged metal plates which were somewhat shorter
than the depth of the box. Every other one was attached to the bottom of the box; the intermediate
plates were fastened to the top. This contrivance muffled the sound considerably, but, as might be
expected, soon began to smoke. There can be little doubt that it was replaced before any of the
outdoor trials began. Another type consisted of a cylindrical metal shell, perhaps six inches in
diameter and ten or twelve inches long. Here a series of perforated baffle plates were inserted, with
alternating solid plates having parts of their external edges cut away. Two bolts running the length

of the muffler held on the cast-iron heads in a manner quite similar to the Model-T Ford mufflers
of later years. Though partially satisfactory, Frank, in a November 6, 1957, interview, complained
that it made a metallic sound. Perhaps this was the muffler he used from September to November
1893.

Figure 21.—Illustration of the no. 2 Samson battery
used by the Duryeas in their vehicle. (Smithsonian photo 46858.)

On August 28 Frank wrote to Charles saying the carriage was almost ready for the road and
that he hoped to take it out for a test on the coming Saturday, "off somewhere so no one will see
us…."[25] There is no evidence showing whether the amount of remaining work permitted the
proposed trial on September 2. The body was finally replaced on the running gear, at which time it
was found necessary to raise the seat cushion several inches by the insertion of a framework made
of old crating boards. This allowed sufficient room between the seat and the frame to suspend the
batteries and coil. Six no. 2 Samson batteries were contained in this space, three on each side, in
rows parallel to the side of the vehicle. The Samson battery consisted of a glass jar containing a
solution of ammonia salts and water, with a carbon rod in the center, housing a zinc rod. It is
difficult to understand why they used Samson batteries rather than dry cells; perhaps they were
concerned with the mounting cost of the machine and were making use of parts already on hand.
[26]
A coil, possibly from an old gaslight igniter system, accompanied the Samson batteries under
the seat. This original coil is now missing.
The iron dash frame, previously recovered and provided with a rain apron to be pulled up over
the knees in the event a heavy rain blew in under the carriage top, was bolted back in place. Frank
and Mr. Markham gave the carriage a quick painting; later Frank admitted, "the machine never had
a good job of painting."[27] Before the motor wagon actually got onto the road, a reporter on the
Springfield Evening Union got some statistics on it and an item appeared on September 16, giving
the first public notice of the machine.

Figure 22.—From the Springfield Evening Union, September 16, 1893.
Text of Article

Toward the latter part of the following week, Frank was ready to give the product of his labors
its first road trial. On September 21 the completed carriage was rolled onto the elevator at Russell's
shop. Seeing that the running gear was too long for the elevator, they raised the front of the
machine, resting the entire weight of 750 pounds on the rear wheels. Once outside the building,
they pushed it into an area between the Russell and Stacy buildings. After dark, "so no one will
see," Will Bemis, Mr. Markham's son-in-law, brought a horse and they pulled the phaeton out to
his barn on Spruce Street.[28] There, on Spruce and Florence Streets the first tests were made. The
next day Frank wrote his brother saying, "Have tried it (the carriage) finally and thoroughly and
quit trying until some changes are made. Belt transmission very bad.[29] Engine all right." He did
admit the engine seemed to be well loaded most of the time. He also had an idea in mind to replace
[30]
the poor transmission, explaining the plan to Charles: "The three gears on secondary shaft have
friction clutches, the two bevel gears on same shaft are controlled by a clutch which frees one and
clutches the other at will. This provides a reverse."

Figure 23.—Type of spark coil the Duryeas are believed to have used in their electrical circuit,
as shown in a catalog illustration. (Smithsonian photo 46858-A.)

The Springfield Evening Union of September 22 carried a notice of the trial. This report, too,
commented on the faulty transmission and the plan already in Frank's mind for the new
transmission.
… The friction belt allowed of the speed being steadily increased or
diminished at the will of the driver and caused no sudden forward motion of
the carriage, but while this arrangement has many advantages it uses up the
power so that the two-horse power furnished by the motor [somewhat less than
the rating Frank gave the engine] was reduced to less than three-fourths horse
power on reaching the main shaft. This would not be sufficient to propel the
carriage up steep grades but would be sufficient to run the carriage on level
road.
The inventors will do away with this belt in favor of a clamp gear and will
make the drum wheel smaller. By this means there will be very little power lost
in transmission to the shaft and by a patented arrangement the carriage may be
started gradually but the speed must be increased by shifting the clamp gear to
a succession of gears on the driving wheel of the motor. The speed of the
carriage will be fixed permanently according to the size of the gear that the
smaller one is shifted to. The test of the machine with the gear arrangement
will be made soon.
In October Frank decided on another vacation and went to Chicago to see the Columbian
Exposition. Charles had come up from Peoria to see the fair and the two talked over the progress
on their motor wagon, and discussed the transmission problem. They gave particular attention to
everything relating to engines and motor carriages, and Frank recalls seeing a Daimler quadricycle
that impressed him with its performance.[31] Just what decisions the two might have made there are
unknown, yet it is likely that they agreed to give the old transmission one more chance to prove
itself.
Returning to Springfield, probably in the first week of November, Frank gave the friction drive
its final test, this time substituting a leather belt for the rubber one first used.[32] Mr. Markham,
though intensely interested in the experiments, apparently was dubious concerning the safety of
the carriage. It had no brakes, and fearing failure of the transmission on a downgrade, he was

reluctant to ride in the machine. On November 9 he asked Will Bemis to try it for him. The
following day the Springfield Morning Union gave a description of the run:
Residents in the vicinity of Florence street flocked to the windows
yesterday afternoon astonished to see gliding by in the roadway a common top
carriage with no shafts and no horse attached. The vehicle is operated by
gasoline and is the invention of Erwin Markham and J. F. Duryea. It has been
previously described in The Union and the trial yesterday was simply to
ascertain the practical value of a leather friction surface which has been
substituted for the rubber one previously used. The vehicle, which was
operated by Mr. Bemis, started from the corner of Hancock avenue and Spruce
street and went up the avenue, up Hancock street and started down Florence
street, working finely, but when about half-way down the latter street it
stopped short, refusing to move. Investigation showed that the bearing had
been worn smooth by the friction and a little water sprinkled upon it put it in
running condition again. The rest of the trip was made down Florence and
down Spruce street, to the residence of the inventors. They hope to have the
vehicle in good working condition soon.

Figure 24.—Running gear of Duryea vehicle,
showing the second engine and
other parts as used in January 1894.

The same evening, the late edition ran a brief paragraph stating that "the test was made to
determine the value of a leather friction surface for propelling the wagon, that had been substituted
in place of the rubber surface, used in the former test." Bemis, according to Frank Duryea's
recollection, was not impressed with the performance of the machine, saying "the thing is
absolutely useless," and for a time it appeared that further support from Markham would not be
forthcoming. Frank, believing eventual success to be near, drew up plans showing his geared
transmission, and with these managed to gain Markham's partial support. Money for material and
use of the shop was to continue, but Frank was to complete the work on his own time.
Now receiving no salary, Frank worked hurriedly on the transmission throughout late
November, December, and the first two weeks of January. First discarding the old friction drum

and shaft, and the shipper-fork carriage, he bolted a rawhide bevel gear to the lower surface of the
flywheel. This turns two bevel gears, in opposite directions, on a countershaft directly underneath,
approximately in the position of the old jackshaft. The right bevel gear is secured to the main
countershaft on which two clutches are mounted, one on each side of the crankshaft. On a sleeve
turning freely around the countershaft is mounted the reverse bevel gear and clutch. Three free-
running clutch drums, the right one carrying the high-speed gear, the two on the left carrying the
combination low speed and reverse gear between them, complete the countershaft assembly. The
clutch assemblies are of Frank Duryea's design, having internal arms, expanding outward to press
leather-faced shoes against the inner surface of the drum, thus securing the drum and its gear to the
shaft. Behind this machinery is the jackshaft with its small differential on the right, two laminated
rawhide gears[33] meshing with the iron gears of the countershaft, and the internal-gear sprockets
hanging on the small pinions at either end. A sliding cam bar, mounted nearly in the position of the
former shipper-fork carriage, is operated by the vertical movement of the tiller handle to engage
any one of the three clutches. With the tiller depressed, the vehicle is in reverse. Elevating it
slightly puts it into low gear, and raising it still higher runs the machine at its highest speed.

Figure 25.—Half of Jackshaft, showing rawhide gears, double shrouded
pinion and half of the Columbia differential.

Figure 26.—Half of Jackshaft showing double-shrouded pinion
and half of the Columbia differential.

Figure 27.—Cam bar in foreground, operated by tiller,
actuates the various clutches of the transmission. The overflow gasoline tank
with the hand pump can be seen in the rear.

Text of Patent Letter

Figure 28.—A drawing and the first page of the specifications of the first patent issued to C. E. Duryea.
It can be readily seen that this drawing was not made after the plan of the first vehicle.
Larger size rotated image.

As the work moved nearer completion Frank realized that the final tests would have to be
conducted on roads made icy by falling snows. He had considerable doubt whether the narrow iron
tires would have enough traction to move the phaeton. Soon he devised an expedient for this
situation, communicating to Charles on December 22 that he was "having Jack Swaine [a local
blacksmith] make a couple of clutch rims so we can get over this snow and ice…. Our detachable
rims referred to will be of ⅛ iron 1¾ wide and drawn together at one point by two screws, one on
either side of felloe. It will be studded with calks in two rows."[34]

Figure 29.—Mr. and Mrs. Frank Duryea examining vehicle in
the Smithsonian Institution before restoration.

January 18, 1894, was a day of triumph for Frank Duryea. Writing Charles about his success
the next day he said, "Took out carriage again last night and gave it another test about 9 o'clock."
The only difficulty he mentioned was a slight irregularity in the engine, caused by the tiny leather
pad in the exhaust-valve mechanism falling out.[35] Speaking of this trip, Frank recalled in 1956:
When I got this car ready to run one night, I took it out and I had a young
fellow with me; I thought I might need him to help push in case the car didn't
work…. We ran from the area of the shop where it was built down on Taylor
Street. We started out and ran up Worthington Street hill,[36] on top of what
you might call "the Bluff" in Springfield. Then we drove along over level
roads from there to the home of Mr. Markham who lived with his son-in-law,
Will Bemis, and there we refilled this tank with water. [At this point he was
asked if it was pretty well emptied by then.] Yes, I said in my account of it that
when we got up there the water was boiling furiously. Well, no doubt it was.
We refilled it and then we turned it back and drove down along the Central
Street hill and along Maple, crossed into State Street, dropped down to
Dwight, went west along Dwight to the vicinity where we had a shed that we
could put the car in for the night. During that trip we had run, I think, just
about six miles, maybe a little bit more. That was the first trip with this
vehicle. It was the first trip of anything more than a few hundred yards that the
car had ever made.

Now Frank could give demonstration rides with the motor carriage, hoping to encourage more
investors to back future work. Cautious Mr. Markham finally got his ride, though Frank had to
assure him that the engine of the brakeless vehicle would hold them back on any hill they would
descend. The carriage on which he had spent so many hours was to see little use after that. Its total
mileage is probably less than a hundred miles. Little additional work is known to have been
performed on the carriage after January 1894; there is, however, a letter[37] Frank sent his brother
on January 19 which tells of contemplated muffler improvements. Another message was
dispatched to Charles on March 22, mentioning the good performance of the phaeton on Harrison
Avenue hill.[38] This was possibly the last run of the machine, for no further references have been
discovered.
Frank spent the months of February and March in preparing drawings, some of which
accompanied their first patent application,[39] while others were to be used in the construction of
an improved, 2-cylinder carriage. Work on the new machine started in April. The old phaeton, in
the absence of used-car lots, was put into storage in the Bemis barn.[40] Later, on the formation of
the Duryea Motor Wagon Company in 1895, it was removed to the barn of D. A. Reed, treasurer of
the company.[41] There it remained until 1920, when it was obtained by Inglis M. Uppercu and
presented to the U.S. National Museum.

Footnotes

[1]
S. H. Oliver, Automobiles and Motorcycles in the U.S. National Museum (U.S. National Museum Bulletin 213,
Washington: Smithsonian Institution, 1957), p. 24.
[2]
G. R. Doyle, The World's Automobiles (London: Temple Press Limited, 1959), p. 67.
[3]
Recorded interview with Frank Duryea in the U.S. National Museum, November 9, 1956.
[4]
Charles Duryea's statement to Springfield Daily Republican, April 14, 1937.
[5]
Frank Duryea, America's First Automobile (Springfield, Mass.: Donald Macaulay, 1942), p. 4.
[6]
Letter from Charles Duryea to Alfred Reeves, March 25, 1920; copy in Museum files.
[7]
History notes dictated by Charles E. Duryea in the office of David Beecroft, editor of Automobile Trade Journal, on
January 10, 1925. Copy in Museum files. Hereinafter, these notes are referred to as "history."
[8]
Frank Duryea in statement made to the Senate Committee on Public Administration of Massachusetts, February 9, 1952.
[9]
Duryea, op. cit. (footnote 5), p. 6.
[10]
Copy of contract in Museum files.
[11]
Affidavit of William Rattman, March 19, 1943, states that the Russell ledgers give that date.
[12]
Recorded interview with Frank Duryea in U.S. National Museum, November 6, 1957.
[13]
Letter from Frank Duryea to David Beecroft, November 15, 1924; copy in Museum files.
[14]
Letter from Charles Duryea to C. W. Mitman, March 21, 1922; copy in Museum files.
[15]
See "history" (footnote 7), p. 6.
[16]
Duryea, op. cit. (footnote 5), p. 8.
[17]
Copy of letter in Museum files.
[18]
Duryea, op. cit. (footnote 5), p. 12.
[19]
Letter from Frank Duryea to Charles Duryea, November 3, 1893, states that the engine could be run at 700 as well as 500
rpm. Copy in Museum files.
[20]
Duryea, op. cit. (footnote 5), p. 14. Also in letter from Charles Duryea to C. W. Mitman, January 11, 1922; copy in
Museum files.
[21]
Letter from Charles Duryea to C. W. Mitman, January 11, 1922; also letter from Frank Duryea to David Beecroft,
November 15, 1924. Copies in Museum files.
[22]
Letter from Charles Duryea to F. A. Taylor, December 5, 1936, says he "thought" they had five teeth. Copy in Museum
files.
[23]
Frank later wrote his brother, January 1894, that he fixed the tank so it would not draw sediment from the bottom. Copy
of letter in Museum files.
[24]
The number of mufflers Frank Duryea constructed is not known. He wrote Charles, December 22, 1893, that he "will try
a new muffler also."
[25]
Selden Patent Evidence, vol. 9, p. 110.
[26]
See "history" (footnote 7), p. 2. Charles wrote, "Some parts of these [referring to the batteries], like the jars, I had on hand
for six or eight years, and did not need to buy."
[27]
Ibid., p. 15.
[28]
Ibid., p. 15
[29]
Frank stated in this letter that the friction drum originally had two belts, forward and reverse, but since they tended to foul
each other, he removed the reverse belt and left the other to serve for both directions. How the shipper fork might have
handled two belts is not understood.

[30]
As actually constructed there are only two gears on the secondary shaft. He obviously discovered that one gear secured to
two clutches would serve for both forward and reverse. Space was also limited.
[31]
Recorded interview with Frank Duryea in U.S. National Museum, November 9, 1956.
[32]
Letter from Frank Duryea to Charles Duryea, November 8, 1893. Copy in Museum files.
[33]
Frank Duryea, in a recorded interview in the U.S. National Museum on November 6, 1957, said that he believed these
had been purchased from Rochester Rawhide Company.
[34]
Letter from Frank Duryea to Charles Duryea, December 22, 1893. Also letter from Frank Duryea to David Beecroft,
November 15, 1924. Copies in Museum files.
[35]
Telling of the first use of the car in later days, Frank Duryea mentions the many noises and vibrations that accompanied
the trip: the vibrating tiller, the tinny sounding muffler, the clattering chains. He later reported speeds of 3 mph in low
gear and 8 mph in high gear.
[36]
Letter from Frank Duryea to Charles Duryea, Jan. 19, 1894, says they went up hill via Summer and Armor Streets, then
out Walnut to Bemis' at Central Street School.
[37]
The letter read: "I have designed a new muffler and we will proceed to make it before long, in a day or two. Instead of
one shell ⅛-inch thick I shall put a shell 11⁄16-inch thick inside another of equal thickness, but about 1 inch greater
diameter i.e., one chamber within another so as to cause sound to turn corners to get out. Still another shell will be
added if it prove insufficient, making it turn about again—taking care in each case to give ample room for expansion—
outer one need not be more than 1⁄32 inch possibly. Will let two threaded rods with nuts hold heads on both or on three
cases, if the 3d be essential."
[38]
This letter gives further proof that the car never had a brake. Frank said the car came back down the hill with no brake,
but that the engine held the vehicle back.
[39]
Duryea, op. cit. (footnote 5), p. 37.
[40]
It is possible that a few parts were removed at this time to be used on the two-cylinder car. The muffler may have been
one of these, and even more likely, the governor parts. Charles Duryea wrote to C. W. Mitman December 27, 1921,
stating that his younger brother Otho and a Henry Wells had put in a battery and gasoline in 1897 and started the
engine. Because the chains were not on the car they could not attempt to operate it; but the engine ran too fast, and
finally something broke, probably the engine frame, found to be broken during the recent restoration. Charles thought
the engine ran too fast because some of the governor parts were already missing.
[41]
Recorded interview with Frank Duryea in the U.S. National Museum, November 9, 1956. On the formation of the Duryea
Motor Wagon Company, Mr. Markham was rewarded for his part of the venture. He had invested nearly $3000 in the
work, and sold out his rights in the company for approximately a $2000 profit.

Text of Letter (page 14)
24 Nov 1920
Dear Mr Mitman
On the train I had some time to puzzle over that car. Been working nights to make up time lost
in the day so did not hav much.
I made a sketch for you but did not show the spring that holds the circuit breaker in contact with
the spark point. That thin finger was part of it. A spring was wound spirally--not helically--around
the projecting end of the breaker pivot and the end of the spring hookt over the thin finger. See
sketch herwith.

Just how the central end of the spring wire was fastened to the square of the pivot I do not kno.
We did in some cases bore a hole thru and simply stick the spring thru but this put most of the
action right at the bend in the wire and it broke quickly. So in other cases we fitted a light grooved
spool or pulley and wound the spring around this and so avoided a sharp bend. If this was used it
has been lost with the spring. A couple generations of boys playing in that barn was too many.
The Haynes steering sketch also worries me. If that vertical post came up thru that slot in the
floor the crank had to be long as the sketch shows in order to get over to the driver conveniently.
Then if he tried to make a complete circle with it he could not reach far enuf forward to do it easily.
And he had to make a turn or two be cause H shows bevel gears of about same size so the post had
to make same number of turns the worm made. Sketch herewith to illustrate my thought.

Text of Article (page 20)

NO USE FOR HORSES.
Springfield Mechanics Devise a New Mode of Travel.
Ingenious Wagon Now Being Made in This City for Which the Makers Claim Great Things.
A new motor carriage, which, if the preliminary tests prove successful as is expected, will
revolutionize the mode of travel on highways, and do away with the horse as a means of
transportation, is being made in this city. It is quite probable that within a short time one may be
able to see an ordinary carriage in almost every respect, running along the streets or climbing
country hills without visible means of propulsion. The carriage is being built by J. F. Duryea, the
designer and B. F. Markham, who have been at work on it for over a year. The vehicle was
designed by C. E. Duryea, a bicycle manufacturer of Peoria, Ill., and he communicated his scheme
to his brother, who is a practical machanic in this city.
The propelling power is furnished by a two-horse power gasoline motor situated near the rear
axle and which, when started, runs continuously to the end of the trip, notwithstanding the number
of times the carriage may be stopped. The speed of the motor is uniform, being about 500
revolutions a minute, and is so arranged that it gives a multiplied power for climbing hills and the
lower the rate of speed the greater power is furnished by the motor. The slowest that the carriage
can be driven is three miles an hour and the speed can be increased to fourteen or fifteen miles an
hour. The power is transferred from the driving wheel of the motor, which runs horizontally with
the main shaft by an endless friction belt running on a drum wheel. The belt is controlled by a lever
within easy reach of the driver and is shifted along the drum wheel to increase or decrease the
speed. The driving wheel is about twenty inches in diameter, having in its center a depression to
which the belt is shifted to stop the carriage.
The carriage can be reversed by shifting the belt from the end of the drum, which gives the
forward motion to the opposite side beyond the depression in the driving wheel. The power which

has been transferred to the driving shaft from the motor is in turn transferred to the two rear wheels
of the carriage by a combination gear and sprockets. An endless chain connects the sprockets on the
carriage wheels to the sprocket wheels on the driving shaft. All of the motive power is located
under the body of an ordinary phaeton, the hight of which is not increased by the machinery. The
motor is started by a crank which is easily applied to a shaft in the rear of the carriage and the
gasoline is ignited in the cylinder by electricity. An automatic device stops the flow of gasoline into
the cylinder when the motor ceases running. The gasoline is carried in tanks, which hold about two
gallons, and which will run the carriage for about eight hours. The wagon is guided by a bicycle
bar, and the speed is also controlled by this bar.
The method employed in this is as follows: To start the carriage press the lever down; to reverse
it throw the lever up and to guide the wagon turn the lever either to the right or left. The front axle
instead of turning horizontally plays up and down, in order that the machinery may be on a level
with the rear wheels, while the front wheels are set on the axle by a pivotal joint and are connected
with the guiding lever by bars with ball bearings. The carriage complete weighs about 220 pounds,
and the essential features are already covered by patents while others are pending.
It is estimated that the carriages can be sold for about $400, and a stock company will probably
be formed to manufacture them.

Text of Patent Letter (page 24)
United States Patent Office.
CHARLES E. DURYEA, OF PEORIA, ILLINOIS.
ROAD-VEHICLE.
SPECIFICATION forming part of Letters Patent No. 540,648, dated June 11, 1895.
Application filed April 30, 1894. Serial No. 509,466. (No model.)
To all whom it may concern:
Be it known that I, Charles E. Duryea, a citizen of the United States, residing at Peoria, in the
county of Peoria and State of Illinois, have invented new and useful Improvements in Road-
Vehicles, of which the following is a specification.
The object of this invention is to produce a road vehicle which shall be self-propelled, not
unduly heavy, simple and easy of control and comparatively inexpensive, together with such minor
objects as will become hereinafter apparent.
The invention more particularly relates to the construction and arrangement of parts for
constituting the driving gearing and to the means for controlling the action thereof; to an improved
manner of mounting the front, or steering, wheels upon the front axle, and of mounting the said
axle relative to the running gear frame, and to the means for effecting the steering; to the appliances
for the support of the motor and driving mechanism in an advantageous and efficient manner, and,
generally, to improved and simplified details of construction throughout the vehicle, all as will

hereinafter be rendered more apparent, and the invention consists in constructions and
combinations of parts, all substantially as will hereinafter fully appear and be set forth in the
claims.
Reference is to be had to the accompanying drawings, in which—
Figure 1 is a sectional elevation from front to rear of the improved road-vehicle. Fig. 2 is a plan
view of the running and driving gear, the vehicle-body being understood as removed. Fig. 3 is a
front elevation of the vehicle. Fig. 4 is a perspective view of the support and suspension devices for
the driving mechanism. Fig. 5 is a vertical sectional view, longitudinally, through the shiftable
driving-gear, the controlling devices employed in conjunction with this mechanism being seen in
side elevation. Figs. 6 and 7 show the above-mentioned controlling devices as in operative relations
differing the one from the other and also from that of Fig. 5.
Similar letters of reference indicate corresponding parts in all of the views.
The parts will now be described in detail with reference to said drawings, and A represents the
body which is spring supported on the frame, B, of the running gear. This frame, as shown, is
rectangular, and has the body-supporting springs, B2, similar to those found in common carriages.
This frame has, affixed thereto, at its rear ends, sleeves, a, a, which loosely embrace the rear wheel
axle, D, which is the driven axle of the vehicle. The axle, E, for the front wheels is centrally
secured to the running gear frame, B, by the horizontal king-bolt, b, whereby such axle may have a
swinging movement relative to the frame in a vertical plane, but it has no swinging movement
horizontally, the wheels being swivel-mounted on the ends of this axle peculiarly, as will shortly
hereinafter be set forth.
The body, as shown, is in the form of an inverted box, the motor, H, and driving gear being
accommodated within the downwardly opening inclosure constituted thereby, and the body also has
the upwardly open box-like forward extension, or pit, A2, for the accommodation of the feet of the
rider, the rider's seat being constituted by the top forward portion of the box body. Some other
suitable design of body may, of course, be used in lieu of this one shown.
The front wheels, d, d, are hung to the front axle, E, so that the center of each wheel base is in a
line coincident with the axis of the pivotal connection which is provided between the journals for
the wheels and the axle, which arrangement practically destroys any tendency to deflection from
the course that might otherwise arise from striking an obstacle, and so renders the steering easier. In
order to effect this the axle is formed with yoked ends, the yoke members, f, f, being above and
below the longitudinal line of the axle. The short journal, g, shown for each wheel, has at its inner
end an upwardly and downwardly extended arm, h, which is return-bent to be loosely embraced by
the axle yoke, f, f. The cone pointed screws, c, passed through the yoke members, f, and into
sockets therefor in the arms, h, of the journals, g, constitute the means for the swivel connection
between said parts. The lock-nuts, c2, manifestly, are employed with utility in this connection.
It will be perceived that inasmuch as in the arrangement shown, the pivotal connections

Paper 34 - Transcriber's Note

Letters printed upside down have been corrected. The transcriptions retain all typographical
and gramatical errors.

Contributions from
The Museum of History and Technology:
Paper 35

The Borghesi Astronomical Clock
In the Museum of History and Technology

Silvio A. Bedini

DEVELOPMENT OF ASTRONOMICAL CLOCKS 32

DESIGNER BORGHESI 33

CLOCKMAKER BERTOLLA 34

FIRST BORGHESI CLOCK 38

SECOND BORGHESI CLOCK 41

BORGHESIAN THEORY OF THE UNIVERSE 54

LAST YEARS 57

THE CLOCKS OF BARTOLOMEO ANTONIO BERTOLLA 59

APPENDIX 71

BIBLIOGRAPHY 76

INDEX

Figure 1.—The dial plate of the Borghesi clock, showing the
horary and astronomical indications which are automatically
presented.

Silvio A. Bedini

The Borghesi Astronomical Clock
In the Museum of History and Technology
The history of the 18th-century Borghesi astronomical clock is described
here from contemporary source material. The evolution of its design by Father
Francesco Borghesi and the building of the complex mechanism devised by the
clockmaker, Bartolomeo Antonio Bertolla, is a story of the vision of one man
turned into reality by another. The result of their collaboration is the unique,
astronomical timepiece now in the Museum of History and Technology.
The Author: Silvio A. Bedini is curator of mechanical and civil
engineering in the Smithsonian Institution's Museum of History and
Technology.

“… All this work I had performed eagerly, so that, while in my room, I
might contemplate leisurely, both during the day and in the night, the true face
of the heavens and of the seas unobscured by clouds, even though I had no
astronomical equipment.” [1]
ith these words, Father Francesco Borghesi (1723-1802) of Mechel described the reasons
W which inspired him to invent a unique astronomical clock which is now in the horological
collection of the Museum of History and Technology.
This complicated mechanism, which performs a multitude of functions, was designed by
Father Francesco Borghesi, a secular priest in Venezia Tridentina. It was constructed in 1764 under
his direction by a provincial clockmaker named Bartolomeo Antonio Bertolla (1702-1789) of
Mocenigo di Rumo. It was the second of two complicated astronomical clocks which Father
Borghesi designed and which Bertolla constructed. According to contemporary sources, this clock
was presented to the Empress Maria Theresa of Austria soon after its completion.
Its history is rather hazy, except for the fact that in 1780 this second Borghesi timepiece was
still in the Imperial Palace in Vienna. The clock was again noted in 1927 when it was sold at a
public auction in New York. [2] Subsequently, it was acquired for the Smithsonian Institution.

ACKNOWLEDGMENTS
The author wishes to acknowledge the valuable assistance received from the
following: Dr. Amos Avery, Amherst, Massachusetts; Mr. Edwin A. Battison, curator
of light machinery and horology, U.S. National Museum; Dott. Richard Blaas,
Oesterreiches Staatsarchiv, Vienna; Dott. Adolfo Cetto, librarian, Biblioteca
Comunale di Trento, who made copies of Borghesi's two volumes available; Signor
Mario di Mario, editor of La Clessidra, Rome, who permitted several of the
illustrations in Sig. Luigi Pippa's article to be used herein; Mr. Walter A. Gilbert,
Norwich, Connecticut; Dr. Heinrich Linardi, Uhrenmuseum der Stadt Wien, Vienna;
Signor Luigi Pippa, Milan, Italy; Cav. Ing. Guido Ucelli di Nemi, Presidente, and

Dott. Federico Morelli and Cav. Orazio Curti of the Museo Nazionale della Scienza
e della Tecnica, Milan, for their cooperation on the descriptions and illustrations of
the restored clockshop of Bartolomeo Antonio Bertolla; and Dr. Edward Waters,
Division of Music, Library of Congress, Washington, D.C.
The translation from Francesco Borghesi's Latin texts, which made this study
possible, were made by: Rev. Neil Herlihy, S.J., Rev. Francis J. Heyden, S.J., and
Rev. Stephen X. Winters, S.J., Georgetown University, Washington, D.C.; and Rev.
Daniel Hunter, O.P., and Rev. Robert Stenger, O.P., Dominican House of Studies,
Washington, D.C.

Development of Astronomical Clocks
The history of the great theoretical and mechanical achievement which the Borghesi clock
represents has been most adequately covered elsewhere.[3] Consideration of the development of
equation and astronomical clocks is required here only for the purpose of relating the Borghesi
timepiece with the other significant developments in this branch of horology.
The invention of the anchor escapement in about 1670, and the consequent greater accuracy in
time-telling, led to increased preoccupation with precision. Daily differences in time as recorded
by sundials and clocks became more noticeable. Finally, in the second half of the 17th century,
some attempt was made to construct mechanical clocks combined with sundials as well as
astronomical clocks.
With the improvement of precision time-telling, it became necessary to reconcile the actual
difference between true and mean time. Although a great variety of time-equation tables were
produced, there was a considerable margin for error in their use. This led to the construction of
mechanical clocks in which the equation of time was automatically accomplished. A few were
produced late in the 17th and early 18th century at considerable cost and, consequently, with little
popularity. Equation sundials were also developed which were elaborately ingenious, but they
were not completely practical. Inevitably, they were supplanted by the mechanical equation clock.
Probably the first documented mention of an equation clock is in the diary of John Evelyn who
recorded that in 1666 he visited the Royal Society where he witnessed a curious clock, which
showed the equation of time, being presented by a certain Mercator. More data on the subject
appeared in the first two decades of the 18th century, when Henry Sully, Joseph Williamson,
Daniel Quare, and Thomas Tompion—who were among the foremost English clockmakers of all
time—produced elaborate examples of these timepieces. Another significant maker was Dowe
Williamson, who became Court Clockmaker to Emperor Charles VI of Austria. In London, Joseph
Williamson produced some of the finest astronomical timepieces of this type that have been
known. The interest in the subject next shifted to France where many fine examples were produced
during the first half of the 18th century.
Just after the middle of the 18th century, the subject of astronomical clocks suddenly became a
major horological preoccupation in another region, namely, Austria, where the work in this field
was apparently done exclusively by members of the clergy. The earliest was Father Philipp
Matthäus Hahn (1739-1790) of Württemberg. [4] Father Hahn considered the equation of time as

only one part of a plan to represent astronomical occurrences by means of clockwork. In addition
to planetaria and similar mechanisms, Father Hahn produced two extraordinary astronomical, tall-
case clocks, both of which survive in public museums.
Another of the clerical clockmakers was Father
Aurelianus à San Daniele (1728-1782), an Augustine
monk in the monastery of the Imperial Court at Vienna.[5]
His four complicated astronomical clocks, which exist in
museums at present, are comparable to those produced by
Father Hahn. The third cleric was Brother David à San
Cajetano (1736-1796) in the same Augustine order to
which Father Aurelianus belonged. He achieved note as
the author of various publications, including Neue
Rädergebäude [6] [New Construction of Wheels] relating
to planet-wheels, or gear-trains containing epicyclic
elements. He constructed a clock based on an elaborate
astronomical design which was substantially different
from the others. The fourth of the ecclesiasts who designed
astronomical clocks in this period was Father Klein of
Prague, who produced a complicated astronomical
timepiece in about 1738.
The fact that such important and outstanding examples
of astronomical clocks were produced exclusively by
Figure 2.—Portrait of Father Francesco ecclesiasts in Austria during the second half of the 18th
Borghesi, inventor and designer of the century is especially significant. It is particularly so when
astronomical clock in the Museum of History a fifth cleric is added to the group, also an Austrian subject
and Technology.
although Italian by heritage, in the person of Father
Francesco Borghesi.
Although only Father Borghesi's second astronomical clock is now known, it is apparent that
this example in the Museum of History and Technology represents an experiment in astronomical
time-telling comparable to any of the timepieces produced by Father Hahn, Father Aurelianus,
Brother David à San Cajetano or Father Klein.
This combination of five clerical clockmakers who lived in the same region during the same
period of time is sufficiently unusual. However, the fact that each of them apparently worked
without association with any of the others leads to the conjecture that a common factor must have
led them to their individual preoccupation with astronomical horology. What the link may have
been is not apparent from the surviving records of the lives and works of these clerics. Certainly it
was not an interest in astronomy or clockmaking per se, because other than the astronomical
clocks, none of these horological inventors—with the possible exception of Father Hahn—worked
in any other aspect of the fields of astronomy or horology. However, after a comprehensive study
of Father Borghesi's writings, there is little doubt of the religious basis of his own inspiration.

Designer Borghesi

Father Borghesi's story takes place in the picturesque mountainous region of what was then
known as Venezia Tridentina (since 1947, Trentino-Alto Adige) in northern Italy, along the
Tyrolean border of Austria. Because of its strategic position as the passage between Innsbruck and
Verona, the possession of the Tridentina was contested again and again in the European wars, but
during Father Borghesi's lifetime, the Tridentina was under Austrian domination.

Figure 3.—Panorama of the village of Mechel in the valley of the Non, birthplace of Father
Borghesi.

Deep within this mountainous district is the romantic valley of the Non, or Anáuni, with its
great forests and ancient castles. Most maps do not mark it, and the tourist guides ignore it. [7] One
of the chief communities is Cles, with its historic Renaissance buildings. The major city of the
region is Trent on the Adige River, with its surviving Roman relics and Romanesque and
Renaissance architecture.
The little villages scattered throughout the valley of the Non played no part in history, but such
names as Mechel and Mocenigo di Rumo reflect the interchange of sovereignty. It was in the little
village of Mechel that Francesco Borghesi was born in 1723. [8] Local records are meager and
inadequate, and many of the details of Borghesi's life must be assumed. Inasmuch as the village
was in a rural, agricultural district, Borghesi may have come from a family of farmers, vintners, or
village tradesmen. Borghesi sought an education by entering the priesthood and was ordained a
secular priest in Salzburg. He was first assigned as curate to the village parish of Rumo in the
valley of the Non, a short distance from his birthplace. [9] Later, he was transferred to his native
Mechel. He was inherently a man of simple tastes and of great piety. He tended to the needs of his
mountain villagers and attended the births, weddings and deaths of his parishioners. It was during
his assignment in this tiny community that Father Borghesi met and became friendly with the
clockmaker, Bartolomeo Antonio Bertolla of nearby Mocenigo di Rumo.

Clockmaker Bertolla
Bartolomeo Antonio Bertolla was born in Mocenigo di Rumo, a short distance from Mechel, in
1702. [10] Nothing is known of his boyhood, other than the fact that he was mechanically inclined.
At the age of 17 he was apprenticed to become a clockmaker with the master, Johann Georg

Butzjäger of Neulengbach, a small village on the edge of the great Vienna woods. [11] This region
was then part of the domain of the Archduke of Austria, of which Sankt Pölten was the capital.

Figure 4.—Portrait of Bartolomeo Antonio
Bertolla, clockmaker, of Mocenigo di Rumo.
The canvas in oils is owned by descendants. In
the upper left-hand corner is an inscription,
now hardly legible, indicating that the portrait
may have been painted after Bertolla's death
on January 15, 1789. Translated, it states:
"Bartolomeo Antonio Bertola [sic] Celebrated
Mechanician and Inventor of various
Instruments. Repairer of the clocks of Venice,
Verona, Trent, and other localities. Maker of
the Work which combines the Copernican and
Ptolemaic Systems devised by Father
Francesco Borghesi of Mechel, Laureate
Mathematician, and humbly offered to Her
Imperial Majesty Maria Theresa. Died in piety
in his home at Rumo on 15 January 1789 at
the age of 86." (Courtesy of Sig. Luigi Pippa of
Milan.)

Figure 5.—The village of Mocenigo di Rumo in the valley of the Non. Arrow points to
Bertolla's home and workshop at far left.

Figure 6.—Certificate of apprenticeship awarded to Bartolomeo Antonio Bertolla upon
completion of his 3-year apprenticeship at Neulengbach, dated December 27, 1722.

Bertolla began his apprenticeship with Butzjäger under the auspices of the Corporation of
Blacksmiths of Sankt Pölten in 1719. His training was supervised by two master locksmiths,
Johann Christian Winz and Peter Wisshofer, who were members of the Corporation, and were
assigned to serve as patrons for the apprentice. It was their obligation to make certain that he
received good care and adequate instruction from his master. While he worked in Butzjäger's shop,
Bertolla lived with the master's family in their home.
Bertolla's 3 years at Neulengbach passed quickly as he sought to absorb all that his master
could teach him. Butzjäger was considered to be a good craftsman in the region, yet today there is
not even a mention of his name in the lists of clockmakers. He specialized in the production and
repair of "great clocks" which included tall-case, domestic timepieces, and tower clocks. Butzjäger
treated his apprentice well, and in return Bertolla rewarded him by being diligent and honest. His
subsequent work is sufficient indication that he developed into an extremely skilled craftsman, and
he became the equal of any clockmaker of his time.
The 3 years of apprenticeship were completed and on December 27, 1722, Bertolla received a
certificate from the Corporation of Blacksmiths which assured whomever it might concern of
Bertolla's skill, diligence and honesty, and permitted him to open his own shop as a clockmaker
under the auspices of the Corporation. This document, which has been preserved by Bertolla's
descendants, is an interesting record of the organization of the trade guilds in the 18th century, and,
for that reason, has been translated from the original German:

We, the Superiors and other masters of the honorable corporation of municipal
blacksmiths, armorers, and of smiths, in the Imperial City of St. Pölten in Austria by the river
Enns, Declare by these Presents put in force by this document to anyone who waits to
hear…. That the honorable and able Bartolomeo Antonio Bertolla of Rumo in Lentzberg,
the Tyrol, on the 27th day of the month of December of the year 1719 was consigned as

apprentice for three years, in the presence of two sponsoring masters for the purpose, the
honorable Johann Christian Winz and Peter Wisshofer, both of them master locksmiths
representing the entire honorable Corporation and others of open shop—to the honorable
Johann Georg Butzjäger, incorporated with us, citizen and master clockmaker for large
clocks in the merchant-village of Neulengbach in Wienerwald, as his master of the art, would
have therefore perfectly and rightfully worked and learned, and
that afterwards, on the day and year noted at the bottom, he will be newly declared free
and independent before us, representative of an entire and honorable Corporation and with
open shop, of his above-mentioned master and of the two sponsoring masters mentioned,
and since he eagerly requested a truthful certificate of apprenticeship for his honest
service as an apprentice and for his good behavior, and we having great pleasure as well as
the duty of favoring the truth and well knowing that the aforesaid Bartolomeo Antonio
Bertolla has learned honestly the art of clockmaking for great clocks from his aforesaid
master, and that he has always behaved with honesty, obedience, faithfulness and diligence
both towards his master and towards us to our complete satisfaction and, therefore, we cannot
in any manner refuse his request, rather we wish to grant it with a clear conscience.
We Therefore Address to Everyone and to anyone in whatever state and rank, but
particularly to those interested in our branch of this art, our respectful and courteous entreaty
and request to consider Bartolomeo Antonio Bertolla well recommended for his honest
apprenticeship and his good behavior, and to desire to favor him in every way, in such a
manner that will assure our gratitude whenever an occasion presents itself.
For this purpose, we issue, as we have declared we wish to issue to you, Bartolomeo
Antonio Bertolla, this certificate of apprenticeship, attaching to it the seal of our
Corporation.

Executed in the city of St. Pölten on 27 December 1722. [12]

His apprenticeship over, Bertolla returned to his native region where he soon established a
reputation for himself as one of the most skillful clockmakers in the Tridentina and produced
timepieces of fine quality in some quantity. No records have survived concerning his personal life,
but it is believed that he married probably soon after his return. He had no children of his own. To
expand his business, he eventually took into his shop two nephews, the sons of a brother and a
sister, as apprentices.
Bertolla's work brought him a sufficient number of clients, and he produced elaborate clocks
for his more wealthy patrons.
In 1752, it is recorded that he repaired the great clock in the campanile of the Church of the
Assumption of the Virgin Mary in Cles, the regional capital of the valley of the Non. The clock
dated probably from the 16th century, and it seems likely that Bertolla replaced the original two-
wheel train with a three-wheel movement, and that he added the present anchor escapement. [13]
It is not possible to determine when Father Borghesi first made Bertolla's acquaintance, but it
may be assumed that they had become friends in the late 1750's.
After he had come to know Bertolla, Father Borghesi apparently spent many hours in the
clockmaker's shop. He was fascinated by mechanics in any form, and the complications of

clockwork particularly intrigued him. Bertolla was patient with the young priest, explaining the
tools he had and their uses, the clocks he produced or repaired, and the principles which were
involved. Father Borghesi listened willingly and as his understanding of timepieces grew, his
curiosity increased.
In spite of himself, the priest could not be satisfied with the ordinary aspects of his friend's
work and wanted to learn more. From a casual pastime, the study of time became an obsession
with him. There was but one recourse: he went back to studying once again. This time it was not
theology, however, but the sciences. Every moment he could spare went into the perusal of books
on mathematics, astronomy, and associated subjects. He progressed rapidly, driven by his
overpowering interest and aided by his quick intellect.
Little by little, Borghesi managed to acquire the basic texts that explained this new world to
him, probably borrowing them from old seminary friends. As each new book came into his hands,
he devoured it in his desire to master its contents. He discussed each new principle or precept that
he learned with Bertolla. Together, they attempted to apply his new learning to the calculations
necessary for a timepiece which would demonstrate the astronomical theories in visual form.
Borghesi taught himself slowly, step by step, and the result was a profound understanding of
astronomical science. He conceived the project of constructing a great astronomical clock which
he felt could be accomplished by combining Bertolla's mechanical skills with his own recent
mastery of astronomy and mathematics.

First Borghesi Clock
It is not difficult to visualize the two men, the priest and the clockmaker, as they sat together
night after night working out their plans. Father Borghesi would painstakingly outline the
astronomical principles he wished to have the clock exhibit and the mathematical principles which
would be involved to operate them. Bertolla concentrated on them and tried to transcribe the
principles into functional mechanical terms, visualizing each operation in terms of wheels and
gears. Little by little the two men coordinated the numerous elements and welded them into an
operating entity. They adjourned either to the stark simplicity of the rectory or, probably more
often, to Bertolla's little home workshop, the priest standing over his friend while the latter worked
at his bench in the dark paneled interior illuminated only by the several lamps on the work
benches.
This first clock which the two men combined to create is a monument to the great scientific
knowledge of the self-taught priest and the technical ability of the clockmaker—a unity combining
astronomical science, mechanics, and artistry. The story of the project is told in a little book,
Novissima Ac Perpetua Astronomica…, which Borghesi later published. Explaining the incentive
which inspired him, and the premises from which he began his work, he wrote:

From the foundation of astronomical science long ago, innumerable
[and] repeated observations of both ancient and modern astronomers,
emerged at last from their hiding places. Made light of by the jests of so
many outstanding intellects, they have so successfully brought to light
the paths of the stars and their motions, which are more complicated to
us than the Gordian knots. Now it is possible for even an amateur in
astronomy, sufficiently instructed, to predict for any given time not only
the mean position of the planets, but also their true longitude and
latitude, and even the true time of their conjunctions, and their ecliptic
oppositions, with all the attendant circumstances. Yet, until now, no
hypothesis has been devised which would force an automaton to show to
us, before our very eyes, the eclipses of the planets in their true and
certain times.
For though there have been men seeking with all their might to bind
by laws their artificial heavens, by I know not how many and how great
calculations, and to systematize the complexities of the rotations of
celestial bodies; nevertheless, all of them, as if by common agreement,
considered themselves to have made great contributions to mechanico-
theoretical astronomy. However, they have only attained, even though
closely, the mean locations of the secondary mobiles, and those by a
certain rather crude calculation. Some attained by more, some by less,
but all by some degree of wandering from the truth, either worn out by
the intricacies of the motions, or deceived and deceiving by the errors of
their calculations. This fact those well know, who, setting about to
collect information of this kind, even those publicized not long ago, with
true astronomical calculation, have been bored to death while digging
out by the most elementary and superficial arithmetical torture, the worst
of fallacies spontaneously erupting from thence.
It would seem that true calculations alone can be desired in
mechanico-astronomics. Long study had not only convinced me that an
automaton was within the realm of possibility, but that there were many
mechanical systems by which it could be achieved. I girded myself for a
new project and developed it theoretically from the ground up, but under
such unhappy auspices that not only did all hope fail that anyone would
ever appear who might have seemed willing to set his hand to the work,
but that the new discovery itself was scoffed at by many as altogether a
nightmarish delirium of an unbridled imagination.
The first months of the project must have seemed like an inspired dream to the two
men, and then must have followed a period of hopeless depression. Bertolla undoubtedly
felt many times that the clock was an aspiration far beyond their combined abilities and
means, but the priest would not be thwarted in his ambition and refused to abandon the
project. He felt that it was a work that they were destined to produce. Many times, he

wrote, he chided and begged and shamed his erstwhile partner into resuming the project
where it had been last abandoned. Little by little, the first clock began to take form. As
each new difficulty was encountered, the two men would go back over the notes and
sketches to trace the problem to its source. Often a new part of the mechanism would
nullify another which had thus far operated successfully, and a complete rearrangement
would be required.

Figure 7.—Title Page of Father Borghesi's first book. The
translation in its entirety is: "The Most Recent, Perpetual,
Astronomical Calendar Clock: Theoretical—Practical: by
means of which besides the hours, the minutes and seconds;
the current year, the month; the day of the month and the day
of the week; the dominical letter, epact, and thence, the day of
all the feastdays, both fixed and movable; the solar cycle; the
golden number; the Roman indiction; the dominant planet of
any year and its sign; the phases of the moon and its mean
age: and all the motions of the sun and the moon as to
longitude, latitude, eccentricity, etc., are immediately seen, so
accurately that [not only] the true new full moons and the true
quadrature, etc., of the sun and moon appear, but also, all
solar and lunar eclipses—both visible and invisible; as in
heaven, so on the clock, they are conspicuously celebrated in
their true times, and those of the past and those of the future,
with their circumstances of time and duration, magnitude,
etc., can be quickly determined. All this was devised and
brought to light by the author, Francesco Borghesi of Anáuni,
a secular priest of Trent, A.A.L.L. & Doctor of Philosophy.
(Trent: From the printshop of Giovanni Battista Monauni,
With Permission of Superiors.)" (Title page reproduced by
permission of the Biblioteca della Citta di Trento.)

Again and again, Bertolla threw up his hands in despair and begged Father Borghesi to
abandon the enterprise. He protested that he was not capable of producing such a
complicated mechanism; he had neither the tools nor the skill. The priest wished to produce
a clock such as the world had never seen before, such as the greatest scientists and
clockmakers of all time had never been able to make. But Bertolla felt that he was only a
provincial craftsman who could not hope to surpass them all with only his simple tools and
training.
In his book on the first clock, Novissima Ac Perpetua Astronomica…, Father Borghesi
wrote that when he had finally come within a few weeks of the embryo stage in the
development of his clock, he was faced with the problem of bolstering the sagging
enthusiasm of Bertolla. The clockmaker's original enthusiasm had shown promise of great
results, but as the days passed and the problems of the multiplex and generally unfamiliar

apparatus to be forged for the workings of the automaton became more complex, his ardor
decreased. Finally, Bertolla became so discouraged by the scoffers and frustrated by the
fact that the work was insufficiently organized that Father Borghesi wrote that "it almost
became a harder task for me to bolster up by daily opportunity and importunity the failing
patience of the artisan, frightened away from the work already begun, than it was for me to
extract from the inner recesses of mathematics and astronomy, without light and without a
guide, the whole fabric of the machine itself!"
In spite of Bertolla's protests, Father Borghesi prevailed, reviving his friend's interest
once more until the two were deep in the project again. Months passed as they worked
together on the mechanism and it seemed as if they lived for no other purpose. Inevitably,
Bertolla's health began to suffer, undermined as it was by the constant nervous tension, and
he eventually became ill from mental strain. He was forced to spend some time in bed, and
for many weeks the subject of the clock was not discussed. Bertolla's other work, by which
he made his living, suffered and it was several months before he was able to return to his
little shop.
One year passed into another and the work progressed slowly. The first clock, which
easily should have been finished in less than a year, was not completed until after three full
years had passed. However, when the priest and the clockmaker put the finishing touches to
their great clock, the result surpassed the greatest possible expectations, for it was truly a
masterpiece. Not only did it illustrate the ecliptic phenomena of the moon, the sun and
earth occurring in their proper time, as well as many other things, but it showed these
operations as they succeeded in proper order, taking place through the centuries.
With mutual feelings of great pride, the two friends surveyed the result of their three
years of endeavor. Bertolla realized that he had reached a point of maximum achievement
in his work. He probably felt that now he could relax again, that his sleep would no longer
be troubled by confused nightmares of wheels and gears that did not mesh together. Time
was to prove otherwise.

PUBLISHED DESCRIPTION OF THE FIRST CLOCK
Father Borghesi soon came to the conclusion that it would be desirable to have a
written description to explain the mechanism of the clock and its many indicators. He
thereupon wrote out the story of how the clock was made, the reasons for embarking on the
enterprise, the difficulties he had encountered, and the success which had crowned his and
Bertolla's mutual labors. Finally, he described the operation of the clock's mechanism and
the functions of its array of indicators.
The little book was written in Latin and only a few copies were printed, presumably at
the priest's own expense, on a handpress by Giovanni Battista Monauni, printer to the
Bishop in Trent. The little volume was stated by contemporary writers to have been
published in 1763, although no date appears on the title page. The title translated is, in part,

The Most Recent, Perpetual Astronomical Calendar Clock, Theoretical—Practical…. The
work begins with an introduction for the reader in which Father Borghesi stated that:

… the little work, which, as far as I was concerned could easily have been finished
in a year, was only completed after about three years. Fortunately, however, it was so
far beyond the expectations of most, that not only am I able to foretell with certainty
all the lunar ecliptic phenomena and the solar, or rather terrestrial, phenomena,
carefully worked out in their true periods, among many other matters exhibited by the
machine; but also, within a few hours, I can exhibit by altogether tangible evidence to
the skeptics and the doubting those very same phenomena, occurring within the space
of many years, or even centuries, and succeeding one another in proper order, with
their many attendant circumstances. I was not much concerned about the other
eclipses, such as those of Mercury, Venus, and the other stars wandering through the
zodiac, or about the other solar eclipses from the transit of Mercury or Venus, since
they are altogether undiscernible to the naked eye, and very few compilers of
ephemerides wish them to be noted, probably for the same reason.
Do not, however, expect, star-loving reader, that here anything at all that you may
wish can be drawn forth as from its source, for to demand this would be almost the
same as to seek to drain as from a cup all the vast knowledge of the many arithmetical
sciences from the narrow confines of one book. You will understand how impossible
that is when, through prolonged labor, you have grown somewhat more mature in this
kind of learning.
Wherefore, rather fully, and out of consideration for you, I have decided, setting
aside these prolixities, with completely synoptic brevity and with all possible clarity
to expound for you simply the proportion of the movements, the description of the
machine, and its usage. As a result, when you have progressed a little in theoretical
mechanics, you will not only be able to reduce all these things to their astronomical
principles, but you may find the way more smoothly laid out for you even for
perfecting the machine itself. And, thus, you may be more effectively encouraged to a
successful conclusion. Let it be so now for you through the following 10 chapters!

After these rather hopeful assurances, Father Borghesi proceeded to provide a detailed
description of the clock dial and functions in the 10 short chapters which he had promised,
under a separate section entitled "Synopsis Totius Operis Mechanici," which is translated in
its entirety in the appendix.
As Father Borghesi prepared his little volume about his first clock, and described its
unusual features and outlined its functions, which were primarily to place in evidence the
celestial constellations, it occurred to him that it would now be easier after the experience
he had acquired with his first timepiece, to construct another clock, which would present
the motions of the two astronomical systems, the Ptolemaic and the Copernican. In this
first book, he promised the reader that he would undertake the second project. It is
fortunate that Father Borghesi undertook this project for the second clock is the only
example of his work that is known to exist today. Extensive research has not shown what

happened to the first clock, although several sources state that both timepieces were
presented to Empress Maria Theresa sometime between 1764 and 1780.

Second Borghesi Clock
Father Borghesi lost no time in initiating the project of the
second clock. The first and most important step was to inform
Bertolla and enlist his assistance. Bertolla was adamant: he had
had enough of complicated astronomical movements. He was
delighted by the prospect of returning to his former simple life,
producing simple, domestic, elementary movements for his
country clients. Father Borghesi begged and cajoled. The
second clock would be a much simpler one to construct, he
persisted. After all, they had gained invaluable experience from
the production of the first clock. Furthermore, he had already
completed its design.
Bertolla apparently wavered in his resolve and, unwillingly
and against his better judgment, he allowed the priest's
inducements to prevail. Once again, the two friends yielded
their leisure hours to a study of the priest's books and drawings
as Father Borghesi enthusiastically elaborated his design for the
timepiece, and Bertolla attempted to transcribe astronomical
indications into terms of wheel counts. The second clock was,
as Borghesi had promised, much easier of execution. Within a
year, it was completed and functioned with complete success.
This is the clock now in the Museum of History and
Technology. It is housed in a tall case of dark-red mahogany
veneered on oak, with restrained carving featuring ribands and
foliate motifs. Gilt-brass decorations flank the face of the hood,
which is surmounted by three gilt-brass finials in the form of
orbs. A wide door in the waist may be opened to attend the
weights. The case is 7 feet 8 inches high, 201/2 inches wide at
the waist, and 14 inches in depth.
The dial is of gilt brass, measuring 21 inches high and 15
inches in width, with a number of supplementary silvered dials Figure 8.—The Borghesi
visible through its openings. Instead of hands, the dial utilizes clock in the Museum of
History and Technology,
three concentric rings moving around a central disc, the constructed in 1764 by
indications of which are read at two bisecting gilt lines Bartolomeo Antonio Bertolla
inscribed in the glass face. Twelve separate functions are of Mocenigo di Rumo from the
designs of Father Francesco
performed by the chapter ring assembly alone, and there are 14 Borghesi of Rumo and Mechel.
openings on the dial. It is estimated that the clock performs 30

separate functions, including striking and chiming. Of the
multiple chapter rings, the outermost is 11/8 inches wide, the
center ring is 3/8 inch wide, and the innermost ring measures
11/4 inches in width.

THE DIAL-PLATE ENGRAVINGS
The gilt dial is incised throughout with figures and
inscriptions in engraving of the very finest quality, as is
evidenced in the illustrations. The frontispiece is surmounted at
its center by the crowned double eagle of the House of
Hapsburg, indicating the identity of the sovereign in whose
reign it was made, Emperor Francis I or the Empress Maria
Theresa of Austria. Below the eagle at either side are flying
cherubs supporting ribands with inscriptions. Centered at the
bottom of the frontispiece immediately above the chapter rings
is the moving silvered orb representing the sun. Surrounding it
is a tableau of the Holy Trinity, with the Virgin Mary being
crowned by Christ holding a cross at the left and God with a
sword in hand at the right, and a dove representing the Holy
Spirit hovering over the Virgin's head. Father S. X. Winters,
S.J., considers it reminiscent of the triptych "The Coronation of
the Virgin" by Fra Lippo Lippi.

Figure 9.—Another view of
the Borghesi clock.

Figure 10.—Diagram of the dial plate. Figure 11.—Dial plate of the Borghesi clock.

KEY TO DIAGRAM OF THE DIAL PLATE
A Dominating planet, represented by its symbol and its house;
B Dominical letter (Lit. Dom.);
C Epacts (Cyc. EpEC);
D Roman indiction (Ind. Rom.), part of the reckoning of the Julian period;
E Solar cycle, (Cyc. Sol.), part of the reckoning for the Julian period;
F Golden number (Num. Aur.), part of the reckoning for the Julian period;
G, H, I, J The era, or the current year; part of the six windows of the Iris, or
rainbow;
K Shuttered winding hole, for winding up the weights; part of the six windows of
the Iris;
L The era, or the month of the current year; part of the Iris, or six windows of the
rainbow;
M The sun in its epicycle;
N The 12 signs of the sun's anomaly;

O, P The first chapter ring representing the equatorial globe of the week, revolving
from left to right;
Q The coming day indicated through the window;
R The second chapter ring; including the synodic-periodic measure of the tides,
the days of the median lunar-synodic age, the signs and degrees of the signs
for mean distance of the moon from the sun;
S Epicycle of the moon with signs of its anomaly;
T Head of the dragon (Cap. Draconis);
U Tail of the dragon (Cauda Draconis), for measuring eclipses of the earth and of
the moon;
V Third chapter ring, with degrees of lunar latitude and some fixed stars;
W Fourth chapter ring, showing firmament of fixed stars, signs of the zodiac and
degrees of the signs, the months of the year, and days of the months,
revolving left to right for the course of a mean astronomical year;
X Adjustment marked Claudit (it closes) and Aperit (it opens) for disengaging dial
work for the purpose of making astronomical experiments and
computations;
Y Adjustment marked Concitat (it accelerates) and Retardit (it retards) for fast
and slow adjustments of the movement.

In the upper spandrels of the dial are two more cherubs bearing ribands with
inscriptions. In the lower left corner is a magnificent engraving of Atlas upholding the
globe of the world, inscribed with the zodiac, over his head. The lower right corner features
the figures of two noblemen apparently examining and discussing an orb upon a table, the
significance of which is not clear.

THE INSCRIPTIONS
Beginning with the uppermost part of the frontispiece, there are nine inscriptions in
Latin on the dial plate. The topmost is Franciscvs I sit plan. Dominator aeternvs. The
phrase has reference to Francis I, who was Emperor of the Holy Roman Empire, from
1745-1765, and husband of Empress Maria Theresa of Austria. The phrase may be
translated as "May Francis I be the eternal ruler by favor of the planets" or more simply
"Long Live Francis I, Emperor." [14] Although the dial plate of the Borghesi clock is
inscribed with his name, the records indicate that the clock was presented to Maria
Theresa. Francis I may have already died before the presentation was made.

Figure 12.—Empress Maria Theresa, to
whom Father Borghesi is stated to have
presented his two astronomical clocks. The
coin bearing her portrait is in the Museum of
History and Technology.

From the left to right over the tableau of
the Holy Trinity is the phrase "Lavs
sacrosanctae Triadi Vni Deo, et Deiparae"
Figure 13.—Portrait of Francis I, Emperor
(Praise [be] to the most Holy Trinity, to the of the Holy Roman Empire, to whom Father
one God, and to the Mother of God). Borghesi's astronomical clock in the Museum
of History and Technology appears to have
Within the upper left and right spandrels been inscribed.
is inscribed:

Isthaec, Signum grande apparvit in Coelo * sancta Dei genitrix amicta sole *
Illibato pede Lvnae et serpentis nigra premens Cornva * bis senis pvlcherrime
Coronata syderibvs * Tempe indesinenter clavsa, scatvrigo signata * Cedrvs in
Libano, Cypresvs in Monte Sion * Mater pvrae Dilectionis sanctaeqve spei * Chara
patris aeterni proles, Verbi Mater, sponsaqve procedentis *, gratiae et gloriae
circvmdata varietate.

This inscription is a eulogy to the Virgin Mary assembled from the texts of Holy
Scripture. In addition, each lemma, contained within asterisks, carries out the chronogram
1764, the year the clock was completed. Each lemma is translated and identified from the
Douay-Rheims version of the Bible:

This woman: a great sign appeared in Heaven (Apocalypse 12:1) * The Holy
Mother of God clothed with the sun (Apocalypse 12:1) * And with unharmed foot
crushing the black horns of the moon (Apocalypse 12:1) and the serpent (Genesis
3:15) * Most beautifully crowned with twice-six (Apocalypse 12:1) * A garden
[Tempe [15]] enclosed, sealed with a fountain [spring of water] (Song of Songs 4:12) *
Like a cedar in Lebanon, and a cypress tree on Mount Zion; (Ecclesiasticus 24:17) *

Mother of pure love and of holy hope: Beloved daughter of the Eternal Father, Mother
of the Word, Spouse of the Holy Spirit: (Ecclesiasticus 24:24) * Surrounded with a
diversity of grace and glory (Psalms 44:10).

Figure 14.—The bottom right corner of the
dial plate, showing two noblemen Figure 15.—The bottom left corner of the
contemplating an orb, with the inscription dial plate, showing the engraving of Atlas, with
"Diligit Avdaces Trepidos Fortvna Repellet." the inscription "Assidvo proni donant di
(Fortune favors the daring and rejects the cvncta labori." (The favorable gods willingly
timid.) grant all things to the assiduous laborer.)

At the lower left corner below the figure of Atlas upholding the world is the phrase,
Assidvo proni donant di cvncta labori. (The favorable gods willingly grant all things to the
assiduous laborer.) The same phrase is quoted by Father Borghesi in the text of his second
volume. The last inscription appears at the lower right corner under the figures of the two
noblemen, Diligit avdaces trepidos fortvna repellet. (Fortune favors the daring and rejects
the timid.) The last two inscriptions are in dactylic hexameter. They appear to be original
compositions inasmuch as no classical prototypes have been identified.

Figure 16.—Detail of frontispiece of the Borghesi clock, showing the apertures for calendar
indicators and the details of the engraving.

CENTER DIAL INSCRIPTIONS
In addition to the inscriptions previously noted on the outer dial plate, there are three
major inscriptions in the central dial. The outermost states Circulus horarius Soli, Lunae,
Fixis, Nodis, Aestuique marino communis (the hour circle, common to the sun, the moon,
the fixed stars, the nodes and to the sea tide). This inscription is divided into four parts by
the insertion of four divisions for the day into canonical hours: [Horae] Nocturnae (night
hours); Matutinae (morning hours); Diurnae (daytime hours) and Vespertinae (evening
hours).
The next section of the central dial is inscribed Intumescite—Detumescite (rise and fall
of the tides) repeated at intervals of approximately every six hours. Within the next section
is the following inscription, inscribed continuously around the ring:
Lege fluunt, refluunt, dormitant hac maris undae: Ad Phoebi et
Phoebes concordia iussa moventur Aequora; discordi iussu suspensa
quiescunt.
Translated, this is:
By this law the sea waves ebb and flow and lie dormant: When
Phoebus and Diana agree in their commands, the waters are moved;

when they disagree, the waters lie silent. [16]
Within the central boss of the dial plate, the name of the maker is inscribed:
Bvrghesio Doctore, et Bertolla Limatore Annaniensibvs*
Translated, this is:
[By] Doctor Borghesi and Bertolla, mechanician citizens of Anáuni.

INDICATORS IN THE FRONTISPIECE
There are 12 windows in the frontispiece, through each of which appears an indication
relating to time. Beginning at the top of the frontispiece of the dial, the first opening occurs
on the breast of the imperial eagle. This indicates the dominating planet, represented by its
symbol, and its house.
The opening in the eagle's left claw, labeled "Lit. Dom." is the dominical letter. The
first seven days in the month of January are each assigned one of the letters a through g in
order of appearance. The letter which coincides with the first Sunday within this period is
called the dominical letter, and it serves for the following year. In leap year, two letters are
required, one to February 29th and the letter next proceeding for the remainder of the year.
This letter is used in connection with establishing the date of Easter Sunday. The date of
Easter regulates the dates of the other movable feasts.
The eagle's right claw is labeled "Cyc. EpEC" and represents the epact, or the age of
the moon on January 1st. It serves to find the moon's age by indicating the number of days
to be added to each lunar year in order to complete a solar year. Twelve lunar months are
nearly 11 days short of the solar year, so that the new moons in one year fall 11 days earlier
than they did the preceding year. However, 30 days are deducted as an intercalary month
since the moon has made a revolution in that time, and the remainder, 3, would be the
epact.
Below the imperial eagle two winged cherubs support a riband with three indictions of
the Julian period. This period of 7980 years is the product derived from multiplying
together the sums of 28, which represents the cycle of the sun; 19, representing the cycle of
the moon; and 15, which represents the Roman indiction. The Julian period is reckoned to
have begun from 4713 B.C. so that the period will be completed in A.D. 3267. The first of
the three openings is marked "Ind. Rom." or "Roman indiction," which was an edict by the
Emperor Constantine in A.D. 312, providing for the assessment of a property tax at the
beginning of each 15-year cycle. It continues to be used in ecclesiastical contracts. The
second opening, which occurs immediately below the eagle, is marked "Cyc. Sol." (cycle
of the sun). This cycle takes a period of 28 years, after which the days of the week once
again fall upon the same days of the month as they did during the first year of the former
cycle. There is no relationship with the course of the sun itself, but was invented for the
purpose of determining the dominical letter which designates the days of the month on

which the Sundays occur during each year of the cycle. Since cycles of the sun date from 9
years before the Christian era, it is necessary to add the digit 9 to the digits of the current
year and then divide the result by 28. The quotient is the number of cycles which has
passed, and the remainder will be the year of the cycle answering to the current year. The
third opening on the riband is labeled "Num. Aur." (golden number). Meton, an astronomer
of Athens, discovered in 432 B.C. that after a period of 19 years the new and the full
moons returned on the same days of the month as they had before, and this is called the
cycle of the moon. The Greeks were so impressed with this calculation that they had it
inscribed in letters of gold upon stone, hence the golden number. The First Council of
Nicaea in A.D. 325 determined that Meton's cycle was to be used to regulate the movable
feasts of the Church.
Immediately above the chapter rings is an opening through which the orb of the sun is
visible.

THE CHAPTER-RING ASSEMBLY
In a separate chapter in his second volume, entitled "Descriptio Authomatis Summa
totius Operis Mechanici" (Description of the Automaton—Summary of the Complete
Mechanism), Father Borghesi provided a description of the functions of the various
indicators, prefixing it with the short poem shown in figure 18. He then continues:
In the middle of the frontispiece, as at the center of the universe, the
terraqueous globe of the week revolves, with a daily motion turning from
right to left, bringing with it from the round window the coming day and
at the circumference the circle of hours common to the sun, to the moon,
to the fixed stars, to the head and tail of the dragon, and to the raging
sea.
The second circle revolves the synodic-periodic measure of the
raging sea, the days of the median lunar-synodic age, the signs and
individual degrees of the signs of the distance of the moon from the
middle of the sun within the time of 29 terrestrial revolutions, hours
12.44.3.13. This circle revolves likewise from right to left around the
center of the earth. In this second circle, another little orb revolves,
bringing with it the epicycle of the moon, in which the little circle of the
moon (whose illuminated middle always faces towards the sun), running
from left to right through the signs of the anomaly; within 13 revolutions
of the earth, hours 18.39.16. It descends from apogee to perigee and in
just as many others it returns from perigee to apogee, to be carried down
thus to true, back and front from the longitude and distance from the sun
and from the middle of the earth.
The third circle (on which I have tried to indicate astronomically-
geometrically in their places, the degrees of lunar latitude both in the

south and in the north, and some fixed stars, those, namely, which can be
separated by us from the moon which goes between) from left to right
turns around the center of the earth, stretching out the head and tail of
the dragon, on the inside above the second circle for noting and
measuring the sun (but I should rather say the earth), and the eclipses of
the moon, within 346 revolutions of the earth, hours 14.52.23.
The fourth circle, in which the heaven of the fixed stars, reduced to
the correct ascent of our times, the signs of the zodiac and the individual
degrees of the signs, the months of the year and the single days of the
month can be seen, likewise makes its journey around the earth from left
to right in 365 terrestrial revolutions, hours 5.48.56.; that is, within a
median astronomical year. Above this annual orb, the sun, in its small
epicycle, gliding through the 12 signs of the anomaly, within the space of
182 terrestrial revolutions, hours 15.6.58., from left to right, falls from
apogee to perigee; and, within the same time, rises from perigee to
apogee, and brings with it, the index, namely its central radius, inhering
to the axis of the equatorial orb and cutting the four greatest circles from
the center.
When the sun has been moved around, Iris shows from six windows
the era, that is, the current year. Two winged youths take their place next
to Iris, carrying the Julian period: namely, the Roman indiction, the cycle
of the sun and the golden number, on a leaf of paper held between them.
The imperial eagle stands out on top (as if added to the frontispiece)
carrying on its breast the dominating planet and in its talons the
ecclesiastical calends (that is, the dominical letter and the epact).

ATTACHMENTS FOR ADJUSTMENT
Two attachments, in the form of small superimposed dials are situated at the base of the
dial plate, at either side and immediately below the fourth chapter ring. In his second
volume, Father Borghesi stated that they "are not moved from inside the clock, but the one
at the right [inscribed concitat and retardat] serves for loosening [accelerating] and
tightening [retarding] time; that is, the reins of the perpendicular."
In other words, the purpose of this attachment is for adjusting the pendulum to make
the clock operate fast or slow. The second attachment, which appears at the left, and which
is inscribed "Claudit" (close) and "Aperit" (open) serves the purpose of "… preparing the
mechanism in a moment, as swiftly as you wish, for sustaining the astronomical
experiments of which you will hear later; when these things have been done, it restores the
mechanism to its natural motion at the same speed."
This adjustment relates to the final section of Father Borghesi's second book, entitled
"Chronologo-Astronomicus Usus Authomatis" (Chronological-Astronomical Use of the

Automaton), which is translated from the Latin in its entirety:
With one glance at this automaton, you can quickly answer these
questions: What hour the sun shows, the moon, any fixed star, the head
and tail of the dragon. Is the sea swelling with periodic heat [at high
tide?] or is it deflated [low tide], or quiescent? How many days is it from
mean new moon or full moon? By how many signs and degrees is the
moon distant from the sun, and from its nodes? What sign of the zodiac
does the sun occupy, the moon, the head and tail of the dragon? Is the
sun or the moon, in apogee or perigee, ascending or descending? What is
the apparent speed of the sun and of the moon? What is the apparent
magnitude of the solar and lunar diameter, and of the horizontal parallax
of the umbra and penumbra of the earth? What is the latitude of the
moon? Is it north or south? Does the moon hide [occult eclipse] any of
the fixed stars from the earth dwellers, and which of these does it
obscure? Is there a true new or full moon? Is the sun in eclipse anywhere
on earth? What is the magnitude, and the duration of this eclipse, with
respect to the whole earth? Can it be seen in the north or in the south? Is
the moon in eclipse? Total or partial? Of what magnitude, etc.? What
limb of the moon is obscured? How many years have passed from a
given epoch? Is this year a leap year, or a common year—first, second,
or third after leap year? What is the current month of the year, and what
day of the month and of the week? Which of the planets is dominant?
What days of the year do the various feasts fall on, and the movable
feasts during the ecclesiastical year? And many other similar questions,
which I pass over here for the sake of brevity.
Besides, this device can be so arranged for any time whatsoever, past
or future, and for the longitude of any region, and can be so manipulated
by hand, that within the space of a very short time there can be provided
in their proper order, the various orbits of the luminous bodies, their
alternating eclipses, as many as have taken place through the course of
many years, or even from the beginning of the world; or those that will
be seen as long as the world itself shall last, with all their attendant
circumstances (year, month, day, duration, magnitude, etc.). All these can
be seen with great satisfaction of curiosity and of learning, and hence
with great pleasure to the soul. In the meanwhile, the little bells
continually play, at their proper, respective times. So that, all
exaggeration aside, a thousand years pass, in the sight of this clock, as
one day!
I am aware of your complaints, O star-loving reader—that my
description is too meager and too succinct. Lay the blame for this on
those cares, hateful both to me and to you, more pressing, which forbid
me and deprive you of a methodical explanation of the work.

THE CLOCK MOVEMENT
Father Borghesi specified that the entire mechanism was equal in weight to a seventh
part of a Centenarii Germanici, a Germanic hundredweight. This is probably the Austrian
centner which is equivalent to 123.4615 pounds. Therefore, the clock mechanism weighs
approximately 17.6 pounds.
The clock operated for a hundred days and more at a single winding, according to
Father Borghesi, and by means of a pendulum with a leaden bob weighing 60 Viennese
pounds, attached at a height of 5 feet. Father Borghesi stated the weight of the pendulum to
be 60 librarum Viennensium, but the Viennese libra does not appear among the weights of
the Austrian Empire. However, using the average libra, an ancient Roman unit of weight
equal to 0.7221 pound, it may be assumed that the driving weight should be approximately
45 pounds.
Father Borghesi, however, does not venture to provide any description whatsoever of
the movement of his second clock in his book. He gave the following reasons:
But beyond this, I entirely omit [a description of] the further
apparatus of the very many wheels, etc., inside the clock which carry on
its functions, lest I become too verbose for some persons. To explain
more thoroughly the internal labyrinth of the entire mechanism, from
which the movement of the circles or heavens, etc., are derived, would
seem to entangle in too many complicated perplexities…. Therefore, that
I might not delay longer, and perhaps to no purpose, I have thought it
better to leave the whole work to the proportionate calculus of the
arithmeticians and the technical skill of mechanics. If they have any
desire to construct a similar mechanism, they will follow the aforesaid
motions of the heavens, etc., not only by one means alone but by many,
more swiftly through thoughtful study than by any amount of instruction.
For whoever is well versed in the theory of calculus and sets to work
at any given project, will discover any desired motion by a thousand and
more ways, by one or another gearing of wheels; which an industrious
mechanic will carry out in actuality and without too much difficulty. Nor
is there any reason for anyone to be discouraged, so long as he is not
disgusted by the amount of labor for there is nothing truer than the old
saying "The favorable gods grant everything to the assiduous laborer."
Nay, further, even this little work itself can be improved on and
surpassed by new inventions. Otherwise that other old adage, almost as
old as the world, would prove false, "What you have found already done,
you can easily repeat, nor is it difficult to add to what has already been
invented." Relying on this principle, I have already conceived some new
things to be added to the present little work.

Figure 17.—Movement of Borghesi clock viewed from the right side, with details of
chiming mechanism.

THE BELLS
There is a discrepancy between Father Borghesi's written description in his second
book of the number of bells and those which currently exist in the clock. At the present
time, there are two sets of bells attached to the upper part of the movement. While Father
Borghesi indicated that there were two sets of bells in the clock, he described the first set
by stating that:
… there are three bells inside the clock: The largest, when struck by
a little hammer at each mean new moon, signifies the new moon. The
smallest indicates in the same way the full moon at the time of the mean
full moon, by automatic sound. When on the equatorial earth, the sun
appears anywhere in eclipse, two bells (the largest and the medium)
sounding together automatically, announce that eclipse at the time of the

mean new moon. (I think it is evident that eclipses of the sun occur at
new moons and eclipses of the moon at full moon.)
When the moon is eclipsed, the smallest and the medium bells,
simultaneously and automatically, announce the event to the ear at the
time of the mean full moon. Besides, at the proper time and
automatically, the largest of these bells announces the current solar hour
and the smallest bell strikes the quarter hours.
In the clock today, the first set consists of a smaller bell fixed within a larger one. It is
presumably these bells that indicate the eclipses and also strike the hours and quarter hours.
A pull cord attached to the striking mechanism repeats the current hour and quarter hours at
will. The second set consists of nine meshed bells struck with individual hammers operated
by means of a pinned cylinder as in a music box. On the hour, the chimes play one of two
melodies, which may be changed at will. While not identified, these appear to be Tyrolean
folk melodies. The largest of this set of bells is dissimilar to the other chimes, and may be
the third bell described by Father Borghesi to signify the new moon.

CHRONOGRAMS
One of the most curious aspects of the second clock produced by Father Borghesi and
Bertolla, as well as of the second published volume, is the presence of chronograms which
occur repeatedly on the clock dial and throughout the Novissimum Theorico-Practicum
Astronomicum Authoma from the title page to the end of the book. Interestingly enough,
Father Borghesi did not utilize this device even once in his first little book.

Figure 18.—A chronogram in the text of Father Borghesi's second volume, indicating the
year 1764. The poem is translated as: "In the Mount of 'Anáuni,' the inscrutable heavens are
led, You learn from these all the labors of the sun and the moon. Here you are shown and hear
the conjunction of the moon: And a bell brings to the ears by its sound, all eclipses."

Webster defines a chronogram as an inscription, sentence, or phrase in which certain
letters express a date or epoch. The method used by Father Borghesi for forming
chronograms was a simple one. He used combinations of uppercase and lowercase letters
in two sizes in the inscriptions on the clock dial and in his writings. At first this curious
combination in the inscriptions on the dial plate was a source of considerable speculation.
The extremely fine quality of the engraving and artistry was such that these combinations
could only be deliberate in nature and not the accidental whims or accidents of the
engraver. Accordingly, they must be chronographic in intention. Such proved to be the
case.
Borghesi used the larger size of uppercase letters to form the chronogram, and each
chronogram was complete within a phrase or line. He accomplished this by using for this
purpose those letters of the alphabet which form the Roman numerals. The uppercase
letters found within words are copied off in the order in which they appear in the
inscription or phrase. These are then converted into their numerical equivalents, and
totaled. Taking the uppermost inscription on the clock dial as the first example:
FranCIsCVs I sIt pLan. DoMInator aeternVs
The letters which are intended to form the chronogram are:
C I C V I I L D M I V

100 1 100 5 1 1 50 500 1000 1 5
These figures added together total 1764.
The second inscription on the clock dial which forms a chronogram is
LaVs saCrosanCtae TrIaDI VnI Deo, et DeIparae

L V C C I D I V I D D I

50 5 100 100 1 500 1 5 1 500 500 1 = 1764.
The third inscription required a little more planning, because of its greater length.
Accordingly, Father Borghesi divided it into nine parts, each of which is separated from the
other by means of asterisks. Each of the nine parts of the inscription formed a chronogram
which, in every instance, totals to the date 1764, the year in which the second clock was
completed. The same procedure was followed with the inscriptions in the lower left and the
lower right corners of the dial as well as with the maker's inscription within the central
disk. This inscription is
BVrghesIo DoCtore, et BertoLLa LIMatore AnnanIensIbVs

V I D C L L L I M I I V

5 1 500 100 50 50 50 1 1000 1 1 5 = 1764.
The inscriptions within the chapter ring are not utilized for chronograms, however. It is
apparent that Father Borghesi was required to make a most careful selection of the texts for
his inscriptions in order that none of the phrases included any additional letters which
formed Roman numerals than would total to the date he desired to indicate, namely, 1764.
Where it was necessary, he employed an asterisk to separate parts of texts so that each
would produce the same total. Any letter that did not form a Roman numeral, even if
capitalized or used in a larger size, did not interfere with the formation of the chronograms.
In spite of his ingenuity in designing a text which would include only such of the letters
representing the Roman numerals which would provide the chronograms for 1764, Father
Borghesi experienced some difficulties, particularly in place names. He accordingly
changed them in order to avoid the inclusion of letters that would have disturbed his totals.
Examples are MEGGL instead of MECHL, which had an extra C, and RVNNO instead of
RVMO, which had an extra M.

PUBLISHED DESCRIPTION OF THE SECOND
CLOCK
When the clock had been completed and proved to work successfully, Borghesi once
more reduced a description of the clock and its function to published form in a second little
volume published by Monauni. This second work was also in Latin, the title of which is
translated as The Most Recent Theoretical-Practical Astronomical Clock According to the
Equally Most Recent System of the World. As with his first book, Father Borghesi devoted a
number of pages to a preface addressed to the reader, which is translated from the Latin:
This mechanical instrument was far from being ready for public
notice. A great deal of time and work remained to produce a machine of
this new system from the very foundations; then, by a most accurate
calculation to bring the motions of many wheels up-to-date with the
most recent astronomical observations; and, finally, to fashion it with the
craftsman's file, often enough with a weary hand. All this work I had
performed eagerly, so that, while in my room, I might contemplate
leisurely, both day and night, the true face of the heavens and the seas
unobscured by clouds, even though I had no astronomical equipment.
But, then I remembered that, in my book on the first clock, I had
promised a description of a new (at least, as far as is known to me)
clock. Moreover, friends with astronomical interest, who took part in the
oft-repeated astronomical experiments concerning this clock, persuaded
me that the intellectual world would enjoy having a greater knowledge
and a description of this work. However, it was not only the promises
nor the desires of many which moved me to write this work, but I also

thought it was necessary to set forth, before the description of the clock,
an exposition of the astronomical system according to which this clock
was constructed, so that the complete work would be evident to all. I was
concerned about making this timepiece more acceptable and more
understandable to those people who are far distant and unable to see it,
so that this present exposition would obtain credulity among all. I could
find no better method than to set forth for the reader the theory of the
universe which I figured out after many sleepless nights.
In testing this theory day after day, it not only appeared to be
complete, and true, but each day it appeared more conformable to reality;
it captured my mind in such a way that I finally adhered to it. I desired,
while I lived, to erect this work as a monument to the theory. To do this,
I digressed a bit from the true-to-life pattern to the mechanical order so
that I could transfer all the movements of the heavens, etc. (which I
enjoyed thinking about more), to the plane surface of the clock's face. In
this way, the ecliptical spectacles of the stars, etc., would appear at their
proper times clearly before the eyes of the viewer. I could also avoid
many difficulties which otherwise, perhaps, even the hands of the most
skillful craftsmen could never solve.

Figure 19.—Movement of the Borghesi clock, viewed from the rear, showing rear of dial
plate.

Figure 20.—Title page of Father
Borghesi's second book. The translation
in its entirety is: "The Most Recent
Theoretical-Practical Astronomical
Clock According to the Equally Most
Recent System of the World. Author:
Francesco Borghesi of Mechel of Anáuni
* Priest of Trent, Doctor of Philosophy *
(The System of the Clock) Ingeniously
connected to new theoretical laws
published 1764: and the constructor,
Bartholomeo Antonio Bertolla of Rumo,
similarly from Anáuni * who skillfully
produced this work * in this same
current year of Our Lord * which is the
year 5713 [sic] since God created this
earth. (Trent: From the Printshop of
Giovanni Battista Monauni, With
Permission of the Superiors.)" (Title
page reproduced by courtesy of the
Biblioteca della Citta di Trento.)

You ought to know, therefore, that as a result of my nightly
meditations, I have rejected, after much consideration, all the
explanations of the universe thus far published. All other theories of the
make-up of the universe, however admirable, and however many there
are, turn the sun and earth around in an ecliptic in an annual movement.
Thus, Philolaus was the first to move the earth from the center of the
universe and move it through the void; afterwards, Aristarchus of Samos
and then Copernicus moved the earth with the moon. The Egyptians, as
well as Pythagoras, Ptolemy, Tycho, Riciolus, Longomontanus, etc.,
thought that the sun moved through the degrees of the ecliptic each year.
But I attributed this movement to neither earth nor sun for the movement
of both is only apparent. I did not vainly surmise the annual equilibrium
in all astronomical observations to be from the daily movement of the
same axis moved at the poles of the heavens. Nor, in like manner, is
there a better way to satisfy physical experiments. To you, then, most
cultured reader: If you, perhaps, can make any use or draw pleasure from
this most faithful description of my new theory and the mechanical
instrument, refer it first to God on High from whom is everything that is

best, and then to those avidly awaiting this little work. Lastly, if you find
any statement less fitting; in your humanity, do not disdain to excuse it.

Borghesian Theory of the Universe
In Father Borghesi's second volume, there is a separate chapter entitled "An Exposition
of the Latest Theory of the Universe." This follows the introduction to the reader, and in it
Father Borghesi proposed:
That you might rightly conceive my new system of the world and
mechanically, as it were, construct it, imagine for yourself, beneath that
most happy seat of the Blessed and above all other heavens, a kind of
spherical convexity, everywhere equidistant from the center of the earth,
and endowed with absolutely no motion.
On the inside, at two points diametrically opposite each other, this
convexity has two most sturdy poles (to speak mechanically), projecting
towards the center (which you call the poles of the heavens), and the
largest immobile semicircle, in some manner is drawn from the center of
one pole to the center of the other. This semicircle in the middle, namely
at a point equidistant from each pole, is thought to be secured by some
sign, for example, by that "o," for arranging more perceptibly the seat of
the sun (as will be shown later). This much must be conceived first.
You must understand that imposed on these poles is the first mobile
[Primum Mobile], everywhere convex, and divided, into 12 equal parts
[Dodecatemoria], by the 6 greatest circles, intersecting each other at the
centers of the poles. Then it is divided by another equally great circle,
everywhere equidistant from the poles, into two hemispheres. One
hemisphere of 12 parts, proceeding in order from west [setting] to east
[rising] should be assigned the respective signs of the zodiac; that is, one
to Aries, the next to Taurus, and so on, etc. The circle which cuts those
12 parts transversely in the middle, you call the ecliptic. Then, these
capital spaces of the Primum Mobile are subdivided by degrees, minutes,
etc., both in longitude and in latitude, so that this heaven represents a
kind of great spherical net, extended to capture the longitude and latitude
of the stars, and Mobile on the aforementioned poles. Note, however
(and this is almost the leading point of the system), in that circle of
longitude which divides the sign of Gemini from Cancer and Arcitenens
[Sagittarius] from Capricorn, you must conceive two points, directly
opposite each other and removed about twenty-three and a half degrees
from the poles: Boreal [the northern] between Gemini and Cancer;
Austral [the southern] between Sagittarius and Capricorn. These two
points by some power (imagine it is magnetic power), equal between

them, hold the terraqueous orb suspended in the middle, by acting on the
axis of the same orb (imagine it is iron) in such a way that the earth is
continually drawn to those two points as to two opposite centers. It is
never nearer to one, for as it is about to move towards one, the opposite
power is constantly drawing it back. Thus, both those points and the axis
of the earth are always held in one common line, wherever those points
happen to be carried by the rotation of this heaven.
Again, it is necessary for you to conceive in this heaven, first, two
great circles, bisecting each other at right angles in the centers of these
two magnets. One of these circles, passing through the first point of
Aries and Libra in the ecliptic, is called equinoctial colure: the other
circle, passing consequently between the first point of Cancer and
Capricorn, is called solstitial colure. Beneath these are likewise imagined
many other great circles, in the centers of the magnets dividing crosswise
in the shape of an "X." But if, receding from these magnets, you describe
circles (parallel to each other and ever greater and greater, up to the
greatest circle which you will perceive is called the equator), equidistant
from each magnet and obliquely splitting the ecliptic in the equinoctial
colure, you can then behold a great, new, woven net in this heaven of the
Primum Mobile. This net most beautifully expands to extract the straight
ascent and descent of the stars, etc., from the vast ocean of the heavens,
catching the straight ascent in the greatest circles and, in other unequal
circles, parallel to each other and obliquely cutting across, most safely
catching the descent.

GLOSSARY
Anomolia or anomaly, is the angular distance of a planet from its
perihelion (that point of the orbit of a planet which is nearest to the sun) as
seen from the sun.
Aequinoctium or the equinox, is the time in which days and nights are
equal in the space of hours. There are two equinoxes: the spring equinox—c. 8
calends of April in the sign of Aries; and the fall equinox—c. 10 calends of
October in the sign of Libra.
Aeras is derived from aera, aerae, which originally meant a given
number, usually used in regard to money. The word was later extended to
mean a number used in any calculation, and finally it came to mean a certain
time from which subsequent times were counted, e.g., Anno Domini, after the
Birth of Christ.

Coluri or the Colures, which are two circles in the heavenly sphere,
passing through the poles of the world and cutting each other at right angles:
the one passes through the equinoctial points of Aries and Libra and is called
Colurus Aequinoctiorum or equinoctial colure; the other touches the
solstitialia of Cancer and Capricorn and is called Colurus Solstitiorum or
solstitial colure. They are called Colurus, which is translated as "mutilated
tails," for the part which emerges in the Antarctic is not visible and is
quasitruncated.
Ecliptica or the ecliptic, is an imaginary line in the heavens in which the
sun was supposed to have performed its annual course.
Epicyclus or epicycle, is a small orb which, being fixed in the deferent of a
planet, is carried along with its motion and yet, with its own peculiar motion,
carries the body of the planet fastened to it round about its proper center.
Iris or the rainbow. In mythology, Iris was the daughter of Thaumatis and
Electra, messenger of Juno of the goddesses and Jove of the gods.
Solstitium or the solstice, is that time when the sun seems to stand still for
a short time: when the sign of Cancer enters the month of June (equivalent to
the summer solstice, when the sun begins to recede from us); and when the
sign of Capricorn enters the month of December (equivalent to the winter
solstice, when the sun begins to accede to us).

Immediately below the Primum Mobile place the heaven of the fixed
stars (and, that the idea might be clearer), revolving separately on the
same poles on which the Primum Mobile revolves. Through this heaven,
the filaments of the little nets, etc., seem to the eyes of you on earth as if
they shine. In this heaven, you should conceive in their fixed places, the
fixed stars, a proportionate, inviolable distance from each other, and,
indeed, if you will, the heavenly images, etc., depicted, and all carried
along at the same time with their heaven by one motion.
Conceive a straight line running from the center of the earth to that
sign "o" noted in the semicircle of the supreme immobile heaven. On this
line, greatly below the heaven of the fixed stars, place the center of the
solar epicycle, holding an area in common with the ecliptic and subject
to absolutely no motions, but at such a distance from the center of the
earth that the semidiameter of the earth has little, if any, proportion with
the distance of the solar epicycle from the earth. Around the sun, moving
continually in this epicycle (its immobile palace) through the degrees of
the anomaly, you can revolve, with motions proportionate to the system,
the five planets: Mercury and Venus (the nearest barons of the sun), then
Mars, Jupiter and, most remote, Saturn, with its respective satellites, etc.,

eccentrically surrounding the earth itself and the moon in their immense
ambit and wandering by their proper motions through the zodiac.
Nevertheless, not far from the earth you should imagine fabricated,
as from most refined crystal, the heaven of the moon everywhere
equidistant from the center of the earth and revolving separately on the
same poles (prolonged even to this place) on which the Primum Mobile
and the heaven of the fixed stars revolve. In the middle of this, that is, in
some point equally removed from the poles, you place the center of the
lunar epicycle, movable also by the common rotation of the lunar
heaven. I refrain from the other movements of the moon in latitude, etc.,
as also those of the five planets, etc., which the theory in no way
excludes, lest by a variety of congested motions explained too
abundantly, either you might be confused about the fundamental concept
of the system or, while adorning the theory and trying to embellish the
least things more widely, you might reject also the things which are
capital.
Here you already have the whole machine, but still inert and to be
animated for the first time by motions accommodated to the system.
Nevertheless, before I assign motion to the individual parts of the world,
so that the thing might later appear more clearly to you, I arrange all
things thus: first, as if by hand, I turn the Primum Mobile until the
Boreal magnetic point comes to the level or the area of the semicircle
described in the supreme immobile convexity; then I turn the heaven of
the fixed stars until, for example, the heel of Castor (a star of the third
magnitude), almost in the ecliptic and indeed in our time not far distant
from the solstitial colure, likewise falls nearly at the level of the
aforesaid semicircle. Later, I turn the lunar heaven until I bring the center
of the lunar epicycle to the same level. Then, I turn the earth until some
predetermined city, for example, Trent, situated in the northern zone with
a latitude of about forty-six degrees, is brought to the oft-mentioned
level.
From things arranged in this way and from what has gone before, it
is evident (with the motions of the luminaries in epicycles left out,
however, lest you be distracted by the explanation) that at Trent, just as
in the whole northern hemisphere, it is the summer solstice; and,
conversely, in the southern hemisphere, it is the winter solstice. The
reason is because the northern magnetic point together with the northern
half of the earthly axis is at its highest point towards the sun, immovably
residing in a line sent through the level of the highest semicircle; and,
conversely, the southern magnetic point with the corresponding half of
the axis is most removed from the same. It further follows, that noonday
and the new moon coincide, and the heel of Castor almost reaches the
summit, etc.

Now, beginning from this hypothetical situation of the whole world
as from the root of the motions, I move all things in their circles so that
the earth turns on its axis with a revolving motion from west to east in
each 24 hours of median time. The lunar heaven completes one circle
around its poles likewise from west to east in the time of 29 terrestrial
revolutions, hours 12.44.3.13.1. The sphere of the fixed stars on the same
poles revolves once from east to west within 365 revolutions of the
earth, hours 6.9.29.1. The Primum Mobile on the poles (common to the
heaven of the fixed stars and the heaven of the moon), is moved once in
the same way from east to west, a little faster, however, than the heaven
of the fixed stars, yet within 365 revolutions of the earth, hours 5.48.56;
that is, within a median astronomical year.
Now, behold for yourself a new world supported on new poles and
provided with new motions and laws. Now you, reader and lover of the
stars, turn it, and revolve it as long as it pleases you, and compare it
astronomically and physically with the Copernican or the Tychonian
systems or with whatever one pleases you more, and judge which one
seems more consonant with nature when all things are examined. But if
you aren't able to reconcile this theory with some astronomical
observations or physical experiments and think it should be eliminated
from the group of theories, see that I might know this while life is still
my companion, so that I might think with you, if this is possible. Also, so
that, in gratitude for the detected or perhaps hidden error, I might speak
or write, and you won't have to shout in vain in bold ridicule and with no
applause after the fleeing shades of the dead and the mute ashes. But, if
you object that the daily motion of the revolving earth and the annual
motion of its whirling axis do not sufficiently agree with certain texts of
Sacred Scripture, and if those things which the Copernicans and the
Longomontanists say do not convince you, then reject my whole system
as an old wives' tale.

Last Years
There is a break in the story of Borghesi and Bertolla for the next five years. The
second clock may have been the last project on which the priest and the clockmaker
worked together, for very good reasons. The two clocks must have represented a
considerable financial investment in materials and in time, and neither of the men was in
sufficiently affluent circumstances to undertake the luxury of such a hobby without some
form of recompense. The publication of the two little volumes must have also been done at
Father Borghesi's expense. The income of the parish priest in a small mountain village
could not have been equal to the relatively great costs of the projects that had been
completed. It seems probable that the priest attempted to sell his clocks to a wealthy patron,

perhaps the Baron of Cles, or he may have attempted to obtain some form of recompense
for the continuation of his research. However, no records can be found of such patronage if
it existed. If Borghesi had received financial assistance while the projects were in progress,
he would certainly have made adequate mention of the patron's name and assistance in one
or the other of the two volumes which he published. [17]
The next record relating to Borghesi which has been found is the description of a letter
written by an anonymous mathematician late in 1768 or early in 1769. It was 28 pages in
length, written in Latin, in the form of a reply to the writer's brother, on the subject of the
clock invented by Borghesi. It consisted primarily of a criticism launched against
Borghesi's first little volume published in 1763.
The anonymous letter is without date, place, or signature. This writer claimed that
Father Borghesi had made many errors in his book, presumably in the description of the
clock's functions, and in the basic theories upon which the priest had predicated his
research. No complete copy of the letter's text has been found for study, although it is
described at length in Tovazzi's Biblioteca Tirolese. Tovazzi noted that four copies of the
letter existed at that time, and that he personally had filed one in the Biblioteca di Cles in
Trent. However, every attempt to locate a copy at the present time has been unsuccessful.
If the anonymous letter was brought to the attention of Father Borghesi, it must have
introduced a disturbing note into his life and cost the priest many unhappy moments. He
was not, however, dissuaded from his preoccupation with horology. Several years later, in
1773, Father Borghesi was working on yet another astronomical clock, this time
presumably without the assistance of Bertolla. This third clock was reported by Tovazzi to
have been "of minimum expense but of maximum ingenuity."
No subsequent information relating to it has come to light, and there is no record that it
was actually completed.
Again there is a period of silence in the life of Father Borghesi which no amount of
research has yet been able to pierce. Whatever the circumstances may have been, it is
reported by several of the sources noted that both the first and the second clock did, in fact,
become the property of the Empress Maria Theresa in Vienna. The presentation was made
sometime during the period between the completion of the second clock in 1764 and the
year 1780. There is some discrepancy in the contemporary accounts as to whether Father
Borghesi presented one or two clocks to the Empress, but all the sources with but one
exception record that both clocks were acquired by the Empress.
It is doubtful that Father Borghesi had originally intended to give his clocks to the
Empress at the time that they were made, for he would most certainly have made some
mention of such an intention in the two little volumes which he published about them. If he
saw the letter published by the anonymous mathematician in late 1768 or 1769, it is
possible that he decided to make the presentation in expiation of his sense of guilt for the
amount of his time which the creation of the timepieces had consumed. On the other hand,
it is just as possible that Father Borghesi may have forwarded copies of his two little

volumes to the Imperial Court at Vienna, and that the Empress expressed a desire to
acquire the clocks.
Father Tovazzi states that in 1780 "the clock invented by him [Borghesi] was preserved
in Vienna, Austria, at the Imperial Court from which the inventor was receiving an annual
pension of 400 florins." No records in the Palace archives relating to the clock have yet
been found, nor records of payment of an annuity to Father Borghesi. However, a more
exhaustive investigation of the Furniture Depository of the Imperial Court may bring forth
related records. It was the implication in Father Tovazzi's account that the second clock had
been presented to the Empress prior to the publication of the anonymous, critical letter in
1768 or 1769. He believed that it was envy of Father Borghesi's ingenuity, fame and
financial benefit that had caused the anonymous mathematician to publish his letter, for
Tovazzi asked "Who would have encountered opposition to such a marvel? Envy is not yet
dead, and has always reigned."
This last-mentioned theory about the presentation may be the most likely one. Some
evidence may be found in the second clock itself which bears out this assumption. The
multiple chapter ring, with its many inscriptions, is engraved and silvered in a relatively
crude manner, presumably by Bertolla himself. The main dial plate, however, which is of
gilt brass, is engraved with the utmost skill by one of the great masters of the art. The
inscription below the Imperial Hapsburg eagle relates to Francis I, Emperor of the Holy
Roman Empire. It is entirely possible that although Father Borghesi originally had no
intention of giving the clock to the Emperor or the Empress at the time that it was made, he
later changed his mind. Accordingly, he may have commissioned a master engraver,
possibly in Trent or in Vienna itself, to produce a dial plate which would be of such a
quality as to be worthy of the Emperor himself. If so, this was done shortly after the clock
was completed, for the Emperor died in August of the following year. Perhaps by the time
that the clock was ready, the Emperor had already died, and Father Borghesi gave the clock
instead to Maria Theresa without revising the inscription.
The acceptance of the clocks by the Empress, and the annuity which was his reward,
would have constituted considerable honor even for one of the foremost clockmakers of the
Empire, but for a humble parish priest in a little village, such notable Imperial recognition
was overwhelming. Possibly as a result of it, a change was noted in Father Borghesi in the
next few years. His conscience began to bother him, and he began to question whether he
had done right in spending so much of his time and thought on his horological research. He
became more and more confused in his own mind. Had he spent too much time in
mechanical studies to the neglect of his ecclesiastical duties? If this had been the case, he
had committed the most grievous sin.
Exaggerated though these thoughts may appear, they were undoubtedly of the most
critical importance to the middle-aged priest. His mental turbulence and confusion
increased daily, and it soon became apparent to others around him. By June 1779, he was
completely in the grip of his obsession, and his parishioners began to whisper amongst
themselves that their pastor was being tortured by the devil. They were unable to help him,

and he became more and more preoccupied with his problem. The years passed slowly as
the pastor became more vague and more tortured by his conscience. [18]
There probably was continued contact between Father Borghesi and Bertolla for at least
some time after the development of his illness. Bertolla had retired from active work, but
continued to pursue his interests in his clockshop as much as his health and advanced years
permitted. A clock which he made at the age of 80 survives and is described and illustrated
in the following section on "The Clocks of Bartolomeo Antonio Bertolla." Finally, on
January 15, 1789, Bertolla passed away and Father Borghesi was left alone, deprived of the
companionship he had enjoyed with the older man for the past two or three decades. One of
Bertolla's nephews continued to work in the master clockmaker's workshop, but there did
not appear to be any association between the younger man and Father Borghesi.
At last, in 1794, Father Borghesi lost his sanity completely, and he was forced to
relinquish his pastoral duties to a curate. For the remaining eight years of his life, he
continued to live in the rectory of the little parish church in Mechel where most of his life
had been spent, his needs undoubtedly attended by the parishioners he could no longer
serve. During this period, until his death at the age of 79 on June 12, 1802, Father Borghesi
lived on, oblivious of those around him. Seemingly, he retired to another world; perhaps to
that universe which he had tried to reproduce in his second clock.

The Clocks of Bartolomeo Antonio Bertolla
The ingenuity displayed in the Borghesi clock by its constructor, Bartolomeo Antonio
Bertolla, requires a consideration of the other examples of his work that have survived. The
most important of his clocks are probably the one in the Episcopal Palace at Trent and
another made for the Baron of Cles.
The one which survives in the Episcopal Palace to the present time, is extremely tall
and is housed in an elaborately decorated narrow case of black or ebonized wood
approximately 9 to 10 feet in height. The upper part of the case is decorated with
elaborately carved and gilt rococo motifs. The movement operates for one year at a
winding, indicates and strikes the hours, and shows the lunar phases. It has an alarm, and
will repeat the strike at will, indicating the number of the past hour and the quarters. The
gilt brass dial is decorated with silver-foliated scrollwork in relief at the corners, inside the
chapter ring, and within the broken arch. Featured above the chapter ring is the coat of
arms, executed in silver, of the patron for whom the clock was made, Cristoforo Sizzo di
Noris. Di Noris was Bishop of Trent for 13 years, from 1763 to 1776.
The clock which Bertolla made for the Baron of Cles is a tall, narrow, case clock of
ebony or ebonized pearwood which is approximately 91/2 feet in height. The decoration of
the case is considerably more conservative than the one made for Di Noris, but the black
wood is decorated with silver trim and carved designs in the wood itself. The dial is
decorated with silver scrollwork and spandrels within and around a raised chapter ring. The

clock operates for one month at each winding, has
an alarm, indicates and strikes the hours, and will
repeat the quarters. This handsome timepiece is
still in the possession of the descendants of the
Baron of Cles.

According to Pippa, [19] certain characteristics
become apparent in a study of the surviving clocks
by Bertolla. The tall-case clocks are narrow and
range in height from 73/4 feet to 101/2 feet. The
cases had this excessive height in order to obtain
the greatest fall for the month and year movements
which Bertolla constructed. For the weight
assembly, he substituted a drum wound with a key
at the point of the driving wheel in place of the
customary pulley. The addition of an intermediate
wheel augmented the drop of the weight.

Figure 21.—Tall-case clock by Bertolla in
the Episcopal Palace in Trent, made for Bishop
Cristoforo Sizzo di Noris. A striking and
repeating clock with lunar phases. (Courtesy of
Museo Nazionale della Scienza e della Tecnica,
Milan.)

Figure 22.—Interior of Bertolla's workshop, showing detail of ceiling. (Courtesy Museo
Nazionale della Scienza e della Tecnica, Milan.)

Figure 23.—Interior of Bertolla's workshop, showing the main workbench and the
collection of clockmakers' tools. (Courtesy of Museo Nazionale della Scienza e della Tecnica,
Milan.)

Figure 24.—Fusee cutter used by Bertolla. Now in the
collection of the Museo Nazionale della Scienza e della
Tecnica, Milan.

Figure 25.—Interior of Bertolla's workshop, showing details of paneling and floor case
with Bertolla manuscripts. (Courtesy of Museo Nazionale della Scienza e della Tecnica, Milan.)

Bertolla's movements were solidly constructed from well-hammered brass and iron. He
favored the recoil anchor escapement in his clocks and the Graham dead-beat anchor
escapement with a seconds' pendulum. The escapement was not always placed in the
traditional location in the upper center between the plates. Bertolla occasionally displaced
the pendulum to one side, to the lower part of the movement or placed it entirely between
two other small plates. [20]
He utilized every type of striking work, including the music-box cylinder common in
the clocks of the Black Forest and the rack and snail. Bertolla most frequently employed
the hour strike and grand sonnerie. He often used a single hammer on two bells of different
sound with the rack and snail. An example of this type is the clock he produced at the age
of 80. To achieve the necessary axis of rotation for the hammer, which is perpendicular to
the plate when it strikes the hours, it moves to an oblique position and displaces one of the
two long pins in an elongated opening.
Bertolla's dial plates were generally well executed, with a raised or separate chapter
ring applied to a brass or copper plate, such as a copper-plate repoussé and gilt with
baroque motifs, or upon a smooth brass plate with spandrels of repoussé work usually of
silver, in relief and attached. The engraving of the chapter rings was excellent. The hands
were well executed in steel or perforated bronze, and occasionally of repoussé copper; gilt
was applied to the hands made of forged steel.

Figure 27.—Movement of a brass lantern
Figure 26.—Dial plate of a brass lantern clock made by Bertolla. (Courtesy of Museo
clock made by Bertolla, found in his workshop Nazionale della Scienza e della Tecnica, Milan.)
after his death. (Courtesy of Museo Nazionale
della Scienza e della Tecnica, Milan.)

In the course of time, Bertolla's home workshop passed from one generation to another
within the family. Inevitably, it underwent many modifications until the only original part
of the building that remained intact from Bertolla's time was his clockshop.
Within the last few years, the workshop room was acquired complete with contents
from Bertolla's descendants, and installed in the Museo Nazionale della Scienza e della
Tecnica in Milan as an exhibit of a typical 18th-century clockmaker's shop. The original
workshop was dismantled in Mocenigo di Rumo and completely rebuilt in the museum,
including the walls, ceiling and floor. The paneling and woodwork of the walls and ceiling,
which have been preserved intact, are hand-cut fir, with columns, trim and moldings carved
by hand. A small painting is featured in the center of the coffered ceiling. The original shop
benches and chests of drawers are set around the reconstructed shop and Bertolla's tools
and equipment laid out as they had been originally. Other clockmaker's tools and
equipment in the museum's collection are also displayed. Approximately 40 percent of the
tools are the original items from Bertolla's shop. Parts of clocks and works in progress are
on view on the benches as they were in Bertolla's time. [21] Also preserved in the museum
are sketches found in Bertolla's manuscripts, some of which are reproduced on the
following pages.

Figure 28.—Detail of wall of Bertolla's workshop, with
regulatory clock made by his nephew, Alessandro Bertolla of
Venice. Note wheel layouts, etc., scribed in the paneling.
(Courtesy of Museo Nazionale della Scienza e della Tecnica,
Milan.)

Figure 29.—Table clock by Bertolla in the collection of
Doctor Vittorio dal Lago of Bergamo. The dial indicates the
days of the week and of the month, the names of the months
and lunar phases. The clock strikes the hours and quarters
and repeats. (Courtesy of Sig. Luigi Pippa of Milan.)

The shop contains two completed clocks made by Bertolla. One is a weight-driven
lantern clock typical of the 18th century, Italian style with brass dial, plates and posts,
anchor escapement, and striking work. The dial is engraved in the usual style of Bertolla's
baroque design, and the hands are of pierced bronze. Another clock associated with
Bertolla and found in the shop, was made by his nephew, Alessandro Bertolla, who worked
in Venice after his apprenticeship with his uncle had been completed. This clock is a
regulator with a seconds' pendulum and sweep hand on an enameled dial. The original case
has not survived.

Figure 30.—Layout of the wheelwork of a clock made by
Bertolla for His Excellency Paulo Dona, inscribed "Design No.
1." (Courtesy of Museo Nazionale della Scienza e della Tecnica,
Milan.)

Figure 31.—Pendulum arrangement sketch for an
unidentified clock found in Bertolla's workshop. (Courtesy of
Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 32.—Striking clock sketch found in Bertolla's
manuscripts. (Courtesy of Museo Nazionale della Scienza e
della Tecnica, Milan.)

Figure 33.—Fifteen-day striking clock sketch, inscribed
"Design No. 3," found in Bertolla's workshop. (Courtesy of
Museo Nazionale della Scienza e della Tecnica, Milan.)

Figure 34.—Dial plate of a brass lantern
clock made by Bertolla at the age of 80.
(Courtesy of Museo Nazionale della Scienza e
della Tecnica, Milan.)

Figure 35.—Movement of brass lantern clock
produced by Bertolla at the age of 80, showing
details of movement and double bell. (Courtesy
of Museo Nazionale della Scienza e della
Tecnica, Milan.)

One of the most interesting of Bertolla's clocks, and probably the last one which he
produced, was found in his workshop. This timepiece indicates the hours, minutes and
quarters by means of a single hand or index. The weight-driven clock strikes the hours and
quarters on two bells with a single hammer. The chapter ring, which is soldered to the dial
plate, is marked for the minutes on the outer rim and for the four quarters inside it. Over
the center of it, is a semicircular opening in the dial plate through which is visible a
revolving disk attached behind the dial plate. This disk is marked with the hours and
revolves from right to left, the current hour being indicated by a projection from the minute
ring. The brass dial plate is engraved with simple floral designs in the corners and around
the broken arch. There is no comparison between this crude and simple decoration and the
extremely fine quality of the engraving on the dial plate of the Borghesi clock, for instance.
In the center of the dial plate is engraved the following:

"Questo orologio l'ideai e lo feci nella mia avanzata età d'anni 80.
Barto Anto Bertolla"
(I designed and made this clock at my advanced age of 80 years.
Bartolomeo Antonio Bertolla.)
FOOTNOTES
[1]
Borghesi, Novissimum Theorico-Practicum Astronomicum Authoma Juxta Pariter Novissimum Mundi
Systema…, pp. 8-9.
[2]
Wenham, "Tall Case Clocks," p. 33.
[3]
Von Bertele, "The Development of Equation Clocks," parts 1 through 5.
[4]
Engelmann, Philipp Matthäus Hahn; Vischer, Beschreibung mechanischer Kunstwerke….
[5]
Lloyd, Some Outstanding Clocks Over Seven Hundred Years, 1250-1950, pp. 116, 118, 120.
[6]
San Cajetano, Praktische Anleitung für Künstler….
[7]
Franch, La Valle di Non.
[8]
Bonomi, Naturalisti, Medici e Tecnici Trentini, p. 16
[9]
Ambrosi, Scrittori ed Artisti Trentini, pp. 132, 525.
[10]
Ibid.
[11]
Pippa, "Antonio Bartolomeo Bertolla," pp. 22-23.
[12]
Ibid., p. 22.
[13]
Ibid., p. 23.
[14]
The abbreviation in the inscription "pLan" is difficult to interpret. According to Father F. X. Winters, S.J.,
it may represent "sit planetis" or "sit planetarum." The use of an abbreviation was necessary to prevent
the addition of another letter I or M, which would have disturbed the formation of the chronogram
desired. Literally, "sit planetis" means "May he be eternal ruler by [or through] favor of the planets,"
while "sit planetarum" is to be translated "May he be eternal ruler of the planets." Father Winters
considered both versions somewhat overexaggerated and proposed that the best translation might be
"Long Live Francis I, Emperor."
[15]
The word "Tempe" refers to the Vale of Tempe, in Thessaly, through which the Peneus River flows. It is
between Mounts Olympus and Ossa, and is situated between the town of Larissa and the sea. In
mythology, it is told that these mounts were originally joined and Hercules separated them to allow the
river to pass between them. The word "Tempe" is also used to mean any pleasant place. Thus, the
inscription "Tempe indesinenter clausa, Scaturigo signata" is literally translated "Tempe always closed,
A fount of water sealed up" or, freely translated, as "A garden enclosed, a fountain sealed up."
[16]
"Phoebi" or Phoebus, called Apollo, the sun god; Phoebes or Diana, the moon goddess, sister of Apollo.
[17]
Pippa, op. cit. (footnote 11), pp. 23-25.
[18]
Perini, Statistica del Trentino, Biblioteca Communale del Trentino, vol. 2, p. 57 (cons. 6, carta 9);
Tovazzi, Biblioteca Tirolese, pp. 406-407.
[19]
Pippa, op. cit. (footnote 11), pp. 24-25.
[20]
Piamonte, La Nauna Descritta al Viaggiattore.
[21]
Esposti, "La Sala 'Innocente Binda' al Museo della Scienza e della Tecnica di Milano," pp. 18-21.

Appendix

SYNOPSIS OF THE COMPLETE
MECHANICAL WORKS OF THE FIRST
CLOCK
[Translated from the section entitled "Synopsis Totius Operis
Mechanici" in Francesco Borghesi's first book Novissima Ac Perpetua
Astronomica Ephemeris Authomatica Theorico-Practica….]

I
Of three movable indices, the farthest from the center of the dial is fitted with an index
on either side and marked with four segments of a circle. Immediately below are five
numbers, divided into the days of setting the measure of the mean-synodic age of the
moon, and into signs, degrees of the signs, and of the distance of the moon from the sun.
These, in each revolution, revolve once around the solar disk superimposed on the mean
synodic-lunar disk, and also around the lunar disk. The upper indices, meanwhile, in the
two external greatest orbits, measure the time continuously, in the accustomed manner of
the Germans—the middle index measuring by hours and the uppermost by the first minutes
[of hours].

II
Inside these three circles, perpendicular above their center, is a small index of the
seconds of minutes. At each first minute of time, being the fastest of all, it describes the
smallest orbit. Next to this are two other slightly larger circles divided into 30 degrees, one
[rotating?] from the right, the other from the left. These two indices are arranged in such a
fashion that the one rotating from the observer's left completes its period 12 times during
one, mean, solar-astronomical year. The one [rotating] from the right likewise completes its
cycle 12 times during the period of one mean-synodic moon. In between these, there is
placed another small sphere, divided into 40 arbitrary parts, whose dial does not move
automatically, but is moved by hand for speeding up or slowing down the course of the
time, or of the perpendicular.

III
Diagonally from the sides of the center of the three larger indices, six other indices
revolve: three on the left from one center, and three on the right from another. The
uppermost of the three which are on the right of the observer [and which are] decorated
with a small disk of the sun, runs its cycle once during a mean solar-astronomical year. The
second measures the distance of the sun from its apogee. The third revolves 12 times, with
each lunar revolution from one node to the same [repeated] node. Under the point of the
uppermost index, first lie the months of the year which are inscribed, and the days of each
month, but having only 28 days assigned to February; then the signs of the zodiac, and
their several degrees. The circle corresponding to the middle index, extending through the
first semicircle from apogee to the lower perigee and returning through the second
semicircle to the upper locations of apogee, shows the true equation or eccentricity of the
sun, joined with the little equation of the moon in syzygy. [These equations are] measured
by geometric-astronomic proportion for each distance of the sun from its apogee or perigee
in degrees, and in sufficiently small parts of degrees, with the title added above in their
proper places, whether an addition is to be made to the mean location of the sun or a
subtraction from the same, so that the true longitude of the sun may be calculated. Three
circles are assigned to the lowest index, of which 30 degrees of distance of the moon from
its nodes comprise the larger. The middle circle is based on the hypothesis of the mean
invariable diameters (that is, of the sun, the moon, and the terrestrial shadow), and is
divided into hours and quarters of duration. The last circle is divided by the trigonometric
laws into the inches of magnitude of lunar eclipses. Lying between these circles, there is
another eccentric circle (black with a spot) exhibiting the shadow of the earth, in which the
little moon sinks itself, carried by the lowest index. In any ecliptic full moons, the patent
number of inches of immersion somehow affects the minds of the cultured, but also the
scheme of maximum obscuration affects the eyes of the illiterate themselves.

IV
Of the three indices which revolve from the left, the uppermost completes its cycle
within 12 hours, just as the hour index. The middle one with two pointers on diametrically
opposite sides, carries the marks of conjunction and opposition of the luminous bodies,
with a movement equal to the course of the sun from lunar apogee or perigee. The lowest
index, fitted with a single pointer, indicates the motion of the moon from its apogee or
perigee. Under these three indices, there is situated a common circle, divided into 12 parts,
each of which are further divided into 30 parts through its outer circumference. I have said
a common circle, for, with respect to the first index, the division represents 12 hours, and
the double subdivision representing the double set of minutes of the hours serves for an
excitator for anytime at all, at will. For as often as the little index reaches the twelfth hour,
first being moved by hand wherever you prefer, a little hammer strikes the little bell many
times. But if you observe the second or the third index, the first division provides the signs,
and the subdivision of the signs gives the individual degrees of the distance of the sun from

the lunar apogee, or of the moon from its apogee, respectively. To this is added two other
interior circles from the same center: to the larger is inserted the equation of the center of
the moon in its conjunctions and oppositions; and on the smaller the equation of the same
moon in its quarters, astronomically-geometrically proportioned to the distance of the
moon from its apogee or perigee. In the first case, the equation is to be subtracted from the
mean longitude of the moon, descending from apogee to perigee; in the second case, to be
added to the mean longitude of the moon ascending from perigee to apogee; and, in the
third semicircle of the index, as the rubric directs, common to both equations, added around
the center.

V
Perpendicularly under the center of the machine, two other indices are carried about
one and the same center. The one nearer to the observer—bearing in one of two points
diametrically opposite the small disk of the sun, in the other the disk of the moon—runs a
course equal to the motion of the sun from the head or the tail of the dragon (Draco). The
other, of simple construction, marked with a small moon, signifies in like manner the
motion of the moon from the head or the tail of the dragon.
Immediately below, there is a larger circle, common [referring] to both these indices,
which is divided into 12 parts. Each of these parts in turn, in the outer periphery, is
subdivided further into 30 parts, which are the 12 signs of the zodiac and the individual
degrees of the signs of distance of the sun and the moon from the head of the dragon.
In the second circle is read the latitude of the moon, measured by degrees, etc., on a
trigonometric scale, by signs and degrees of distance of the moon from its nodes, that is,
from the head or tail of the dragon. When the second index is descending from the head of
the dragon to the tail, the latitude will be to the north of the solar path; that is, the ecliptic.
On the other hand, it will be south of the ecliptic when the same index is returning upward
from the tail to the head of the dragon as advised by the title inscribed on the third circle.
Finally, on the fourth and last circle are seen more prime minutes of the circle for
reducing the orbit of the moon to the ecliptic. That the true longitude of the moon may be
obtained more accurately, these must be subtracted from the longitude of the moon already
calculated in the first and third quadrant of the circle of the second index. On the other
hand, they are to be added to the same in the second and fourth quadrant, as is noted in
their respective places, according to the theory of right ascensions.
Here, then, [you have] as finally completed, delineation of the great index which was
partially described before in this book.
From two points of that index which perpendicularly correspond to the center of these
circles, a pair of compasses, by an unvaried aperture up to the circumference of the first
larger circle, has marked off four segments of a circle. The two larger segments, equal
among themselves, in one aperture refer to the sun, and the two smaller in the other,
likewise equal, refer to the moon. The one pointer is for determining the solar eclipses; the

other, for lunar. Both segments of each division, like little wings of the index, stretch to the
extent of the degree of distance of the moon from its nodes, and to which that determined
latitude corresponds. On one side, that latitude precisely equals the radii of the earth, the
sun, and the moon, as the termini of solar eclipses; and, on the other side, precisely equals
the radii of the earth's shadow and of the moon, as the confines of lunar eclipses. The
apexes of the last index, diametrically limited [opposite], indicate the age of the moon, and
its mean distance from the sun; one pointer, upon which the sun sits, measuring the mean
days and degrees from the full moon; the other, on which the moon sits, measuring the
mean days and degrees from the new moon.

VI
Besides the larger and smaller indices already mentioned, all [of which] revolve within
the periphery of the three largest circles, six dials in this clock also revolve within the same
circles which are to be seen through six openings of the frontispiece. The first of these,
intended to indicate the phases of the moon by an unusual method (completely black, and
decorated with the characters of the principal aspects of the moon) continually revolves
interiorly around the center of the machine and at the new moon, it completely removes
from sight the face of the moon through the round window. It continually recedes through
the first half of the circle until, at the time of the full moon, it restores the moon, looking
out with a full star. Soon again, too slow to be observed, it returns through the other half of
the circle, so that in the next conjunction, the whole face of the moon may have a covering
of darkness, once again to be removed.
The other dials are moved by spontaneous advances at stated times. The first of these
shows, through a square opening, the day of the month; the second, through another
opening, shows the current day of the week with the characters of the seven planets which,
according to ancient superstition, preside over each day of the week (now, by a truer form
of religion divided by the Church into ferias, etc.); that is, the sun, the moon, Mars,
Mercury, Jupiter, Venus and Saturn, to which I have added the numbers of the ferias. These
two little dials are advanced daily, by a sudden movement at midnight. The remaining three
are changed automatically only once a year on the first of January.
The first of these dials contains five little cells, opening from a common window: in the
first cell, at the edge of the dial, is found the dominical letter; in the second, the cycle of the
sun; in the third, the character; in the fourth, the sign; and, in the fifth, the house of the
planet dominating the year. The second dial shows the epacts, with the golden number. The
third, and last of all, shows the Roman cycle.
Finally, as indicated by the epact and the dominical letter in an immovable table added
outside, are the feastdays and other movable events of the year; that is, Easter, the four
seasons, the Rogation Days, etc.

VII

But lest the various movements of the indices and the various beginnings of the
divisions tend to cause some fatigue, the precaution has been taken, that all the indices by
common law are moved from the top towards the right of the observer, and from thence all
the arithmetic divisions of the circles take their beginning. And lest the multitude of
different figures should deceive the eye, the larger divisions of the circles have been
marked by Roman numbers, that is, by capital letters of the alphabet; others, in other
places, by differently colored numbers. Thus, the movements of the indices, the distribution
of the circles and the multitude of numbers not only do not disturb the eyes and the mind,
but rather marvelously delight them.

VIII
After having completed briefly the description of the dial and the indices and their
motions, I have not without reason delayed in satisfying the desires of many who wish to
learn at least the method by which, from this mechanism, may be calculated the true times
of new and full moons, and their ecliptics. In order to make these matters clearer, it is
necessary that they be explained here at greater length.
With the indices, then, adjusted astronomically-geographically to the longitude of any
given region, and to the mean time whether past, present or future, and assuming the clock
to be in normal operation (as at present it has been for a whole year and more), then the
moon will be in conjunction with the sun in the heavens. When the equations on the
mechanism are examined, the sun and moon shall be found to be in the same degree of
longitude, and in the same part of a degree. There will also be an ecliptic new moon that is
in conjunction with a solar eclipse, or rather with a terrestrial eclipse. This will occur if, at
that time, both apexes of the first index, located below the center of the clock, are hidden
by the two segments of the circle extending from the center of the mechanism through the
lowest index.
And the eclipse will be greater and greater and, consequently, visible in more regions of
the earth, the more deeply the two pointers, indicating the distance of the sun from its
apogee, are hidden in the center of the segments.
But whether the eclipse takes place in the head or in the tail of the dragon, or whether it
is north or south, is indicated by the small disk of the sun attached to one of the two
pointers hidden by the segments of the circle. If, at that time, the little disk shall be found
in the head of the dragon inscribed on the plane of the dial, then the sun has been snatched
from the earth and ingloriously entombed, as it were, in the huge jaw of the dragon. Then,
… the heavens themselves will lend aid to the woeful pomp of the senseless funeral in full
darkness by suddenly lighting the unhappy lamps of the fixed stars. However, if the little
disk occupies the tail of the dragon on the mechanism, then the sun in the heavens also, as
if freed from the toils of the immense dragon's tail, will emerge without difficulty.
The center of the eclipse will traverse the hemisphere of the earth north of the solar
path, always nearer to the pole of the ecliptic, in proportion to the inclination of the disk to

the north. On the other hand, if the little disk inclines to the left semicircle, then the people
south of the solar path will enjoy the spectacle of the total central eclipse.
But if the little disk remains neutral (inclining neither way) and remains halfway
between the two sections of the circle, then the greatest solar eclipse will take place at the
equator and those who live near the poles of the ecliptic will not enjoy a trace of that
eclipse. This is because the half of the equatorial diameter enormously outmeasures even
the greatest apparent semidiameters of the sun and of the moon, even taking as a norm the
smallest horizontal parallax of the moon.
What has been said about the true new moon is to be understood also, proportionately,
about the true full moon. For when, with respect to the equations of the centers, the moon
shall be distant on the mechanism by a full semicircle from the sun (also in the heavens it
will be truly in opposition to the sun) there will be a true full moon. Likewise, the moon in
the heavens will be in eclipse if, at the time of opposition, the pointers of the little index
(which we mentioned before) situated below the center of the clock are so far away from
the belly of the dragon that they are forced to lie under the two smaller segments of the
circle which, in all full moons, are always to be moved from the index of the synodic moon
to the region of that little index. As a matter of fact, the closer the little pointers approach to
the middle of the segments, the more obscured it will be.
You will know, furthermore, that the eclipse of the moon occurs in the head of the
dragon if the disk of the little moon, attached to the other point of the little index, is raised
to the head of the dragon; conversely, when the little disk of the moon inclines to the tail,
the eclipse is taking place in the tail of the dragon.
And, accordingly, when you observe the little moon of the index inclined to one or
other section of the circle, so also in the heavens, the eclipse of the moon is only partial and
the northern or the southern part of the moon is illuminated.
The current time will indicate whether the lunar eclipse is visible or not. As the new
moon ecliptic falls during the day, the eclipse will not be visible, since the earth denies a
sight of the moon which is below the horizon. But, conversely, if there are no clouds, the
eclipse will be visible anywhere, if the luminous bodies are ecliptically in opposition at
night.
Since lunar eclipses appear to all people as being of the same magnitude and duration,
and begin and dissipate at the same absolute moment of time, I decided to reveal another
facet of this spectacle on the right side of the center of the clock (see chapter III above).
There, at the time of the true ecliptic full moon, as the pointer of the third little index
shows, you can ascertain the hours, etc., of duration, and the inches of greatest obscuration.
The little moon attached to the index is a model of the actual eclipsed moon.

IX

Thus, with the aid of this machine, solar and lunar eclipses of the past can be recalled
and future ones can be foreseen. Indeed, if the index of prime minutes is speeded up by
hand, whose wheel imparts motion to the other indices and shields, then, the dials and
openings will foretell the year, month, day, hour, etc., of any future eclipse. I foresaw that
the times would thus be evolved too slowly, and that the clock wheels would be
considerably worn by repeated experiments (if, for instance, by the rotation of the index of
prime minutes, to whose period only a single hour corresponds, the future new and full
moon ecliptics were being investigated). Therefore, I took care that the wheel which
immediately communicates motion to the index of the synodic moon should be so fitted
internally to the mechanism that by the reversal of any external index, the wheel would be
removed from its proper position; whenever desired, it could be quickly and most
accurately restored to its proper place.
In this way, since the close meshing of the wheels is released, you can extend the
experiment for many years, even for many centuries. You have only to guide with your
hand the index of the synodic moon on the circles, always intently observing whether, in
the passage which this index makes over the little index, both pointers of the little index are
hidden by the segments of the circle. Having observed this, look at the index moved by
hand, for if this has carried the solar disk halfway between the two larger segments of the
circle to the region of the hidden little index, then you will know that eclipse will be a solar
eclipse. On the other hand, you will know that it will be a lunar eclipse, if the index (moved
by hand) has carried the moon, situated between the two smaller segments of the circle, to
the same region (i.e., the hidden part of the circle). The solar disk and the lunar disk
alternately will reveal to you the circumstances of both eclipses. The current year will be
given by the Julian period, reducible to any desired epoch, and, contained in the solar
cycle, the golden number and the Roman cycle. The month of the year and also the day of
the month will be indicated by the pointer of the little index, first on the right side of the
clock. And what I have said of future eclipses should be equally understood of past
eclipses, so long as the index, which can be moved either way at will, is moved in reverse.
Finally, though 55 wheels were employed to carry so many dials, all are driven by one
source of power not exceeding the third part of a Germanic hundred-weight which,
suspended at the geometric height of five feet (about the ordinary stature of a man), keeps
the whole machine in operation for a hundred days and more.
Although the machine repeats hours and quarter hours at will and, consequently, the
number of wheels and the rest of the apparatus necessary for these functions is thereby
increased, it has not grown to an unwieldy size, however much one might erroneously
imagine it to be. It does not exceed the bulk of ordinary clocks hanging from a wall;
indeed, it scarcely equals these.
The entire machine, ready for operation, does not weigh more than 156 ounces,
although it is made of steel or brass throughout and further weighted with two bells and a
rather large brass dial-plate.

Of course, there are many more things to be said, especially about the mechanical
structure of the wheels, but fearing to tire my kind reader unduly by exceeding the bounds
of a summary, I am forced to put an end, though unwillingly, to this sufficiently shortened
explanation of the work. I have hope of giving satisfaction to many more when I shall have
communicated to the learned world another and completely new automatic work, grander
than this present one. It is already theoretically completed in all its calculations, but still to
be worked out mechanically from the very beginning, if but God, thrice Best and Greatest,
bless the undertaking and mercifully grant life and health—to whom be in, and from, and
through all things, all honor and glory in eternity and beyond.

BIBLIOGRAPHY
The following works have been used in compiling the material for this paper. They are
frequently referred to in the text in shortened form.
Ambrosi, Francesco. Scrittori ed artisti Trentini. Trent: Giovanni
Zippel, 1883.
Bonomi, L. Naturalisti, medici e tecnici Trentini. Trent: privately
printed, 1930.
Borghesi, Francesco. Novissima ac Perpetua Astronomica
Ephemeris Authomatica Theorico-Practica. Trent: Giovanni Battista
Monauni, 1763(?).
—— Novissimum Theorico-Practicum Astronomicum Authoma Juxta
Pariter Novissimum Mundi Systema. Trent: Giovanni Battista Monauni,
1764.
Engelmann, Max. Philipp Matthäus Hahn. Berlin: Verlag Fischer,
1923.
Esposti, Alfredo degli. La sala 'Innocente Binda' al Museo della
Scienza e della Tecnica di Milano. La Clessidra (July 1960), anno 16,
no. 7, pp. 18-21.
Franch, Leone. La Valle di Non. Trent, 1953.
Lloyd, H. Alan. Some outstanding clocks over seven hundred years,
1250-1950. London: Leonard Hill, 1958.
Mosna, Ezio. Trento. Trent, 1914.

Perini, Agostino (compilatore). Statistica del Trentino, Biblioteca
Communale del Trentino. Vol. 2, p. 57 (cons. 6, carta 9).
Piamonte, Guiseppe. La nauna descritta al viaggiattore. Milan, 1829.
Pippa, Luigi. Antonio Bartolomeo Bertolla. La Clessidra (January
1961), anno 17, no. 1, pp. 22-25.
San Cajetano, David à. Praktische Anleitung für Künstler, alle
astronomische Perioden durch brauchbare bisher noch nie gesehene
ganz neue Räderwerke mit Leichtigkeit vom Himmel unabweichlich
genau auszuführen, sammt Erweiterung der Theorie des neuen
Rädergebäudes. Vienna: privately printed, 1793.
Tovazzi, Giangrisostomo. Biblioteca Tirolese. Vol. 2, art. 329, MS.
168, pp. 406-407. Trent, 1780.
Vischer, George F. Beschreibung mechanischer Kunstwerke, welche
unter der Direktion und Anweisung M. Philipp Matth. Hahn, Pfarrers in
Kornwestheim…. Stuttgart: Mezler, 1774.
Von Bertele, Hans. The development of equation clocks. La Suisse
Horologere (1959-1961), parts 1 through 5.
Wenham, Edward. Tall case clocks. The Antiquarian Magazine (May
1927), vol. 8, no. 4, p. 33. [The Borghesi clock is illustrated only from a
photograph of the Anderson Art Galleries in New York, and mislabeled
"Astronomical Clock made in Jena, 1656, in elaborate mahogany case."]

Paper 35 - Transcriber's Note
Footnotes have been moved to the end of the main section of the paper, and
illustrations have been moved to eliminate breaks in paragraphs. Minor punctuation
errors have been corrected without note. The following typographical errors have
been corrected:
p. 41 … Bertolla apparently wavered in … [Had 'waivered'.]
p. 45 … Assidvo proni donant di cvncta labori. [Had 'ronip'.]
Footnote 4: Philipp Matthäus Hahn [Had 'Matthaus'.]

Contributions from
The Museum of History and Technology:
Paper 36

The Engineering Contributions
of Wendel Bollman

Robert M. Vogel

EARLY CAREER 80

THE BOLLMAN TRUSS 85

W. BOLLMAN AND COMPANY 91

FINAL USE OF THE BOLLMAN TRUSS 95

KNOWN BOLLMAN WORKS 99

BIBLIOGRAPHY 104

INDEX

Figure 1.—Wendel Bollman, C.E. (1814-1884). (Photo
courtesy of Dr. Stuart Christhilf.)

Robert M. Vogel

THE ENGINEERING CONTRIBUTIONS
OF WENDEL BOLLMAN

The development of structural engineering has always been as
dependent upon the availability of materials as upon the expansion of
theoretical concepts. Perhaps the greatest single step in the history of
civil engineering was the introduction of iron as a primary structural
material in the 19th century; it quickly released the bridge and the
building from the confines of a technology based upon the limited
strength of masonry and wood.
Wendel Bollman, self-taught Baltimore civil engineer, was the first to
evolve a system of bridging in iron to be consistently used on an
American railroad, becoming one of the pioneers who ushered in the
modern period of structural engineering.
The Author: Robert M. Vogel is curator of civil engineering in the
Smithsonian Institution’s Museum of History and Technology.

endel Bollman’s name survives today solely in association with the Bollman truss,
W and even in this respect is known only to a few older civil and railroad engineers.
The Bollman system of trussing, along with those of Whipple and Fink, may be
said to have introduced the great age of the metal bridge, and thus, directly, the modern
period of civil engineering.
Bollman’s bridge truss, of which the first example was built in 1850, has the very
significant distinction of being the first bridging system in the world employing iron in all
of its principal structural members that was used consistently on a railroad.
The importance of the transition from wood to iron as a structural and bridge building
material is generally recognized, but it may be well to mention certain aspects of this
change.
The tradition of masonry bridge construction never attained the great strength in this
country which it held in Europe, despite a number of notable exceptions. There were
several reasons for this. From the very beginning of colonization, capital was scarce, a
condition that prevailed until well into the 19th century and which prohibited the use of
masonry because of the extremely high costs of labor and transport. An even more
important economic consideration was the rapidity with which it was necessary to extend
the construction of railways during their pioneer years. Unlike the early English and
European railways, which invariably traversed areas of dense population and industrial
activity, and were thus assured of a significant financial return almost from the moment
that the first rail was down, the Baltimore and Ohio and its contemporaries were launched
upon an entirely different commercial prospect. Their principal business consisted not so
much in along-the-line transactions as in haulage between principal terminals separated by
great and largely desolate expanses. This meant that income was severely limited until the
line was virtually complete from end to end, and it meant that commencement of return

upon the initial investment was entirely dependent upon the speed of survey, graduation,
tunneling, and bridging.

Figure 2.—Model of B. H. Latrobe’s truss, built in 1838, over the Patapsco River at
Elysville (now Daniels), Maryland. (Photo courtesy of Baltimore and Ohio Railroad.)

The need for speed, the general attenuation of capital, and the simple fact that all the
early railroads traversed thickly forested areas rendered wood the most logical material for
bridge and other construction, both temporary and permanent.
The use of wood as a bridge material did not, of course, originate with the railroads, or,
for that matter, in this country. The heavily wooded European countries—Switzerland in
particular—had a strong tradition of bridge construction in timber from the Renaissance on,
and naturally a certain amount of this technique found its way to the New World with the
colonials and immigrants.
America’s highway system was meager until about the time the railroad age itself was
beginning. However, by 1812 there were, along the eastern seaboard, a number of fine
timber bridges of truly remarkable structural sophistication and workmanship.
It was just previous to the advent of the railroads that the erection of highway bridges
in this country began to pass from an art to a science. And an art it had been in the hands of
the group of skilled but unschooled master carpenters and masons who built largely from
an intuitive sense of proportion, stress, and the general “fitness of things.” It passed into an
exact science under the guidance of a small number of men trained at first in the scientific
and technical schools of Europe, and, after about 1820, in the few institutions then
established in America that offered technical instruction.
The increasing number of trained engineers at first affected highway bridge
construction not so much in the materials used but in the way they were assembled. In a
bridge designed by a self-taught constructor, the cheapness of wood made it entirely
feasible to proportion the members by enlarging them to the point where there could be no
question as to their structural adequacy. The trained engineer, on the other hand, could
design from the standpoint of determining the entire load and then proportioning each
element according to the increment of stress upon it and to the unit capacity of the material.
By the time railroads had started expanding to the West there had been sufficient
experience with the half dozen practical timber truss systems by then evolved, that there
was little difficulty in translating them into bridges capable of supporting the initial light
rail traffic.

In spite of its inherent shortcomings, wood was so adaptable that it met almost
perfectly the needs of the railroads during the early decades of their intense expansion, and,
in fact, still finds limited use in the Northwest.

Early Career
Wendel Bollman was born in Baltimore of German parents in 1814. His father was a
baker, who in the same year had aided in the city’s defense against the British. Wendel’s
education, until about the age of 11, was more or less conventionally gained in public and
private schools in Baltimore. He then entered into informal apprenticeship, first to an
apothecary in Sheperdstown, Virginia (now West Virginia), and then to one in Harpers
Ferry. In 1826 or 1827 he became ill and returned to Baltimore for cure. From that time on
his education was entirely self-acquired.

Figure 3.—Trussed beam.

It is of interest, in light of his later career, to note that on the Fourth of July 1828, he marched
with other boys in a procession that was part of the Baltimore and Ohio Railroad’s cornerstone-
laying ceremony. Shortly afterward, he apprenticed himself to a carpenter for a brief time, but
when the work slacked off he obtained work with the B. & O. The right-of-way had been graded
for about five miles by that time, but no rail was down. The boy was at first given manual work,
but soon advanced to rodman and rapidly rose as he gained facility with the surveying apparatus.
In the fall of 1829 he participated in laying the first track. As his mother was anxious that he
continue his education in carpentry, he left the railroad in the spring of 1830 to again enter
apprenticeship. He finished, became a journeyman, helped build a planter’s mansion in Natchez,
and returned to Baltimore in 1837 to commence his own carpentry business. The next year, while
building a house in Harpers Ferry, he was asked to rejoin the B. & O. to rebuild parts of its large
timber bridge over the Potomac there, which had fallen victim to various defects after about a
year’s use.

Figure 4.—Simple beam of 50-foot span with three independent trussing systems. Bollman’s
use of this method of support led to the development of his bridge truss. This drawing is of a
temporary span used after the timber bridge at Harpers Ferry was destroyed during the Civil
War. (In Baltimore and Ohio Collection, Museum of History and Technology.)

Shortly after the Harpers Ferry bridge reconstruction, Bollman was made foreman of bridges.
It is apparent that, on the basis of his practical ability, enhanced by the theoretical knowledge
gained by intense self-study, he eventually came to assist Chief Engineer Benjamin H. Latrobe in
bridge design. He later took this work over entirely as Latrobe’s attentions and talents were
demanded in the location and extension of the line between Cumberland and Wheeling.

Figure 5.—Bollman’s original patent drawing, 1851. (In National Archives, Washington,
D.C.)

The B. & O. did not reach its logical destination, Ohio (actually Wheeling, West Virginia, on
the east bank of the Ohio River) until 1853. In the years following Bollman’s return to the railroad,
the design of bridges was an occupation of the engineering staff second in importance only to the
location of the line itself. During this time Bollman continued to rise and assume greater
responsibilities, being appointed master of road by Latrobe in 1848. In this position he was
responsible for all railroad property that did not move, principally the right-of-way and its
structures, including, of course, bridges.
The recognition of Bollman’s abilities was in the well-established tradition of the B. & O., long
known as America’s first “school of engineering,” having sponsored many early experiments in
motive power, trackwork, and other fundamental elements of railroad engineering. It furnished the
means of expression for such men as Knight, Wright, Whistler, Latrobe, and Winans.

Figure 6.—Plan of Harpers Ferry bridge as built by Latrobe. The second Winchester track
was later removed.

Of these pioneer civil and mechanical engineers, some were formally trained but most were
self-taught. Bollman’s career on the B. & O. is of particular interest not only because he was
perhaps the most successful of the latter class but because he was probably also the last. He may
be said to be a true representative of the transitional period between intuitive and exact
engineering. Actually, his designing was a composite of the two methods. While making consistent
use of mathematical analysis, he was at the same time more or less dependent upon empirical
methods. For years, B. & O. employees told stories of his sessions in the tin shop of the railroad’s
main repair facility at Mount Clair in Baltimore, where he built models of bridges from scraps of
metal and then tested them to destruction to locate weaknesses. It seems most likely, however, that
the empirical studies were used solely as checks against the mathematical.

Figure 7.—Recent model of Bollman’s Winchester span. Only two of the three lines of
trussing are shown. The model is based on Bollman’s published description and drawings of
the structure. (USNM 318171; Smithsonian photo 46941.)

In the period when Bollman began designing—about 1840—there were fewer than ten men in
the country designing bridges by scientifically correct analytical methods, Whipple and Roebling
the most notable of this group. By 1884, the year of Bollman’s death, the age of intuitive design
had been dead for a decade or longer.

Figure 8.—The Baltimore and Ohio Railroad’s Potomac River crossing at Harpers Ferry,
about 1860. Bollman’s iron “Winchester span” of 1851 is seen at the right end of Latrobe’s
timber structure of 1836, which forms the body of the bridge. (Photo courtesy of Harpers
Ferry National Historical Park.)

The B. & O. was in every way a truly pioneer enterprise. It was the first practical railroad in
America; the first to use an American locomotive; the first to cross the Alleghenies. The spirit of
innovation had been encouraged by the railroad’s directors from the outset. It could hardly have
been otherwise in light of the project’s elemental daring.
The first few major bridges beyond the line’s starting point on Pratt Street, in Baltimore, were
of rather elaborate masonry, but this may be explained by the projectors’ consciousness of the
railroad’s significance and their desire for permanence. However, the aforementioned economic
factors shortly made obvious the necessity of departure from this system, and wood was thereafter
employed for most long spans on the line as far as Harpers Ferry and beyond. Only the most minor
culverts and short spans, and those only in locations near suitable quarries, were built of stone.
In addition to the economic considerations which prompted the company to revert to timber for
the major bridges, there were several situations in which masonry construction was unsuitable for
practical reasons. If stone arches were used in locations where the grade of the line was a relatively
short distance above the surface of the stream to be crossed, a number of short arches would have
been necessary to avoid a very flat single arch. In arch construction, the smaller the segment of a
circle represented by the arch (that is, the flatter the arch), the greater the stress in the arch ring and
the resulting horizontal thrust on the abutments.

Figure 9.—Bollman skew bridge at Elysville (now Daniels), Maryland, built in 1853-1854.
(Photo courtesy of Maryland Historical Society.)

The piers for the numerous arches necessary to permit an optimum amount of rise relative to
the span would have presented a dangerous restriction to stream flow in time of flood. By the use
of timber trusses such crossings could be made in one or two spans with, at the most, one pier in
the stream, thus avoiding the problem.
The principal timber bridges as far west as Cumberland were of Latrobe’s design. These were
good, solid structures of composite construction, in which a certain amount of cast iron was used
in joints and wrought iron for certain tension members. They were, however, more empirical than
efficient and, for the most part, not only grossly overdesigned but of decidedly difficult fabrication
and construction.
What is interesting about the Latrobian timber trusses, however, is the effect they appear to
have had upon Bollman’s subsequent work in the design of his own truss. This effect is evidenced

by the marked analogy between the primary structural elements of the two types. The Latrobe truss
at Elysville (fig. 2) was only partially a truss, inasmuch as the greater part of the load was not
carried from panel to panel, finally to appear at the abutments as a pure vertical reaction, but was
carried from each panel (except the four at the center) directly to the bearing points at the piers by
heavy diagonal struts, after the fashion of the famous 18th-century Swiss trusses of the
Grubenmanns. It was a legitimate structural device, and the simplest means of extending the
capacity of a spanning system. However, it was defective in that the struts applied considerable
horizontal thrust to the abutments, requiring heavier masonry than would otherwise have been
necessary.
It is quite likely that Latrobe did not have absolute confidence in the various pure truss systems
already patented by Town, Long, and others, and preferred for such strategic service a structure in
which the panel members acted more or less independently of one another. It will be seen that,
similarly, the individual panel loads in Bollman’s truss were carried to the ends of the frame by
members acting independently of one another.

The Bollman Truss
There had never been any question about the many serious inadequacies of wood as a bridge
material. Decay and fire risk, always present, were the principal ones, involving continuous
expenditure for replacement of defective members and for fire watches. It was, in fact, understood
by the management and engineering staff of the B. & O. that their timber bridge superstructures,
though considered the finest in the country, were more or less expedient and were eventually to be
replaced. In this regard it is not surprising that Latrobe, a man of considerable foresight, had, at an
early date, given serious thought to the possible application of iron here.

Figure 10.—Potomac River crossing of the Baltimore and Ohio at North Branch, Maryland,
built in 1856. There are three Bollman deck trusses. (Photo courtesy of Baltimore and Ohio
Railroad.)

Figure 11.—The Fink truss. (Smithsonian photo 41436.)

Figure 12.—Advertisement in the Railroad Advocate, August 1855. Click here to read
transcription.

The world’s first major iron bridge, the famed cast-iron arch at Coalbrookdale, England, had
been constructed in 1779. Its erection was followed by rather sporadic interest in this use of the
material. The first significant use of iron in this country was in a series of small trussed highway
arches erected by Squire Whipple over the Erie Canal in the early 1840’s, over 60 years later. In
these, as in most of the earlier iron structures, an arch of cast iron was the primary support. The
thrust of the arches was counteracted by open wrought-iron links with other wrought- and cast-iron
members contributing to the truss action.

The Whipple bridges promoted a certain amount of interest in the material. In the B. & O.’s
annual report for the fiscal year 1849 appears the first record of Latrobe’s interest in this important
matter. In the president’s message is found the following, rather offhand, statement:
$6,183.19 have been expended toward the renewal of the Stone Bridges on
the Washington Branch, carried off by the flood of Oct. 7th, 1847. Preparations
are made and contracts entered into, for the reconstruction of the large Bridges
at Little Patuxent and at Bladensburg which will be executed in a few
months…. It is proposed to erect a superstructure of Iron upon stone
abutments, at each place—with increased span, for greater security against
future floods.
It is interesting to note that it was indeed Bollman trusses to which the president of the railroad
had referred. How much earlier than this date Bollman had evolved his peculiar trussing system is
not clear. The certain influence of Latrobe’s radiating strut system of trussing has been mentioned.
As likely an influence was another basic technique commonly used to increase the capacity of a
simple timber beam—that of trussing—i.e., placing beneath the beam a rod of iron that was
anchored at the ends of the beam and held a certain distance below it at the center by a vertical
strut or post. This combination thus became a truss in that the timber portion was no longer subject
to a bending stress but to a simple one of compression, the rod absorbing the tensile stress of the
combination. The effect was to deepen the beam, increasing the distance between its extreme
fibers and—by thus reducing the bending moment—reducing the stress in them (see fig. 3).

Figure 13.—The four Bollman spans at Harpers Ferry that survived the Civil War. The
spans were completed in 1862-1863. (Photo courtesy of Baltimore and Ohio Railroad.)

It apparently occurred to Bollman that by extending the number of rods in a longitudinal
direction, this effect could be practically amplified to such an extent as to be capable of spanning
considerable distances. He almost certainly did not at first contemplate an all-iron system, but
rather a composite one such as described. It is entirely likely that such trussed beams, with
multiple systems of tension rods, were used by Bollman as bridging in temporary trestlework
along the line as early as 1845 (see fig. 4).
It is impossible to say whether Bollman himself, or Latrobe, was struck with the logic of
further elaborating upon the system and, simultaneously, translating the timber compression
member into one of cast iron. Cast iron would naturally have been selected for a member that
resisted a compressive stress, as it was considerably cheaper than wrought iron. But more
important, at that time wrought iron was not available in shapes of sufficient sectional area to resist
the appreciable buckling stresses induced in long compression members. The cost of building up

members to sufficient size from the very limited selection of small shapes then rolled would have
been prohibitive.
The trussing rods, subjected to tension, were of wrought iron inasmuch as the sectional area
had only to be sufficient to resist the primary axial stress.
The first all-iron Bollman truss was constructed over the Little Patuxent River at Savage
Factory, near Laurel, Maryland, in 1850. In the chief engineer’s report for the year 1850, Latrobe
was able to state that the truss had been completed and was giving “much satisfaction.” He went
on at some length to praise the “valuable mechanical features” embodied therein, and expressed
great confidence that iron would become as important a material in the field of civil engineering as
it was in mechanical engineering.

Figure 14.—The Harpers Ferry bridge as completed after the Civil War. It was used by the
Baltimore and Ohio until 1894, and as a highway bridge until 1936. (Photo 690, Baltimore
and Ohio Collection, Museum of History and Technology.)

The cost of this first major Bollman bridge was $23,825.00. Its span was 76 feet. Latrobe’s
confidence was well placed. The Savage span and another at Bladensburg may be considered
successful pilot models, for, in spite of a certain undercurrent of mistrust of iron bridges within the
engineering profession—due mainly to a number of failures of improperly designed spans—
Latrobe felt there was sufficient justification for the unqualified adoption of iron in all subsequent
major bridge structures on the B. & O.
Almost immediately following completion of the Savage Bridge, Bollman undertook the
design of replacements for the large Patapsco River span at Elysville (now Daniels), Maryland,
and the so-called Winchester span of the B. & O.’s largest and most important bridge, that over the
Potomac at Harpers Ferry. Harpers Ferry bridge, a timber structure, had been designed by Latrobe
and built in 1836-1837 by the noted bridge constructor Lewis Wernwag. It was peculiar in having
a turnout, near the Virginia shore, whereby a subsidiary road branched off to Winchester (see
fig. 6). Only the single span on this line, situated between the midriver switch and the shore, was
slated for replacement, as the other seven spans of the bridge had been virtually reconstructed in
the decade or so of their history and were in sound condition at the time.
The Winchester span (fig. 8), which was the first Bollman truss to embody sufficient
refinement of detail to be considered a prototype, was completed in 1851. Bollman was extremely
proud of the work, with perfect justification it may be said. The 124-foot span was fabricated in
the railroad’s extensive Mount Clair shops. It was subdivided into eight panels by seven struts and
seven pairs of truss rods. An interesting difference between this span and Bollman’s succeeding

bridges was his use of granite rather than cast iron for the towers. The span consisted of three
parallel lines of trussing to accommodate a common road in addition to the single-track
Winchester line.
The distinctive feature of the Bollman system was the previously mentioned series of diagonal
truss links in combination with a cast-iron compression chord, which Bollman called the
“stretcher.” The spacing between the chord and the junction of each pair of links was maintained
by a vertical post or strut, also cast.

Figure 15.—North Street (now Guilford Avenue) bridge, Baltimore. In this transitional
composite structure cast iron was used only in the relatively short sections of the upper chord.
For the long unsupported compression members of the web system, standard wrought-iron
angles and channels were built up into a large section. The decorative cast-iron end posts
were non-structural. (Photo in the L. N. Edwards Collection, Museum of History and
Technology.)

Much of the appeal of this design lay unquestionably in the sense of security derived from the
fact that each of the systems acted independently to carry its load to the abutments. The lower
chords, actually nonfunctional in the primary structure, were included merely to preserve the
proper longitudinal spacing between the lower ends of the struts. A certain lack of rigidity was
inherent in the system due to that very discontinuity which characterized its action; however, this
was compensated for by a pair of light diagonal stay rods crossing each panel. These rods served
the additional function of distributing concentrated loads to adjacent struts much in the manner of
the bridging between floor joists in a building.
In the Winchester span the floor system was of timber for reasons of economy. This was a very
minor weakness inasmuch as any stick could be quickly replaced, and without disturbing the
function of the structure. Bollman received a patent for his truss in January 1852, and in the same

year published a booklet describing his system in general and the Harpers Ferry span in particular.
Here, he first calls it a “suspension and trussed bridge,” which is indeed an accurate designation
for a system which is not strictly a truss because it has no active lower chord. (The analogy to a
suspension bridge is quite clear, each pair of primary rods being comparable to a suspension
cable.) Thereafter, Bollman’s invention was generally termed a suspension truss.

INFLUENCE OF THE TRUSS
Bollman’s 1852 publication was widely disseminated here and abroad and studied with
respectful interest by the engineering profession. Its drawings of the structure were copied in a
number of leading technical journals in England and Germany. Although there is no record that the
type was ever reproduced in Europe, there can be little doubt that this successful structural use of
iron by the most eminent railroad in the United States and its endorsement by an engineer of
Latrobe’s status gave great impetus to the general adoption of the material. This influence was
certainly equal to that of Stephenson’s tubular iron bridge of 1850 over the Menai Strait, or
Roebling’s iron-wire suspension bridge of 1855 over Niagara gorge. The Bollman design had
perhaps even greater influence, as the B. & O. immediately launched the system with great energy
and in great numbers to replace its timber spans; on the other hand, Roebling’s structure was never
duplicated in railroad service, and Stephenson’s only once.

Figure 16.—Left: conjectural section of Bollman’s segmental wrought-iron column, about
1860, and section of the standard Phoenix column; right: Phoenix column as used in truss-
bridge compression members.

EVALUATION OF THE TRUSS
By the late 1850’s iron was well established as a bridge material throughout the world. Once
the previous fears of iron had been stilled and the attention of engineers was directed to the
interpretation of existing and new spanning methods into metal, the Bollman truss began to suffer
somewhat from the comparison. Although its components were simple to fabricate and its analysis
and design were straightforward, it was less economical of material than the more conventional
panel trusses such as the Pratt and Whipple types. Additionally, there was the requisite amount of
secondary metal in lower chords and braces necessary for stability and rigidity.
A factor difficult to assess is Bollman’s handling of his patent, which was renewed in 1866.
There is sufficient evidence to conclude that he considered the patent valuable because it was
based upon a sound design. Therefore, he probably established a high license fee which, with the
truss’s other shortcomings, was sufficient to discourage its use by other railroads. As patron, the B.
& O. had naturally had full rights to its use.

An additional defect, acknowledged even by Bollman, arose because of the unequal length of
the links in each group except the center one. This caused an unevenness in the thermal expansion
and contraction of the framework, with the result that the bridges were difficult to keep in
adjustment. This had the practical effect of virtually limiting the system to intermediate span
lengths, up to about 150 feet. For longer spans the B. & O. employed the truss of another of
Latrobe’s assistants, German-born and technically trained Albert Fink.
The Fink truss was evolved contemporaneously with Bollman’s and was structurally quite
similar, being a suspension truss with no lower chord. The principal difference was the symmetry
of Fink’s plan, which was achieved by carrying the individual panel loads from the panel points to
increasingly longer panel units before having them appear at the end bearings. This eliminated the
weakness of unequal strains. The design was basically a more rational one, and it came to be
widely used in spans of up to 250 feet, generally as a deck-type truss (see fig. 11).

W. Bollman and Company
Bollman resigned from the Baltimore and Ohio in 1858 to form, with John H. Tegmeyer and
John Clark, two of his former B. & O. assistants, a bridge-building firm in Baltimore known as W.
Bollman and Company. This was apparently the first organization in the United States to design,
fabricate, and erect iron bridges and structures, pioneering in what 25 years later had become an
immense industry. The firm had its foundation at least as early as 1855 when advertisements to
supply designs and estimates for Bollman bridges appeared over Tegmeyer’s name in several
railroad journals (see fig. 12).
Bollman’s separation from the B. & O. was not a complete one. The railroad continued its
program of replacing timber bridges with Bollman trusses, and contracted with W. Bollman and
Company for design and a certain amount of fabrication. There is some likelihood that eventually
fabrication was entirely discontinued at Mount Clair, and all parts subsequently purchased from
Bollman.
The firm prospered, erecting a number of major railroad bridges in Mexico, Cuba, and Chile.
Operations ceased from 1861 to 1863 because of difficult wartime conditions in the border city of
Baltimore. Following this, Bollman reentered business as sole proprietor of the Patapsco Bridge
and Iron Works.

Figure 17.—Chicago, Burlington and Quincy Railroad bridge over Quincy Bay (branch of the
Mississippi River) at Quincy, Illinois. The pivot draw-span was formed of two Bollman deck trusses
supported at their outer ends by hog chains. The bridge was built in 1867-1868 by the Detroit Bridge and
Iron Co., Bollman licensee. (Clarke, Account of the Iron Railway Bridge … at Quincy, Illinois.)

The most noteworthy of Bollman’s works in this period was a series of spans at Harpers Ferry.
The B. & O.’s timber bridge had been destroyed by Confederate forces in June 1861, and the

crossing was thereafter made upon temporary trestlework. This was a constant source of trouble,
with continuing interruptions of the connection from high water, washouts, and military actions.
The annoyance and expense of this became so great that the company decided to risk an iron
bridge at the crossing. In July and August 1862, two sections of Bollman truss, spans no. 4 and no.
5 were completed. As this occurred during the time when W. Bollman and Company was
inoperative, the work was produced at Mount Clair to Bollman’s design and, undoubtedly, erected
under his supervision. Five weeks later, on September 24, these and Bollman’s famous Winchester
span of 1851 were blown up by the Confederates, and the line’s business was again placed at the
mercy of trestling.
The spirit of the B. & O. administration indeed seems to have been unshakable when, in the
face of such heartbreaking setbacks, it determined to again bridge the river with iron, even at the
height of the hostilities. In November, span no. 5 was erected, and by April 1863 nos. 3, 4, and 6
also. These were the four straight spans in midriver between the “wide” (or “branch,” or “wye”)
span and the span on the Maryland shore over the Chesapeake and Ohio Canal (see fig. 13).
Although the wood floor system of these spans was burned for strategic reasons by U.S. troops
later in 1863, they survived the war.
In 1868 the remaining trestlework was replaced with Bollman trusses. This magnificent
structure served the railroad until 1894 when the right-of-way was realigned at Harpers Ferry.
However, the half used by the common road remained in use until carried away by the disastrous
flood in 1936. The piers may still be seen.
During the prewar years, Bollman evolved a structural development of most profound
importance, which is usually associated with the Phoenix Iron Works and its founder, Samuel J.
Reeves. In the erection of a high trestlework viaduct for the Havana Railroad, Bollman apparently
became concerned with the tensile weakness of cast iron when applied in long, unsupported
columns. Although a column is normally subjected to compressive stresses, when the slenderness
ratio—that is, the length divided by the radius of gyration of the cross section—becomes great, a
secondary bending stress may be produced. If this stress becomes great enough, the value of the
tensile stress in one side of the column may actually exceed the principal compressive stress, and a
net effect of tension result.

Figure 18.—Ohio River crossing of the Baltimore and Ohio at Benwood, West Virginia,
completed in 1870. Bollman deck trusses were used in the approaches on both sides. (Photo
693, Baltimore and Ohio Collection, Museum of History and Technology.)

Figure 19.—Patapsco River crossing of the Baltimore and Ohio between Thistle and
Ilchester, Maryland. (Photo 695, Baltimore and Ohio Collection, Museum of History and
Technology.)

As already mentioned, the few available rolled-iron shapes were of relatively small area and
quite unsuitable for use as columns unless combined and built up in complex fabrications. The
normal practice at the time was to use cast compression members in iron bridges and structures,
with their sectional area so proportioned to the length that a state of tension could not exist. In the
case of long members, this naturally meant that an excessive amount of material was used.

Figure 20.—Two views of Bollman-built “water-pipe truss” that carries Lombard Street
over Jones Falls in Baltimore. Built in 1877.

Bollman was conscious of the problem from his experience with the stretchers and struts of his
truss, and he must have been aware of the great advantage which would be obtained by a practical
method of forming such members in wrought iron, the tensile resistance of which is equivalent to
the compressive. He eventually developed the forerunner of what came to be known as the
Phoenix form by having special segmental wrought-iron shapes rolled by Morris, Tasker and
Company of Philadelphia, these shapes being combined into a circular section with out standing
flanges for riveting together. The circular section is theoretically the most efficient to bear
compressive loading. A column of any required diameter could be produced by simply increasing
the number of segments, the individual size of which never exceeded contemporary rolling mill
capacity (see fig. 16).
The design exhibits the inspired combination of functional perfection and simplicity that seems
to characterize most great inventions.

Figure 21.—The Harpers Ferry bridge toward the end of its career, carrying a common
road over the Potomac. The westernmost line of trussing and span no. 1 had been removed
long before. View through the Winchester span looking toward Maryland in 1933. (Photo
courtesy of Harpers Ferry National Historical Park.)

It may have been because he had no facilities for rolling that Bollman communicated his idea
to Reeves, although this seems illogical. At any rate, Reeves and his associates patented the system
extensively, and the Phoenix column was eventually employed to the virtual exclusion of cast-iron
and other types of wrought-iron columns. By the end of the 19th century it began to pass from use,
as mills became capable of producing larger sections with properties relatively favorable to
column use and more adaptable to connection with other members.

Final Use of the Bollman Truss
The Bollman truss found occasional use elsewhere than on the B. & O. lines, but generally
only when erected on contract by Patapsco Bridge and Iron Works. However, the fact that Bollman
could profitably erect this bridge in the severely competitive 1870’s indicates that the harsh
criticism of the system by authorities of such stature as Whipple was not necessarily justified.
Bollman’s advertisements, in fact, refer to the favorable recommendations of other such renowned
engineers as Herman Haupt and M. C. Meigs.

Figure 22.—Bollman deck trusses in the North River Bridge built in 1873 at Mount
Crawford, Virginia, on the Valley Railroad of Virginia (B. & O.). Each end span is 98 ft. 6 in.;
the river span is 148 ft. 9 in. (Photo 756, Baltimore and Ohio Collection, Museum of History
and Technology.)

An interesting application of the system was in a drawbridge, formed of two Bollman deck
spans, over an arm of the Mississippi at Quincy, Illinois (see fig. 17). The first iron bridge in
Mexico was erected by Bollman over the Medellín River about 1864. Another work of this period,
which attracted considerable attention, was a pair of bridges that Bollman erected over North
Carolina’s Cape Fear River in 1867-1868. These bridges were notable for their foundation on cast-
iron cylinders, sunk pneumatically. This was one of the first instances of the use of the process in
America, and the depth of 80 feet below the water surface reached by one cylinder was considered
remarkable for years afterward.
In the last active decade or so of his career, Bollman produced hundreds of minor bridges and
other structures. In 1873 he supplied the castings for the splendid iron dome of Baltimore’s City
Hall and erected the ingenious water-main truss which carries Lombard Street over Jones Falls in
that city. In this structure the top and bottom chords of the central line of trussing are cast-iron
water mains, bifurcated at the abutments, and joined by cast- and wrought-iron web members (see
fig. 20).
In the mid 1870’s Bollman saw his truss pass into obsolescence. This was due primarily to the
generally increasing distrust of cast iron for major structural members due to its brittleness, but
advances in structural theory, availability of a greater variety of rolled structural shapes, and the
increasing loading patterns of the period all contributed.

Figure 23.—The only surviving Bollman truss bridge, at Savage, Maryland. The bridge
was built elsewhere in 1852 and was moved to this now-abandoned Baltimore and Ohio
industrial siding in about 1888.

Although no Bollman trusses were built by Bollman or the B. & O. after 1875, those in use
were only removed as required by heavier motive power. The Harpers Ferry span, as noted,
remained in full main-line service until 1894. Bollman trusses on feeder lines were continued in
use until much later; a number of them on the Valley Railroad of Virginia (see fig. 22) were not
removed until 1923. However, only on the most isolated spurs was the Bollman truss permitted to
reach really ripe age. The sole known remaining example (fig. 23) stands on such a branch—
ironically, at Savage, over the Little Patuxent, the site of the first Bollman span. This is not the
1850 bridge, but one built in 1852 and moved to the present site 30 years later. The fate of the first
span is not known.

Figure 24.—Hot-water and chocolate pitchers of the 10-piece, silver tea service presented
to Bollman by his fellow employees when he resigned from the Baltimore and Ohio in 1858. A
railroad motif was used throughout, each piece being circled at top and bottom by a track,
complete with rail of accurate section and ties. Spouts are in simulation of hexagonal sheet-
iron chimneys, with seams riveted, and the handles are in the form of a surveyor’s telescope.
On the various pieces are engraved the designs of the more important B. & O. bridges.
Throughout is a wonderful profusion of bits and objects of railroadiana in low relief, high
relief, and fully modeled. In Board of Directors Room, Baltimore and Ohio Railroad
Company, Baltimore, Md. (Photo courtesy of Baltimore and Ohio Railroad.)

Known Bollman Works
(All B. & O. works listed were designed by Bollman and built by the railroad, unless otherwise
indicated.)
No. spans /
Dates of
Location Type length of Remarks
service
each
Savage, Md.,
Bollman 1 First Bollman truss erected; granite
1850-? Little Patuxent / '
through truss 76 towers; cost, $23,825. B. & O. RR.
River
Bladensburg, Md., Bollman Second Bollman truss erected; granite
1851-? 1/?
Anacostia River through truss towers; cost, $19,430. B. & O. RR.
Winchester span; first major Bollman
Harpers Ferry,
Bollman 1 truss; three lines of truss; granite towers;
1851-1862 Va., Potomac / '
through truss 124 blown up by Confederate Army on
River
September 24, 1862. B. & O. RR.

Wood trestle bents with wrought-iron
Baltimore, Md., diagonals. First use of iron structural
1851-? Trestle —
Carey Street members in trestlework. Total length 76
feet. B. & O. RR.
Still standing. Moved to Savage in 1888;
Savage, Md.,
Bollman original location unknown. This and
1852- Little Patuxent 2/?80'
through truss succeeding Bollman trusses use iron
River
towers. B. & O. RR.
Marriottsville,
1852 (or One of first Bollman trusses with iron
Md., Patapsco Bollman truss 1/50'
1853)-? towers. B. & O. RR.
River
4
/124' (or Double track, Central Ohio RR.
Zanesville, Ohio,
1853-? Bollman truss 5 Designed by Bollman; built by Douglas,
Muskingum River /160') Smith & Co., Zanesville.
Elysville (now
1854- Bollman 3 Upper bridge, skew. Cost, $24,477.59.
Daniels), Md., / '9"
1870(?) through truss 97 B. & O. RR.
Patapsco River
Monocacy, Md., Blown up September 8, 1862; rebuilt in
1854-1862 Bollman truss 3/119'
Monocacy River 1864. Cost, $22,722.59. B. & O. RR.
Bollman 1 C. O. RR. Section 76 adjacent to 300-ft.
1854-? Eastern Ohio /40'
truss(?) tunnel.
Bridgeville, Ohio, Bollman deck 1
1855-? /71' C. O. RR.
Salt Creek truss
Unidentified. Mentioned by George
Pre-1855-? Buffalo, N.Y. — — Vose in Railroad Advocate (June 9,
1855).
Elysville, Md.,
about 11/4 miles
Bollman 3
1856-? east of 1854 /111' Lower Bridge. B. & O. RR.
through truss
bridge, Patapsco
River
Marriottsville, Bollman 1 Referred to as “Tunnel Bridge” in B. &
Pre-1856-? /48'9"
Md. truss(?) O. RR. annual report, 1856.
Near Ijamsville, 3 Possibly trussed beams; mentioned in B.
1856-? Iron girders /23'9"
Md., Bush Creek & O. RR. annual report, 1856.
Near Ijamsville, 2
1856-? Iron girders /23'9" As above.
Md., Bush Creek
North Branch,
1856- Bollman deck 3 Partially destroyed in Civil War. B. & O.
Md., Potomac /142'
c.1862 truss RR.
River
Chilean Railways. Designed and built
Chile, Angostura Bollman 4
1860-1906 /115' by Bollman. Replaced by bridge built by
River truss(?)
French firm of Schneider, Cruesot & Co.
Bollman
1860-1910 Chile, Paine River 1/? As above.
truss(?)

Post- Ilchester, Md., Bollman
1/? B. & O. RR.
1860-? Patapsco River through truss
All bridges on Havana RR., including
Bridges and
Pre-1861-? Cuba — iron station house and bridge at Guines.
station house
Designed and built by Bollman.
All bridges on Cienfuegos RR.,
Pre-1861-? Cuba Bridges — Cárdenas RR., and Havana & Matanzas
RR. Designed and built by Bollman.
Trestle with wrought-iron columns (the
Pre-1861-? Cuba Trestle — first such ever constructed). Havana RR.
Designed and built by Bollman.
Harpers Ferry, Span no. 3 (July 24) and span no. 4
Bollman 2
1862-1862 Va., Potomac /160' (August 21). Blown up September 24,
through truss
River 1862. B. & O. RR.
Harpers Ferry,
Bollman 1
1862-1936 Va., Potomac /160' Span no. 5 (November). B. & O. RR.
through truss
River
Harpers Ferry,
Bollman 3 Spans nos. 3, 4, and 5. Constructed
1863-1936 Va., Potomac /160'
through truss previous to April 1863. B. & O. RR.
River
Berwyn, Md., Bollman Iron bridge mentioned in B. & O. RR.
1863-? ?
Paint Branch truss(?) annual report, 1863
Built by Detroit Bridge & Iron Works. It
Clinton, Iowa, 1
1863(4?)-? Pivot draw /360' was the longest in the world at time of
Mississippi River
completion. Designed by Bollman.
Laurel, Md., Replaced stone arch that had been
1864-? Bollman truss ?
Patuxent River washed out. B. & O. RR.
Near Veracruz, Veracruz & Jucaro RR. First iron bridge
Bollman 1
c. 1864-? Mexico, Medellín /115' in Mexico. Designed and built by
hrough truss
River Bollman.
Near Point of Iron bridge mentioned in B. & O. RR.
Bollman 1
1864-? Rocks, Md., Back /80'(?) annual report, 1864. The span length
truss(?)
Creek given is that of previous stone arch.
Bladensburg, Md., Span for second track, to match 1851
1864-? Bollman truss 1/?
Anacostia River span. B. & O. RR.
Wilmington Railway Bridge Co. This
2
Cape Fear, N.C., / 146 '6" bridge was connected to that over the
Bollman 1 1
1868-? Northeast Branch,
truss(?) /164' pivot Northwest Branch by 2 /2 miles of
Cape Fear River draw/150' timber trestling. Designed and built by
Bollman.
Cape Fear, N.C., 1
/217'(?)
Northwest Bollman
1868-? pivot See above.
Branch, Cape Fear truss(?)
River draw/150'
1868-? Quincy, Ill., Bollman deck 4/85' pivot Chicago, Burlington & Quincy RR. The
Quincy Bay (in truss draw/190' pivot draw was formed of two 85-ft.

Mississippi River) simple Bollman deck spans whose outer
ends hung from hog chains. Designed by
Bollman; built by Detroit Bridge & Iron
Works.
Baltimore, Md., North Avenue Bridge. Composite double
over Jones Falls, 2
/100' intersection truss; timber top chord and
1869-
B. & O. RR., and Warren truss 2 posts, wrought-iron lower chord and
c.1892 /55'6"
Northern Central ties. In 55-ft. spans, both chords timber.
RR. Cost, $73,588. Built by Bollman.
Canal span (no. 8), Wide span (no. 2),
Harpers Ferry,
c.1869- Bollman Winchester span, and West End span.
Va., Potomac 4/?
1936 through truss Destroyed by flood in 1936. B. & O.
River
RR.
Iron
“Isometrical Charles Street Bridge. Three lines of
Baltimore, Md., 1
1870-.1895 truss” /108' trussing.Cost, $20,297. Built by
Jones Falls
(probably Bollman.
Pratt type)
Bellaire, Ohio-
1870-1893 Bollman deck 9 In approaches; 2 spans on Ohio side; 7
Benwood W. Va., /107'-125'
& 1900 truss on West Virginia side. B. & O. RR.
Ohio River
Belpre, Ohio-
1870- Bollman deck In approaches; 7 spans on Ohio side; 9
Parkersburg, W. 16/?
c.1895 truss on West Virginia side. B. & O. RR.
Va., Ohio River
Elysville, Md., Bollman Skew; replacement of Upper Bridge(?).
1870-? 4/?
Patapsco River through truss B. & O. RR.
Decker Street (now Maryland Avenue)
1871- Baltimore, Md., Timber and
? Bridge. Cost, $24,975. Built by
c.1895 Jones Falls iron truss
Bollman.
Baltimore, Md., North Avenue Bridge. Composite double
1871- over Northern intersection truss; cast-iron top chord
Warren truss 1/100'
c.1892 Central RR. at and posts; wrought-iron bottom chord
Jones Falls and ties. West span. Built by Bollman.
Valley Railroad of Virginia (B. & O.)
1
Cave Station, Va., Bollman deck /98'7" Bridge no. 120. The main span was a
1873-1923 1
Middle River truss /63'5" Whipple deck truss. Replaced with plate
girders. Designed by Bollman.
2
Mount Crawford, Bollman deck /98'6" Valley Railroad of Virginia (B. & O.)
1873-1923 1
Va., North River truss /148'9" Bridge no. 117. Designed by Bollman.
Valley Railroad of Virginia (B. & O.)
Verona, Va., North Bollman deck 3 Bridge no. 129. The main span was a
1873-1923 /98'7"
River truss 147-ft. Whipple deck truss. Designed by
Bollman.
Span length given is that of previous
Wadesville, Va., Bollman 1
1873-? /147'8" wood span that burned in 1862. B. & O.
Opequon Creek through truss
RR.

Iron roof First Presbyterian Church. Built by
c. 1873- Baltimore, Md. ?
trusses Bollman; possibly designed by him.
City Hall. Cost, $12,840. Designed by
Cast-iron
1873- Baltimore, Md. George A. Frederick, architect; built by
stairs
Bollman.
Dome of the City Hall. Cost, $70,525.
Cast-iron
1873- Baltimore, Md. Designed by George A. Frederick; built
framework
by Bollman.
1875- Baltimore, Md., Fayette Street Bridge. Cost, $9,396.
Iron truss 1/?
c.1913 Jones Falls Built by Bollman.
Single-beam
1876- Baltimore, Md., Canton Avenue (now Fleet Street)
iron bridge 1/?
c.1913 Jones Falls Bridge. Cost, $8,904. Built by Bollman.
(truss?)
Single-beam
1876- Baltimore, Md., Eastern Avenue Bridge. Cost, $12,382.
iron bridge 1/?
c.1913 Jones Falls Built by Bollman.
(truss?)
Lombard Street Bridge. Three lines of
truss; two outer trusses, composite cast-
and wrought-iron polygonal Pratt type;
center composite bowstring with Pratt-
Pratt and
Baltimore, Md., 1 system web. Both chords are cast-iron
1877- bowstring /88'6"
Jones Falls water mains, bifurcated at the end
truss
bearings; cast-iron posts and wrought-
iron ties. In service. Cost, $7,632.
Designed by Jas. Curran, Baltimore
water department; built by Bollman.
1877- Baltimore, Md., Bath Street Bridge. Cost, $4,172. Built
Iron truss 1/?
c.1913 Jones Falls by Bollman.
Over entrance to City Dock. Cost,
1879-? Baltimore, Md. Drawbridge 1/?
$13,182. Built by Bollman.
North Street (now Guilford Avenue)
Bridge. Composite trusses; cast-iron top
Baltimore, Md.,
1879- 2 chord and end posts; wrought-iron
over Jones Falls Warren truss /173'9"
c.1930 bottom chord and web members. Cost,
and railroad tracks
$38,772.45. Built by Bollman; designed
by Latrobe.
Baltimore, Md.,
Wrought-iron Union Avenue Bridge. Built by
1881-1960 (Woodberry), 1/?
Pratt truss Bollman; possibly designed by him.
Jones Falls
Arsenal Branch, B. & O. RR. Skew
Harpers Ferry, Bollman 1
?-? /148' type. Span length is that of previous
Va., Arsenal Canal through truss
timber span.
Baltimore, Md., Bollman
?-? 2/? B. & O. RR.
Gwynns Falls through truss

BIBLIOGRAPHY
A history and description of the Baltimore and Ohio Railroad by a citizen of Baltimore.
Baltimore, 1853.
Baltimore and Ohio Railroad Company. A list of the officers and employees of the Baltimore
and Ohio Railroad for November, 1857. Baltimore, 1857.
——. Third annual report of the president and directors to the stockholders of the Baltimore
and Ohio Rail Road Company. Baltimore: 1829. (Also the fourth through 38th annual reports.
Baltimore, 1830-1864.)
——. Baltimore and Ohio exhibits at the Century of Progress. Chicago, 1934.
Biographical cyclopedia of representative men of Maryland and the District of Columbia.
Baltimore, 1879.
Bollman, Wendel. Iron suspension and trussed bridge as constructed for the Baltimore and
Ohio Rail Road Co. at Harper’s Ferry, and on the Washington branch of this road. Baltimore,
1852.
——. Letter to John W. Garrett dated June 17, 1862. In files of Division of Mechanical and
Civil Engineering, United States National Museum, Washington, D.C.
——. Report of Mr. Bollman in relation to Central Ohio Rail Road. Baltimore, 1854.
Bryant, William C. Picturesque America. New York, 1874.
Clarke, Thomas Curtis. An account of the iron railway bridge across the Mississippi River at
Quincy, Illinois. New York, 1869.
Colburn, Zerah. American iron bridges. Minutes of the proceedings of the Institution of
Mechanical Engineers (1863), vol. 22, pp. 540-573.
Condit, Carl. American building art:—The nineteenth century. New York: Oxford Press,
1960.
Gray, George E. Notes on early practice in bridge building. Transactions of the American
Society of Civil Engineers (1897), vol. 37, pp. 2-16.
Greiner, John E. The American railroad viaduct—Its origin and evolution. Transactions of the
American Society of Civil Engineers (1891), vol. 25, pp. 349-372.
Lang, Philip George. Bollman trusses on Valley of Virginia Branch will soon be memories.
Baltimore and Ohio Magazine (October 1923), pp. 18-19.
——. The old Baltimore and Ohio bridge crossing the Potomac River at Harpers Ferry, West
[sic] Virginia. Engineering News-Record (September 17, 1931), p. 446.
Malezieux, Emile. Travaux publics des Etats-Unis d’Amerique en 1870. Paris, 1873.
McDowell, W. H. Unpublished engineer’s report to the president and directors of Wilmington
Railway Bridge Company, Wilmington, North Carolina, dated March 12, 1868. Typewritten copy

in files of Division of Mechanical and Civil Engineering, U.S. National Museum, Washington,
D.C.
Smith, Charles Shaler. Comparative analysis of the Fink, Murphy, Bollman and triangular
trusses. Baltimore, 1865.
Smith, William P. The book of the great railway celebrations of 1857. Baltimore, 1858.
Tyrrell, Henry G. History of bridge engineering. Chicago, 1911.
Whipple, Squire. Bridge building. Albany, New York, 1869.

Transcription of Figure 12 for screen readers.

WENDEL BOLLMAN’S

Patent Iron Suspension Railroad Bridge.
The undersigned would inform the officers of Railroads and others,
that he is prepared to furnish Drawings and Estimates for Bridges, Roofs,
etc., on the plan of Bollman’s Patent.
The performance of these bridges, some of which have been in use for
six years, has given entire satisfaction. Their simplicity of construction
renders repairs easy and cheap, and by a peculiar connection of the Main
and Panel Rods at the bottom of the Posts, all danger from the effects of
expansion, which has heretofore been the chief objection to Iron Bridges,
is entirely removed.
J. H. TEGMEYER,
Baltimore, Md.

Paper 36 - Transcriber’s Note
Inconsistencies in punctuation have been corrected without note. Inconsistent
hyphenation is as per the original.

Contributions from
The Museum of History and Technology:
Paper 37

Screw-Thread Cutting by the
Master-Screw Method Since 1480

Edwin A. Battison

Edwin A. Battison

SCREW-THREAD CUTTING BY THE
MASTER-SCREW METHOD SINCE 1480
Among the earliest known examples of screw-thread cutting machines are
the screw-cutting lathe of 1483, known only in pictures and drawings, and an
instrument of the traverse-spindle variety for threading metal, now in the
Smithsonian Institution, dating from the late 17th or early 18th century. The
author shows clearly their evolution from something quite specialized to the
present-day tool. He has traced the patents for these instruments through the
early 1930’s and from this research we see the part played by such devices in
the development of the machine-tool industry.

The Author: Edwin A. Battison is associate curator of mechanical and
civil engineering in the Smithsonian Institution’s Museum of History and
Technology.
irectness and simplicity characterize pioneer machine tools because they were intended to

D accomplish some quite specialized task and the need for versatility was not apparent. History
does not reveal the earliest forms of any primitive machines nor does it reveal much about
the various early stages in evolution toward more complex types. At best we have discovered and
dated certain developments as existing in particular areas. Whether these forms were new at the
time they were first found or how widely dispersed such forms may have been is unknown.
Surviving evidence is in the form of pictures or drawings, such as the little-known screw-cutting
lathe of 1483 (fig. 1) shown in Das mittelalterliche Hausbuch.
This lathe shows that its builder had a keen perception of the necessary elements, reduced to
bare essentials, required to accomplish the object. Present are the coordinate slides often credited
to Henry Maudslay. His slides are not, of course, associated with the spindle; neither is there any
natural law which compels them to guide the tool exactly parallel with the axis of revolution. In
this sense the screw-cutting lathe in the Hausbuch is superior because it is in harmony with natural
law and can generate a true cylinder, whereas Maudslay’s lathe can only transfer to the work
whatever accuracy is built into it.
In principle this machine shown in the Hausbuch is very advanced as we see when we follow
the design through to the present time. The artist, whose drawings give us our only knowledge of
the machine, himself was obviously not very familiar with the details of its function. Reference to
figure 1 shows that the threads on the lead screw and on the work, wind in opposite directions.
This must be an error in delineation since the two are closely coupled together without any
intervening mechanism so that the only possible result on the work must be a thread winding in the
same direction as on the original screw. The work also is shown threaded for its entire length; this
cannot be accomplished with any one location of the cross-slide. We are left with the question of
whether this slide was used in two locations or whether the artist, possibly working from notes or
an earlier rough sketch, failed to show an unthreaded portion on one end or the other of the work.

Figure 1.—Earliest representation found of a master-screw type of thread-cutting
machine. From the inconsistencies, such as right- and left-hand threads on master and work,
it appears that the artist had scant insight into actual function. From plate 62 of Das

mittelalterliche Hausbuch, nach dem Originale im Besitze des Fürsten von Waldburg-Wolfegg-
Waldsee, im Auftrage des Deutschen Vereins für Kunstwissenschaft, herausgegeben von
Helmuth Th. Bossert und Willy F. Storck (Leipzig: E. A. Seemann, 1912).

Of at least equal importance with the lead screw and work and their relationship to each other
is the tool-support with its screw-adjusted cross-slide (fig. 2). Just how this was attached to the
frame of the machine so that it placed the tool at a suitable radius is again a questionable point.
The very well-developed cutting tool is sharpened to a thin, keen edge totally unsuited for cutting
metal but ideal for use on a softer, fibrous substance: undoubtedly wood, in this instance.
Unfortunately, the angle at which the artist chose to show us this cutter is not a view from which it
is possible to judge whether or not the tool has been made to conform to the helix angle of the
thread to be cut. This cross-slide, in conjunction with the traversing work spindle, gives us a
machine having two coordinate slides yielding the same effect as the slide rest usually attributed to
Henry Maudslay at the end of the 18th century. Actually, an illustration of coordinate slides
independent of the spindle had been published as early as 1569 by Besson [1] and knowledge of
them widely disseminated by his popular work on mechanics. These slides are shown as part of a
screw-cutting machine with a questionably adequate connection, by means of cords, between the
master screw and the work.
It was the author’s pleasure recently to obtain for the Smithsonian Institution and identify a
small, nicely made, brass instrument which had been in two collections in this country and one
collection in Germany as an unidentified locksmith’s tool (fig. 3). This proved to be an instrument
of the traverse-spindle variety for threading metal. Fortunately, all essential details were present
including a cutter (A in figure 4); this instrument was identified by the signature “Manuel
Wetschgi, Augspurg.” The Wetschgis were a well-known family of gunsmiths and mechanics in
Augsburg through several generations. Two bore the given name Emanuel: the earlier was born in
1678 and died in 1728. He was quite celebrated in his field of rifle making and became chief of
artillery to the Landgrave of Hesse-Kassel shortly before his death in his 51st year. Little is known
of the later Emanuel Wetschgi except that he was at Augsburg in 1740. Tentative attribution of the
instrument has been made to the earlier Emanuel, chiefly on the basis of his recognized position as
an outstanding craftsman.

Figure 2.—Cross-slide for the thread-cutting lathe of Das mittelalterliche Hausbuch, shown
in figure 1. It is remarkable not only for its early date, but also for its high state of
development with a crossfeed screw which had not become universally accepted 300 years
later. The cutter, shown out of its socket, is obviously sharpened for use on wood.

In several respects this little machine differs from its predecessor of the Hausbuch, as might be
expected when allowance is made for the generations of craftsmen who undoubtedly worked with
such tools over the roughly 200 years of time separating them. Another factor to consider when
comparing these two machines is that one was used on metal, the other probably only on wood.
Therefore, it is not surprising to find on the later machine an outboard or “tailstock” support for
the work. The spindle of this support has to travel in unison with the work-driving spindle so that it
is not an unexpected discovery to find that it is spring-loaded. Figure 5 shows how this spring may
be adjusted to accommodate various lengths of work by moving the attachment screw to various
holes in both the spring and in the frame. Also visible in the same illustration is a rectangular
projection at the other end of the spring which engages a mating hole in the “tailstock” spindle to
prevent its rotation.

Figure 3.—Small thread-cutting lathe which was made to be held in a vise during use. It
was found as shown here, with only the operating crank missing. The overall length is
approximately 12 inches, depending on the adjustment of parts. (Smithsonian photo 46525B.)

Figure 6 shows the traversing spindle and nut removed from the machine. Provision has been
made for doing this so easily that there is every reason to believe that, originally, there were
various different spindle and nut units which could be interchangeably used in the machine.
Additional evidence tending to support this concept exists in the cutting tool (fig. 4), which must
have been intended for serious work as it has been carefully fitted in its unsymmetrical socket. The
cutting blade of this tool, which works with a scraping rather than a true cutting action, is too wide
to form a properly proportioned thread when used with the existing lead screw. This may well
indicate that the tool was made for use with a lead of coarser pitch, now lost.

Figure 4.—The working area of figure 3, showing the tool and signature. (Smithsonian photo
46525A.)

Perhaps the most startling feature of this machine when compared with the machine of the
Hausbuch, is the absence of a cross-slide for adjusting the tool. Possibly this can be explained by
the blunt scraping edge on the tool. In actual use, recently, to cut a sample screw, using a tool
similar to the one found in the machine (fig. 7), it was found advantageous to be free of a cross-
slide and thus be able to feed the tool into the work by feel rather than by rule, as would be done
with a slide rest. In this way, it was possible to thread steel without tearing, as the cutting pressure
could readily be felt and the tool could release itself from too heavy a cut. Size on several screws
could be repeated by setting the tool to produce the desired diameter when its supporting arm came
to rest against the frame of the machine. The screws used in the machine itself were apparently
made in just such a way. They were not cut with a die as the thread blends very gradually into the
body of the screw without the characteristic marks left by the cutting edges of a die. Threads cut
with a single-point tool controlled by a cross-slide usually end even more abruptly than those cut
by a die, while it would be quite simple with a machine of the nature we are considering to bring
the thread to a gentle tapering end as seen in figure 8 (another view of the screw A in fig. 3) by
gradually releasing the pressure necessary to keep the tool cutting as the end of the thread was
approached.

Figure 5.—Spring for keeping the follower spindle against the work, showing the method
and range of adjustment. Note the rectangular projection to engage a mating socket in the

spindle, to prevent spindle rotation. (Smithsonian photo 46525.)

Figure 6.—Work spindle and its nut removed from the machine to illustrate how easily
another spindle and nut of different pitch could be substituted. (Smithsonian photo 46525C.)

That machines of this general type having the lead screw on the axis of the work were
competitive with other methods and other types of machines over a long period of time may be
seen from figures 9 and 10. The machine, left front in figure 9 and in more intimate detail in figure
10, can be seen to differ little from that shown in Das mittelalterliche Hausbuch of 1483. The
double work-support is, of course, a great improvement, while the tool-support is regressive since
it lacks a feed screw.
The development of engineering theory, coupled with the rising needs of industry, particularly
with the advent of the Industrial Revolution, brought about accelerated development of screw-
cutting lathes through the combination of screw-cutting machines with simple lathes as seen in
figure 9 and in detail in figure 11. One important advance shown here is driving the machine by
means of a cord or band so that any means of rotary power could be applied, not just hand or foot
power. Of greater interest and technical importance to this study is the provision, seen to better
advantage in figure 11, for readily changing from one master lead screw to another. This had
already been achieved in the Manuel Wetschgi machine, as far as versatility is concerned, although
not in quite such a convenient way.

Figure 7.—Thread of modern form recently cut, using the
old screw and nut but with a new tool. The material threaded
is carbon-steel drill rod. (Smithsonian photo 49276A.)

Figure 12, the headstock of another and more advanced lathe than shown in figures 9 and 11
but of the same type, shows “keys” (D), each of which is a partial nut of different pitch to engage
with a thread of mating pitch. The dotted lines in figure 13 show the engaged and disengaged
positions of one of these keys, and figure 14 shows the spindle with the various leads, C. At D is a
grooved collar to be engaged by the narrow key shown in operating position at the left in figure 12
for the purpose of controlling the endwise movement of the spindle when used for ordinary turning
instead of thread-cutting. In return for greater convenience and freedom from the expense of the
many separate spindles, as typified by the Wetschgi machine, a sacrifice has been made in the
length of the thread which can be cut without interruption.

Figure 8.—Binding screw seen at A in figure 3, showing the long smooth fadeout of the
thread below the shoulder. (Smithsonian photo 49276.)

Figure 9.—Making screws in France in the third quarter of the 18th century. From
L’Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers … receuil de
planches sur les sciences, les arts libéraux, et les arts méchaniques, avec leur explication (Paris:
1762-1772), vol. 9, plate 1.

Figure 10.—Details of the machine in the left foreground of figure 9, showing the crude
tool-support without screw adjustment. From L’Encyclopédie, vol. 9, plate 2.

This reduction in the length that could conveniently be threaded was no great drawback on
many classes of work. This can be realized from figure 16 which shows a traverse-spindle lathe
headstock typical of the mid-19th century. During the years intervening between the machines of
figures 12 and 16, the general design was greatly improved by removing the lead screws from the
center of the spindle. This made possible a shorter, much stiffer spindle and supported both ends of
the spindle in one frame or headstock rather than in separate pieces attached to the bed. The screws
were now mounted outside of the spindle-bearings, one at a time, while the mating nuts were cut
partially into the circumference of a disk which could be turned to bring any particular nut into
working position as required. With this arrangement, a wide variety of leads either right or left
hand could be provided and additional leads could be fitted at any future time. Screw-cutting
lathes of this design were popular for a very long time with instrument makers and opticians who
had little need to cut screws of great length.

Figure 11.—Details of the threading lathe seen in the right foreground of figure 9 showing
the method of drive and support for the work. From L’Encyclopédie, vol. 9, plate 1.

The demands of expanding industry for greater versatility in the production of engineering
elements late in the 18th century set the stage for the evolution of more complex machines tending
to place the threaded spindle lathes in eclipse. Maudslay’s lathe of 1797-1800 (fig. 15) appeared at
this time when industry was receptive to rapid innovation. Unfortunately, the gearing which once
existed to connect the headstock spindle with the lead screw has long been lost. At this time it is
quite difficult to say with certainty whether the original gear set offered a variety of ratios, as was
true of slightly later Maudslay lathes, or a fixed ratio. The plausibility of the fixed ratio theory is
supported by the very convenient means, seen in figure 15, for removing the lead screw in
preparation for substitution of one of another pitch. All that is required is to back off its supporting
center at the tailstock end and withdraw the screw from its split nut [2] and from the driving clutch
near the headstock. This split nut also would have to be changed to one of a pitch corresponding to
that of the screw. While more expensive than a solid nut, it neatly circumvents the need (and saves
the time involved) to reverse the screw in order to get the tool back to the point of beginning
preliminary to taking another cut. David Wilkinson’s lathe of 1798 (fig. 17) which was developed
in Rhode Island at the same time shows the same method of mounting and driving the master
screw. At least in the United States, this method of changing the lead screw instead of using
change gears remained popular for many years. Examples of this changeable screw feature are to
be found in the lathes constructed for the pump factory of W. & B. Douglas Company,
Middletown, Connecticut, [3] in the 1830’s. Middletown, at that time one of the leading metal-
working centers in one of the chief industrial States, had been for many years the site of the
Simeon North arms factory which rivaled Whitney’s. In this atmosphere, it is reasonable to expect
that machinery constructed by local mechanics, as was the custom in those days, would reflect the
most accepted refinements in machine design.

Figure 12.—Well-developed example of lathe headstock having several leads on the spindle
and provision for mounting the work or a work-holding chuck on the spindle. Adapted from
L’Encyclopédie, vol. 10, plate 13.

Figure 13.—End view of the headstock seen in figure 12, showing the keys or half nuts
which engage the threaded spindle, in engaged and disengaged positions. From
L’Encyclopédie, vol. 10, plate 13.

Figure 14.—Spindle of figures 12 and 13, showing the several leads and the many-sided seat
for the driving pulley. Note the scale of feet. From L’Encyclopédie, vol. 10, plate 16.

Roughly twenty years later, Joseph Nason of New York patented [4] the commercially very
important “Fox” brassworker’s lathe (fig. 18). While this does have a ratio in the pair of gears
connecting the work spindle and master screw, it is clear from the patent that various pitches are to
be obtained by changing screws, not by changing gears. The patent sums it up as follows:
A nut upon the end of the stud … is unscrewed when the guide screw is to
be removed or changed. The two wheels … should have in their number of
teeth a common multiple. They are seldom or never removed and their
diameters are made dissimilar only for the purpose of giving to the guide screw
a slower rate of motion than that of the mandrel whereby it may be made of
coarser pitch than that of the screw to be cut and its wear materially lessened.
The introduction of gearing between the spindle and the lead screw, for whatever purpose,
could not help but introduce variable factors caused by inaccuracies in the gears themselves and in
their mounting. These were of little consequence for common work, particularly when coupled to a
screw which, itself, was of questionable accuracy. The increasing refinements demanded in
scientific instruments and in machine tools themselves after they had reached a relatively stable
form dictated that attention be dedicated to improved accuracy of the threaded components.

Figure 15.—Maudslay’s well-known screw-cutting lathe of 1797-1800, showing the method
of mounting and driving changeable master screws. (Photo courtesy of The Science Museum,
London.)

Figure 16.—Headstock of a German instrument-maker’s lathe, typical of the mid-19th
century, showing the traverse spindle, interchangeable lead screws, and semicircumferential
nut containing several leads. The nut may be brought into engagement by the lever at top
rear of the headstock. This releases the end thrust control on the spindle simultaneously with
engagement of the nut. (Smithsonian photo 49839.)

Figure 17.—David Wilkinson’s screw-cutting lathe, patented in the United States in 1798.
Note the ready facility with which the lead screw may be exchanged for another and the same
means of supporting and driving as in figure 15. (U.S. National Archives photo.)

An attack on this problem, which interestingly reverts to the fundamental principle of motion
derived from a master screw without the intervention of other mechanism (fig. 19), is covered by a
patent [5] issued to Charles Vander Woerd, one-time superintendent of the Waltham Watch
Company. The problem is well stated in the patent:
This invention relates to the manufacture of leading screws to be used for
purposes requiring the highest attainable degree of correctness in the cutting of
the screw-threads of said screw … as, for example, in machines for ruling lines
in glass plates to produce refraction [sic] gratings for the resolution of the lines
of the solar spectrum, such machines being required to rule many thousands of
lines on an inch of space by a marking device which is reciprocated over the
glass plate and is fed by the action of a leading screw after the formation of
each line. Great difficulty has been experienced in constructing a leading screw
for this and other purposes, in which the thread is so nearly correct as to
produce no perceptible variation in the microscopic spaces between the ruled
lines or gratings…. Various causes prevent the formation of a thread on the rod
or blank, which is absolutely uniform and accurate from end to end of the rod.
Among other causes are the variations of temperature from time to time, the
imperfections of the operating leading screw, the springing of the leading
screw and of the rod that is being threaded, and other unavoidable causes, all
of which, although apparently trivial and producing only slight variations in
the thread at different parts of the rod or blank, are of sufficient moment to be
seriously considered when a screw of absolute accuracy is desired.

Figure 18.—Nason’s lathe, patented in 1854, showing a master lead screw driven at less than
work speed so that the master could be of a coarser and more durable pitch than the work.
U.S. patent 10383.

It is interesting to note in figure 19 that Vander Woerd’s machine, to avoid the problems
outlined in his patent, has returned to a starkly simple design. We are not told, however, how he
originated this master screw which is used to produce the accurately threaded work pieces. Later
generations, in the search for ever-greater accuracy, also returned to the fundamental simplicity of
a master screw as we shall see when we consider the refinements in mechanism necessary to the
extended development of the automobile and the airplane.

Figure 19.—Vander Woerd’s patent, seen here, covered the combination of a master screw,
toolslide and work in a rigid frame to be supported and driven by outside means of no
required precision. U.S. patent 293930 dated February 1884.

As the power and speed of automobiles and aircraft increased, critical parts became more
highly stressed. Gears and threaded parts were particularly troublesome details of the mechanism
because of the stresses concentrated in them, and, in the case of gears, because of the internal and
external stresses originating in minute deviations from the ideal of tooth form and spacing. The
problems were not entirely new but had hitherto been solved by increasing the size of the parts, an
avenue of limited utility to designers in these fields where total weight as well as the effects of
mass and inertia are so important. By making these parts of heat-treated steel, the strength could be
made suitable while the size and mass of the parts were kept within bounds. The necessary
processes of heat-treating were not always applicable to finished parts as they sometimes
destroyed both finish and accuracy. Grinding, which was well developed for the simple plane,
cylindrical, and conical surfaces so widely used in mechanisms, had to be extended to threads and
gears so that they could be finished after heat-treating. Sometimes the gear teeth themselves were
ground; for other applications it was sufficient to improve the accuracy of the gear cutters.

Figure 20.—A hob-grinding machine patented in 1932 and incorporating the master-screw
principle. Carl G. Olson’s U.S. patent 1874592.

Attempts to produce gear hobs free of the imperfections and distortions introduced by heat
treatment led to another return to the use of the master lead screw. Figure 20 illustrates a machine
having this feature which was patented in 1932 by Carl G. Olson. [6] In speaking of the spindle-
driving mechanism disclosed in earlier patents, the patent goes on to say:
This driving mechanism includes an integral spindle 20, one extremity
thereof being designed for supporting a hob 22 and the other extremity thereof
being formed so as to present a lead screw 24. The spindle 20 is mounted
between a bearing 26 and a bearing 28, the latter bearing providing a nut in
which the lead screw 24 rotates…. From the description thus far given it will
be apparent that the rotation of the lead screw 24 within the bearing or nut 28
will cause the hob to be moved axially, the lead of the screw 24 being equal to
the lead of the thread in the hob.
Claim 8 which concludes the descriptive portion of the patent states in part:
In a hob grinding machine of the class described, a rotary work supporting
spindle, means for effecting longitudinal movement of the spindle, a tool
holder for supporting a grinding wheel in operative position with respect to the
work supported by the spindle during the rotary and longitudinal movement
thereof, …
Even before this patent was applied for, another patent was pending for the purpose of
modifying the pitch of the lead screw without the use of change gears in spite of the wide
acceptance of such gear mechanisms for over a hundred years.

Figure 21.—A hob-grinding machine of 1933, showing use of the master screw with a
modifier but without change gears. Carl G. Olson’s U.S. patent 1901926.

Figure 22.—A sine-bar device to modify the effective lead of a master lead screw without
introducing a complex mechanism which would be both difficult to make and to operate
within the required close limits. Carl G. Olson’s (1933) U.S. patent 1901926.

Figure 21 shows a plan view [7] of the machine, and figure 22 a detailed view of the sine-bar
mechanism actuated by the master screw, 6, to modify the effective pitch of the lead screw in
accordance with the realities of practice as stated in the preamble of the patent:
This invention relates to material working machines, and particularly to
machines such as hob grinders and the like, wherein the work is reciprocated
through the agency of a lead screw.

In the manufacture of hobs it is common practice to employ the same
machine for grinding hobs of varied diameters, and in order to employ such a
machine in this manner the pitch of the lead screw, thereof, which actuates the
work carrier, must conform to the axial pitch of the hob to be ground. This will
be readily apparent when it is understood that the helix angles of hobs vary in
accordance with their diameters and, consequently, the difference between the
normal pitch and the axial pitch correspondingly varies. While the requirement
for the normal pitch may be the same for hobs of different diameters, it is
necessary to change the axial pitch in accordance with a change in the hob
diameter, and this axial pitch of the hob is equal to the pitch of the lead screw
which actuates the work carrier in grinding machines heretofore used. Hence,
in order to adapt such machines to cover a wide range of leads, it is necessary
to provide a large number of interchangeable lead screws and obviously this
represents a large investment, and the interchanging of these screws requires
the expenditure of considerable time in setting up the machine for each job.
Thread-grinding machines were being designed concurrent with the development of hob-
grinding machines. Many were entirely concerned with features peculiar to the problems of wheel-
dressing and to automatic characteristics. An invention to embody the use of a master screw and
concerned with the precision grinding of worm threads, for use in gearing, was patented by
Frederick A. Ward in this era. [8] That part of the invention pertaining to the use of a master screw,
“a rotary work holder mounted on said carriage and provided with a driving spindle, an
exchangeable master screw and stationary nut detachably secured to said spindle and head, …” is
shown in figure 23.

Figure 23.—Details of a work spindle with work, showing the use of a master lead screw to
control the pitch of a precision worm thread being ground. From the 1933 U.S. patent
1899654, of F. A. Ward’s worm-grinding machine.

Machines embodying the principle of the master lead screw are found in constant use by
industry at the present time for specialized application. Whenever technological changes again
reopen the topic of thread-cutting to a new degree of accuracy or call for a reevaluation of popular
methods for any other reason, we may expect to see another resurgence of the master-screw
method, for no other design eliminates so many variables or rests on such firm and fundamental
natural principles as the machine of Das mittelalterliche Hausbuch of 1483, the earliest such
machine now known.
FOOTNOTES

[1]
Jacques Besson, Des instruments mathématiques, et méchaniques, servants à l’intelligence de plusieurs choses
difficiles, & nécessaires à toutes républiques, 1st ed. (Orleans, 1569). [Also available in later editions in French,
German, and Spanish.]
[2]
J. Foster Petree, introduction, Henry Maudslay, 1771-1831, and Maudslay Sons and Field, Ltd. (London: The
Maudslay Society, 1949).
[3]
American Machinist (September 28, 1916), vol. 45, no. 13, pp. 529-531.
[4]
U.S. patent 10383 issued to Joseph Nason of New York, January 3, 1854.
[5]
U.S. patent 293930 issued to Charles Vander Woerd of Waltham, Massachusetts, February 19, 1884.
[6]
U.S. patent 1874592, filed June 8, 1929, issued to C. G. Olson of Chicago, Illinois, August 30, 1932, and assigned to
the Illinois Tool Works, also of Chicago.
[7]
U.S. patent 1901926, filed February 16, 1928, issued to C. G. Olson of Chicago, Illinois, March 21, 1933, and
assigned to the Illinois Tool Works, also of Chicago.
[8]
U.S. patent 1899654, filed August 31, 1931, issued to F. A. Ward of Detroit, Michigan, February 28, 1933, and
assigned to the Gear Grinding Company of Detroit, Michigan.

Paper 37 - Transcriber’s Note
Page 110: “… the spindle, to prevent …” (had “pindle”)
Page 120: “… servants à l'intelligence de plusieurs choses difficiles, & nécessaires …”
(had “a,” “plusiers,” “necessaires”)

Produced by Chris Curnow, Joseph Cooper, Louise Pattison and the Online Distributed
Proofreading Team at http://www.pgdp.net

"> Contributions from
The Museum of History and Technology:
Paper 38

The Earliest Electromagnetic Instruments

Robert A. Chipman

ELECTROSTATIC INSTRUMENTS BEFORE 1800 123

INSTRUMENTING VOLTAIC OR GALVANIC ELECTRICITY, 1800-1820 124

ELECTRICAL INSTRUMENTATION, 1800-1820 125

OERSTED’S DISCOVERY 126

BEGINNINGS OF ELECTROMAGNETIC INSTRUMENTATION 126

CHRONOLOGY AND PRIORITY 127

ORIGINAL ELECTROMAGNETIC MULTIPLIERS 129

CONCLUSIONS 135

ACKNOWLEDGMENTS 136

INDEX

Figure 1.—Models of various electromagnetic instruments created by Schweigger,
Poggendorf and Cumming in 1821, made for an exhibit in the Museum of History and
Technology, Smithsonian Institution. (Smithsonian photo 49493.)

Robert A. Chipman

THE EARLIEST ELECTROMAGNETIC
INSTRUMENTS
The history of the early stages of electromagnetic instrumentation is traced
here through the men who devised the theories and constructed the
instruments.
Despite the many uses made of voltaic cells after Volta’s announcement of
his “pile” invention in 1800, two decades passed before Oersted discovered
the magnetic effects of a voltaic circuit. As a result of this and within a five-
month period, three men, apparently independently, announced the invention
of the “first” electromagnetic instrument. This article details the merits of
their claims to priority.
The Author: Robert A. Chipman is chairman of the Department of
Electrical Engineering at the University of Toledo in Toledo, Ohio, and
consultant to the Smithsonian Institution.

Electrostatic Instruments before 1800
t is the fundamental premise of instrument-science that a device for detecting or measuring a

I physical quantity can be based on any phenomenon associated with that physical quantity.
Although the instrumentation of electrostatics in the 18th century, for example, relied mainly
on the phenomena of attraction and repulsion and the ubiquitous sparks and other luminosities of

frictional electricity, even the physiological sensation of electric shock was exploited
semiquantitatively by Henry Cavendish in his well-known anticipation of Ohm’s researches.
Likewise, Volta in 1800 [1] described at length how the application of his pile to suitably placed
electrodes on the eyelids, on the tongue, or in the ear, caused stimulation of the senses of sight,
taste and hearing; on the other hand, he reported that electrodes in the nose merely produced a
“more or less painful” pricking feeling, with no impression of smell. The discharges from the
Leyden jars of some of the bigger frictional machines, such as van Marum’s at Leyden, were found
by 1785 to magnetize pieces of iron and to melt long pieces of metal wire. [2]
The useful instruments that emerged from all of this experience were various deflecting
“electrometers” and “electroscopes” (the words were not carefully distinguished in use), including
the important goldleaf electroscope ascribed to Abraham Bennet in 1787. [3]
In 1786, Galvani first observed the twitching of the legs of a dissected frog produced by
discharges of a nearby electrostatic machine, thereby revealing still another “effect” of electricity.
He then discovered that certain arrangements of metals in contact with the frog nerves produced
the same twitching, implying something electrical in the frog-metal situation as a whole. Although
Galvani and his nephew Aldini drew from these experiments erroneous conclusions involving
“animal electricity,” which were disputed by Volta in his metal-contact theory, it is significant from
the instrumentation point of view that the frog’s legs were unquestionably by far the most sensitive
detector of metal-contact electrical effects available at the time. Without their intervention the
development of this entire subject-area, including the creation of chemical cells, might have been
delayed many years. Volta himself realized that the crucial test between his theory and that of
Galvani required confirming the existence of metal-contact electricity by some electrical but
nonphysiological detector. He performed this test successfully with an electroscope, using the
“condensing” technique he had invented more than a decade earlier.

Instrumenting Voltaic or Galvanic Electricity,
1800-1820
In his famous letter of March 20, 1800, written in French from Como, Italy, to the president of
the Royal Society in London, Volta made the first public announcement of both his “pile” (the first
English translator used the word “column”), and his “crown of cups” (the same translator used
“chain of cups” for Volta’s “couronne de tasses”). The former consisted of a vertical pile of
circular disks, in which the sequence copper-zinc-pasteboard, was repeated 10 or 20 or even as
many as 60 times, the pasteboard being moistened with salt water. The “crown of cups” could be
most conveniently made with drinking glasses, said Volta, with separated inch-square plates of
copper and zinc in salt water in each glass, the copper sheet in one glass being joined by some
intermediate conductor and soldered joints to the zinc in the next glass.
Volta considered the “crown of cups” and the “pile” to be essentially identical, and as
evidences of the electrical nature of the latter, said:
… if it contains about 20 of these stories or couples of metal, it will be
capable not only of emitting signs of electricity by Cavallo’s electrometer,
assisted by a condenser, beyond 10° or 15°, and of charging this condenser by

mere contact so as to make it emit a spark, etc., but of giving to the fingers
with which its extremities (the bottom and top of the column) have been
touched several small shocks, more or less frequent, according as the touching
has been repeated. Each of these shocks has a perfect resemblance to that
slight shock experienced from a Leyden flask weakly charged, or a battery still
more weakly charged, or a torpedo in an exceedingly languishing state, which
imitates still better the effects of my apparatus by the series of repeated shocks
which it can continually communicate. [4]
The “effects” provided by Volta’s pile and crown-of-cups are therefore electroscope deflection,
sparks, and shocks. Later in the letter, he describes the stimulation of sight, taste, and hearing as
noted earlier, but nowhere does he mention chemical phenomena of any kind, or the heating of a
wire joining the terminals of either device. Hence, except for the additional physiological
responses, he adds nothing to the catalog of observations on which instruments might be based.
His familiarity with the moods of the torpedo (electric eel) seems to be intimate.
The reading of Volta’s letter to the Royal Society on June 26, 1800, its publication in the
Society’s Philosophical Transactions (in French) immediately thereafter, and its publication in
English in the Philosophical Magazine for September 1800, [5] gave scientists throughout Europe
an easily constructed and continuously operating electric generator with which innumerable new
physical, chemical, and physiological experiments could be made. Editor-engineer William
Nicholson read Volta’s letter before its publication and, by the end of April, he and surgeon
Anthony Carlisle had built a voltaic pile. Applying a drop of water to improve the “connection” of
a wire lying on a metal plate, they happened to notice gas bubbles forming on the wire, and
pursued the observation to the point of identifying the electrical decomposition of water into
hydrogen and oxygen.
Within two or three years innumerable electrochemical reactions had been described, some of
which, one might think, could have served as operating principles for electrical instruments.
Although the phenomena of gas formation and metal deposition were in fact widely used as crude
indicators of the polarity and relative strength of voltaic piles and chemical cells during the period
1800-1820 (and the gas bubbles were made the basis of a telegraph receiver by S. T. Soemmering),
the quantitative laws of electrolysis were not worked out by Faraday until after 1830, and not until
1834 was he satisfied that the electrolytic decomposition of water was sufficiently well understood
to be made the basis for a useful measuring instrument. Describing his water-electrolysis device in
that year, he wrote:
The instrument offers the only actual measurer [italics his] of voltaic
electricity which we at present possess. For without being at all affected by
variations in time or intensity, or alterations in the current itself, of any kind, or
from any cause, or even of intermissions of actions, it takes note with accuracy
of the quantity of electricity which has passed through it, and reveals that
quantity by inspection; I have therefore named it a VOLTAELECTROMETER. [6]
In passing, Faraday commented that the efforts by Gay-Lussac and Thenard to use chemical
decomposition as a “measure of the electricity of the voltaic pile” in 1811 had been premature
because the “principles and precautions” involved were not then known. He also noted that the
details of metal deposition in electrolysis were still not sufficiently understood to permit its use in
an instrument. [7]

The heating of the wires in electric circuits must have been observed so early and so often with
both electrostatic and voltaic apparatus, that no one has bothered to claim or trace priorities for this
“effect.” The production of incandescence, however, and the even more dramatic combustion or
“explosion” of metal-foil strips and fine wires has a good deal of recorded history. Among the first
to burn leaf metal with a voltaic pile was J. B. Trommsdorff of Erfurt who noted in 1801 the
distinctly different colors of the flames produced by the various common metals. In the succeeding
few years, Humphry Davy at the Royal Institution frequently, in his public lectures, showed wires
glowing from electric current.
Early electrical instrumentation based on the heating effect took an unusual form. Shortly after
1800, W. H. Wollaston, an English M.D., learned a method for producing malleable platinum. He
kept the process secret, and for several years enjoyed an extremely profitable monopoly in the sale
of platinum crucibles, wire, and other objects. About 1810, he invented a technique for producing
platinum wire as fine as a few millionths of an inch in diameter, that has since been known as
“Wollaston wire.” For several years preceding 1820, no other instrument could compare the
“strengths” of two voltaic cells better than the test of the respective maximum lengths of this wire
that they could heat to fusion. One can sympathize with Cumming’s comment in 1821 about “the
difficulty in soldering wires that are barely visible.” [8]

Electrical Instrumentation, 1800-1820
The 20 years following the announcement of the voltaic-pile invention were years of intense
experimental activity with this device. Many new chemical elements were discovered, beginnings
were made on the electrochemical series of the elements, the electric arc and incandescent
platinum wires suggested the possibilities of electric lighting, and various electrochemical
observations gave promise of other practical applications such as metal-refining, electroplating,
and quantity production of certain gases. Investigators were keenly aware that all of the available
means for measuring and comparing the electrical aspects of their experiments (however vaguely
these “electrical aspects” may have been conceived), were slow, awkward, imprecise, and
unreliable.
The atmosphere was such that prominent scientists everywhere were ready to pounce
immediately on any reported discovery of a new electrical “effect,” to explore its potentialities for
instrumental purposes. Into this receptive environment came H. C. Oersted’s announcement of the
magnetic effects of a voltaic circuit, on July 21, 1820. [9]

Figure 2.—“Galvanometer” was the name given by Bischof to this goldleaf electrostatic
instrument in 1802, 18 years before Ampère coupled the word with the use of Oersted’s
electromagnetic experiment as an indicating device.

Oersted’s Discovery
Many writers have expressed surprise that with all the use made of voltaic cells after 1800,
including the enormous cells that produced the electric arc and vaporized wires, no one for 20
years happened to see a deflection of any of the inevitable nearby compass needles, which were a
basic component of the scientific apparatus kept by any experimenter at this time. Yet so it
happened. The surprise is still greater when one realizes that many of the contemporary natural
philosophers were firmly persuaded, even in the absence of positive evidence, that there must be a
connection between electricity and magnetism. Oersted himself held this latter opinion, and had
been seeking electromagnetic relationships more or less deliberately for several years before he
made his decisive observations.
His familiarity with the subject was such that he fully appreciated the immense importance of
his discovery. This accounts for his employing a rather uncommon method of publication. Instead
of submitting a letter to a scientific society or a report to the editor of a journal, he had privately
printed a four-page pamphlet describing his results. This, he forwarded simultaneously to the
learned societies and outstanding scientists all over Europe. Written in Latin, the paper was
published in various journals in English, French, German, Italian and Danish during the next few
weeks.[10]

In summary, he reported that a compass needle experienced deviations when placed near a wire
connecting the terminals of a voltaic battery. He described fully how the direction and magnitude
of the needle deflections varied with the relative position of the wire, and the polarity of the
battery, and stated “From the preceding facts, we may likewise collect that this conflict performs
circles….” Oersted’s comment that the voltaic apparatus used should “be strong enough to heat a
metallic wire red hot” does not excuse the 20-year delay of the discovery.

Beginnings of Electromagnetic
Instrumentation
The mere locating of a compass needle above or below a suitably oriented portion of a voltaic
circuit created an electrical instrument, the moment Oersted’s “effect” became known, and it was
to this basic juxtaposition that Ampère quickly gave the name of galvanometer. [11] It cannot be
said that the scientists of the day agreed that this instrument detected or measured “electric
current,” however. Volta himself had referred to the “current” in his original circuits, and Ampère
used the word freely and confidently in his electrodynamic researches of 1820-1822, but Oersted
did not use it first and many of the German physicists who followed up his work avoided it for
several years. As late as 1832, Faraday could make only the rather noncommittal statement: “By
current I mean anything progressive, whether it be a fluid of electricity or vibrations or generally
progressive forces.” [12]
Nevertheless, whatever the words or concepts they used, experimenters agreed that Oersted’s
apparatus provided a method of monitoring the “strength” of a voltaic circuit and a means of
comparing, for example, one voltaic battery or circuit with another.
It was perfectly clear, from Oersted’s pamphlet, that if a compass needle was deflected
clockwise when the wire of a particular voltaic circuit lay above it in the magnetic meridian, the
same needle would also be deflected clockwise if the wire was turned end-for-end and placed
below the compass needle, without changing the rest of the circuit. Anyone perceiving this fact
might deduce, as a matter of logic, that if the wire of the circuit was first passed above the needle,
in the magnetic meridian, then folded and returned in a parallel path below the needle, the
deflecting effect on the needle would be repeated, and a more sensitive indicator would result,
assuming that any additional wire introduced has not affected the “circuit” excessively.
Since 1821, historical accounts of the origins of electromagnetism seem to have limited their
credit assignments for the conception and observation of this electromagnetic “doubling” effect (or
“multiplying” effect, if the folding is repeated) to three persons. Almost without exception,
however, these accounts have given no specific information as to precisely what each of these
three accomplished, what physical form their respective creations took, what experiments they
performed, and what functional understanding they apparently had of the situation. The usual
statement is simply that a compass needle was placed in a coil of wire. [13] The main purpose of
the present review is to recount some of these details.
The following are the three candidates whose names are variously associated with the
“invention” of the first constructed electromagnetic instrument, or “multiplier,” or primitive
galvanometer.

Johann Salomo Christoph Schweigger (1779-1857) in 1820 had already been editor for
several years of the Journal für Chemie und Physik, and was professor of chemistry at the
University of Halle.
Johann Christian Poggendorf (1796-1877) in 1820 had only recently entered the University of
Berlin as a student following several years as an apothecary’s apprentice and a brief period as an
apothecary. Four years later, he succeeded Gilbert as editor of the influential Annalen der Physik, a
position he held for more than 50 years.
James Cumming (1771-1861) in 1820 was professor of chemistry at Cambridge University.

Chronology and Priority
The earliest established date in the “multiplier” record is September 16, 1820, when
Schweigger read his first paper to the Natural Philosophy Society of Halle. There seems to be no
reason to doubt that this report justifies the frequently used label “Schweigger’s multiplier.”

In an exuberant support of Schweigger’s position, Speter [14] with no mention of Cumming and
no hint of “invention” details, shows that Poggendorf in 1821 admitted Schweigger’s priority, but
suffered some lapse of memory 40 years later when writing sections of his biographical dictionary,
leaving a distinct suggestion that the invention was his. Further confusion for later generations
resulted from some ambiguous entries in the Allgemeine Deutsche Biographie of 1888. The name
“multiplier” seems not to have originated with Schweigger himself. Speter credits it to Meineke as
“working” editor of Schweigger’s Journal, but Seebeck seems to have used it much earlier. [15]
Conceding priority of conception to Schweigger (Cumming has not been a real competitor on
this point) does not alter the fact that all three seem to have reached their results independently of
one another, that the first work of each on this subject was published within a period of five
months, that there were significant differences in their conceptions of the uses and the optimum
design of their devices and that between them they provided an adequate foundation for the
subsequent development of the galvanometer to become the primary electrical-measuring
instrument.
In the matter of publication, Schweigger, as editor of what was popularly called Schweigger’s
Journal, had an obvious advantage, and presented his experiments beginnings on page 1 of the
first volume of his Journal for 1821, published January 1 of that year. [16] Oersted’s paper had
appeared two volumes previously. He began by referring to Oersted’s discovery as “the most
interesting to be presented in a thousand years of the history of magnetism.” He was, in fact, so
impressed with the epochal nature of Oersted’s achievement that he commemorated it by giving
his Journal a second title so that “volume one” of the new title could begin in the year after
Oersted’s publication.
Poggendorf, as a relatively junior student, had no such easy access to publicity, but he had a
staunch admirer in one of his professors, Paul Erman at the University of Berlin. Erman added a
seven-page postscript on Poggendorf’s invention to his book Outline of the Physical Aspects of the
Electro-chemical Magnetism Discovered by Professor Oersted, published before April 1821, [17]
with an introductory paragraph:

Herr Poggendorf, who is one of the most excellent ornaments of the lecture
room and laboratory of the University here, carried out a very coherent and
well-conceived investigation of electro-chemical magnetism, leading step-by-
step to a method of amplifying this activity-phenomenon by means of itself.
The postscript begins by referring to the “condenser [Kondensator] just brought to my
attention by Herr Poggendorf” and explains that he cannot release his treatise “without preliminary
announcement of this subject of the highest importance.” (It can be inferred from the text that the
name “condenser” was chosen because of the device’s enhancing of magnetic measurements
analogously to the enhancing of electric measurements by Volta’s electrostatic “condenser.”)
Immediately on reading the book, Schweigger published extracts, mainly of the postscript,
with indignant comments on Erman’s remissness (or worse) in having failed to mention
Schweigger’s prior work. [18]
However, Erman was not alone in his unawareness, if it was that, of Schweigger’s discovery.
Rival editor Gilbert of the Annalen der Physik reviewed Erman at much greater length than
Schweigger, reprinting most of the postscript with evident enthusiasm, and stating in his preamble
that the invention is attributed to “a young physicist studying here in Berlin, Herr Poggendorf.” [19]
Only in a footnote is the reader directed to another footnote in the next article in the volume, where
Gilbert finally states that he “cannot leave unmentioned the fact that this amplifying apparatus
seems to be due to Herr Professor Schweigger.” He then quotes rather fully from Schweigger’s
first two papers.[16] Oersted in 1823 explained the situation thus: “The work of M. Poggendorf,
having been mentioned in a book on electromagnetism by the celebrated M. Erman published very
shortly after its discovery, became known to many scientists before that of M. Schweigger. This is
the reason for the same apparatus carrying different names.” [20]
The same confusion is well illustrated by the paper to which Gilbert attached his confessional
footnote mentioned above. Written by Professor Raschig of Dresden, on April 3, 1821, the paper is
entitled “Experiments with the Electro-magnetic Multiplier,” but the device, throughout the paper,
is repeatedly referred to in the phrase “Poggendorf’s condenser, or rather multiplier,” an awkward
combination that suggests editorial intervention. [21]
The work of James Cumming at Cambridge is described in two papers which he read to the
Cambridge Philosophical Society in 1821, which were then duly published in the Transactions of
that Society. The first, “On the Connexion of Galvanism and Magnetism,” was read April 2, 1821,
[22]
and the second, “On the Application of Magnetism as a Measure of Electricity,” was read a few
weeks later on May 21st. [23]
Though he quotes some unrelated 18th-century experiments by Ritter in Germany, an 1807
publication of Oersted’s, and electromagnetic experiments with solenoids performed by Arago and
Ampère in late 1820, Cumming makes no mention of Schweigger or Poggendorf, and never uses
the word “multiplier.” It, therefore, seems probable that his work was done without knowledge of
the German publications or inventions.

Original Electromagnetic Multipliers

Of the three sets of instruments made, respectively, by Schweigger, Poggendorf and Cumming,
those of Schweigger are the most elementary, and the least realistic from a practical point of view.
He makes little effort to investigate the effect of any design parameters, but presents some odd
conductor configurations that involve unimportant variations of the basic principle. The following
extracts from his first three papers[13] contain the major references to his conception, construction,
and use of his multiplier.

PAPER READ IN HALLE, SEPTEMBER 16, 1820

That a powerful voltaic pile is required for these experiments (of Oersted) I
have confirmed in my physics lectures, using an electric pile that was so strong
it would easily produce potassium metal the second and third day after it was
built. However, I soon saw that the electromagnetic effect was related, not to the
pile, but to the simple circuit, and I was thereby led to perform the experiment
with much greater sensitivity. To amplify these electromagnetic phenomena of
the simple circuit it seemed to me necessary to adopt a different arrangement
from that initiated by Volta, in order that the electrical phenomena of his simple
circuit might be raised to a higher degree.
Since a reversal of the effect occurs according to whether the connecting-
wire lies over or under the needle, and likewise according to whether the wire
leads from the positive or negative pole, thence I say it is an easy inference that
a doubling of the effect is attainable, which is verified in practice.
I present to the Society the simple “doubling apparatus” [Verdoppelungs-
Apparat], where the compass is placed between two wires passing around it. A
multiplication of the effect is easily obtained when the wire is not just once but
many times wound around. A single turn suffices, however, to demonstrate
Oersted’s experiments, using small strips of zinc and copper dipped in
ammonium-chloride solution.
Amid innumerable, rambling theorizations (such as, that “hydrogenation affects magnetism as
oxidation affects galvanism,” or “sulphur, phosphorous and carbon are especially significant in
magnetism, since iron in combination with any of these inflammable materials becomes a magnet-
material”), Schweigger announces that he looked for the reactive force of the needle on the
connecting wire in the simple Oersted experiment, and that he used his “amplifying apparatus” to
look for magnetic effects from an electrostatic machine, but without success in both cases. He
suggests that he will continue with many more electromagnetic experiments because “with the use of
the doubling-apparatus, the needle, instead of needing for excitation a cell capable of generating
sparks, approaches more closely the sensitivity of a twitching nerve.” However, “additional special
experiments are required to find to what limits the amplification can be increased by the method I
have created in the construction of this doubling-apparatus, using multiple turns of wire.”

Figure 3.—This wire “bow-pattern” was the first illustration Schweigger gave of his
“doubling apparatus,” though he had presented a verbal description of a single-coil
arrangement somewhat earlier. The purpose of the bow pattern was to show that compass

needles at the centers of the two loops deflected in opposite directions. (From Journal für
Chemie und Physik.)

PAPER READ IN HALLE, NOVEMBER 4, 1820
[The first half of this paper describes successful observations of the reaction-force of a magnetic
needle on the connecting wire of a voltaic circuit, achieved by pivoting the connecting wire in the
form of brass needles above and below the compass needle. Though the multiplier configuration of
needle and wire is in fact present here, Schweigger does not mention it, evidently regarding this as a
separate project. He continues.]
In my lecture of September 16th, I showed that Oersted’s results depend, not
on the voltaic cell, but only on the connecting circuit. The principle I have used
for amplification of the effects, for the construction of an electromagnetic
battery as it were, was the winding of wire around the compass, and I now
present to the Society a bow-pattern of multiple-wound, wax-insulated wire,
Figure 3. [There were no illustrations with Schweigger’s first paper.] While a
single wire, using the weak electric circuit here, deflects the magnetic needle
only 30° or 40°, if the compass is placed in one of the openings of this pattern,
the needle is deflected 90° to the east, or in the other opening 90° to the west,
using the same weak electric circuit….
The “bow-pattern” device has novelty interest only, adding nothing to the elucidation of the
multiplier phenomenon. The same is true of Schweigger’s next proposal, shown in figure 4. “… I
will now add another apparatus, which is just an extension of the previous one, whereby the needle
can take up any angle from 0° to 180°.” A short length of circular glass tubing, of inside diameter
large enough to contain a compass needle, stands with its axis vertical and has single or multiple
loops of wire wound on it in vertical diametral planes. In the illustration, successive plane coils are
inclined at 30° to one another. “… the electric current flows through the whole wire, and the needle
moves under all of these currents, and coming always into another loop can take any desired angle.”
With much further theorizing about “the correlation of magnetism with the cohesion of bodies,”
Schweigger states again his evaluation of his discovery: “Oersted succeeded in electromagnetic
research by using a spark-producing cell, which could make a wire glow. My amplifying
electromagnetic device needs only a weak circuit of copper, zinc, and ammonium chloride solution.”
[24]

Figure 4.—Schweigger made this peculiar construction of wire coils, wound endwise on a
short vertical section of glass tubing with a compass needle inside, merely to startle his Halle
audience with the fact that the compass needle could rest in any of several stable positions.
(From Journal für Chemie und Physik.)

Figure 5.—Schweigger’s suggestion of one possible design for an amplifying
electromagnetic indicator. The components are wooden rods and insulated wire. Position b
referred to in the text is at the bottom of the diagram between the letters a and c. (From
Journal für Chemie und Physik.)

“FURTHER WORDS ABOUT THE NEW MAGNETIC
PHENOMENA”
[This was presumably written between November 4, 1820, and the January 1, 1821, publication
date of his Journal.]

These wonderful new electrical effects [25] are most easily rendered
perceptible with the help of the previously described wire loops. To focus
attention on just one of the windings of Figure 3, we sketch a new drawing,
Figure 5…. Since it is of major importance that these loops be made of silk-

covered wire lying evenly on one another, it is convenient to wind the loops on
two small slotted sticks of wood, although it is also possible to hold the wires
together with wax or shellac, or to tie them together in an orderly manner with
silk thread….
In Figure 5, Aa and Cc represent little slotted rods of wood on which the
silk-covered wire is wound. Only three windings are shown in the figure, but I
generally adopt three times that many. Now t is connected with the copper and d
with the zinc, and the compass B set between the rods Aa and Cc with the coil
perpendicular to the magnetic meridian and the terminals d, t at the east.
The instant Z and K are dipped in the ammonium chloride solution, the
needle turns around and stays with the north pole point south….
If now the compass is taken out of the coil and put in position b, all effects
are reversed, and are considerably weaker, for obvious reasons….
It is of the same significance whether we bring the compass from B to b in
Figure 5, or from mesh 1 to mesh 2 in Figure 3, only that in the latter case,
because the compass is enclosed by the two sides, a stronger effect results….
If now the coil is rotated … so that the face previously north now faces
south, then on connecting the electric circuit there is absolutely no trace of effect
on the needle, assuming that the terminal wires are not reversed….
It seems unnecessary to note that our magnetic coil can be placed in the
direction of the magnetic meridian or at any arbitrary angle with it….
Following several pages of further talk about the relation of “cohesion to magnetism” and about
“unipolar and bipolar conductors,” the only additional item of interest is the observation that
discharges of a Leyden jar (Kleistichen Flasche) strong enough to burn strips of leaf gold and to
magnetize an iron rod in a coil, produced no compass-needle deflections, even with the help of the
“amplifying apparatus.”
Schweigger, therefore, described the basic multiplier idea clearly enough in his first paper, but
offered no sketch of the simplest construction until the third paper. In the second paper, meanwhile,
he had illustrated two peculiar designs involving the principle in less elementary ways.
His indifference to whether the wire loops lie in the magnetic meridian (fig. 3) or perpendicular
to it (fig. 5) or “at any other arbitrary angle to it,” reveals a poor appreciation of the measuring-
instrument potentialities. His conception seems to be primarily that of a detector.
Poggendorf’s invention, as first reported by Erman and presented to a wider audience by Gilbert
[26]
was described as consisting of typically 40 to 50 turns of 1/10-line diameter, silk-covered copper
wire tied tightly together, with the whole pressed laterally to form an elliptical opening in which a
pivoted compass needle could move freely while maintaining clearance of about 2 lines from the
wire at all points. [27]
“This magnetic condenser can be a great boon to electro-chemistry,” said Erman, for “it avoids
all the difficulties of electric condensers.” He noted that, using the condenser, Poggendorf had
already established the electric series for a great number of bodies, discovered various anomalies
about conductivities, and found a way of detecting dissymmetry of the poles of a compass needle.

On the other hand, even with the condenser, no magnetic effects have so far been obtainable from a
strong tourmaline, or from a 12,000-pair, Zamboni dry cell.
Poggendorf’s own account of his work finally appeared as a very long article in the journal
known as “Oken’s Isis.” [28] The editorial controversies mentioned earlier may have occasioned this
use of a periodical of such minor status in the fields of physics and chemistry.
The source of Poggendorf’s vision of the multiplier principle was a little different from
Schweigger’s inspiration. Aiming at some detailed analysis of Oersted’s observation, Poggendorf ran
the connecting wire of his cell-circuit along a vertical line to just above or below the pivot-point of
the compass needle, then, after a right-angle bend, horizontally above or below one of the poles of
the needle. As he studied the deflections produced for all four possible positions of such a wire, with
both cell polarities, he came to realize that if a rectangular wire loop in a vertical plane enclosed a
compass needle, all parts of the horizontal sides of the loop would produce additive deflections. By a
separate experiment, he showed that the vertical sides of the loop would also increase the
deflections. He saw at the same time that the effect of additional turns would be cumulative.
The multiple surrounding of the needle by a silk-covered wire, in a plane
perpendicular to the long axis of the needle, affords the physicist a very simple
and sensitive means of detecting the slightest trace of galvanism, or of
magnetism produced by it, so that I have given the name of magnetic condenser
to this construction, though I attach no special value to this name …
In analyzing the astonishingly increased power which the condenser gives to
the magnetic effect of a circuit, the first question that arises is how the effect
varies with the number of turns, whether it increases indefinitely or reaches a
maximum beyond which additional turns have no effect. The answer to this first
question is linked to the solution of another, viz, whether the degrees deflection
are a direct expression of the measure of the magnetic force or not.
To instruct myself on this point I made use of three separate circuits, each
containing an 8-turn condenser, and put these as close together as possible in the
magnetic meridian … with the needle between the windings. Each single circuit
… gave a deflection of 45° … When two were connected the deflection was 60°,
and when finally all three were put in magnetic operation, the deflection grew to
only 70°. It appears clearly from this that the angle of deflection is not in a
simple ratio with the magnetic force acting on the needle….
Neither Poggendorf nor Schweigger seems to have ruled out, on logical grounds alone, the
possibility of deflections greater than 90°, with the loop-plane in the magnetic meridian, though
Poggendorf does add a vague note that if the needle deflected too far it would encounter forces of the
opposing sign.
Poggendorf experimented with the size of the circuit wires, finding that larger wires led to
greater deflections. He noted that the size of the cell plates and the nature of the cell’s moist
conductors would certainly have a great effect, but that to investigate these in detail would take
undue time, and he therefore proposed to keep this part of the apparatus constant, using one pair of
zinc and copper plates 3.6 inches in diameter, separated by cloth soaked in ammonium-chloride
solution.
Poggendorf’s principal quantitative study of his magnetic condenser used 13 identical coils, each
with 100 turns. In order that the turns should all be at approximately the same distance from the

needle, the coils were wound of the finest brass wire that could be silk-insulated, the wire diameter
being 0.02 lines. On adding coils one at a time across the cell (i.e., connecting them in parallel), the
deflections were as follows:
Turns 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300
Deflection
45 50 55 59-60 62 63 64 65 651/2 66 66 66 66
in degrees
Adding some coils with fewer turns, and connecting various combinations “as a continuum” (i.e.,
in series), the deflections using the same cell were:
Turns 1 5 10 25 50 75 100 200 300 400 500 600 700 800 900 1000
Deflection 35-
10 22 27 30 40 40 40 40 40 41 40 40 40 40 40
in degrees 40

Making a few coils from wire with 1/8-line diameter, the deflections, again using the same cell
were:
Turns 5 25 50 100 Over 100
Deflection
20-22 40-45 45 65 65
in degrees
Since the needle used in these experiments was almost as long as the inside clearance of the
coils, no simple tangent law can be applied, and it is not possible to discover an equivalent circuit in
modern terms. However, the constancy of the deflections for large numbers of turns in each case
indicates that the cell voltage and resistance were fairly constant, and a rough estimate suggests that
the cell resistance was comparable to the resistance of one of the 100-turn coils of fine wire. Such a
value means that cell resistance limited the maximum deflections for the parallel-connected
multipliers, while coil resistance fixed the limit in the series case.
For all of these reasons, it was impossible that any useful functional law could be obtained from
the data.
Poggendorf concluded only that “the amplifying power of the condenser does not increase
without limit, but has a maximum value dependent on the conditions of plate area and wire size.” He
added two other significant comments derived from various observations, that the basic Oersted
phenomenon is independent of the earth’s magnetism, and that the phenomenon is localized, i.e., is
not affected by distant parts of the circuit.
Only a small fraction of Poggendorf’s paper is devoted to elucidating the properties of the
condenser. A similar amount is concerned with refuting various proposals, such as those of Berzelius
and Erman, about distributions of magnetic polarity in a conducting wire to account for Oersted’s
results. More than half of the paper describes results obtained by using the condenser to compare
conductivities and cell polarities under conditions where no effect had previously been detectable.
Notable is the observation of needle deflections in circuits whose connecting wires are interrupted by
pieces of graphite, manganese dioxide, various sulphur compounds, etc., materials which had
previously been considered as insulators in galvanic circuits. Poggendorf gives these the name of
“semi-conductor” (halb-Leiter).

Figure 6.—Electromagnetic instruments of James Cumming, used at Cambridge in 1821.
One is a single-wire “galvanometer,” following Ampère’s definition. Cumming called the
multiple-turn construction “galvanoscopes.” He showed how to increase their sensitivity by
partial cancellation of the earth’s magnetism at the location of the compass needle. (From
Transactions of the Cambridge Philosophical Society, vol. 1, 1821.)

Cumming’s first mention of the multiplier phenomenon, in his paper of April 2, 1821,[22] is quite
casual, and describes only a one-turn construction. He speaks first of single-turn ring of thick, brass
wire, and after noting that the sides of a circuit produce additive effects on a needle, he comments
that a flattened rectangular loop produces nearly quadruple the effect of a single wire. The paper is
primarily a review of Oersted’s work, with references to electromagnetic observations before
Oersted, and accounts of various related but nonmultiplier experiments that Cumming has made. His
second paper, of May 21st, contains a fine plate (fig. 6) illustrating arrangements used in
investigating the subject of the paper’s title “The Application of Magnetism as a Measure of
Electricity.” (Neither Poggendorf nor any of his commentators ever illustrated his “condenser.”)
Although this plate is never referred to in the paper itself, a nearby “Description” gives a few
comments. The two wire patterns shown are noted as simply “forms of spiral for increasing the
electromagnetic intensity.” The mounted wire loop, with enclosed compass needle and terminal
mercury cups, is clearly identical in principle with the devices of Schweigger and Poggendorf, and is
called a “galvanoscope.” The largest structure illustrated does not involve the multiplying effect. It is
called a “galvanometer,” consistent with Ampère’s definition of that word. To use it, two leads of a
voltaic circuit are inserted into the mercury cups AC and BD, and the board EFGH carrying the cups
is moved vertically until some “standard” deflection is obtained on the compass needle below. The
relative “strength” of the circuit is then given by the calibrated position of the sliding section.
Uncertainties are undoubtedly introduced by the arbitrary positions of the connecting wires from the
test circuit to the mercury cups, but Cumming drew some interesting conclusions from various
measurements he made.

Observing needle deflections for various positions of the wire A-B, with a “constant” voltaic
circuit, he found that “the tangent of the deviation varies inversely as the distance of the connecting
wire from the magnetic needle.” Here is a combination of the deflection law for a needle in a
transverse horizontal field and the magnetic-force law for a long, straight wire. The latter had been
determined experimentally by Biot and Savart, in November 1820, by timing the oscillations of a
suspended magnet. [29]
Cumming considers his straight-wire calibrated
“galvanometer” to be a device for “measuring” galvanic
electricity; on the other hand, his multiple-loop
“galvanoscopes” are for “discovering” galvanic electricity.
With the multiplier instrument, he found galvanic effects
(i.e., needle deflections) using copper and zinc electrodes
with several acids not previously known to create galvanic
action. A potassium-mercury amalgam electrode created a
powerful cell with zinc as the positive electrode, establishing
both the metallic nature of potassium and the fact that it is
the most negative of all metals.

In a third paper, presented April 28, 1823, [30] Cumming
reports use of the galvanoscope in experiments on the
thermoelectric phenomena recently discovered by Seebeck.
His note that “for the more minute effects a compass was
employed in the galvanoscope, having its terrestrial
magnetism neutralized …” seems to be the earliest mention
of this version of the astatic principle, a technique whose
dramatic effects were especially valuable in low-resistance
thermoelectric circuits, where the extra resistance of
additional multiplier turns largely offsets their magnetic
contribution. In detail, “the needle is neutralized by placing a Figure 7.—“Schweigger multiplier” used by
powerful magnet North and South on a line with its center; Oersted in 1823. A thin magnetic needle is held
and another, which is much weaker, East and West at some in a light, paper sling at F, suspended by a fine,
vertical fiber. (From Annales de Chimie et de
distance above it: by means of the first the needle is placed Physique.)
nearly at right angles to the meridian, and the adjustment is
completed by the second.”
On varying the length of the connecting wire of the circuit, Cumming found the deflections of
the multiplier needle to be in a nearly reciprocal relation. He speaks of the “conducting power of the
wire,” and seems not far from visualizing Ohm’s law, of which no published form appeared until
1826. Ohm’s own experiments were made with very similar apparatus.

Conclusions
An effort has been made to show that electrical experimenters prior to Oersted’s discovery in
1820 were in desperate need of some electrical instrument for galvanic or voltaic circuits that would
combine sensitivity, simplicity, reliability, and quick response. The nearly simultaneous creation by

Schweigger, Poggendorf and Cumming of an arrangement consisting of a coil of wire and a compass
needle provided the first primitive version of a device to fill that need.
It appears that Schweigger is clearly entitled to credit for
absolute priority in the discovery, but the original sources
suggest that both his understanding of the device and the
subsequent researches he performed with it were markedly
inferior to those of the other independent discoverers. In
using the generic label, “Schweigger’s Multiplier,” there
have been historical examples of attributing to Schweigger
considerably more sophistication than is justified. Figure 7
shows an instrument designed by Oersted in 1823, [20] which
he says “differs in only minor particulars from that of M.
Schweigger.” On comparing figure 7 with figures 3, 4, or 5,
the remark seems overly generous.
The history of the multiplier instruments has had its fair
share of erroneous reports and misleading clues. A fine
example is the illustration of figure 8, taken from what is
often quoted as the first report in English on Poggendorf’s
“Galvano-Magnetic Condenser.” [31] The sketch is the
editor’s interpretation of a verbal description given him by a
visiting Danish chemist who, in turn, had received the
information in a letter from Oersted. It incorporates, faithful
Figure 8.—Completely useless arrangement to the description, a “spiral wire … established vertically,”
of vertical coil and horizontal, unmagnetized
needle, presented in the Edinburgh with a needle “in the axis of the spiral,” yet by
Philosophical Journal of 1821 as misunderstanding of the axial relations and of the ratio of
“Poggendorf’s Galvano-Magnetic Condenser.” length to diameter for the coil, a completely meaningless
Almost every aspect of Poggendorf’s
instrument has been incorrectly represented. arrangement has resulted. The confusion is compounded by
the specifying of an unmagnetized needle.
Schweigger and Poggendorf, through their editorial positions, were among the best known of all
European scientists for several decades. On one basis or another their reputations are firmly
established. Comparison of the accounts of the early “multipliers,” however, suggests that the
Reverend James Cumming, professor of chemistry at the University of Cambridge, was a very
perceptive philosopher. This was well understood by G. T. Bettany who wrote in the Dictionary of
National Biography that Cumming’s early papers “though extremely unpretentious,” were
“landmarks in electromagnetism and thermoelectricity,” and concluded that: “Had he been more
ambitious and of less uncertain health, his clearness and grasp and his great aptitude for research
might have carried him into the front rank of discoverers.”

ACKNOWLEDGMENTS
I wish to thank Dr. Robert P. Multhauf, chairman of the Department of Science and Technology
in the Smithsonian Institution’s Museum of History and Technology, for encouragement in the
writing of this paper and for the provision of opportunity to consult the appropriate sources. To Dr.

W. James King of the American Institute of Physics, I am grateful for many provocative discussions
on this and related topics.

FOOTNOTES
[1]
A. Volta, “On the Electricity Excited by the Mere Contact of Conducting Substances of Different Kinds,” Philosophical
Transactions of the Royal Society of London (1800), vol. 90, pp. 403-431.
[2]
Some little-known but delightful observations in the prehistory of electromagnetism are described in a letter written by G. W.
Schilling from London to the Berlin Academy on July 8, 1769, published as “Sur les phénomènes de l’Anguleil
Tremblante” [Nouveaux Mémoires de l’Académie Royale des Sciences et Belles-Lettres, 1770 (Berlin, 1772), pp. 68-74],
translated to French from the original German. The letter recounts a multitude of experiments with various electric eels.
The two observations of electromagnetic interest are that a piece of iron held by the hand in the eel’s tank could be felt
quivering even when the fish was stationary several inches away, and a compass needle showed a deflection, both in the
water near the fish, and outside the tank, also with the fish stationary.
[3]
Abraham Bennet, Philosophical Transactions of the Royal Society of London (1787), p. 26.
[4]
Op. cit. (footnote 1), p. 403.
[5]
Philosophical Magazine (1800), vol. 7, pp. 289-311. [For a facsimile reprint, see Galvani-Volta (Bern Dibner’s Burndy
Library Publication No. 7), Norwalk, Connecticut, 1952.]
[6]
Michael Faraday, Experimental Researches in Electricity, vol. 1 (London, 1839), paragraph 739, dated January 1834.
[7]
Ibid., sec. 741.
[8]
James Cumming, “On the Application of Magnetism as a Measure of Electricity,” Transactions of the Cambridge
Philosophical Society (1821), vol. 1, pp. 282-286. [Also published in Philosophical Magazine (1822), vol. 60, pp. 253-
257.]
[9]
H. C. Oersted, Experimenta Circa Effectum Conflictus Electrici in Acum Magneticam (Copenhagen, July 21, 1820).
[10]
Full details of Oersted’s work and publications are in Oersted and the Discovery of Electromagnetism (Bern Dibner’s
Burndy Library Publication No. 18), Norwalk, Connecticut, 1961. The original Latin version and first English translation
are reproduced in Isis (1928), vol. 34, pp. 435-444.
[11]
A. M. Ampère, Annales de Chimie et de Physique (1820), vol. 15, p. 67. The word “galvanometer” had been used much
earlier by Bischof, “On Galvanism and its Medical Applications,” The Medical and Physical Journal (1802), vol 7, p.
529, for a form of goldleaf electroscope shown here in figure 2, but this use of the word does not seem to have been
adopted by others.
[12]
Op. cit. (footnote 6), paragraph 283, dated January 1833. A similar attitude was expressed in the same year by Christie,
Philosophical Transactions of the Royal Society of London (1833), vol. 123, p. 96: “I adopt the word current as a
convenient mode of expression, … but I would not be considered as adopting any theoretical views on the subject….”
[13]
Some prominent examples of this brevity of treatment are in E. Hoppe, Geschichte der Elektrizität (Leipzig, 1884); O.
Mahr, Geschichtliche Einzeldarstellungen aus der Elektrotechnik (Berlin, 1941); R. S. Whipple, “The Evolution of the
Galvonometer,” Journal of Scientific Instruments (1934), vol. 7, pp. 37-43; William Sturgeon, Scientific Researches
(Bury, 1850); A. W. Humphreys, “The Development of the Conception and Measurement of Electric Current,” Annals of
Science (1937), vol. 2, pp. 164-178.
[14]
M. Speter, “Klärung der Multiplikator-Prioritätsfrage Schweigger-Poggendorf,” Zeitschrift für Instrumentenkunde (1937)
vol. 57, pp. 29-32.
[15]
T. Seebeck, “Über den Magnetismus der Galvanischen Kette,” Abhandlungen der Koenigliche Akademie der Wissenschaften
zu Berlin (1820-1821), pp. 289-346. The phrase “Schweigger’s multiplier” is used on page 319. The many experiments
described in this paper added little or nothing to contemporary appreciation of the multiplier as an instrument.
[16]
J. S. C. Schweigger, Journal für Chemie und Physik (1821), vol. 31, pp. 1-18, 35-42. Pages 1-6 are the paper presented in
Halle on September 16, 1820; pages 7-18 are the paper presented in Halle on November 4, 1820, and pages 35-42 are “a
few additional words.” The preface to the whole volume is dated January 1, 1821. A somewhat earlier public
announcement referring to Schweigger’s discovery appeared in the Allgemeine Literatur-Zeitung (November 1820), no.
296, cols. 622-624, but this was lacking in detail and seems not to have been noticed by any scientists.

[17]
P. Erman, Umrisse zu den physischen Verhältnissen des von Herrn Prof. Oersted entdeckten elektro-chemischen
Magnetismus (Berlin, 1821). Hoppe (footnote 13) states that Erman’s book was published in May; however, it is referred
to in a letter dated April 3, 1821, by Raschig, Annalen der Physik (1821), vol. 67, pp. 427-436.
[18]
Op. cit. (footnote 16), vol. 32, pp. 38-50.
[19]
Annalen der Physik (1821), vol. 67, pp. 382-426, and footnote on pages 429-430 of same volume. The footnote accompanies
the article by Raschig mentioned in footnote 17.
[20]
H. C. Oersted, “Sur le Multiplier electro-magnetique de M. Schweigger, et sur quelques applications qu’on en a faites,”
Annales de Chimie et de Physique (1823), vol. 22, pp. 358-365.
[21]
“Versuche mit dem electrisch-magnetischen Multiplicator,” Annalen der Physik (1821), vol. 67, pp. 427-436.
[22]
Transactions of the Cambridge Philosophical Society (1821), vol. 1, pp. 269-278.
[23]
Op. cit. (footnote 8).
[24]
The German word Kette has been translated as “circuit” throughout. Although the equivalence of these words is clear, for
example, in Ohm’s work of 1826, the context in which Kette is sometimes used in 1820 and 1821 indicates that the
concept of a “circuit,” in the sense of the wiring external to the source of electricity, has not been established. The wiring
is regarded more as something incidental, used to “close” the cell, the cell being considered essentially the whole of the
apparatus. This view underlies the many attempts to correlate the Oersted phenomena with cell materials and design, and
with the use of such terms as “chemical magnetism” by Erman and others.
[25]
The reference here is to the Oersted-type experiments described in two papers by authors other than Schweigger on pages 19
to 34 of the volume.
[26]
Op. cit. (footnote 19), pp. 422-426.
[27]
One “line” seems to have been about 1/12 inch.
[28]
J. G. Poggendorf, “Physisch-chemische Untersuchungen zur näheren Kenntniss des Magnetismus der voltaischen Säule,”
Isis von Oken (1821), vol. 8, pp. 687-710. Most of Poggendorf’s numerical data is also in C. H. Pfaff, Der
Elektromagnetismus (Hamburg, 1824), along with some of Pfaff’s own work.
[29]
Reported in Annales de Chimie et de Physique (1820), vol. 15, pp. 222-223.
[30]
“On the Development of Electro-Magnetism by Heat,” Transactions of the Cambridge Philosophical Society (1823), vol. 2,
pp. 47-76.
[31]
“Account of the New Galvano-Magnetic Condenser invented by M. Poggendorf of Berlin,” Edinburgh Philosophical
Journal (July 1821), vol. 5, pp. 112-113.

Paper 38 - Transcriber’s Note
The following assumed typographical errors have been corrected:
ge 125: J. B. [Johann Bartholomacus] Tromsdorff—should be Johann Bartholomäus Trommsdorff
ge 134: “paper of April 2, 1821,[22] is quite”—had “1921.”
otnote 13: “Geschichte der Elektrizität”—had “Elektrizitat.”
otnote 16: “Journal für Chemie und Physik”—had “and.”

One questionable spelling has been retained as follows:

otnote 20: “Sur le Multiplier electro-magnetique”—should be “Multiplicateur”?

"> Contributions from
The Museum of History and Technology:
Paper 39

Fulton’s “Steam Battery”:
Blockship and Catamaran

Howard I. Chapelle
SURVIVING DESIGNS FOR FLOATING BATTERIES 145

CONTROVERSIAL DESCRIPTIONS 147

COPENHAGEN PLANS 150

HISTORY OF DOUBLE-HULL CRAFT 152

SAIL AND INBOARD PLANS 157

RECONSTRUCTING THE PLANS 161

NAVAL STEAMERS 167

INDEX

Figure 1.—Scale model of Fulton's Steam Battery in the Museum of History and Technology.
(Smithsonian photo P-63390-F.)

Howard I. Chapelle

FULTON’S
“STEAM BATTERY”:
BLOCKSHIP and CATAMARAN
Robert Fulton’s “Steam Battery,” a catamaran-type blockship, was built
during the War of 1812. Until recently, not enough material has been available
to permit a reasonably accurate reconstruction of what is generally
acknowledged to be the first steam man-of-war.

With the discovery, in the Danish Royal Archives at Copenhagen, of plans of
this vessel, it is now possible to prepare a reconstruction and to build a model.
This article summarizes the history of the vessel, describes the plans and the
reconstruction, and also evaluates its design with particular attention to the
double-hull construction.
The Author: Howard I. Chapelle is curator of transportation in the
Smithsonian Institution’s Museum of History and Technology.
he identity of the first steam man-of-war has been known for many years, and a great deal
T has been written and published on the history of this American vessel. Until recently, the only
available drawing of the ship has been a patent drawing made for Robert Fulton. This does not
comply with contemporary descriptions of the steamer and the drawing or plan is out of proportion
with the known dimensions. The lack of plans has heretofore made it impossible to illustrate the
vessel with any degree of precision, or to build a scale model.
The discovery in 1960 of some of the plans of this historic ship in the Danish Royal Archives at
Copenhagen now makes possible a reasonably accurate reconstruction of the vessel and also clarifies
some of the incomplete and often confusing descriptions by contemporary writers.
Of the numerous published accounts of the ship that are available, the most complete is David B.
Tyler’s “Fulton’s Steam Frigate.” [1] A contemporary description of the vessel by the British Minister
to Washington, 1820-23, Stratford Canning, was published by Arthur J. May. [2] In Naval and Mail
Steamers of the United States, by Charles B. Stuart, [3] and The Steam Navy of the United States, by
Frank M. Bennett, [4] the history of the ship and some descriptive facts are given. Stuart, in an
appendix, gives in full the report of the Supervisory Committee (set up to administer the building
contract). Tyler and Stuart, and the Committee Report are the principal sources from which the
following summary of the ship’s history is drawn.

Figure 2.—“Demologos,” a wood engraving based on the sketch which Robert Fulton
showed to President Madison in 1813. This wood engraving appears as plate 1 in Charles B.
Stuart’s Naval and Mail Steamers of the United States, and illustrates the section on Naval
Steamers, from which the account “The Demologos; or, Fulton the First,” is here reproduced
(pp. 167-171). Stuart obtained the sketch, assumed to have been made for Fulton’s patent on
the design of the Steam Battery, from the files of the U.S. Navy Department.

On December 24, 1813, Robert Fulton invited a group of friends—prominent merchants,
professional men and naval officers—to his home in New York City and there presented a proposal
for a project of great local interest. At that time the War of 1812 was in its second year and the
economic effect of the British naval blockade was being felt severely. The blockade cut off seaborne
trade and posed a constant threat of attack upon New York and other important ports, particularly
Baltimore. To defend the ports, it had been proposed to build mobile floating batteries or heavily
built and armed hulks with small sailing rigs, but the high cost of these and their doubtful value in
helping to break the blockade, compared to the value and action of a very heavy, large frigate, or a
74-gun ship, caused authorities to hesitate to proceed with the construction of any blockships or
floating batteries.
Fulton’s proposal concerned a floating battery propelled by steam power. He believed that steam
propulsion not only would give it effective maneuverability with no loss of gunpower, but also
would allow a successful attack upon the Royal Navy blockading ships during periods of protracted

calm, when sailing men-of-war were nearly helpless. The blockaders then could be attacked and
picked off, one by one, by the heavily armed steamboat.
Among those present at the meeting was Major General Henry Dearborn, a leading citizen and
soldier who was later to become noted in American political history. The first step taken during this
meeting was the founding of the Coast and Harbor Defense Company with Dearborn as president,
Fulton as engineer, and Thomas Morris as secretary. Next, a committee was established to raise
funds from Federal, State, and New York City governments as well as from individual contributors
to build the battery. The members of this committee consisted of General Dearborn, Commodore
Stephen Decatur, U.S.N.; General Morgan Lewis; Commodore Jacob Jones; U.S.N.; Noah Brown,
shipbuilder; Samuel L. Mitchill; Henry Rutgers; and Thomas Morris.
The committee proved cumbersome and was reduced to General Lewis, Issac Bronson, Henry
Rutgers, Nathan Sanford, Thomas Morris, Oliver Wolcott, and John Jacob Astor. Known as the Coast
Defense Society and with the name of Pyremon given the ship in prospectus, they attempted,
unsuccessfully, to raise funds privately.
The estimated sums to build a battery 130 feet long, with a 50-foot beam, capable of a speed of 5
mph, and carrying 24 long guns (18-pdr.), was $110,000. Fulton, still the chief engineer, in an effort
to interest the Federal Government, built a model of the proposed vessel and submitted it to some
prominent naval officers—Commodore Stephen Decatur, Jacob Jones, James Biddle, Samuel Evans,
Oliver Perry, Samuel Warrington, and Jacob Lewis. All gave their support to the Society in a written
statement and this recommendation proved helpful to the project in Congress and in the Navy
Department. In the process of passing a bill which went to the Senate Naval Affairs Committee
calling for $250,000 for the construction of the floating battery, the sum was raised to $1,500,000 for
the construction of “one or more” floating batteries and passed on March 9, 1814.
To supervise the start of construction, the Coast Defense Society appointed a committee
consisting of Dearborn, Wolcott, Morris, Mitchill, and Rutgers, with Fulton as engineer, and a model
and drawing of the proposed vessel was submitted to the Patent Office. The Secretary of the Navy,
although supporting the project, delayed action until he had weighed the importance of the batteries
in relation to other war needs, for at this time the naval shipbuilding program on the Great Lakes was
considered of prime importance. He also raised some technical questions concerning the design of
the batteries, which Fulton answered with a description of the vessel as 138 feet on deck, 120 feet on
the keel, 55 feet beam (each hull to have a 20-foot beam and the “race” between to be 15 feet wide),
draft 8 or 9 feet loaded, and the intended speed was to be 41/2 to 5 mph. The ship was to carry 24
long guns (32-pdr.), the engine was to be 130 hp, and the total cost, $200,000. In his letters to the
Secretary of the Navy, Fulton stated that Adam and Noah Brown would build the hull for $69,800
and that he would build the engine, machinery and boilers for $78,000, a total of $147,800. He
intended to have the boilers, valves, fastenings, and air pumps of brass or copper, which would raise
the machinery costs 59 percent above that of stationary engines and boilers then in use.
On May 23, 1814, the Secretary of the Navy authorized the Coast Defense Society and its
committee to act as Navy agents and to enter into the contracts required to build a vessel, and to
draw on the Navy storekeepers or Navy Yard commandants for such stores or articles on hand
needed for construction. The contracts were prepared and the committee now was officially
empowered to act for the Society, with Rutgers, Wolcott, Morris, Dearborn, Mitchill, and Fulton. On
June 4, Dearborn asked the Navy Department for $25,000 advance, for work had started. On the 6th,
he informed the Secretary that he had been ordered to assume command of the defenses of Boston
and that Rutgers had been appointed chairman of the construction committee in his place.

It is apparent that the Navy Department was pressed for funds, due to the very extensive
shipbuilding programs on Lakes Erie, Ontario, and Champlain in addition to the seagoing vessels
being built in some of the coastal ports. This was certainly one cause for the Secretary of the Navy’s
reluctance to carry out the requirements of the bill passed by Congress immediately after its
signature and, also, this reluctance caused the supervisory committee much embarrassment in its
administration of the contract.
Another factor which caused difficulty in the administration of the contract was the position of
Adam and Noah Brown. The brothers were deeply involved in the shipbuilding program on the
Lakes, in which they were associated at times with Henry Eckford. The Browns constructed a
blockhouse, shops, and quarters at Erie; in addition to Perry’s two brigs and five of his schooners,
they also built some of the Lake Ontario vessels and, later, the Saratoga on Lake Champlain. In their
New York yard, whose operation continued throughout the war, they built some large letter-of-
marques: the General Armstrong, Prince de Neufchatel, Zebra, Paul Jones, and some smaller
vessels. They also cut down the 2-decked, merchant ship China into a single flush-deck letter-of-
marque, renamed Yorktown; and they had a contract to build the sloop-of-war Peacock. It is
remarkable that the Browns could undertake and complete so much work between 1813 and 1815
and still be able to build the steam battery in a very short time.
With the contracts in order, the Browns began building. The keels of the battery were laid June
20, 1814. It is apparent that the Browns prepared the original hull plans, undoubtedly before the
building authority was obtained. The vessel required only about four months to build; she was
launched October 29, 1814, at 9 a.m. This was an excellent performance, considering the size of the
vessel, the amount of timber required and handled in her massive construction, and the other work
being done by the builders. During the ship’s construction, sightseers were a nuisance and finally
guards had to be obtained. During the building of the steam battery, work had to be practically
stopped on the sloop-of-war Peacock at one period after she had been partially planked.
There were difficulties in obtaining metalwork for the vessel during her construction, due to the
blockade and the demand for such material for other shipbuilding at New York. On November 21,
1814, the ship was towed from the Browns’ yard on the East River by Fulton’s Car of Neptune and
Fulton, each lashed to the sides of the battery, and taken to Fulton’s works on the North River. There
Fulton supervised in person the completion of the vessel and construction of her machinery.
Undoubtedly only a little of his time was required in inspection of the Browns’ work on the battery,
for the shipbuilders had been closely associated with Fulton throughout the life of the project and
were fully capable as ship designers. The work on the machinery was another matter, however, for
men capable of working metal were scarce and few workmen could read plans. Fulton had some of
the work done outside of his own plant, particularly the brass and copper work (mostly by John
Youle’s foundry). As a result, Fulton was required to move from plant to plant, keeping each job
under almost constant observation and personally supervising the workmen. The equipment then
available for building a large engine was inadequate in many ways. The large steam cylinder
presented a problem: it had to be recast several times and some of the other parts gave trouble, either
in casting or in machining and fitting.

Figure 3.—Scale model of Steam Battery, showing double hull, in the
Museum of History and Technology. (Smithsonian photo P-63390-D.)

Guns for the battery were another problem. Only 3 long guns (32-pdr.), were available at the
Navy Yard. The Secretary of the Navy promised some captured guns then at Philadelphia. Because
of the blockade, these had to come overland to New York. The captured guns thus obtained were
probably English, part of the cargo of the British ship John of Lancaster captured by the frigate
President early in the war. Apparently 24 guns were obtained this way; only 2 were obtained from
the Navy Yard. In July the Supervising Committee carried out some experimental damage studies, in
which a 32-pdr. was fired at a target representing a section of the topsides of the battery. Drawings of
the result were sent to the Secretary of the Navy.

Further problems arose over the delays of the government in making payments: the banks
discounted the Treasury notes, so the Committee members had to advance $5,000 out of their own
pockets. There was fear that British agents might damage the vessel, and although the project was
undoubtedly known to the British, no evidence of any act of sabotage was ever found. Captain David
Porter was assigned to the command of the battery in November, and it was upon his request that the
vessel was later rigged with sails.
With the Steam Battery approaching completion, the Secretary of the Navy became more
enthusiastic and the construction of other batteries of this type was again proposed. Captain Stiles, a
Baltimore merchant, offered to build a steam battery, the hull to cost $50,000; the entire cost of the
vessel, $150,000, was raised in Baltimore and the frames of a battery erected. Another battery was
projected at Philadelphia and the Secretary of the Navy wanted one or more built at Sackett’s Harbor,
but naval officers and Fulton objected. A bill put before Congress to authorize another half million to
build steam batteries passed the first reading January 9, 1815, went to the House February 22, 1815,
but the end of the war prevented any further action on it.
On February 24, 1815, Fulton died. He had been to Trenton, New Jersey, to attend a hearing on
the steamboat monopoly and, on the way back, the ferry on North River was caught in the ice. Fulton
and his lawyer, Emmet, had to walk over the ice to get ashore. On the way, Emmet fell through and
Fulton got wet and chilled while helping him. After two or three days in bed Fulton went to his
foundry to inspect the battery’s machinery causing a relapse from which he died. This resulted in
some delay in completing the machinery and stopped work on the Mute, an 80-foot, manually
propelled, torpedo boat that Fulton was having built in the Browns’ yard.
It was decided to suspend work on the Baltimore battery after an expenditure of $61,500, but the
New York battery was to be completed to prove the project was practical. The final payment of
$50,000 was made four months after it was requested.
Charles Stoudinger, Fulton’s foreman or superintendent, was able to complete and install the
ship’s machinery. On June 10, 1815, the vessel was given a short trial run in the harbor with
Stoudinger and the Navy inspector, Captain Smith, on board. This trial revealed the need of some
mechanical alterations; sails were not used, and it was found she could stem the strong tide and a
fresh headwind. The vessel also was visited by the officers of French men-of-war at anchor in the
harbor.
On July 4, 1815, she was given another trial. She left Fulton’s works at Corlear’s Hook at 9 a.m.,
ran out to Sandy Hook Lighthouse, bore west and returned, a total of 53 miles under steam, reaching
her slip at 5:20 p.m. She was found to steer “like a pilot boat.” This prolonged trial revealed that the
stokehold was not sufficiently ventilated and more deck openings were required. The windsails used
in existing hatches were inadequate. The paddle wheel was too low and had to be raised 18 inches,
and there were still some desirable modifications to be made in the machinery.
On September 11, 1815, she was again given a trial run. All alterations had been made, including
the addition of hatches and raising the paddle wheel, and her battery was on board with all stores,
supplies, and equipment. She had 26 long guns (32-pdr.), mounted on pivoted carriages, and now
drew 10 feet 4 inches. On this day she left her slip at 8:38 a.m. and went through the Narrows into
the Lower Bay, where she maneuvered around the new frigate Java at anchor there. The battery then
was given a thorough trial under steam and sail and, with the ship underway, her guns were fired to
see if concussion would damage the machinery. The vessel was found to be a practical one, capable
of meeting the government’s requirements in all respects; her speed was 51/2 knots. However, the
stokehold temperature had reached 116° Fahrenheit! She returned to her slip at 7:00 p.m.

On December 28, 1815, the Committee in a written report to the Secretary of the Navy, [5] gave a
description of the vessel and praised her performance. At this time a set of plans was made by “Mr.
Morgan,” of whom no other reference has appeared, and sent to the Navy Department. These cannot
now be found. The Committee recommended the battery be commissioned and used for training
purposes. This suggestion was not followed.
The ship remained in her slip during the winter, and in June 1816 she was turned over to the
Navy and delivered to Captain Samuel Evans, commandant of the New York Navy Yard. Captain
Joseph Bainbridge was assigned to her command. However, she was not commissioned and soon
after her delivery she was housed over and placed “in ordinary,” that is, laid up. The final settlement
showed that the Committee, as Navy agents, had paid out $286,162.12 with $872.00 unpaid, as well
as a claim for $3,364.00 by Adam and Noah Brown, making a total of $290,398.12.
The following year, on June 18, 1817, she was unroofed and put into service with a small crew.
With President James Monroe on board, she left the Navy Yard about noon for a short trip to the
Narrows and then to Staten Island and returned in the evening. The next day she was again placed
“in ordinary.”
Four years later, in 1821, when her guns and machinery were removed, it was found that she was
rapidly becoming rotten. She was then utilized as a receiving ship. At 2:30 p.m. on June 4, 1829, she
blew up, killing 24 men and 1 woman, with 19 persons listed as injured. Among those killed was one
officer, Lt. S. M. Brackenridge. Two lieutenants and a Sailing Master were hurt, four midshipmen
were severely injured, and five persons were listed as missing. The explosion of 21/2 barrels of
condemned gunpowder was sufficient, due to her rotten condition, to destroy the ship completely. A
Court of Inquiry blamed a 60-year-old gunner, who supposedly entered a magazine with a candle to
get powder for the evening gun. It was stated to the court that about 300 pounds of powder in casks
and in cartridges was on board the ship at the time.[3]
She was not replaced until the coast-defense steamer Fulton was built in 1837-38, though in
1822 the Navy purchased for $16,000 a “steam galliot” of 100 tons, the Sea Gull, to be used as a
dispatch boat for the West Indian squadron engaged in suppressing piracy during 1823. In 1825 she
was laid up at Philadelphia, and in 1840 she was sold for $4,750.
It is a curious fact that the battery did not receive an official name, as did the sailing blockship on
the ways at New Orleans, which at the end of the War of 1812 was officially listed as the Tchifonta.
Nor was the battery given a number, as were the gunboats. In official correspondence and lists, the
steam battery is referred to as the “Fulton Steam Frigate,” or as the “Steam Battery,” but in later
years she was referred to as the “Fulton” or “Fulton the First.” Perhaps the explanation is that as she
was the only one of her kind she was not numbered, and as she was not considered fit for coastal or
extended ocean voyages, she was not given a name.

Surviving Designs for Floating Batteries
The designs of American blockships that have survived are those of the Tchifonta, [6] 145 feet
long, 43-foot moulded beam, 8-foot 6-inch depth in hold, and about 152 feet 9 inches on deck. She
was to carry a battery of 22 long guns (32-pdr.), on the main deck 12 carronades (42-pdr.), on
forecastle and quarter decks. She was to have been rigged to rather lofty and very square topgallant
sails, and would have been capable of sailing fairly well, though of rather shoal draft, drawing only

about 8 feet 6 inches when ready for service. She was sold on the stocks at the end of the war and her
later history is not known.
Another and earlier design for a blockship, or floating battery, was prepared by Christian Bergh
for Captain Charles Stewart in 1806. This was a sailing vessel for the defense of the port of New
York, planned to mount 40 guns (32-pdr.), on her two lower decks and 14 carronades (42-pdr.), on
her spar deck. She was to be 103 feet 6 inches between perpendiculars, a 44-foot moulded beam, 10-
foot depth of hold, and drawing about 9 feet when ready for service. She was intended to be ship-
rigged, but was never built. [7] A few small sloop-rigged block vessels also were built during
Jefferson’s administration. The sloop-of-war Saratoga, built on Lake Champlain by the Browns, in
1813, was practically a blockship. A plan for a proposed “Guard Ship,” or “Floating Battery,” was
made by James Marsh at Charleston, South Carolina, in 1814. This was an unrigged battery, 200 feet
extreme length, 50-foot moulded beam, 9-foot depth of hold, to mount 32 guns (42-pdr.), on a flush
deck, with a covering deck above.[8]

Figure 4.—Design for an unrigged floating battery proposed by James Marsh, Charleston,
South Carolina, March 14, 1814.

Through the courtesy of the trustees of the National Maritime Museum, Greenwich, England, the
Rigsarkivet, Copenhagen, Denmark, and the Statens Sjöhistoriska Museum, Stockholm, Sweden, the
author has been able to illustrate in this article the designs of some of the early floating batteries.
In the last quarter of the 18th century and later, the Danes had built sail-propelled floating
batteries or blockships, which were employed in the defense of Copenhagen. The British built at
least one sail-propelled battery, the Spanker, in 1794. This was a scow of very angular form with
overhanging gun-deck, bomb-ketch-rigged, and about 120 feet overall 42-foot 4 inches moulded
beam and 8-foot depth of hold. She is said to have been a failure due to her unseaworthy proportions
and form; the overhanging gun deck and sides were objected to in particular. She is called a
“Stationary Battery” in her plans, which are in the Admiralty Collection of Draughts, National
Maritime Museum, Greenwich.

Controversial Descriptions
The contemporary descriptions of the Fulton Steam Battery do not agree. This was in part due to
differences between the dimensions given out by Fulton during the negotiations with the Federal
Government, and after the ship’s construction was authorized. From the context of various
statements concerning the projected vessel, such as that of the naval officers, the changes in the
intended dimensions of the ship can be seen. For example, the officers state the model and plan
shown them would produce a battery carrying 24 guns (24- and 32-pdrs.), and a letter from Fulton to
Jones, [9] shows she was to be 138 feet on deck and 55-foot beam. The final reported dimensions,
given by the Supervisory Committee, [10] are 156 feet length, 56 feet beam, and 20 feet depth.
In addition there are a few foreign accounts which give dimensions and descriptions. The most
complete was probably that of Jean Baptiste Marestier, a French naval constructor who visited the
United States soon after the end of the War of 1812 and published a report on American steamboats
in 1824. [11] The Steam Battery is barely mentioned though a drawing of one of her boilers is given.
Marestier made another report on the American Navy, however. Extensive searches have been made
for this in Paris over the last 14 years, but this paper has not been found in any of the French
archives. References to the original text indicate that the naval report dealt very extensively with the
Steam Battery. Some of his comments on the battery appeared in Procès-verbaux des Séances de
l’Académie des Sciences. [12] Marestier considered the powers of the battery to have been overrated
due to fanciful accounts of some laymen writers. He was aware of the shortcomings of the double
hull in a steam vessel at the then-possible speeds, but he apparently thought two engines, one in each
hull and each with its boilers would be better than Fulton’s arrangement of boilers in one hull and
engine in the other. He noted that the paddle wheel turned 16-18 rpm and that steam pressure
sustained a column of mercury 25 to 35 centimeters. The safety valve was set at 50 centimeters. Fuel
consumption was 35/8 cords of pine wood per hour.

In view of the access Marestier is known to have had to American naval constructors,
shipbuilders, and engineers, it is highly probable that he not only obtained the building plan of the
ship but also some of the earlier project plans from the builders and from Fulton’s superintendent,
Stoudinger. It is, therefore, a great misfortune that his lengthy report on the Battery cannot be
produced.
A French naval officer who investigated the ship, M. Montgéry, also wrote a description,
published in “Notice sur la Vie et les Travaux de Robert Fulton.”[13]

Figure 5.—Floating battery Spanker built, in England by William
Barnard, at Deptford on the Thames, and launched June 14, 1794. Rigged
as a bomb ketch, its length is 111 feet 7 inches in the keel, extreme beam
42 feet 4 inches, depth of hold 8 feet. Upper deck plan also shown.
It should be noted in regard to what Montgéry wrote about the Battery, that in 1821 it had been
considered desirable to disarm the ship. The engineer in charge, William Purcell, had reported that as
there were not proper scuppers, dirt and water had entered the hull and had collected under the
engine and boilers, causing damage to the hull, and also that with guns removed, the Battery would
float too high for the paddle wheel to propel the vessel; so it had been decided to remove all
machinery as well as the armament.

Figure 5.

Montgéry’s description, published in 1822, was taken from his report to the Minister of Marine
and Colonies. It noted the battery was made of two hulls separated by a channel, or “race,” 151/2 feet
wide, running the full length of the vessel. The two hulls were joined by a deck just above the
waterline, as well as by an upper deck, and also connected at their keels by means of 12 oak beams
each 1 foot square. The vessel was 152 feet long, 57 feet beam, and 20 feet deep. Sides were 4 feet
10 inches thick, and the ends of the hull were rounded and alike. There were two rudders at each end,
one on each hull, alongside the race. The eight paddle blades, each 141/2 feet by 3 feet, turned in
either direction by stopping the engine piston at half-stroke and reversing the flow of steam. Rigged
with two lateen sails and two jibs, the ship sailed either end first. The engine of 120 hp was in one
hull and two boilers were in the other. Other sources, Marestier, and Colden in Procès-verbaux des
Séances de l’Académie des Sciences, [14] gave additional information (some of it incorrect): the
engine was inclined, with a 4-foot-diameter cylinder, 5-foot stroke, direct-connected to the paddle
wheel, which was turned at 18 rpm. The boilers were 8 × 22 feet with the fireboxes in inside
cylinders, each about 5 feet in diameter, and extending about half the length of the boiler from the
fire doors. Two fire tubes, each about 3 feet in diameter, returned the gases from the inside end of the
fireboxes to the stacks at the firing end. Except at the fire-door end, the firebox was completely
surrounded by water. The boiler pressure of about 6 psi was not maintained, varying somewhat with
each stroke of the engine.

Water level in the boilers was indicated by try cocks. The safety valve was controlled by a
counterbalanced lever. A jet of salt water was injected into the exhaust trunk to form a vacuum by
condensation. An air pump transferred condensate and sea water into a tank from which it passed
overboard. Only about a tenth of this water was returned to the boilers.
Montgéry stated also that only the lower or gun deck was to be armed. No bulwarks were on the
spar deck, only iron stanchions to which were fastened a breastwork of wet cotton bales when the
Steam Battery was in action.
The Battery was designed to carry 30 guns (32-pdr.), with 3 guns in each end and 12 on each
side, but no guns in the wake of paddle wheel and machinery. Hatches to give air to the stokehold
were located amidships. The Battery was to have been supplemented at the ends of each hull by a
Columbiad “submarine gun” (100-pdr.), Fulton’s invention, but these were not fitted. Provision was
to be made in the fireboxes for heating shot, and a force pump with a cylinder 33 inches in diameter
was employed to throw a stream of cold water, about 60-80 gallons per minute, for a distance of
about two hundred feet. This could be done only when the paddle wheel was not in operation. The
paddle wheel was housed, the top fitted with stairs to the spar deck. The gun deck, over the race, was
used in part for staterooms, of which the bulkheads were permanent. Hammocks for the complement
of 500 men were to be slung on the rest of the gun deck. The ship drew 10 feet 4 inches, with the
port sills about 51/2 feet above the loadline. Burning wood, the vessel could carry about 4 days’
supply of fuel; burning coal, she carried 12 days’ supply.
Montgéry said that the vessel would be vulnerable to bombshells and hot shot, and that
furthermore she could be boarded. The displacement of the ship, at service draft, was 1,450 tons, a
figure Montgéry obtained from a copy of the original plan given him by Noah Brown.

Figure 6.—French sketch, in Rigsarkivet, Copenhagen, of
inboard profile and arrangement of Fulton’s Steam Battery,

showing details of the Fulton engine, probably taken from one
of his preliminary designs.

In 1935, Lieutenant Ralph R. Gurley, USN, attempted a reconstruction in sketches of the vessel
published in his article “The U.S.S. Fulton the First” in the U.S. Naval Institute Proceedings. [15]
This reconstruction was based on the Patent Office drawing prepared for Fulton, and published by
Stuart and Bennett, and the foregoing French sources. The Patent Office drawing showed the engine
was an inclined cylinder and Lt. Gurley shows this in his sketch; in his text (p. 323) he says, “The
engine was an inclined, single-cylinder affair with a 4-foot base and a 5-foot stroke.” Gurley’s
attempt to reconstruct the Steam Battery is the only one known to the author.

Copenhagen Plans
In 1960, Kjeld Rasmussen, naval architect of the Danish Greenland Company, was requested by
the author to inspect in the Danish Royal Archives at Copenhagen a folio of American ship plans, the
index of which had listed some Civil War river monitors. Mr. Rasmussen found the monitor plans
had been withdrawn but discovered that three plans of Fulton’s Steam Battery existed, as well as
plans of the first Princeton, a screw sloop-of-war.
Copies of the Steam Battery’s plans were obtained at Copenhagen in September 1960 through the
courtesy of the archivist, and were found to consist of the lines, copied in 1817, an inboard profile
and arrangement, and a sail and rigging plan. From these the reconstruction for a scale model was
drawn and is presented here with reproductions of the original drawings upon which the
reconstruction is based.
It is apparent that Montgéry’s description is generally accurate. The vessel is a catamaran, made
of two hulls, double-ended and exactly alike. The outboard sides are “moulded,” with round bilges,
the inboard sides are straight and flat, as though a hull had been split along the middle line and then
planked up flat where split. The hulls are separated by the race, in which the paddle wheel is placed
at mid-length. The topsides are made elliptical at the ends, and the midsection shows a marked
tumble-home over the thick topside planking but less on the moulded lines.

Figure 6.

The lines plan agreed rather closely to Montgéry’s description of the hull. After careful fairing it
was found the lines drawing would produce a vessel 153 feet 2 inches overall outside the stems, or
about 151 feet over the planked rabbets, with a moulded beam of 56 feet and extreme beam of 58
feet. The moulded depth was 22 feet 9 inches and the width of the race was 14 feet 10 inches, plank
to plank. The room and space of framing shown was 2 feet. The designed draft appears to be 13 feet
and this would bring the port sills 5 feet 6 inches above the loadline and the underside of the gun-
deck beams about 2 feet 9 inches above the loadline.
The lines plan is a Danish copy, probably of the building plan by Noah Brown, and may be based
on the plan Montgéry obtained from Brown. The spar deck has the iron stanchions (Gurley translated
these as “chandeliers”) which are set inboard 4 feet from the plank-sheer. This gives room for cotton
bales, outboard the stanchions, to form a barricade. As will be seen by comparing the original Danish
drawing with the model drawing, the construction indicates that the iron stanchions should be carried
around the ends of the hull in the same manner as along the sides, since the lower ends of the iron
stanchions pass through the spar deck and are secured to the inside of the inner ceiling of the gun
deck. The rudders are as shown in the Danish drawing, and it is supposed that they were operated
ferryboat fashion, one at each end of the vessel. Hence, each pair of rudders was toggled together by
a cross-yoke. This was probably operated by a tiller (possibly the cross-yokes and tillers were of
iron) pivoted under the beams of the gun deck close to the ends of the ship. Tiller ropes led from a
tackle under the gun-deck through trunks to the spar deck, where the wheels were placed. This
allowed proper sweep to the tillers and operation of each pair of rudders. The paddle wheel was
apparently of iron, with wooden blades, and agrees with Montgéry’s description. In the plan for the
model it is shown raised 18 inches above the original design position, to agree with trial
requirements.
It should be observed that the close CL-to-CL frame spacing created a hull having frames
touching one another, at least to above the turn of the bilge, so the vessel was almost solid timber,
before being planked and ceiled, from keel to about the loadline. The sides are not only heavily
planked but, after the frames were ceiled with extraordinarily heavy, square timbering, a
supplementary solid, vertical framing was introduced inboard and another ceiling added. The sides

scale about 5 feet from outside the plank to the inboard face of the inner ceiling at the level of the
gunports.
The hulls were tied together athwartship by the deck beams of the gun deck and spar deck,
except in the wake of the paddle wheel. Knees were placed along the sides of the race at alternate
gun-deck beams. In addition, the 12 1-foot-square timbers, crossing the race at the rabbets of the
hulls, (mentioned by Montgéry) are shown. These must have created extraordinary resistance, even
at the low speed of this steamer. The deck details shown are the results of reconstruction of the
inboard works.

Figure 7.—Original lines of Robert Fulton’s Steam Battery, a Danish copy dated
September 12, 1817; found in Rigsarkivet, Copenhagen.

History of Double-Hull Craft
The use of catamaran hulls, or “double-hulls,” has been periodically popular with ship designers
since the time of Charles II of England. The earliest of such vessels known in the present day were
four sloops or shallops designed 1673-1687 by Sir William Petty, who was an inventor in the field of
naval architecture and received some attention from Charles II and from the Royal Society.
The first Petty experiment, the Simon & Jude, later called Invention I, was launched October 28,
1662. She was designed with two hulls cylindrical in cross section, each 2 feet in diameter, and 20
feet long. A platform connected the hulls, giving the boat a beam of a little over 9 feet. She had a 20-
foot mast stepped on one of the crossbeams connecting the hulls, with a single gaff sail. In sailing
trials she beat three fast boats: the King’s barge, a large pleasure boat, and a man-of-war’s boat. This
“double-bottom,” also called a “sluiceboat” or “cylinder,” was later lengthened at the stern to make
her 30 feet overall.

Figure 7.

The King did not support Petty, to the latter’s great disappointment, and Petty next built a larger
double-bottom, Invention II. This catamaran was lapstrake construction. Not much is known of this
boat except that she beat the regular Irish packet boat, running between Holyhead and Dublin, in a
race each way, winning a £20 wager. She was launched in July 1663; what became of her was not
recorded.
A third and still larger boat, the Experiment, launched December 22, 1664, appears to have been
a large sloop. This vessel sailed by way of the Thames in April 1665 and went to Oporto, Portugal.
She left Portugal October 20, 1665, for home, but apparently went down with all hands in a severe
storm.

Figure 8.—Danish copy of original sail plan of Robert Fulton’s Steam Battery, dated
September 12, 1817, in Rigsarkivet, Copenhagen.

Figure 9.—Lines of Fulton’s Steam Battery, as reconstructed for a model in the Museum of History and Technology.

Figure 10.—A reconstruction of inboard works of the Steam Battery, for construction of the model in the Museum of
History and Technology.

For 18 years Petty did no more with the type, but finally, in July 1684, he laid down a still larger
sloop with two decks and a mast standing 55 feet above her upper deck. She was named St. Michael

the Archangel and is probably the design in Pepys’ Book of Miscellaneous Illustrations in Magdalene
College, Cambridge, England. This vessel proved unmanageable and was a complete failure.

Figure 11.—Model lines redrawn to outside of plank to show hydrodynamic form of the
Steam Battery.

Though the double canoes of the Pacific Islands were probably known to some in Europe in
1662, there is no evidence that Petty based his designs on such craft. He appears to have produced
his designs spontaneously from independent observations and resulting theories. Before Petty
concluded his experiments, a number of double-hull craft had been produced by others; however,
some “double” craft, such as “double shallops” may have been “double-enders,” as shown by a
“double-moses boat” of the 18th century and later. [16]
The use of two canoes, joined by a platform or by poles was common in colonial times; in
Maryland and Virginia, dugouts so joined were used to transport tobacco down the tidal creeks to
vessels’ loading. Such craft were also used as ferries. M. V. Brewington’s Chesapeake Bay Log
Canoes [17] and Paul Wilstack’s Potomac Landings [18] illustrate canoes used in this manner. A
catamaran galley, two round-bottom hulls, flat on the inboard side (a hull split along the centerline
and the inboard faces planked up), 113 feet long and each hull a 7-foot moulded beam, 6-foot 6
inches moulded depth, and placed 13 feet apart, was proposed by Sir Sidney Smith, R.N., in the
1790’s, and built by the British Admiralty. Named Taurus, she is shown by the Admiralty draught to
have been a double-ender, with cabins amidships on the platform, an iron rudder at each end
(between the hulls) steered with tillers (to unship), and with a ramp at one end. The plans are
undated, signed by Captain Sir Sidney Smith, and a field-carriage gun is shown at the ramp end of
the boat. This, and the heavy rocker in the keels, suggests the Taurus was intended for a landing
boat. No sailing rig is indicated, but tholes for 12 oars or sweeps on each side are shown. The
oarsmen apparently sat on deck, or on low seats, with stretchers in hatches between each pair of
tholes (Admiralty Collection of Draughts, The National Maritime Museum, Greenwich, England).

Figure 12.—General plan of the Taurus, a catamaran galley gunboat proposed by Sir Sidney
Smith, R.N., to the British Admiralty in the early years of the French Revolution. From the
Admiralty Collection of Draughts, National Maritime Museum, Greenwich.

Another experimenter with the double-hull type of vessel was a wealthy Scot named Patrick
Miller who was particularly interested in manual propulsion of vessels, employing geared capstans
to operate paddle wheels. In a letter dated June 9, 1790, Miller offered Gustav III of Sweden a design
for a double-hulled 144-gun ship-of-the-line (rating as a 130-gun ship) propelled by manually
operated capstans connected to a paddle wheel between the hulls. She was rigged to sail, with five
masts and was to be 246 feet long, 63 feet beam, and 17 feet draft; the hulls were 16 feet apart.
This project was submitted by the King to Fredrik Henrik af Chapman, the great Swedish naval
architect, who made an adverse report. Chapman pointed out in great detail that the weight of the
armament, the necessary hull structure, the stores, crew, ammunition, spars, sails, rigging and gear,
would greatly exceed Miller’s designed displacement. He also pointed out the prime fault of
catamarans under sail—slow turning in stays. He suggested that the speed under sail would be
disappointing. He doubted that a double-hull ship of such size could be built strong enough to stand
a heavy sea. He remarked that English records showed that a small vessel of the catamaran type had
been built between 1680 and 1700 which had sailed well (this may have been one of Petty’s boats),
and that “36 years ago” he had seen 8 miles from London, a similar boat that had been newly built
by Lord Baltimore and was about 50 feet long; this was a failure and was discarded after one trial.
Therefore, said Chapman, the Miller project was not new but rather an old idea. Chapman’s final
remark is perhaps the best illustration of his opinion of the catamaran, “Despite all this, two-hull
vessels are completely sound when the theory can be properly applied; that is in vessels of very light
weight, and of small size, with crews of one or two men.”
A “model” of such a double-hull ship—the Experiment, built at Leith, Scotland, in 1786 by J.
Laurie—was sent to Sweden by Miller. She was 105 feet long, 31 feet beam, and cost £3000. This
vessel arrived in the summer of 1790 and King Gustav in a letter dated July 26 ordered Col. Michael
Anckerswärd to welcome the vessel at Stockholm. The King presented Miller with a gold snuffbox
and a painting was made of the vessel. The Experiment had five paddle wheels in tandem between
her hulls, operated by geared capstans on deck. These gave her a speed of 5 knots but caused the
crew to suffer from exhaustion in a short time. The vessel was badly strained in a storm and was
finally abandoned at St. Petersburg, Russia.[19]
Miller later turned to the idea of employing steam instead of manual power and built a 25-foot
double-hulled pleasure boat of iron fitted with a steam engine built by William Symington. Also

named Experiment, she was an apparent success, so Miller
had a 60-foot boat built of the double-hull design and fitted
with an engine built by Symington. She reached a speed of 7
mph on the Forth and Clyde Canal. However, Miller lost
interest when he found that the Symington engine was
unreliable and that Great Britain showed very little public
support for such projects.
Fulton was acquainted with Symington’s work and
probably had heard of Miller’s vessels. At any rate, he
employed the double-hull principle in his steam ferryboats,
the first of which was the Jersey, a 188-ton vessel built by
Charles Browne, which began service July 2, 1812. The next
year he had a sister ship built, the York. These vessels were
based on his patent drawing of 1809. In 1814 he had another
vessel of this type built, the Nassau. It was, therefore, logical
that he should apply this design to the Steam Battery. The
double-hull design had worked well in these ferries, and the
design would give protection from shot to the paddle wheel.
The Battery would have the ability to run forward or astern
so as not to be exposed to a raking fire from the enemy while
maneuvering in action. The application of this “ferryboat”
principle to the Battery reduced the need for extreme
maneuverability, the catamaran’s weakest point, even at low
speed.
The resistance factors in the design are of relatively
small importance, for the speed possible under steam in this
period was very low. However, the plans show an apparently
Figure 12. efficient hull form for the power available, aside from the
drag of the beams across the race in the vicinity of the keel.
The displacement was adequate. The height of the gun-deck above the water at the race made the
Battery unsuitable for rough-water operation, but there is no evidence that Fulton or the sponsors of
the vessel considered the Battery as a coastwise or seagoing steamer. However, the clearance of the
gun deck above the water and the dip of the paddle wheel would have made the additional weight of
an upper- or spar-deck battery prohibitive even had experience in action proven it desirable.

Sail and Inboard Plans

Figure 13.—Lines of Taurus. From the Admiralty Collection of Draughts, National Maritime
Museum, Greenwich.

The sail and rigging plan is likewise a Danish copy and shows the two-masted lateen rig
employed. The hull is shown with bulwarks and gunports on the spar deck but no other evidence that
the Battery was finished in this manner has been found. The rig resembles that of some of Josiah
Fox’s designs for Jeffersonian gunboats—double-enders designed to sail in either direction but
without the jibs. The topmasts do not appear to be more than signal poles and apparently were not
fitted with sails; however, some European lateeners did have triangular topsails over a lateen and it is
possible the Battery may have carried such sails. Considering the stability and displacement of the
Battery, the rig is very small and not sufficiently effective. Shrouds were not required; the masts
were supported by runners that were shifted when the yards were reversed, and in tacking.
Apparently the jibstays also could be slacked off so that the lateen yards would not have to be dipped
under them.

Figure 14.—Rudder detail of Taurus. From the Admiralty Collection of Draughts, National
Maritime Museum, Greenwich.

The inboard profile is on tracing paper and the notes are in French. This drawing is of a
simplified hull form having flat-bottom hulls with chines. It is possible that this is a tracing of a
preliminary drawing obtained by Marestier or Montgéry, but no documentation can be found. Its

importance is that it shows in some detail the engine and boilers, as well as the wheelbox, and
another drawing of the paddle wheel, more or less duplicating the wheel shown in the Danish plan.
No details of the deck arrangements are shown in any of the plans, except for the dome skylight over
the fireroom in the boiler hull.
Both the lines plan and the inboard drawing show construction midsections and hull connections.
These plans show that the engine was not inclined, but rather was vertical, contrary to Fulton’s
patent drawing. The piston rod and the crosshead obviously passed through its gun deck in a large
hatch. Also it is plain that there must have been large hatches afore and abaft the wheelbox to make
the stepped wheelbox construction desirable. There also must have been a hatch in the gun deck
under the domed skylight. It is improbable that the engine and skylight hatches were used for
ladderways, passing scuttles, or companionways.
The boilers are shown in the inboard profile about as described and drawn by Marestier but with
two stacks on each boiler, one to each flue; Marestier’s sketch in his report on American steamships
shows the flues of each boiler trunked into a single stack. The battery had two boilers and the stacks
are at the boilers’ fire-door end. The steam lines came off the crown of the boilers and probably
passed through the ends of the wheelbox to the engine; a trunk for the steam lines would
undoubtedly have been necessary.

Figure 15.—Sketch of 130-gun ship proposed by Patrick Miller to King Gustav III of
Sweden in 1790. In Statens Sjöhistoriska Museum, Stockholm.

Figure 16.—Patrick Miller’s manually propelled (paddle-wheel) catamaran ship
Experiment, built at Leith, Scotland, 1786. Scale drawing in Statens Sjöhistoriska Museum,
Stockholm

The engine is shown to have had counterbalanced side levers, one on each side, and a single
flywheel on the outboard side. The cylinder is over the condenser or “cistern,” connected by the
steam line and valve box on the side. The cylinder crosshead is shown in the inboard profile to have
reached the underside of the beams of the upper deck. The crosshead was connected by two
connecting rods to the side levers. These levers operated the paddle wheel by connecting rods to
cranks on the paddle-wheel shaft. There is another pair of connecting rods from the side levers to the
crosshead of the air pump. All connecting rods are on one arm of the side levers, the other end
having only a counterbalance weight beyond the fulcrum bearing. The flywheel has a shaft fitted
with two gears, and is driven through idler gears from gears on the paddle-wheel shaft; it turns at
about twice the speed of the paddle wheel. No other pumps or fittings are shown in the engine hull,
although manual pumps were probably fitted to fill and empty the boilers. Piping is not shown.

Figure 17.—Painting of the Experiment in the Statens Sjöhistoriska Museum, Stockholm.

The four rudders, toggled in pairs, are shown in both the lines and inboard drawings, but the
shape is different in the two plans. Operation must have been by a tiller under the gun-deck beams.
The outer end of the tiller may have been pivoted on the toggle bar and the inboard end fitted, as
previously described, with steering cable or chain tackles. This seems to be the only practical
interpretation of the evidence.

Reconstructing the Plans
In the model it was necessary to reconstruct the deck arrangements without enough
contemporary description. The outboard appearance and hull form, rig, and arrangement of
armament require no reconstruction, for all that is of importance is shown in the lines and rig
drawings, or in the inboard profile. The masts are shown to have been stepped over the race on the
gun deck. The iron stanchions are shown in the lines drawing and in the construction section.

However, their position at the ends of the Battery are apparently incorrectly shown in the original
lines plan. The construction section shows these stanchions to have been stepped on the inside face
of the inner ceiling and, as the ceiling structure was carried completely around the ship, the
stanchions in the ends must have been placed inboard, as along the sides. The bowsprit was above
deck and would probably be secured in the knighthead timbers at the ends of the hull, as well as by
the heel bitts shown in the Danish lines drawing. With the riding bitts shown inboard of the heel bitts
at each end of the vessel, it is obvious that she would work her ground tackle at both ends and would
therefore require two capstans; the wheelbox would prevent effective use of a single one. The
capstans might be doubleheaded, as in some large frigates and ships-of-the-line.

Figure 18.—Sail plan of Fulton’s Steam Battery as reconstructed for model in the Museum
of History and Technology.

As to the remaining deck fixtures, hatches and fittings, these must be entirely a matter of
speculation. Ladderways, passing scuttles, hatches, trunks, galley, heads and cabins were obviously
required in a fighting ship and can only be located on the theory that, when completed, the Battery
was a practical vessel.
It has been stated that the officers’ cabins were over the race; the logical place for the heads,
galley, wardroom and mess also would be over the race, giving the remaining part of the gun deck
for the necessary hatches, ladderways, trunks, etc., in the two hulls, space required for armament,
and to sling the hammocks of a watch below. As the vessel was never fully manned, apparently, the
space for hammocks is not a serious problem in a reconstruction. If the vessel had been manned as
proposed by 500 men, hammocks for over 200 would have been required, which would give very
crowded quarters in view of the limited space available.
Though no specific requirements were stated in the reports of the trials, it seems reasonable to
suppose that additional hatches were cut in the decks to improve the fireroom ventilation. In the
reconstruction drawings, these hatchways as well as the other deck openings and deck fittings—such
as bilge pumps, companionways, skylights, binnacles, wheels and wheel-rope trunks, cable trunks,
steampipe casings, and stack fiddleys—have been located in an effort to meet the imagined
requirements of the working of a ship of this unusual form.

Figure 19.—Model of Steam Battery in the Museum of History and Technology. (Smithsonian
photo 63990-E.)

Figure 20.—Lines of steamer Congo, built in 1815-1816 for the British Admiralty and
converted to a sailing survey vessel. From Admiralty Collection of Draughts, National
Maritime Museum, Greenwich.

There are some unanswered questions that arose in the preparation of the reconstruction
drawings. As has been shown, the original inboard arrangement plan found in Copenhagen shows
four smokestacks, while Marestier’s sketch of the vessel’s boilers shows trunked flues indicating that
two stacks were used. It is possible that the boilers were first fitted so that four stacks were required;
alterations made as a result of steaming trials may well have included the introduction of trunked
flues and the final use of two stacks in line fore-and-aft. This would have required a rearrangement
of the fiddley hatches amidships.
Another troublesome question was the doubtful arrangement of the four companionways on the
spar deck. Perhaps only two were fitted, one on each side of the officers’ staterooms while the
ladderways at the crew’s end of the ship were simple ladder hatches.

The decision to use four bilge pumps is based upon the lack of drag in the keel of the hulls,
which would prevent accumulation of bilge water at one end of the hull. The use of four single-barrel
pumps instead of four double-barrel pumps may be questioned, for chain pumps requiring two
barrels would have been practical.
Allowance for stores was made by use of platforms in the hold. It is known from statements
made to the Court of Inquiry, that the magazines were amidships and that a part of these was close to
the boilers. Fuel and water would be in the lower hold under the platforms; hatches and ladderways
are arranged to permit fueling the ship.
A few prints or drawings of the ship, aside from the patent drawing, have been found. There are
two prints that show the launch of the vessel. One, a print of 1815, is in possession of the Mariners’
Museum, Newport News, Va., and is reproduced in Alexander Crosby Brown’s Twin Ships, Notes on
the Chronological History of the Use of Multiple Hulled Vessels.[20] A poor copy of this print appears
on page 13 of Bennett’s Steam Navy of the United States, and another and inaccurate sketch is shown
on page 8. These pictures were of no use in the reconstruction as they show no details that are not in
the Copenhagen plans. The patent drawing does not show deck details and in fact does not represent
the vessel as built in any respect other than in being a catamaran with paddle wheel amidships
between the hulls.
The Steam Battery did not have any particular influence on the design of men-of-war that
followed her. In the first place, steampower was not viewed with favor by naval officers generally.
This was without doubt due to prejudice, but engines in 1820-30 were still unreliable when required
to run for long periods, as experienced by the early ocean-going steamers. The great weight of the
early steam engines and their size in relation to power were important, and also important were
practical objections that prevented the design of efficient naval ocean steamers until about 1840;
even then, the paddle wheels made them very vulnerable in action. Until the introduction of the
screw propellor it was not possible to design a really effective ocean-going naval steamer; hence
until about 1840-45, sail remained predominant in naval vessels for ocean service, and steamers
were accepted only in coast defense and towing services, or as dispatch vessels.
No immediate use of the double hull in naval vessels of the maritime powers resulted from the
construction of the Steam Battery. The flat-bottom chine-built design employed by Fulton in North
River, Raritan, and other early steamboats was utilized in the design for a projected steamer by the
British Admiralty in 1815-16. This vessel was about 76 feet overall, 16-foot beam, and 8-foot 10
inches depth in hold. Her design was for a flat-bottom, chine-built hull with no fore-and-aft camber
in the bottom, a sharp entrance, and a square-tuck stern with slight overhang above the cross-seam.
Her side frames were straight and vertical amidships, but curved as the bow and stern were
approached. She was to be a side-paddle-wheel steamer, and her hull was diagonally braced; the
wheel and engine were to be about amidships where she was dead flat for about 14 feet. However,
the engine and boilers were not installed; the engine was utilized ashore for pumping, and the vessel
was completed in the Deptford Yard as a sailing ship. Under the name Congo she was employed in
the African coast survey. Her plan is in the Admiralty Collection of Draughts, at the National
Maritime Museum, Greenwich, England.
The double hull continued to be employed in both steam and team ferryboats in the United States
and in England and France. A few river and lake steamers were also built with this design of hull.
Continued efforts to obtain fast sailing by use of the double hull produced a number of sailing
catamarans; of these the Herreshoff catamarans of the 1870’s showed high speed when reaching in a
fresh breeze.

Designs for double-hulled steamers appeared during the last half of the 19th century; in 1874 the
Castalia, a large, double-hull, iron, cross-channel steamer, was built by the Thames Iron-works
Company at Blackwall, England. She was 290 feet long, and each hull had a beam of 17 feet. The
paddle wheel was placed between the hulls and, ready for sea, she drew 61/2 feet. She ran the 22
miles between Dover and Calais in 1 hour and 50 minutes, a speed much slower than that of the
paddle-wheel, cross-channel steamers having one hull. Another double-hull steamer was built for
this service by Hawthorn, Leslie and Company, Newcastle-on-Tyne, Scotland, in 1877. First named
Express, she was renamed Calais-Douvres when she went into service in May 1878. Her length was
302 feet, her extreme beam 62 feet, and each hull had a beam of 18 feet, 3 inches. She drew 6-foot
71/2 inches ready for sea and the paddle wheel was between the hulls. On her trials she made 14
knots and burned coal excessively. Sold to France in 1880, she was taken out of service in 1889.
Though popular, she was not faster than the single-hull steamers in this service and had been a
comparatively expensive vessel to build and operate.
The many attempts to produce a very fast double-hull steamer and large sailing vessels have led
to disappointment for their designers and sponsors. In the history of naval architecture, since Petty’s
time, there have been a number of periods when the new-old idea of the double hull has become
popular. Craft of this type have been commonly well publicized but, on the whole, their basic
designs have followed the same principles over and over again and have not produced the sought-for
increase in speed and handiness.
In very recent years there has been a revival in interest in sailing double-hull boats that is
enthusiastic as to very small craft and somewhat restrained as to large boats. A few projects are under
development for double-hull craft, power and sail, of over 90-foot length, including an
oceanographic research vessel. In general, however, the performance of double-hull boats has shown
that Chapman’s estimate of the type was reasonably correct and that there are limitations,
particularly in maneuverability in the double-hull craft that could have been found by reference to
the history of past experiments with the type.

NAVAL STEAMERS.

THE DEMOLOGOS; OR, FULTON THE FIRST.
At the close of the year eighteen hundred and thirteen, Robert Fulton exhibited to
the President of the United States, the original drawing from which the engraving on
Plate One is sketched, being a representation of the proposed war-steamer or floating-
battery, named by him, the Demologos. This sketch possesses more than ordinary
interest, from the circumstance that it is, doubtless, the only record of the first war-
steamer in the world, designed and drawn by the immortal Fulton, and represented by
him to the Executive, as capable of carrying a strong battery, with furnaces for red hot
shot, and being propelled by the power of steam, at the rate of four miles an hour.
It was contemplated that this vessel, besides carrying her proposed armament on
deck, should also be furnished with submarine guns, two suspended from each bow, so

as to discharge a hundred pound ball into an enemy’s ship at ten or twelve feet below
her water-line. In addition to this, her machinery was calculated for the addition of an
engine which would discharge an immense column of water upon the decks, and
through the port-holes of an enemy, making her the most formidable engine for warfare
that human ingenuity has contrived.
The estimated cost of the vessel was three hundred and twenty thousand dollars,
nearly the sum requisite for a frigate of the first class.
The project was zealously embraced by the Executive, and the national legislature in
March, eighteen hundred and fourteen, passed a law, authorizing the President of the
United States to cause to be built, equipped, and employed, one or more floating
batteries, for the defense of the waters of the United States.
The building of the vessel was committed by the Coast and Harbor Defense
Association, to a sub-committee of five gentlemen, who were recognized by the
Government as their agents for that purpose, and whose interesting history of the Steam
Frigate is copied in Note A, of the Appendix to this volume.
Robert Fulton, whose soul animated the enterprise, was appointed the engineer; and
on the twentieth day of June, eighteen hundred and fourteen, the keel of this novel
steamer was laid at the ship-yard of Adam and Noah Brown, her able and active
constructors, in the city of New York, and on the twenty-ninth of the following October,
or in little more than four months, she was safely launched, in the presence of
multitudes of spectators who thronged the surrounding shores, and were seen upon the
hills which limited the beautiful prospect around the bay of New York.
The river and bay were filled with steamers and vessels of war, in compliment to the
occasion. In the midst of these was the enormous floating mass, whose bulk and
unwieldy form seemed to render her as unfit for motion, as the land batteries which
were saluting her.
In a communication from Captain David Porter, U. S. Navy, to the Hon. Secretary of
the Navy, dated New York, October 29, 1814, he states,—“I have the pleasure to inform
you that the “Fulton the First,” was this morning safely launched. No one has yet
ventured to suggest any improvement that could be made in the vessel, and to use the
words of the projector, ‘I would not alter her if it were in my power to do so.’
“She promises fair to meet our most sanguine expectations, and I do not despair in
being able to navigate in her from one extreme of our coast to the other. Her buoyancy
astonishes every one, she now draws only eight feet three inches water, and her draft
will only be ten feet with all her guns, machinery, stores, and crew, on board. The ease
with which she can now be towed with a single steamboat, renders it certain that her
velocity will be sufficiently great to answer every purpose, and the manner it is intended
to secure her machinery from the gunner’s shot, leaves no apprehension for its safety. I
shall use every exertion to prepare her for immediate service; her guns will soon be
mounted, and I am assured by Mr. Fulton, that her machinery will be in operation in
about six weeks.”
On the twenty-first of November, the Steam Frigate was moved from the wharf of
Messrs. Browns, in the East River, to the works of Robert Fulton, on the North River, to
receive her machinery, which operation was performed by fastening the steamboat “Car

of Neptune,” to her larboard, and the steamboat “Fulton,” to her starboard side; they
towed her through the water from three and a-half to four miles per hour.
The dimensions of the “Fulton the First” were:—
Length, one hundred and fifty-six feet.
Breadth, fifty-six feet.
Depth, twenty feet.
Water-wheel, sixteen feet diameter.
Length of bucket, fourteen feet.
Dip, four feet.
Engine, forty-eight inch cylinder, and five feet stroke.
Boiler, length, twenty-two feet; breath, twelve feet; and depth,
eight feet.
Tonnage, two thousand four hundred and seventy-five.
By June, eighteen hundred and fifteen, her engine was put on board, and she was so
far completed as to afford an opportunity of trying her machinery. On the first of June,
at ten o’clock in the morning, the “Fulton the First,” propelled by her own steam and
machinery, left the wharf near the Brooklyn ferry, and proceeded majestically into the
river; though a stiff breeze from the south blew directly ahead, she stemmed the current
with perfect ease, as the tide was a strong ebb. She sailed by the forts and saluted them
with her thirty-two pound guns. Her speed was equal to the most sanguine expectations;
she exhibited a novel and sublime spectacle to an admiring people. The intention of the
Commissioners being solely to try her enginery, no use was made of her sails. After
navigating the bay, and receiving a visit from the officers of the French ship of war
lying at her anchors, the Steam Frigate came to at Powles’ Hook ferry, about two
o’clock in the afternoon, without having experienced a single unpleasant occurrence.
On the fourth of July, of the same year, she made a passage to the ocean and back,
and went the distance, which, in going and returning, is fifty-three miles, in eight hours
and twenty minutes, without the aid of sails; the wind and tide were partly in her favor
and partly against her, the balance rather in her favor.
In September, she made another trial trip to the ocean, and having at this time the
weight of her whole armament on board, she went at an average of five and a half miles
an hour, with and against the tide. When stemming the tide, which ran at the rate of
three miles an hour, she advanced at the rate of two and a-half miles an hour. This
performance was not more than equal to Robert Fulton’s expectations, but it exceeded
what he had premised to the Government, which was that she should be propelled by
steam at the rate of from three to four miles an hour.
The English were not uninformed as to the preparations which were making for
them, nor inattentive to their progress. It is certain that the Steam Frigate lost none of
her terrors in the reports or imaginations of the enemy. In a treatise on steam vessels,
published in Scotland at that time, the author states that he has taken great care to

procure full and accurate information of the Steam Frigate launched in New York, and
which he describes in the following words:—
“Length on deck, three hundred feet; breadth, two hundred feet; thickness of her
sides, thirteen feet of alternate oak plank and cork wood—carries forty-four guns, four
of which are hundred pounders; quarter-deck and forecastle guns, forty-four pounders;
and further to annoy an enemy attempting to board, can discharge one hundred gallons
of boiling water in a minute, and by mechanism, brandishes three hundred cutlasses
with the utmost regularity over her gunwales; works also an equal number of heavy iron
pikes of great length, darting them from her sides with prodigious force, and
withdrawing them every quarter of a minute”!!
The war having terminated before the “Fulton the First” was entirely completed, she
was taken to the Navy Yard, Brooklyn, and moored on the flats abreast of that station,
where she remained, and was used as a receiving-ship until the fourth of June, eighteen
hundred and twenty-nine, when she was blown up. The following letters from
Commodore Isaac Chauncey (then Commandant of the New York Navy Yard) to the
Honorable Secretary of the Navy, informing him of the distressing event, concludes this
brief history of the first steam vessel of war ever built.

U. S. Navy Yard, New York,
June 5th, 1829.
Sir:
It becomes my painful duty to report to you a most unfortunate occurrence which
took place yesterday, at about half past two o’clock, P. M., in the accidental blowing up
of the Receiving Ship Fulton, which killed twenty-four men and a woman, and wounded
nineteen; there are also five missing. Amongst the killed I am sorry to number
Lieutenant S. M. Brackenridge, a very fine, promising officer, and amongst the
wounded are, Lieutenants Charles F. Platt, and A. M. Mull, and Sailing-Master Clough,
the former dangerously, and the two last severely; there are also four Midshipmen
severely wounded. How this unfortunate accident occurred I am not yet able to inform
you, nor have I time to state more particularly; I will, as soon as possible, give a detailed
account of the affair.
I have the honor to be, Sir,
Very respectfully,
J. CHAUNCEY.
Hon. John Branch,
Secretary of the Navy, Washington.

U.S. Navy Yard, New York,
June 8th, 1829.
Sir:
I had been on board the “Fulton” all the morning, inspecting the ship and men,
particularly the sick and invalids, which had increased considerably from other ships,

and whom I had intended to ask the Department permission to discharge, as being of
little use to the service. I had left the ship but a few moments before the explosion took
place, and was in my office at the time. The report did not appear to me louder than a
thirty-two pounder, although the destruction of the ship was complete and entire, owing
to her very decayed state, for there was not on board, at the time, more than two and a-
half barrels of damaged powder, which was kept in the magazine for the purpose of
firing the morning and evening gun. It appears to me that the explosion could not have
taken place from accident, as the magazine was as well, or better secured, than the
magazines of most of our ships, yet it would be difficult to assign a motive to those in
the magazine for so horrible an act, as voluntarily to destroy themselves and those on
board. If the explosion was not the effect of design, I am at a loss to account for the
catastrophe.
I have the honor to be, Sir,
Very respectfully,
J. CHAUNCEY.
Hon. John Branch,
Secretary of the Navy, Washington.

APPENDIX.

Note A.

STEAM FRIGATE.
Report of Henry Rutgers, Samuel L. Mitchel, and Thomas Morris, the Commissioners
superintending the construction of a steam vessel of war, to the Secretary of the Navy.
New York, December 28th, 1815.
Sir:
The war which was terminated by the treaty of Ghent, afforded, during its short
continuance, a glorious display of the valor of the United States by land and by sea—it
made them much better known to foreign nations, and, what is of much greater
importance, it contributed to make them better acquainted with themselves—it excited
new enterprises—it educed latent talents—it stimulated to exertions unknown to our
people before.
A long extent of coast was exposed to an enemy, powerful above every other on the
ocean. His commanders threatened to lay waste our country with fire and sword, and,
actually, in various instances, carried their menaces into execution. It became necessary,
for our defense, to resist, by every practicable method, such a formidable foe.

It was conceived, by a most ingenious and enterprising citizen, that the power of
Steam could be employed to propel a floating battery, carrying heavy guns, to the
destruction of any hostile force that should hover on the shores, or enter the ports of our
Atlantic frontier. The perfect and admirable success of his project for moving boats
containing travelers and baggage by the same elastic agent, opened the way to its
employment for carrying warriors and the apparatus for fighting.
The plan was submitted to the consideration of the executive of an enlightened
government. Congress, influenced by the most liberal and patriotic spirit, appropriated
money for the experiment, and the Navy Department, then conducted by the honorable
William Jones, appointed commissioners to superintend the construction of a convenient
vessel under the direction of Robert Fulton, the inventor, as engineer, and Messrs.
Adam and Noah Brown, as naval constructors. The enterprise, from its commencement,
and during a considerable part of its preparatory operations, was aided by the zealous
co-operation of Major General Dearborn, then holding his head-quarters at the city of
New York, as the officer commanding the third military district. The loss of his valuable
counsel in conducting a work which he had maturely considered, and which he strongly
recommended, was the consequence of his removal to another section of the Union,
where his professional talents were specially required.
The keels of this steam-frigate were laid on the twentieth day of June, eighteen
hundred and fourteen. The strictest blockade the enemy could enforce interrupted the
coasting trade, and greatly enhanced the price of timber. The vigilance with which he
guarded our coast against intercourse with foreign nations, rendered difficult the
importation of copper and iron. The same impediment attended the supplies of coal
heretofore brought to New York from Richmond and Liverpool. Lead, in like manner,
was procured under additional disadvantages. These attempts of the enemy to frustrate
the design, were vain and impotent. All the obstacles were surmounted. Scarcity of the
necessary woods and metals were overcome by strenuous exertions; and all the
blockading squadron could achieve, was not a disappointment in the undertaking, but
merely an increase of the expense.
So, in respect to tradesmen and laborers, there was an extraordinary difficulty.
Shipwrights had repaired to the lakes, for repelling the enemy, in such numbers, that,
comparatively speaking, few were left on the seaboard. A large portion of the men who
had been engaged in daily work, had enlisted as soldiers, and had marched under the
banners of the nation to the defense of its rights—yet amidst the scarcity of hands, a
sufficient number were procured for the purpose which the Commissioners had in
charge. An increase of wages was the chief impediment, and this they were enabled
practically to overcome.
By the exemplary combination of diligence and skill, on the part of the Engineer and
Constructors, the business was so accelerated, that the vessel was launched on the
twenty-ninth day of October, amidst the plaudits of an unusual number of citizens.
Measures were immediately taken to complete her equipment; the boiler, the engine,
and the machinery were put on board with all possible expedition. Their weight and size
far surpassed any thing that had been witnessed before among us.
The stores of artillery in New York not furnishing the number and kind of cannon
which she was destined to carry, it became necessary to transport guns from

Philadelphia. A prize, taken from the enemy, put some fit and excellent pieces at the
disposal of the Navy Department. To avoid the danger of capture by the enemy’s
cruisers, these were carted over the miry roads of New Jersey. Twenty heavy cannon
were thus conveyed by the strength of horses. Carriages of the most approved model
were constructed, and every thing done to bring her into prompt action, as an efficient
instrument of war.
About this time, an officer, pre-eminent for bravery and discipline, was
commissioned by the government to her command. Prior to this event, it had been
intended by the Commissioners to finish her conformably to the plan originally
submitted to the Executive. She is a structure resting upon two boats and keels,
separated from end to end by a canal fifteen feet wide, and sixty-six long. One boat
contained the caldrons of copper to prepare her steam. The vast cylinder of iron, with its
piston, levers, and wheels, occupied a part of its fellow; the great water-wheel revolved
in the space between them; the main or gun-deck supported her armament, and was
protected by a bulwark four feet ten inches thick, of solid timber. This was pierced by
thirty port-holes, to enable as many thirty-two pounders to fire red hot balls; her upper
or spar deck was plain, and she was to be propelled by her enginery alone.
It was the opinion of Captain Porter and Mr. Fulton, that the upper deck ought to be
surrounded with a bulwark and stanchions—that two stout masts should be erected to
support latteen sails—that there should be bowsprits for jibs, and that she should be
rigged in a corresponding style. Under authorities so great, and with the expectation of
being able to raise the blockade of New London, by destroying, taking, or routing the
enemy’s ships, all these additions were adopted and incorporated with the vessel.
It must here be observed, that during the exhaustion of the treasury, and the
temporary depression of public credit, the Commissioners were exceedingly
embarrassed—their payments were made in treasury notes, which they were positively
instructed to negotiate at par. On several occasions even these were so long withheld,
that the persons who had advanced materials and labor were importunate for payment,
and silently discontented. To a certain extent, the Commissioners pledged their private
credit. Notwithstanding all this, the men, at one time, actually broke off. The work was
retarded, and her completion unavoidably deferred, to the great disappointment of the
Commissioners, until winter rendered it impossible for her to act.
Under all this pressure, they, nevertheless, persevered in the important object
confided to them. But their exertions were further retarded by the premature and
unexpected death of the Engineer. The world was deprived of his invaluable labors
before he had completed this favorite undertaking. They will not inquire, wherefore, in
the dispensations of Divine Providence, he was not permitted to realize his grand
conception. His discoveries, however, survive for the benefit of mankind, and will
extend to unborn generations.
At length all matters were ready for a trial of the machinery to urge such a bulky
vessel through the water. This essay was made on the first day of June, eighteen
hundred and fifteen. She proved herself capable of opposing the wind, and of stemming
the tide, of crossing currents, and of being steered among vessels riding at anchor,
though the weather was boisterous and the water rough. Her performance demonstrated
that the project was successful—no doubt remained that a floating battery, composed of
heavy artillery, could be moved by steam. The Commissioners returned from the

exercise of the day, satisfied that the vessel would answer the intended purpose, and
consoled themselves that their care had been bestowed upon a worthy object.
But it was discovered, that various alterations were necessary. Guided by the light of
experience, they caused some errors to be corrected, and some defects to be supplied.
She was prepared for a second voyage with all practicable speed.
On the fourth of July she was again put in action. She performed a trip to the ocean,
eastward of Sandy Hook, and back again, a distance of fifty-three miles, in eight hours
and twenty minutes. A part of this time she had the tide against her, and had no
assistance whatever from sails. Of the gentlemen who formed the company invited to
witness the experiment, not one entertained a doubt of her fitness for the intended
purpose.
Additional expedients were, notwithstanding, necessary to be sought for quickening
and directing her motion. These were devised and executed with all possible care.
Suitable arrangements having been made, a third trial of her powers was attempted
on the eleventh day of September, with the weight of twenty-six of her long and
ponderous guns, and a considerable quantity of ammunition and stores on board; her
draft of water was short of eleven feet. She changed her course by inverting the motion
of the wheel, without the necessity of putting about. She fired salutes as she passed the
forts, and she overcame the resistance of the wind and tide in her progress down the bay.
She performed beautiful manœuvres around the United States’ Frigate Java, then at
anchor near the light-house. She moved with remarkable celerity, and she was perfectly
obedient to her double helm. It was observed that the explosion of powder produced
very little concussion. The machinery was not affected by it in the smallest degree. Her
progress, during the firing, was steady and uninterrupted. On the most accurate
calculations, derived from heaving the log, her average velocity was five and a-half
miles per hour. Notwithstanding the resistance of currents, she was found to make
headway at the rate of two miles an hour against the ebb of the East River, running three
and a-half knots. The day’s exercise was satisfactory to the respectable company who
attended, beyond their utmost expectations. It was universally agreed that we now
possessed a new auxiliary against every maratime invader. The City of New York,
exposed as it is, was considered as having the means of rendering itself invulnerable.
The Delaware, Chesapeake, Long Island Sound, and every other bay and harbor in the
nation, may be protected by the same tremendous power.
Among the inconveniences observable during the experiment, was the heat endured
by the men who attended the fires. To enable a correct judgment to be formed on this
point, one of the Commissioners (Dr. Mitchel) descended and examined, by a
thermometer, the temperature of the hold, between the two boilers. The quicksilver,
exposed to the radiant heat of the burning fuel, rose to one hundred and sixteen degrees
of Fahrenheit’s scale. Though exposed thus to its intensity, he experienced no
indisposition afterwards. The analogy of potteries, forges, glass-houses, kitchens, and
other places, where laborers are habitually exposed to high heats, is familiar to persons
of business and of reflection. In all such occupations, the men, by proper relays, perform
their services perfectly well.
The Government, however, will understand that the hold of the present vessel could
be rendered cooler by other apertures for the admission of air, and that on building

another steam frigate, the comfort of the firemen might be provided for, as in the
ordinary steamboats.
The Commissioners congratulate the Government and the nation on the event of this
noble project. Honorable alike, to its author and its patrons, it constitutes an era in
warfare and the arts. The arrival of peace, indeed, has disappointed the expectations of
conducting her to battle. That last and conclusive act of showing her superiority in
combat, has not been in the power of the Commissioners to make.
If a continuance of tranquillity should be our lot, and this steam vessel of war be not
required for the public defense, the nation may rejoice that the fact we have ascertained
is of incalculably greater value than the expenditure—and that if the present structure
should perish, we have the information never to perish, how, on a future emergency,
others may be built. The requisite variations will be dictated by circumstances.
Owing to the cessation of hostilities, it has been deemed inexpedient to finish and
equip her as for immediate and active employ. In a few weeks every thing that is
incomplete could receive the proper adjustment.
After so much has been done, and with such encouraging results, it becomes the
Commissioners to recommend that the steam frigate be officered and manned for
discipline and practice. A discreet commander, with a selected crew, could acquire
experience in the mode of navigating this peculiar vessel. The supplies of fuel, the
tending of the fire, the replenishing of the expended water, the management of the
mechanism, the heating of shot, the exercise of the guns, and various matters, can only
become familiar by use. It is highly important that a portion of seamen and marines
should be versed in the order and economy of the steam frigate. They will augment,
diffuse, and perpetuate knowledge. When, in process of time, another war shall call for
more structures of this kind, men, regularly trained to her tactics, may be dispatched to
the several stations where they may be wanted. If, on any such disposition, the
Government should desire a good and faithful agent, the Commissioners recommend
Captain Obed Smith to notice, as a person who has ably performed the duties of
inspector from the beginning to the end of the concern.
Annexed to the report, you will find, Sir, several statements explanatory of the
subject. A separate report of our colleague, the honorable Oliver Wolcott, whose
removal from New York precluded him from attending to the latter part of the business,
with his accustomed zeal and fidelity, is herewith presented. A drawing of her form and
appearance, by Mr. Morgan, as being like to give satisfaction to the department, is also
subjoined, as are likewise an inventory of her furniture and effects, and an account of
the timber and metals consolidated in her fabric.
It is hoped these communications will evince the pains taken by the Commissioners,
to execute the honorable and responsible trust reposed in them by the Government.
SAMUEL L. MITCHEL.
THOMAS MORRIS.
HENRY RUTGERS.

Footnotes
[1]
The American Neptune (1946), vol. 6, pp. 253-274.
[2]
The American Neptune (1944), vol. 4, pp. 327-329.
[3]
New York, 1853, pp. 13-17.
[4]
Pittsburgh, 1896, pp. 8-16.
[5]
See pages 172 through 176 for this report, which is reproduced from Charles B. Stuart, Naval
and Mail Steamers of the United States (New York, 1853), app., pp. 155-159.
[6]
National Archives, Navy Records Plans, 80-7-14; and Howard I. Chapelle, History of the
American Sailing Navy (New York: W. W. Norton & Co., 1949), pp. 293-295.
[7]
National Archives, Navy Records Plans, 80-7-9; and Chapelle, History of the American Sailing
Navy, pp. 226, 228.
[8]
National Archives, Navy Records Plans, 80-7-15.
[9]
National Archives, Naval Records Collection, Miscellaneous Letters, 1819, II.
[10]
See p. 169, reproduced from Charles B. Stuart, Naval and Mail Steamers of the United States
(New York, 1853), p. 15.
[11]
Jean Baptiste Marestier, Mémoire sur les bateaux à vapeur des États-Unis d’Amérique, avec un
appendice sur diverses machines relatives à la Marine (Paris: L’imprimerie Royal, 1824).
[12]
1820-1823, vol. 7, p. 437.
[13]
Annales de l’industrie nationale et étrangère, ou Mercure Technologique (Paris, 1822), pp. 760-
762.
[14]
January 27, 1823, vol. 7, pp. 436-438.
[15]
January-March 1935, vol. 61, pp. 322-328.
[16]
Howard I. Chapelle, American Small Sailing Craft (New York: W. W. Norton & Co., Inc., 1951),
pp. 29, 31.
[17]
Newport News, Va.: The Mariners’ Museum, 1937, p. 23.
[18]
Indianapolis, Ind.: Bobbs Merrill, 1932, p. 291.
[19]
Henry William Edward, The Double Bottom or Twin Hulled Ship of Sir William Petty (Oxford:
The Roxburghe Club, 1931).
[20]
Publication No. 5 (Newport News: The Mariners’ Museum, 1939), p. 22.

Paper 39 - Transcriber’s Note
P. 152: ‘the Simon & Jude, later’—was ‘the Simon & Jude, latter’.

Transcription of the text in
Figure 2.
Plate No. 1.
‘DEMOLOGOS’

Figure Ist Transverse section A her Boiler. B the steam Engine. C
the water wheel. E E her wooden walls 5 feet thick, diminishing to
below the waterline as at F.F draught of water 9 feet D D her gun
deck

Figure IId This shews her gun deck, 140 feet long 24 feet wide,
mounting 20 guns. A the Water wheel

Figure IIId Side View
ROBERT FULTON November 1813.

S Mc Elroy del. "Stuart's Naval & Mail Steamers U.S."
Sarony & Major. Eng. N.Y.

Contributions from
The Museum of History and
Technology:
Paper 40

History of Phosphorus

Eduard Farber

THE ELEMENT FROM ANIMALS AND PLANTS 178

EARLY USES 181

CHEMICAL CONSTITUTION OF PHOSPHORIC ACIDS 182

PHOSPHATES AS PLANT NUTRIENTS 185

FROM INORGANIC TO ORGANIC PHOSPHATES 187

PHOSPHATIDES AND PHOSPHAGENS 189

NUCLEIN AND NUCLEIC ACIDS 192

PHOSPHATES IN BIOLOGICAL PROCESSES 197

MEDICINES AND POISONS 198

INDEX

Eduard Farber

HISTORY OF PHOSPHORUS
The “cold light” produced by phosphorus caused it to be
considered a miraculous chemical for a long time after its
discovery, about 1669. During the intervening three centuries
numerous other chemical miracles have been found, yet
phosphorus retains a special aura of universal importance in
chemistry. Many investigators have occupied themselves with

this element and its diverse chemical compounds. Further
enlightenment and insight into the ways of nature can be
expected from these efforts.
Not only is the story of phosphorus a major drama in the
history of chemistry; it also illustrates, in a spectacular example,
the growth of this science through the discovery of connections
between apparently unrelated phenomena, and the continuous
interplay between basic science and the search for practical
usage.
The Author: Eduard Farber is a research professor at
American University, Washington, D.C., and has been associated
with the Smithsonian Institution as a consultant in chemistry.
was discovered, nearly three centuries ago, it was
W
hen phosphorus
considered a miraculous thing. The only event that provoked a similar
emotion was the discovery of radium more than two centuries later. The
excitement about the Phosphorus igneus, Boyle’s Icy Noctiluca, was slowly
replaced by, or converted into, chemical research. Yet, if we would allow room
for emotion in research, we could still be excited about the wondrous substance
that chemical and biological work continues to reveal as vitally important. It is a
fundamental plant nutrient, an essential part in nerve and brain substance, a
decisive factor in muscle action and cell growth, and also a component in fast-
acting, powerful poisons. The importance of phosphorus was gradually
recognized and the means by which this took place are characteristic and similar
to other developments in the history of science. This paper was written in order
to summarize these various means which led to the highly complex ways of
present research.

The Element from Animals and Plants
It was a little late to search for the philosophers’ stone in 1669, yet it was in
such a search that phosphorus was discovered. Wilhelm Homberg (1652-1715)
described it in the following manner: Brand, “a man little known, of low birth,
with a bizarre and mysterious nature in all he did, found this luminous matter
while searching for something else. He was a glassmaker by profession, but he
had abandoned it in order to be free for the pursuit of the philosophical stone
with which he was engrossed. Having put it into his mind that the secret of the

philosophical stone consisted in the preparation of urine, this man worked in all
kinds of manners and for a very long time without finding anything. Finally, in
the year 1669, after a strong distillation of urine, he found in the recipient a
luminant matter that has since been called phosphorus. He showed it to some of
his friends, among them Mister Kunkel [sic].”[1]
Neither the name nor the phenomenon were really new. Organic
phosphorescent materials were known to Aristotle, and a lithophosphorus was the
subject of a book published in 1640, based on a discovery made by a shoemaker,
Vicenzo Casciarolo, on a mountain-side near Bologna in 1630.[2] Was the
substance new which Brand showed to his friends? Johann Gottfried Leonhardi
quotes a book of 1689 in which the author, Kletwich, claims that this phosphorus
had already been known to Fernelius, the court physician of King Henri II of
France (1154-1189).[3] To the same period belongs the “Ordinatio Alchid Bechil
Saraceni philosophi,” in which Ferdinand Hoefer found a distillation of urine
with clay and carbonaceous material described, and the resulting product named
escarbuncle.[4] It would be worth looking for this source; although Bechil would
still remain an entirely unsuccessful predecessor, it does seem strange that in all
the distillations of arbitrary mixtures, the conditions should never before 1669
have been right for the formation and the observation of phosphorus.

Figure 1.—The alchemist discovers phosphorus. A painting by Joseph Wright (1734-1779)
of Derby, England.

For Brand’s contemporaries at least, the discovery was new and exciting. The
philosopher Gottfried Wilhelm von Leibniz (1646-1716) considered it important
enough to devote some of his time (between his work as librarian in Hanover and
Wolfenbüttel, his efforts to reunite the Protestant and the Catholic churches, and
his duties as Privy Councellor in what we would call a Department of Justice) to
a history of phosphorus. This friend of Huygens and Boyle tried to prove that
Kunckel was not justified in claiming the discovery for himself.[5] Since then, it

has been shown that Johann Kunckel (1630-1703) actually worked out the
method which neither Brand nor his friend Kraft wanted to disclose. Boyle also
developed a method independently, published it, and instructed Gottfried
Hankwitz in the technique. Later on, Jean Hellot (1685-1765) gave a meticulous
description of the details and a long survey of the literature. [6]

Figure 2.—Galley-oven, 1869. The picture is a cross section through the front of the oven
showing one of the 36 retorts, the receivers for the distillate, and the space in the upper story
used for evaporating the mixture of acid solution of calcium phosphate and coal. (According
to Anselme Payen, Précis de Chimie industrielle, Paris, 1849; reproduced from Hugo Fleck,
Die Fabrikation chemischer Produkte aus thierischen Abfällen, Vieweg, Braunschweig, 1862,
page 80 of volume 2, 2nd group, of P. Bolley’s Handbuch der chemischen Technologie.)

To obtain phosphorus, a good proportion of coal (regarded as a type of
phlogiston) was added to urine, previously thickened by evaporation and
preferably after putrefaction, and the mixture was heated to the highest attainable
temperature. It was obvious that phlogiston entered into the composition of the
distillation product. The question remained whether this product was generated
de novo. In his research of 1743 to 1746, Andreas Sigismund Marggraf (1709-
1782) provided the answer. He found the new substance in edible plant seeds,
and he concluded that it enters the human system through the plant food, to be
excreted later in the urine. He did not convince all the chemists with his
reasoning. In 1789, Macquer wrote: “There are some who, even at this time, hold
that the phosphorical (‘phosphorische’) acid generates itself in the animals and
who consider this to be the ‘animalistic acid.’”[7]
Although Marggraf was more advanced in his arguments than these chemists,
yet he was a child of his time. The luminescent and combustible, almost wax-like
substance impressed him greatly. “My thoughts about the unexpected generation
of light and fire out of water, fine earth, and phlogiston I reserve to describe at a
later time.” These thoughts went so far as to connect the new marvel with

alchemical wonder tales. When Marggraf used the “essential salt of urine,” also
called sal microcosmicum, and admixed silver chloride (“horny silver”) to it for
the distillation of phosphorus, he expected “a partial conversion of silver by
phlogiston and the added fine vitrifiable earth, but no trace of a more noble metal
appeared.” [8]
Robert Boyle had already found that the burning of phosphorus produced an
acid. He identified it by taste and by its influence on colored plant extracts
serving as “indicators.” Hankwitz [9] described methods for obtaining this acid,
and Marggraf showed its chemical peculiarities. They did not necessarily
establish phosphorus as a new element. To do that was not as important, at that
time, as to conjecture on analogies with known substances. Underlying all its
unique characteristics was the analogy of phosphorus with sulfur. Like sulfur,
phosphorus can burn in two different ways, either slowly or more violently, and
form two different acids. The analogy can, therefore, be extended to explain the
results in both groups in the same way. In the process of burning, the combustible
component is removed, and the acid originally combined with the combustible is
set free. Whether the analogy should be pursued even further remained doubtful,
although some suspicion lingered on for a while that phosphoric acid might
actually be a modified sulfuric acid. Analogies and suspicions like these were
needed to formulate new questions and stimulate new experiments. They are
cited here for their important positive value in the historical development, and
not for the purpose of showing how wrong these chemists were from our point of
view, a point of view which they helped to create.
The widespread interest in the burning of sulfur and of phosphorus, naturally,
caught Lavoisier’s attention. In his first volume of Opuscules Physiques et
Chimiques (1774), he devoted 20 pages to his experiments on phosphorus. He
amplified them a few years later [10] when he attributed the combustion to a
combination of phosphorus with the “eminently respirable” part of air. In the
Méthode de Nomenclature Chimique of 1787, the column of “undecomposed
substances” lists sulfur as the “radical sulfurique,” and phosphorus,
correspondingly, as the “radical phosphorique.” The acids are now shown to be
compounds of the “undecomposed” radicals, the complete reversion of the
previous concept of this relationship. A part of the old analogy remained as far as
the acids are concerned: sulfuric acid corresponds to phosphoric; sulfurous acid
to phosphorous acid with less oxygen than in the former. [11]

Early Uses
In the 18th century, phosphorus was a costly material. It was produced mostly
for display and to satisfy curiosity. Guillaume François Rouelle (1703-1770)
demonstrated the process in his lectures, and, as Macquer reports, he “very often”
succeeded in making it. [12] Robert Boyle had the idea of using phosphorus as a
light for underwater divers. [13] A century later, “instant lights” were sold, with
molten phosphorus as the “igniter,” but they proved cumbersome and unreliable.
[14]
Because white phosphorus is highly poisonous, an active development of the
use in matches occurred only after the conversion of the white modification into
the red had been studied by Émile Kopp (1844), by Wilhelm Hittorf (1824-1914)
and, in its practical application, by Anton Schrötter (1802-1875). [15]

Figure 3.—Distillation apparatus (1849) for refining crude phosphorus. The crude
phosphorus is mixed with sand under hot water, cooled, drained, and filled into the retort.
The outlet of the retort, at least 6 cm. in diameter, is partially immersed in the water
contained in the bucket. A small dish, made from lead, with an iron handle, receives the
distilled phosphorus. (From Hugo Fleck, Die Fabrikation chemischer Produkte … page 90.)

The most exciting early use, however, was in medicine. It is not surprising
that such a use was sought at that time. Any new material immediately became
the hope of ailing mankind—and of striving inventors. [16] Phosphorus was
prescribed, in liniments with fatty oils or as solution in alcohol and ether, for
external and internal application. A certain Dr. Kramer found it efficient against
epilepsy and melancholia (1730). A Professor Hartmann recommended it against
cramps. [17] However, in the growing production of phosphorus for matches, the
workers experienced the poisonous effects. In the plant of Black and Bell at
Stratford, this was prevented by inhaling turpentine. Experiments on dogs were

carried out to show that poisoning by phosphorus could be remedied through oil
of turpentine. [18]

Figure 4.—Apparatus for converting white phosphorus into the red allotropic form, 1851.
Redistilled phosphorus is heated in the glass or porcelain vessel (g) which is surrounded by a
sandbath (e) and a metal bath (b). Vessel (j) is filled with mercury and water; together with
valve (k), it serves as a safety device. The alcohol lamp (l) keeps the tube warm against
clogging by solidified vapors. Because of hydrogen phosphides, the operation, carried out at
260° C., had to be watched very carefully. (According to Arthur Albright, 1851; reproduced
from Hugo Fleck, Die Fabrikation chemischer Produkte …, page 112.)

Chemical Constitution of Phosphoric Acids
In a long article on phosphorus, Edmond Willm wrote in 1876: “For a
century, urine was the only source from which phosphorus was obtained. After
Gahn, in 1769, recognized the presence of phosphoric acid in bones, Scheele
indicated the procedure for making phosphorus from them.”[19] Actually, Gahn
used at first hartshorn (Cornu cervi ustum), and Scheele doubted, until he
checked it himself, that his esteemed friend was right. A few years later, Scheele
corrected Gahn’s assumption that the sal microcosmicum was an ammonia salt;
instead, it is “a tertiary neutral salt, consisting of alkali mineralifixo (i.e.,
sodium), alkali volatili, and acido phosphori.” [20]
In the years after 1770, phosphorus was discovered in bones and many other
parts of various animals. Treatment with sulfuric acid decomposed these
materials into a solid residue and dissolved phosphoric acid. Many salts of this
acid were produced in crystalline form. Heat resistance had been considered one

of the outstanding characteristics of phosphoric acid. Now, however, in the
processes of drying and heating certain phosphates, it became clear that three
kinds of phosphoric acids could be produced: ortho, pyro, and meta.
Berzelius cited these acids as examples of compounds which are ISOMERIC.
This word was intended to designate compounds which contain the same number
of atoms of the same elements but combined in different manners, thereby
explaining their different chemical properties and crystal forms. It was in 1830
that Berzelius propounded this companion of the concept, ISOMORPHISM, which
was to collect all cases of equal crystal form in compounds in which equal
numbers of atoms of different elements are put together in the same manner.
Together, the two concepts of isomerism and isomorphism seemed to cover all
the known exceptions from the simplest assumption as to specificity and
chemical composition.
However, only a few years later Thomas Graham (1805-1869) proved that the
three phosphoric acids are not isomeric. He used the proportion of 2 P to 5 O in
the oxide which Berzelius had thought justified at least until “an example of the
contrary could be sufficiently established.”[21] Refining the techniques of Gay-
Lussac (1816) and several other investigators, Graham characterized the three
phosphoric acids as “a terphosphate, a biphosphate, and phosphate of water.”
Actually, this was the wrong terminology for what he meant and formulated as
trihydrate, bihydrate, and monohydrate of phosphorus oxide. In his manner of
writing the formulas, each dot over the symbol for the element was to indicate an
atom of oxygen; thus, he wrote:
… :: .. … . . [22]
H3 P H2 P and H P.

Figure 5.—Oven for the calcination of
bones, about 1870. “The operation is carried
out in a rather high oven, such as shown….
The fresh bones are thrown in at the top of the
oven, B. First, fuel in chamber F is lighted, and Figure 6.—An advertisement with view of
a certain quantity of bones is burnt on the grid plant for manufacturing superphosphate
D. When these bones are burning well, the about 1867. (From E. T. Freedley,
oven is gradually filled with bones, and the Philadelphia and its Manufacturers in 1867,
combustion maintains itself without addition page 288.)
of other fuel. A circular gallery, C, surrounds
the bottom of the oven and carries the
products of combustion into the chimney, H.
The calcined bones are taken out at the lower
opening, G, by removing the bars of grid B.”
(Translation of the description from Figuier,
Merveilles de l’industrie, volume 3, 1874, page
537.)

Figure 7.—Florida hard-rock phosphate mining. (From Carroll D. Wright, The Phosphate
Industry of the United States, sixth special report of the Commissioner of Labor, Government
Printing Office, Washington, 1893, plate facing page 43.)

Graham had come to this understanding of the phosphoric acids through his
previous studies of “Alcoates, definite compounds of Salts and Alcohol
analogous to the Hydrates” (1831). Liebig started from analogies he saw with
certain organic acids when he formulated the phosphoric acids with a constant
proportion of water (aq.) and varying proportions of “phosphoric acid” (P) as
follows:
2 P 3 aq. phosphoric acid
3 P 3 aq. pyrophosphoric acid

6 P 3 aq. metaphosphoric acid.
Salts are formed when a “basis,” i.e., a metal oxide, replaces water. When
potassium-acid sulfate is neutralized by sodium base, the acid-salt divides into
Glauber’s salt and potassium sulfate, which proves the acid-salt to be a mixture
of the neutral salt with its acid. Sodium-acid phosphate behaves quite differently.
After neutralization by a potassium “base” (hydroxide), the salt does not split up;
a uniform sodium-potassium phosphate is obtained. Therefore, phosphoric acid is
truly three-basic![23]
This result has later been confirmed, but the analogy by means of which it
had been obtained was very weak, in certain parts quite wrong.
The acids from the two lower oxides of phosphorus were also considered as
three-basic. Adolphe Wurtz (1817-1884) formulated them in 1846, according to
the theory of chemical types:
(PO) · · ·
O3 phosphoric acid
H3
(PHO) · ·
O2 phosphorus acid
H2

(PH2O) ·
O hypophosphorous acid.[24]
H
Further proof for these constitutions was sought in the study of the esters
formed when the acids react with alcohols.
Among the analogies and generalizations by which the research on
phosphoric acid was supported, and to the results of which it contributed a full
share, was the new theory of acids. Not oxygen, Lavoisier’s general acidifier, but
reactive hydrogen determines the character of acids. In this brief survey, it seems
sufficient just to mention this connection without describing it in detail.
The study of phosphoric acids led to important new concepts in theoretical
chemistry. The finding of polybasicity was extended to other acids and formed
the model that helped to recognize the polyfunctionality in other compounds, like
alcohols and amines. The hydrogen theory of acids was fundamental for further

advance. In another dimension, it is particularly interesting to see that large-scale
applications followed almost immediately and directly from the new theoretical
insight. The first and foremost of these applications was in agriculture.

Phosphates as Plant Nutrients
One hundred years after the discovery of “cold light,” the presence of
phosphorus in plants and animals was ascertained, and its form was established
as a compound of phosphoric acid. This knowledge had little practical effect until
the “nature” of the acid, in its various forms, was explained through the work of
Thomas Graham. From it, there started a considerable technical development.
At about that time (1833), the Duke of Richmond proved that the fertilizing
value of bones resided not in the gelatin, nor in the calcium, but in the
phosphoric acid. Thus, he confirmed what Théodore de Saussure had said in
1804, that “we have no reason to believe” that plants can exist without
phosphorus. Unknowingly at first, the farmer had supplied this element by means
of the organic fertilizers he used: manure, excrements, bones, and horns. Now,
with the value of phosphorus known, a search began for mineral phosphates to be
applied as fertilizers. Jean Baptiste Boussingault (1802-1887), an agricultural
chemist in Lyons, traveled to Peru to see the guano deposits. Garcilaso de la Vega
(ca. 1540 to ca. 1616) noted in his history of Peru (1604) that guano was used by
the Incas as a fertilizer. Two hundred years later, Alexander von Humboldt
revived this knowledge, and Humphry Davy wrote about the benefits of guano to
the soil. Yet, the application of this fertilizer developed only slowly, until Justus
Liebig sang its praise. Imports into England rose and far exceeded those into
France where, between 1857 and 1867, about 50,000 tons were annually
received.
The other great advance in the use of phosphatic plant nutrients started with
Liebig’s recommendation (1840) to treat bones with sulfuric acid for
solubilization. This idea was not entirely new; since 1832, a production of a
“superphosphate” from bones and sulfuric acid had been in progress at Prague.
At Rothamsted in 1842, John Bennet Lawes obtained a patent on the
manufacture of superphosphate. Other manufactures in England followed and
were successful, although James Muspratt (1793-1886) at Newton lost much
time and “some thousands of pounds” on Liebig’s idea of a “mineral manure.”

Figure 8.—Florida land-pebble phosphate mining. (From Carroll D. Wright, The Phosphate
Industry of the United States …, plate facing page 58.)

It was difficult enough to establish the efficacy of bones and artificially
produced phosphates in promoting the growth of plants under special conditions
of soils and climate; therefore, the question as to the action of phosphates in the
growing plant was not even seriously formulated at that time. The beneficial
effects were obvious enough to increase the use of phosphates as plant nutrients
and to call for new sources of supply. Active developments of phosphate mining
and treating started in South Carolina in 1867, and in Florida in 1888.[25]
In a reciprocal action, more phosphate application to soils stimulated
increasing research on the conditions and reactions obtaining in the complex and
varying compositions called soil. The findings of bacteriologists made it clear
that physics and chemistry had to be amplified by biology for a real
understanding of fertilizer effects. After 1900, for example, Julius Stoklasa
(1857-1936) pointed out that bacterial action in soil solubilizes water-insoluble
phosphates and makes them available to the plants.[26]

Figure 9.—Florida river-pebble phosphate mining. (From Carroll D. Wright, The Phosphate
Industry of the United States …, plate facing page 64.)

The insight into the importance of phosphorus in organisms, especially since
Liebig’s time, is reflected in the work of Friedrich Nietzsche (1844-1900). This
“re-valuator of all values” who modestly said of himself: “I am dynamite!” once
explained the human temperaments as caused by the inorganic salts they contain:
“The differences in temperament are perhaps caused more by the different
distribution and quantities of the inorganic salts than by everything else. Bilious
people have too little sodium sulfate, the melancholics are lacking in potassium
sulfate and phosphate; too little calcium phosphate in the phlegmatics.
Courageous natures have an excess of iron phosphate.” (See volume 12 of
Nietzsche’s Works, edit. Naumann-Kröner, Leipzig, 1886.) In this strange
association of inorganic salts with human temperaments, the role of iron
phosphate as a producer of courage is particularly interesting. What would a
modern philosopher conclude if he followed the development of insight into the
composition and function of complex phosphate compounds in organisms?

From Inorganic to Organic Phosphates
By the middle of the 19th century, the source of phosphorus in natural
phosphates and the chemistry of its oxidation products had been established. The
main difficulty that had to be overcome was that these oxidation products existed

in so many forms, not only several stages of oxidation, but, in addition,
aggregations and condensations of the phosphoric acids. Once the fundamental
chemistry of these acids was elucidated, the attention of chemists and
physiologists turned to the task of finding the actual state in which phosphorus
compounds were present in the organisms. It had been a great advance when it
had been shown that plants need phosphates in their soil. This led to the next
question concerning the materials in the body of the plant for which phosphates
were being used and into which they were incorporated. Similarly, the knowledge
that animals attain their phosphates from the digested plant food called, in the
next step of scientific inquiry, for information on the nature of phosphates
produced from this source.
The method used in this inquiry was to subject anatomically separated parts
of the organisms to chemical separations. The means for such separations had to
be more gentle than the strong heat and destructive chemicals that had been
considered adequate up to then. The interpretation of the new results naturally
relied on the general advance of chemistry, the development of new methods for
isolating substances of little stability, of new concepts concerning the
arrangements of atoms in the molecules, and of new apparatus to measure their
rates of change.

Figure 10.—Electric furnace for producing elemental phosphorus, invented by Thomas
Parker of Newbridge, England, and assigned to The Electric Construction Corporation of the
same place. The drawing is part of United States patent 482,586 (September 13, 1892). The
furnace was patented in England on October 29, 1889 (no. 17,060); in France on June 23,
1890 (no. 206,566); in Germany on June 17, 1890 (no. 55,700); and in Italy on October 23,
1890 (no. 431). The following explanation is cited from the U.S. patent:

Figure 1 [shown here] is a vertical section of the
furnace, and Fig. 2 is a diagram to illustrate the means for
regulating the electro-motive force or quantity of current
across the furnace.
F is the furnace containing the charge to be treated. It
has an inlet-hopper at a, with slides AA, by which the
charge can be admitted without opening communication
between the interior of the furnace and the outer air.

B is a screw conveyer by which the charge is pushed
forward into the furnace.
c´c´ are the electrodes, consisting of blocks or cylinders
or the like of carbon fixed in metal socket-pieces c c, to
which the electric-circuit wires d from the dynamo D are
affixed. The current, as aforesaid, may be either continuous
or alternating. c2c2 are rods of metal or carbon, which are
used to establish the electric circuit through the furnace, the
said rods being inserted into holes in conductors c3 (in
contact with the socket-pieces c) and in the furnace, as
shown.
g is the outlet for the gas or vapor, h the slag-tap hole,
and x the opening for manipulating the charge, the said
openings being closed by clay or otherwise when the
furnace is at work.
I use coke or other form of carbon in the charge
between the electrodes c´, the said coke being in contact
with the said electrodes, so that complete incandescence is
insured.
A means for varying the electro-motive force or
quantity of current across the furnace with the varying
resistance of the charge is illustrated by the diagram, Fig. 2.
c´ c2 indicate the electrodes in the furnace, as in Fig. 1, and
D is the dynamo and T its terminals. E represents the
exciting-circuit. R R are resistances, and R S is the
resistance-switch, which is operated to put in more or less
resistance at R as the resistance of the charge in the furnace
lessens or increases. This switch may be automatically
operated, and a suitable arrangement for the purpose is a
current-regulator such as is described in the specification of
English Letters Patent No. 14,504, of September 14, 1889,
granted to William Henry Douglas and Thomas Hugh
Parker.

Figure 11.—Dipping of matchsticks in Figure 12.—Pan for dipping matchsticks into
France, about 1870. The frame which holds phosphorus paste, about 1870. The letters on
the matches so that one end protrudes at the the picture are: A, matches; B, water bath; C,
bottom, is lowered over a pan containing frame; D, plate; E, phosphorus paste; F, oven.
molten sulfur. The sulfur-covered matches are The phosphorus paste of Böttger, 1842,
then dropped into a phosphorous paste. See contained 10 phosphorus, 25 antimony sulfide,
figure 12. (From Figuier, Merveilles de 12.5 manganese dioxide, 15 gelatin. According
l’industrie, volume 3, 1874, page 575.) to Figuier (page 579), R. Wagner substituted
lead dioxide for the manganese dioxide. (From
Figuier, volume 3, 1874, page 576.)

In the system of chemistry, as it developed in the first half of the 19th
century, the new development can be characterized as the turn from inorganic to
organic phosphates, from the substance of minerals and strong chemical
interactions to the components in which phosphate groups remained combined
with carbon-containing substances.

Phosphatides and Phosphagens
The important phosphorus compounds in organisms are much more complex
than the simple salts, to which Nietzsche attributed such influence on man’s
character. Long before he wrote, it was known that phosphoric acid combines not
only with inorganic bases to form salts, but with alcohols to form esters. In the
middle of the 19th century, Théophile Juste Pelouze (1807-1867) extended this
knowledge to an ester of glycerol. This proved to be significant in several

respects. Glycerol had been shown by Michel Chevreul (1786-1889) as the
substance in fats that is released in the process of soap boiling, when the fatty
acids are converted into their salts. That it has the nature of an alcohol had been
demonstrated by Marcellin Berthelot. Instead of one “alcoholic” hydroxyl group,
OH, like ethanol (the alcohol of fermentation), or two hydroxyl groups (like
ethylene glycol), glycerol contains three such groups. It was the only “natural”
alcohol known at that time. That this alcohol would combine with phosphoric
acid could be predicted, but that the ester, as obtained by Pelouze, still contained
free acidic functions and formed a water-soluble barium salt was a new
experience.

Figure 13.—Survey of alcoholic fermentation, 1951. The “well-known scheme of alcoholic
fermentation” according to Albert Jan Kluyver (1888-1956), presented before the Society of
Chemical Industry in the Royal Institution, March 7, 1951. In Chemistry & Industry, 1952,
page 136 ff., Kluyver restates that “… the fermentation of one molecule of glucose is
indissolubly connected with the formation of two molecules of adenosine triphosphate (ATP)
out of two molecules of adenosine diphosphate (ADP).”

Shortly after this experience had been gained, it became valuable for
understanding the chemical nature of a new substance extracted from a natural
organ. This substance was named lecithin by its discoverer, Nicolas Théodore
Gobley[27] (1811-1876), because he obtained it from egg yolk (in Greek, lékidos).
He used ether and alcohol for this extraction. Had he used water and mineral acid
instead, he would not have found lecithin, but only its components. As Gobley
and, slightly later, Oscar Liebreich (1839-1908), subjected lecithin to treatment
with boiling water and acid, they separated it into three parts. One of them was
the glycerophosphoric acid of Pelouze, the second was the well-known stearic
acid of Chevreul, but the third was somewhat mysterious. This third substance
was the same as one previously noticed when nerves had been subjected to an
extraction by boiling water and acid and, therefore, called nerve-substance or
neurine. Adolf Friedrich Strecker (1822-1871) established the identity of this
neurine with a product he had extracted from bile and which went under the
name of choline. Adolphe Wurtz (1817-1884) succeeded in synthesizing this
substance from ethylene oxide, CH2.O.CH2 and trimethylamine N(CH3)3.[28]
Thus, all three parts were identified, and Strecker put them together to construct a
chemical formula for lecithin, glycerophosphoric acid combined with a fatty acid
and with choline (a hydrate of neurine).
OH
N (CH ) } Choline
{ 3 3
C2H4O

C18H33O2
} HO
} PO
C16H31O2 C3H5O
Fatty Acids Glycerophosphate
'—————v————'
Lecithin
according to Strecker
This formula was not quite correct. Richard Willstätter showed that an
internal neutralization takes place between the amino group and the free acidic
residue. This is expressed in his lecithin formula of 1918.

Lecithin (1918)
When the aim was to distill elementary phosphorus out of an organic
material, it did not matter whether this was fresh or putrified. For obtaining
lecithin out of egg yolk and similar materials, it was essential to use it in fresh
condition. Otherwise, enzymes would have decomposed it. Through more recent
work, four enzymes have been separated, which act specifically in decomposing
lecithin. Enzyme A removes one fatty acid and leaves a complex residue, called
lysolecithin, intact. Enzyme B attacks this residue and splits off the remaining
fatty acid group from it, enzyme C liberates only the choline from lecithin, and
enzyme D opens lecithin at the ester bond between glycerol and phosphoric acid.
This is shown in the following diagram.
Enzymatic Splitting of Lecithins
Enzyme Substrate Products
A Lecithin Lysolecithin and fatty acids.
B Lysolecithin Glycero-phospho-choline and fatty acids.
C Lecithin Phosphatidic acid and choline.
D Lecithin Phosphoryl choline and diglyceride.
Several fatty acids can be present in lecithin from various sources: palmitic
and oleic acid, besides the stearic acid which at first had been thought the only
one involved. In another group of extracts from brain or nerve tissue, amino-
ethanol H2NCH2CH2OH is found instead of the choline of lecithin. The
variations include the alcohol, to which the fatty acids and choline phosphate are
attached. For example, glycerol can be replaced by the so-called meat-sugar,
inositol, which has six hydroxyl groups in its hexagon-shaped molecule
C6H6(OH)6.

The generally similar behavior of these phosphate-and fat-containing
substances was emphasized by Ludwig Thudichum (1829-1901). He coined the

name phosphatides for this group of
substances from seeds and nerves.[29] His
work on the phosphates in brain
substance aroused particular interest.
When William Crookes drew his highly
imaginative picture of an “evolution” of
the chemical elements, he put into it
“phosphorus for the brain, salt for the
sea, clay for the solid earth….” [30] But
phosphatides occur in many places of
organisms, in bacteria, in leaves and
roots of plants, in fat and tissues of
animals. And where phosphatides are
found, there are also enzymes that
specifically act on them. They are called
phosphatases to imply that they split the
phosphatides. In addition, enzymes are
present, which transfer phosphate groups
Figure 14.—Eduard Buchner (1860-1917) from one compound to another. They are
received the Nobel Prize in Chemistry for his more abundant in seeds of high fat
discovery of cell-free fermentation, the first
step in finding the role of phosphate in content than in the more starch-
fermentations (1907). containing seeds, but even potatoes and
orange juice have phosphatases. [31]
Thus, from phosphatides, phosphoric acid is generated, and they could also
be called phosphagens. Since 1926, however, the name phosphagens has been
reserved for a group of organic substances that release their phosphoric acid very
readily. The link between phosphorus and carbon is provided by oxygen in the
phosphatides, by nitrogen in the phosphagens. In vertebrates, the basis for the
phosphoric acid is creatine, whereas invertebrates have arginine instead.

Creatine

Phosphate

Arginine
phosphate

Nuclein and Nucleic Acids
All parts of an organism are essential for life. Only with this in mind does it
make sense to say that the most important part of the cell is its nucleus. From the
nuclei of cells in pus and in salmon sperm, Johann Friedrich Miescher (1811-
1887) obtained a peculiar kind of substance, which he named nuclein (1868). Its
phosphate content was easily discovered, but to find the exact proportions and
the nature of the other components required special methods of separation from
phosphatides and other proteins. It was difficult to develop such methods at a
time when little was known about the properties, and particularly the stability, of
a nuclein. For preparing nuclein from yeast cells, Felix Hoppe-Seyler (1825-
1895) described the following details: Yeast is dispersed in water to extract
soluble materials, like salts or sugars. After a few hours, the insoluble material is
separated, washed once more with water, and then extracted with a very dilute
solution of sodium hydroxide. The slightly alkaline solution, freed from insoluble
residues, is slowly added to a weak hydrochloric acid. A precipitate forms which
is separated by filtration, washed with dilute acid, then with cold alcohol, and
finally extracted by boiling alcohol. The dried residue is the nuclein.[32] It
contains six percent phosphorus. A little more washing with water, a slightly
longer treatment with acid or alcohol gives products of lower phosphorus
content. Many experimental variations were necessary to establish the procedure
that leads to purification without alteration of the natural substance.

This was also true for the methods of chemical degradation, carried out in
order to find the components of nucleins in their highest state of natural
complexity. It was learned for example, that the special kind of carbohydrate
present in nucleins was very susceptible to change under the conditions of
hydrolysis by acids. Phoebus Aaron Theodor Levine (1869-1940), therefore, used
the digestion by a living organism. With E. S. London, he introduced a solution
of nucleic acid into, e.g., the gastrointestinal segment of a dog through a gastric
fistula and withdrew the product of digestion through an intestinal fistula.
Fortunately, the products obtained in such degradations were not new in
themselves. The carbohydrate in this nucleic acid proved to be identical with D-
ribose, which Emil Fischer had artificially made from arabinose and named
ribose to indicate this relationship (1891). The nitrogenous products of the
degradation were identical with substances previously prepared in the long study
of uric acid. In the course of this study, Emil Fischer established uric acid and a
number of its derivatives as having the elementary skeleton of what he called
“pure uric acid,” abbreviated to purine. Out of Adolf Baeyer’s work on barbituric
acid came the knowledge of pyrimidine and its derivatives.

Figure 15.—Albrecht Kossel (1853-1927) received the Nobel Prize in Medicine and
Physiology in 1910 for his work on nucleic substances, which contain a high proportion of
phosphorus. The chemical bonds of this phosphorus in the molecules of nucleic substances
were determined in later work. (Photo courtesy National Library of Medicine, Washington,
D.C.)

From these findings, together with what Oswald Schmiedeberg (1838-1921)
had established concerning the presence of four phosphate groups in the

molecule (1899), Robert Feulgen (1884-1955) constructed the following scheme
of a nucleic acid. Feulgen’s formula of 1918 is:
Phosphoric acid—Carbohydrate—Guanine
Phosphoric acid—Carbohydrate—Cytosine
Phosphoric acid—Carbohydrate—Thymine
Phosphoric acid—Carbohydrate—Adenine
Of the four basic components on the right, thymine occurs in the nucleic acid
from the thymus gland. Yeast contains uracil instead. The difference between
these two bases is one methyl group: thymine is a 5-methyluracil. In all of these

basic substances, the structure of urea is involved, and they form pairs
of oxidized and reduced states:

Purine Pyrimidine
(reduced) Adenine + (oxidized) Thymine
(oxidized) Guanine + (reduced) Cytosine

Pyrimidine

Purine

Adenine

Uracil
Guanine

Cytosine
The carbohydrate is ribose or deoxyribose.

l-Ribose
Arabinose

Fischer and Piloty, 1891

Deoxyribose
The exact position of phosphoric acid was established after long work and
verified by synthesis.[33]
A compound of adenine, ribose, and phosphoric acid was found in yeast,
blood, and in skeletal muscle of mammals. From 100 grams of such muscle,
0.35-0.40 grams of this compound were isolated. If the muscle is at rest, the

compound contains three molecules of phosphoric acid, linked through oxygen
atoms. It was named adenosine triphosphate or adenyltriphosphoric acid,[34]
usually abbreviated by the symbol ATP. It releases one phosphoric acid group
very easily and goes over in the diphosphate, ADP, but it can also lose 2 P-groups
as pyrophosphoric acid and leave the monophosphate, AMP.

This change of ATP was considered to be the main source of energy in
muscle contraction by Otto Meyerhof.[35] The corresponding derivatives of
guanine, cytosine, and uracil were also found, and they are active in the
temporary transfer of phosphoric acid groups in biological processes.
Thus, the study of organic phosphates progressed from the comparatively
simple esters connected with fatty substances of organisms to the proteins and
the nuclear substances of the cell. The proportional amount of phosphorus in the
former was larger than in the latter; the actual importance and function in the life
of organisms, however, is not measured by the quantity but determined by the
special nature of the compounds.

Figure 16.—Otto Meyerhof (1884-1951) received one-half of the Nobel Prize in Medicine
and Physiology in 1922 for his discovery of the metabolism of lactic acid in muscle, which
involves the action of phosphates, especially adenosine duophosphates. (Photo courtesy
National Library of Medicine, Washington, D.C.)

Figure 17.—Arthur Harden (1865-1940), left, and Hans A. S. von Euler-Chelpin (b. 1875),
right, shared the Nobel Prize in Chemistry in 1929. Harden received it for his research in
fermentation, which showed the influence of phosphate, particularly the formation of a
hexose diphosphate. Euler-Chelpin received his award for his research in fermentation. He
found coenzyme A which is a nucleotide containing phosphoric acid.

Figure 18.—George de Hevesy (b. 1885) received the Nobel Prize in Chemistry in 1943 for
his research with isotopic tracer elements, particularly radiophosphorus of weight 32
(ordinary phosphorus is 31).

Figure 19.—Carl F. Cori (b. 1896) and his wife, Gerty T. Cori (1896-1957) received part of
the Nobel Prize in Medicine and Physiology in 1947 for their study on glycogen conversion. In
the course of this study, they identified glucose 1-phosphate, now usually referred to as “Cori
ester,” and its function in the glycogen cycle. (Photo courtesy National Library of Medicine,
Washington, D.C.)

The study of this function is the newest phase in the history of phosphorus
and represents the culmination of the previous efforts. This newest phase
developed out of an accidental discovery concerning one of the oldest organic-
chemical industries, the production of alcohol by the fermentative action of yeast
on sugar. A transition of carbohydrates through phosphate compounds to the end
products of the fermentation process was found, and it gradually proved to be a
kind of model for a host of biological processes.
Specific phosphates were thus found to be indispensable for life. In reverse,
the wrong kind of phosphates can destroy life. As a result, an important part of
the new phase in phosphorus history consisted in the study—and use—of
antibiotic phosphorus compounds.

Phosphates in Biological Processes
The first indication that phosphorus is important for life came from the
experience that plants take it up from the substances in the soil. They incorporate
it in their body substance. What makes phosphorus so important that they cannot
grow without it? The next insight was that animals acquire it from their plant
food. It is then found in bones, in fat and nerve tissue, in all cells and particularly
in the cell nuclei. What are its functions there?
The answers to such questions were developed from the study of a long-
known process, the conversion of carbohydrates into carbon dioxide and alcohol
by yeast. It started with Eduard Buchner’s discovery of 1890, that fermentation is
produced by a preparation from yeast in which all living cells have been
removed. When yeast is dead-ground and pressed out, the juice still has the
ability to produce fermentation.
It is strange, but in many ways characteristic for the process of science, that
the “riddle” of phosphorus in life was solved by first eliminating life. In such
“lifeless” fermentations, Arthur Harden found that the conversion of sugar begins
with the formation of a hexose phosphate (1904). The “ferment” of yeast, called
zymase, proved to be a composite of several enzymes. Hans von Euler-Chelpin
isolated one part of zymase, which remains active even after heating its solution

to the boiling point. From 1 kilogram of yeast, he obtained 20 milligrams of this
heat-stable enzyme, which he called cozymase and identified as a nucleotide
composed of a purine, a sugar, and phosphoric acid.[36] In the years between the
two World Wars, zymase was further resolved into more enzymes, one of them
the coenzyme I, which was shown to be ADP connected with another molecule of
ribose attached to the amide of nicotinic acid, or diphosphopyridine nucleotide:

Figure 20.—Fritz A. Lipmann (b. 1899) shared
with Hans Adolf Krebs the Nobel Prize in
Medicine and Physiology in 1953 for his work Figure 21.—Alexander R. Todd (b. 1907)
on coenzyme A. He discovered acetyl received the Nobel Prize in Chemistry in 1957
phosphate as the substance in bacteria, which for his research on nucleotides. He determined
transfers phosphate to adenylic acid. the position of the phosphate groups in the
molecule and confirmed it by synthesis of
dinucleotide phosphates.

Its function is connected with the transfer of hydrogen between intermediates
formed through phosphate-transferring enzymes. Fermentation proceeds by a
cascade of processes, in which phosphate groups swing back and forth, and
equilibria between ATP with ADP play a major role.
Many of the enzymes are closely related to vitamins. Thus, cocarboxylase A,
which takes part in the separation of carbon dioxide from an intermediate
fermentation product, is the phosphate of vitamin B1. Others of the B vitamins
contain phosphate groups, for example those of the B2 and B6 group, and in B12,
one lonely phosphate forms a bridge in the large molecule that contains one atom
of cobalt: C63H90N14O14PCo. The formation of vitamin A from carotine occurs
under the influence of ATP.
The first stages in fermentation are like those in respiration, which ends with
carbon dioxide and water. These two are the materials for the reverse process in

photosynthesis. When light is absorbed by the chlorophyll of green plants, one of
the initial reactions is a transfer of hydrogen from water to a triphosphopyridine
nucleotide, which later acts to reduce the carbon dioxide. Under the influence of
ATP, phosphoglyceric acid is synthesized and further built up by way of
carbohydrate phosphates to hexose sugars and finally to starch. In many starchy
fruits, a small proportion of phosphate remains attached to the end product.
The synthesis of proteins is under the control of deoxyribonucleic acid or
ribonucleic acid, abbreviated by the symbols DNA and RNA. The genes in the
nucleus are parts of a giant DNA molecule. RNA is a universal constituent of all
living cells. Where protein synthesis is intense, the content in RNA is high. Thus,
the spinning glands of silkworms are extraordinarily rich in RNA.[37]

In his research on the radioactive isotope P32, George de Hevesy gained some
insight into the surprising mobility of phosphates in organisms: “A phosphate
radical taken up with the food may first participate in the phosphorylation of
glucose in the intestinal mucose, soon afterwards pass into the circulation as free
phosphate, enter a red corpuscle, become incorporated with an adenosine
triphosphoric-acid molecule, participate in a glycolytic process going on in the
corpuscle, return to circulation, penetrate into the liver cells, participate in the
formation of a phosphatide molecule, after a short interval enter the circulation in
this form, penetrate into the spleen, and leave this organ after some time as a
constituent of a lymphocyte. We may meet the phosphate radical again as a
constituent of the plasma, from which it may find its way into the skeleton.”[38]
Much has been added in the last 30 years to complete this picture in many details
and to extend it to other biochemical processes, including even the changes of the
pigments in the retina in the visual process, or in the conversion of chemical
energy to light by bacteria and insects.

Medicines and Poisons
In the delicate balance of these processes, disturbances may occur which can
be remedied by specific phosphate-containing medicines. Thus, adenosine
phosphate has been recommended in cases of angina pectoris and marketed under
trade names like sarkolyt, or in compounds named angiolysine. A considerable
number of physiologically active organic phosphates can be found in the patent
literature.[39] Yeast itself is considered to be a valuable food additive.

On the other hand, there are phosphate compounds that act as poisons. One
group of such compounds was discovered in 1929 by W. Lange, who wrote: “Of
interest is the strong action of mono-fluorophosphate esters on the human body
—the effect is produced by very small quantities.”[40] Diisopropyl
fluorophosphate has since become a potential agent for chemical warfare. It
inactivates an enzyme which controls the transmission of nerve impulses to
muscle, acetylcholine esterase.
Organic esters of phosphoric acids are used as insecticides. The hexa-
ethylester of tetraphosphoric acid, prepared by Gerhard Schrader by heating
triethylphosphate with phosphorus oxychloride,[41] actually contains
tetraethylpyrophosphate (TEPP) among others. Bayer’s Dipterex, the dimethyl
ester of 2,2,2-trichloro-1-hydroxyethyl-phosphonate, has been modified to
dimethyl-2,2-dichlorovinyl-phosphate and is especially active against the oriental
fruit fly.[42]

Bayer's L 13/59
(Dipterex)

Schradan
Octamethylpyrophosphoramide

Figure 22.—Arthur Kornberg (b. 1918) and Severo Ochoa (b. 1905) shared the Nobel Prize
in Medicine and Physiology in 1959. Kornberg received it for research on the biological
synthesis of deoxyribonucleic acid. In particular, he found that four triphosphate components
and a small amount of the end product as a “template” had to be present for the enzymatic
synthesis. Ochoa received his share of the prize for research in ribonucleic acid and
deoxyribonucleic acid. In particular, Ochoa synthesized polyribonucleotides and used the
radioactive isotope, P32. The synthetic polyribonucleotides were found to resemble the natural
substances in all essentials.

Figure 23.—Melvin Calvin (b. 1911) received the Nobel Prize in Chemistry in 1961 for his
research in photosynthesis, in which he specified the function of phosphoglyceric acid as an
intermediate in the synthesis of carbohydrates from carbon dioxide and water by green
plants.

The story of phosphorus, which began 300 years ago, has acquired new
importance in this century. Many scientists have contributed to it: 13 of them
have received Nobel Prizes for work directly bearing on the chemical and
biological importance of phosphorus compounds. In chronological order, they
are: Eduard Buchner, Albrecht Kossel, Otto Meyerhof, Arthur Harden, Hans von
Euler-Chelpin, George de Hevesy, Carl F. Cori, Gerty T. Cori, Fritz Lipmann,
Lord Alexander Todd, Arthur Kornberg, Severo Ochoa, and Melvin Calvin. The
developers of industrial production and commercial utilization of phosphate
compounds have had other rewards.

Some impression of the continuing growth in this field [43] can be gained
from the following data.

Phosphate Rock
annually “sold or used by producer” in the United States
in million long tons (2,240 lbs.)
1880 0.2
1890 0.5
1900 1.5
1910 2.655
1920 4.104
1930 3.926
1940 4.003
1945 5.807
1950 11. 114
1955 12.265
1955 (world: about 56)
1960 17.202
1962 19.060
Sources: U.S. Bureau of the Census. Historical Statistics of the United States
1789-1945 (1949); Statistical Abstract of the United States.

Elemental Phosphorus
annually produced in the United States

in short tons (2,000 lbs.)
1939 43,000
1944 85,679
1950 153,233
1956 312,200
1958 335,750
1959 366,350
1960 409,096
1961 430,617
1962 451,970
Source: U.S. Department of Commerce.

FOOTNOTES
[1]
Wilhelm Homberg, Mémoires Académie, 1666-1699 (Paris, 1730), vol. 10, under date of April 30,
1692, pp. 57-61.
[2]
Fortunio Licetus, Lithiophosphorus sive de lapide Bononiensi (Venice, 1640).
[3]
Cited in Peter Joseph Macquer Chymisches Wörterbuch, 2nd ed. (Leipzig: Weidmann, 1789), vol.
4, p. 508, footnote “c” as “Kletwich (de phosph. liqu. et solid. 1689, Thes. II).”
[4]
Ferdinand Hoefer, Histoire de la Chimie (Paris, 1843), vol. 1, p. 339.
[5]
G. W. von Leibniz, Mémoires Académie (Paris, 1682); Akademie der Wissenschaften, Miscellanea
Berolinensia (Berlin, 1710), vol. 1, p. 91.
[6]
Jean Hellot, Mémoires Académie 1737 (Paris, 1766), under date of November 13, 1737, pp. 342-
378.
[7]
Macquer, op. cit. (footnote 3), p. 551.
[8]
A. S. Marggraf, Akademie der Wissenschaften, Miscellanea Berolinensia (Berlin, 1743), vol. 7,
342 ff.; see also Wilhelm Ostwald Klassiker der Exakten Naturwissenschaften (Leipzig:
Engelmann, 1913), no. 187.
[9]
G. Hanckewitz, [Hankwitz], Philosophical Transactions of the Royal Society of London, 1724-
1734, abridged (London, 1809), vol. 7, pp. 596-602.
[10]
Antoine Laurent Lavoisier, “Sur la Combustion du Phosphore de Kunckel, Et sur la nature de
l’acide qui resulte de cette Combustion,” Mémoires Académie 1777, (Paris, 1780), pp. 65-78.
[11]
Guyton de Morveau and others, Méthode de Nomenclature Chimique, Proposée par MM. de
Morveau, Lavoisier, Bertholet, & de Fourcroy (Paris, 1787), plate 9.
[12]
Macquer, op. cit. (footnote 3), p. 513.

[13]
Marie Boas, Robert Boyle and Seventeenth Century Chemistry (New York: Cambridge University
Press, 1958), p. 226; see also Wyndham Miles, “The History of Dr. Brand’s Phosphorus
Elementarus,” Armed Forces Chemical Journal (November-December 1958), p. 25.
[14]
Archibald Clow and Nan L. Clow, The Chemical Revolution (London: Batchworth Press, 1952),
p. 451.
[15]
Émile Kopp, Comptes-rendus hebdomadaires des Séances de l’Académie des Sciences, Paris
(1844), vol. 18, p. 871; Wilhelm Hittorf, Annalen der Chemie und Pharmazie, suppl. to vol. 4,
p. 37; Anton Schrötter, Annales de Chimie et de Physique, series 3, vol. 24 (1848), p. 406;
see also Schrötter’s report on “Phosphor und Zündwaaren” in A. W. von Hofmann, Bericht
über die Entwicklung der Chemischen Industrie (Braunschweig: Vieweg, 1875), pp. 219-246.
[16]
R. Glauber, Furni Novi Philosphici (Amsterdam, 1649), vol. 2, pp. 12 ff.
[17]
Hermann Schelenz, Geschichte der Pharmazie (Berlin: Springer, 1904), p. 598.
[18]
J. Personne, Comptes-rendus …, Paris (1869), vol. 68, pp. 543-546.
[19]
A. Wurtz, Dictionnaire de Chimie (Paris, 1876), vol. 2, part 2, p. 951.
[20]
Karl W. Scheele, Nachgelassene Briefe und Aufzeichnungen, edit. A. E. Nordenskiöld
(Stockholm: Norstedt, 1892), pp. 38, 144.
[21]
J. J. Berzelius, Lehrbuch, transl. F. Wöhler (Dresden, 1827), vol. 3, part 1, p. 96.
[22]
Thomas Graham, Philosophical Transactions of the Royal Society of London (1833), pp. 253-284.
[23]
Justus Liebig’s Annalen der Pharmacie (1838), vol. 26, p. 113 ff.
[24]
A. Wurtz, Annales de Chimie et de Physique, series 3, vol. 16 (1846), p. 190.
[25]
Carroll D. Wright, The Phosphate Industry in the United States, sixth special report of the
Commissioner of Labor (Washington, 1893).
[26]
J. Stoklasa, Biochemischer Kreislauf des Phosphat-Ions im Boden, Centralblatt für Bakteriologie
… (Jena: Fischer, March 22, 1911), vol. 29, nos. 15-19.
[27]
N. T. Gobley, Comptes-rendus …, Paris (1845), vol. 21, p. 718.
[28]
A. Wurtz, Comptes-rendus …, Paris (1868), vol. 66, p. 772.
[29]
L. Thudichum, Die chemische Constitution des Gehirns des Menschen und der Tiere (1901); see
also H. Wittcoff, The Phosphatides (New York: Reinhold, 1951).
[30]
William Crookes, British Association for the Advancement of Science, Reports (1887), sec. B, p.
573.
[31]
J. E. Courtois and A. Lino, Progress in the Chemistry of Organic Natural Products, edit. L.
Zechmeister (Vienna: Springer Verlag, 1961), vol. 19, p. 316-373.
[32]
A. Wurt, Dictionnaire de Chimie, supp. part 2, [n.d.] p. 1087; A. Kossel, Zeitschrift für
physiologische Chemie, series 3 (1879), p. 284.
[33]
Alexander Todd, Les Prix Nobel en 1957 (Stockholm).
[34]
Hans von Euler-Chelpin, Les Prix Nobel en 1929 (Stockholm).

[35]
O. Meyerhof and E. Lundsgaard, Naturwissenschaften (Berlin, 1930), vol. 18, pp. 330, 787.
[36]
K. Lohmann, Naturwissenschaften (Berlin, 1929), vol. 17, p. 624; C. H. Fiske and Y. Subbarow,
Science (Washington, 1929), vol. 70, p. 381 f.
[37]
J. Brachet, Scientia, Revista di Scienza (1960), vol. 95, p. 119.
[38]
George de Hevesy, Les Prix Nobel en 1940 (Stockholm). See also Eduard Farber, Nobel Prize
Winners in Chemistry, 2nd ed. (New York: Schuman, 1963), p. 179.
[39]
See, e.g., Chemical Week, vol. 77 (September 3, 1955), p. 79 f.; J. Bolle, Chimie et Industrie
(1960), vol. 83, p. 252.
[40]
W. Lange, Berichte der Deutschen Chemischen Gesellschaft (Berlin, 1929), vol. 62, p. 793; vol.
65 (1932), p. 1598.
[41]
Gerhard Schrader, U.S. patent 2,336,302 of 1943 (priority in Germany, 1938); S. A. Hall and
M. Jacobson, Industrial and Engineering Chemistry (1943), vol. 40, p. 694.
[42]
A. M. Mattsen and others, Journal of Agriculture and Food Chemistry (1955), vol. 3, p. 319.
[43]
John B. Van Wazer, Phosphorus and its Compounds, 2 vols. (vol. 1, Chemistry; vol. 2
Technology, Biological Functions and Applications), New York: Interscience, 1958, 1961.

Paper 40 - Transcriber’s Note
The following typographical errors have been corrected:
ge 180 “Abfällen, Vieweg, Braunschweig,” - had “Viewig”.
ge 192 “But phosphatides occur” - had “phosphatide soccur”.
ge 193 “the nucleic acid from the thymus” - had “nucleidic”.
ge 199 “acetylcholine esterase.” - had “acetylcholin”.
ge 200 “George de Hevesy, Carl F. Cori,” - comma added after Hevesy.
otnote 39: “See, e.g., Chemical Week, vol. 77” - had “See. e.g.”
The spelling of “Bertholet” [Claude Louis Berthollet] is as given on
the original title page of the work referenced in this paper.

Inconsistent hyphenation of chemical names has been retained.

Contributions from
The Museum of History and
Technology.
Paper 41

Tunnel Engineering—A Museum
Treatment

Robert M. Vogel

INTRODUCTION 203

ROCK TUNNELING 206

SOFT-GROUND TUNNELING 215

BIBLIOGRAPHY 239

FOOTNOTES

INDEX

Figure 1.—Mining by early European civilizations, using fire setting and hand
chiseling to break out ore and rock. MHT model—3/4" scale. (Smithsonian photo
49260-H.)

Robert M. Vogel

TUNNEL ENGINEERING—A
MUSEUM TREATMENT
During the years from 1830 to 1900, extensive developments
took place in the field of tunneling, which today is an important,
firmly established branch of civil engineering. This paper offers
a picture of its growth from the historical standpoint, based on a
series of models constructed for the Hall of Civil Engineering in
the new Museum of History and Technology. The eight models
described highlight the fundamental advances which have
occurred between primitive man’s first systematic use of fire for
excavating rock in mining, and the use in combination of
compressed air, an iron lining, and a movable shield in a
subaqueous tunnel at the end of the 19th century.
The Author: Robert M. Vogel is curator of heavy machinery
and civil engineering, in the Smithsonian Institution’s Museum of
History and Technology.

Introduction
ith few exceptions, civil engineering is a field in which the ultimate goal
W isscientifically
the assemblage of materials into a useful structural form according to a
derived plan which is based on various natural and man-
imposed conditions. This is true whether the result be, for example, a dam, a
building, a bridge, or even the fixed plant of a railroad. However, one principal
branch of the field is based upon an entirely different concept. In the engineering
of tunnels the utility of the “structure” is derived not from the bringing together
of elements but from the separation of one portion of naturally existing material
from another to permit passage through a former barrier.
In tunneling hard, firm rock, this is practically the entire compass of the
work: breaking away the rock from the mother mass, and, coincidently, removing
it from the workings. The opposite extreme in conditions is met in the soft-
ground tunnel, driven through material incapable of supporting itself above the

tunnel opening. Here, the excavation of the tunneled substance is of relatively
small concern, eclipsed by the problem of preventing the surrounding material
from collapsing into the bore.

Figure 2.—Hoosac Tunnel. Method of working early sections of the project; blast
holes drilled by hand jacking. MHT model—1/2" scale. (Smithsonian photo 49260-L.)

In one other principal respect does tunnel engineering differ widely from its
collateral branches of civil engineering. Few other physical undertakings are
approached with anything like the uncertainty attending a tunnel work. This is
even more true in mountain tunnels, for which test borings frequently cannot be
made to determine the nature of the material and the geologic conditions which
will be encountered.
The course of tunnel work is not subject to an overall preliminary survey; the
engineer is faced with not only the inability to anticipate general contingencies
common to all engineering work, but with the peculiar and often overwhelming
unpredictability of the very basis of his work.
Subaqueous and soft-ground work on the other hand, while still subject to
many indeterminates, is now far more predictable than during its early history,
simply because the nature of the adverse condition prevailing eventually was
understood to be quite predictable. The steady pressures of earth and water to
refill the excavated area are today overcome with relative ease and consistency
by the tunneler.
In tunneling as in no other branch of civil engineering did empiricism so long
resist the advance of scientific theory; in no other did the “practical engineer”
remain to such an extent the key figure in establishing the success or failure of a
project. The Hoosac Tunnel, after 25 years of legislative, financial, and technical
difficulties, in 1875 was finally driven to successful completion only by the
efforts of a group who, while in the majority were trained civil engineers, were to
an even greater extent men of vast practical ability, more at home in field than
office.

DeWitt C. Haskin (see p. 234), during the inquest that followed the death of a
number of men in a blowout of his pneumatically driven Hudson River Tunnel in
1880, stated in his own defense: “I am not a scientific engineer, but a practical
one … I know nothing of mathematics; in my experience I have grasped such
matters as a whole; I believe that the study of mathematics in that kind of work
[tunneling] has a tendency to dwarf the mind rather than enlighten it….” An
extreme attitude perhaps, and one which by no means adds to Haskin’s stature,
but a not unusual one in tunnel work at the time. It would not of course be fair to
imply that such men as Herman Haupt, Brunel the elder, and Greathead were not
accomplished theoretical engineers. But it was their innate ability to evaluate and
control the overlying physical conditions of the site and work that made possible
their significant contributions to the development of tunnel engineering.
Tunneling remained largely independent of the realm of mathematical
analysis long after the time when all but the most insignificant engineering works
were designed by that means. Thus, as structural engineering has advanced as the
result of a flow of new theoretical concepts, new, improved, and strengthened
materials, and new methods of fastening, the progress of tunnel engineering has
been due more to the continual refinement of constructional techniques.

A NEW HALL OF CIVIL ENGINEERING
In the Museum of History and Technology has recently been established a
Hall of Civil Engineering in which the engineering of tunnels is comprehensively
treated from the historical standpoint—something not previously done in an
American museum. The guiding precept of the exhibit has not been to outline
exhaustively the entire history of tunneling, but rather to show the fundamental
advances which have occurred between primitive man’s first systematic use of
fire for excavating rock in mining, and the use in combination of compressed air,
iron lining, and a movable shield in a subaqueous tunnel at the end of the 19th
century. This termination date was selected because it was during the period from
about 1830 to 1900 that the most concentrated development took place, and
during which tunneling became a firmly established and important branch of civil
engineering and indeed, of modern civilization. The techniques of present-day
tunneling are so fully related in current writing that it was deemed far more
useful to devote the exhibit entirely to a segment of the field’s history which is
less commonly treated.