Every-day Science_ Volume 6. The Conquest of Nature Henry Smith Williams and Edward Huntington Williams 1002 downloads.pdf

The Project Gutenberg eBook of Every-day Science: Volume 6.
The Conquest of Nature
This eBook is for the use of anyone anywhere in the United States and most
other parts of the world at no cost and with almost no restrictions
whatsoever. You may copy it, give it away or re-use it under the terms of
the Project Gutenberg License included with this eBook or online at
www.gutenberg.org. If you are not located in the United States, you will
have to check the laws of the country where you are located before using
this eBook.

Title: Every-day Science: Volume 6. The Conquest of Nature

Author: Henry Smith Williams
Edward Huntington Williams

Release date: December 24, 2013 [eBook #44502]
Most recently updated: October 23, 2024

Language: English

Other information and formats: www.gutenberg.org/ebooks/44502

Credits: Produced by Chris Curnow, John Campbell, Albert László
(bertzi) and the Online Distributed Proofreading Team at
http://www.pgdp.net (This file was produced from images
generously made available by The Internet Archive)

*** START OF THE PROJECT GUTENBERG EBOOK EVERY-DAY
SCIENCE: VOLUME 6. THE CONQUEST OF NATURE ***

TRANSCRIBER'S NOTES

Obvious typographical and punctuation errors have been corrected after careful
comparison with other occurrences within the text and consultation of external sources.
More detail can be found at the end of the book.

A PRIMITIVE USE OF THE ANIMAL MACHINE THAT IS
STILL IN VOGUE IN MANY EUROPEAN COUNTRIES.
(From the painting by J. Didier, in the Musée du Luxembourg,
Paris.)

EVERY-DAY SCIENCE

BY

HENRY SMITH WILLIAMS, M.D., L.L.D.
ASSISTED BY

EDWARD H. WILLIAMS, M.D.

VOLUME VI

THE CONQUEST OF NATURE
ILLUSTRATED

NEW YORK AND LONDON

T H E G O O D H U E C O M PA N Y

PUBLISHERS MDCCCCIX

Copyright, 1910, by The Goodhue Co.

All rights reserved

CONTENTS
ILLUSTRATIONS vii
THE CONQUEST OF NATURE 1
CHAPTER I MAN AND NATURE 3
CHAPTER II HOW WORK IS DONE 29
CHAPTER III THE ANIMAL MACHINE 43
CHAPTER IV THE WORK OF AIR AND WATER 62
CHAPTER V THE STORY OF THE STEAM ENGINE 79
CHAPTER VI THE MASTER WORKER 110
CHAPTER VII GAS AND OIL ENGINES 133
CHAPTER VIII THE SMALLEST WORKERS 148
CHAPTER IX MAN'S NEWEST CO-LABORER: THE DYNAMO 173
CHAPTER X NIAGARA IN HARNESS 184
CHAPTER XI THE BANISHMENT OF NIGHT 202
CHAPTER XII THE MINERAL DEPTHS 242
CHAPTER XIII THE AGE OF STEEL 271
CHAPTER XIV SOME RECENT TRIUMPHS OF APPLIED SCIENCE 298
APPENDIX 320

CHAPTER I
MAN AND NAT URE
The Conquest of Nature, p. 4—Man's use of Nature's gifts, p. 6—Man the "tool-making animal," p. 7
—Science and Civilization, p. 8—Clothing and artificially heated dwellings of primitive man, p. 10
—Early domestication of animals, p. 11—Early development to the time of gunpowder, p. 12—The
coming of steam and electricity, p. 15—Mechanical aids to the agriculturist, p. 19—The development
of scientific agriculture, p. 20—Difficulties of the early manufacturer, p. 21—The development of
modern manufacturing, p. 24—The relation of work to human development, p. 25—The decline of
drudgery and the new era of labor-saving devices, p. 27.

CHAPTER II
HOW WORK I S DONE
Primitive man's use of the lever, p. 29—The use of the lever as conceived by Archimedes, p. 21—
Wheels and pulleys, p. 32—Other means of transmitting power, p. 35—Inclined planes and derricks,
p. 37—The steam-scoop, p. 38—Friction, p. 39—Available sources of energy, p. 41.

CHAPTER III
T HE ANI MAL MACHI NE
The oldest machine in existence, p. 43—The relation of muscle to machinery, p. 44—How muscular
energy is applied, p. 44—The two types of muscles, p. 45—How the nerve-telegraph controls the
muscles, p. 47—The nature of muscular action, p. 49—Applications of muscular energy, p. 52—The
development of the knife and saw, p. 53—The wheel and axle, p. 55—Modified levers, p. 57—
Domesticated animals, p. 59—Early application of horse-power, p. 60—The horse-power as the
standard of the world's work, p. 61.

CHAPTER IV
T HE WORK OF AI R AND WAT E R
First use of sails for propelling boats, p. 62—The fire engine of Ctesibius, p. 63—Suction and
pressure as studied by the ancients, p. 64—Studies of air pressure, p. 65—The striking demonstration
of Von Guericke, p. 66—The sailing chariot of Servinus, 1600 a.d., p. 68—The development of the
windmill, p. 69—The development of the water-wheel, p. 70—The invention of the turbine, p. 72—
Different types of turbines, p. 73—Hydraulic power and its uses, p. 74—The hydraulic elevator, p. 76
—Recent water motors, p. 77.

CHAPTER V
CAP T I VE MOL E CUL E S : T HE S TORY OF T HE S T E AM E NGI NE
The development of the steam engine, p. 79—The manner in which energy is generated by steam, p.
80—Action of cylinder and piston, p. 81—Early attempts to utilize steam, p. 82—Beginnings of

modern discovery, p. 83—The "engine" of the Marquis of Worcester, p. 84—Thomas Savery's steam
pump, p. 85—Denis Papin invents the piston engine, p. 88—Newcomen's improved engine, p. 89—
The use of these engines in collieries, p. 90—The wastefulness of such engines, p. 92—The coming
of James Watt, p. 93—Early experiments of Watt, p. 95—The final success of Watt's experiments, p.
97—Some of his early engines, p. 98—Rotary motion, p. 99—Watt's engine, "Old Bess," p. 101—
Final improvements and missed opportunities, p. 102—The personality of James Watt, p. 107.

CHAPTER VI
T HE MAS T E R WORKE R
Improvements on Watt's engines, p. 110—Engines dispensing with the walking beam, p. 111—The
development of high-pressure engines, p. 112—Advantages of the high-pressure engine, p. 114—
How steam acts in the high-pressure engine, p. 116—Compound engines, p. 117—Rotary engines, p.
119—Turbine engines, p. 124—The Turbinia and other turbine boats, p. 125—The action of steam in
the turbine engine, p. 126—Advantages of the turbine engine, p. 127.

CHAPTER VII
GAS AND OI L E NGI NE S
Some early gas engines, p. 133—Dr. Stirling's hot-air engine, p. 133—Ericsson's hot-air engines, p.
134—The first practical gas engine, p. 135—The Otto gas engine, p. 136—Otto's improvement by
means of compressed gas, p. 138—The "Otto cycle," p. 139—Adaptation of gas engines to
automobiles, p. 140—Rapid increase in the use of gas engines, p. 141—Defects of the older hot-air
engines, p. 145—Recent improvements and possibilities in the use of hot-air engines, p. 146.

CHAPTER VIII
T HE S MAL L E S T WORKE RS
The relative size of atoms and electrons, p. 148—What is electricity? p. 149—Franklin's one-fluid
theory, p. 150—Modern views, p. 153—Cathode rays and the X-ray, p. 156—How electricity is
developed, p. 159—The work of the dynamical current, p. 162—Theories of electrical action, p. 165
—Practical uses of electricity, p. 168.

CHAPTER IX
MAN' S NE WE S T CO- L ABORE R: T HE DYNAMO
The mechanism of the dynamo, p. 173—The origin of the dynamo, p. 176—The work of Ampère,
Henry, and Faraday, p. 177—Perfecting the dynamo, p. 178—A mysterious mechanism, p. 180—
Curious relation between magnetism and electricity as exemplified in the dynamo, p. 182.

CHAPTER X
NI AGARA I N HARNE S S
The volume of water at the falls, p. 184—The point at which the falls are "harnessed," p. 185—
Within the power-house, p. 186—Penstocks and turbines, p. 188—A miraculous transformation of
energy, p. 189—Subterranean tail-races, p. 191—The effect on the falls, p. 192—The transmission of
power, p. 194—"Step-up" and "step-down" transformers, p. 198.

CHAPTER XI
T HE BANI S HME NT OF NI GHT
Primitive torch and open lamp, p. 202—Tallow candle and perfected lamp, p. 205—Gas lighting, p.
207—The incandescent gas mantle, p. 208—Early gas mantles, p. 209—How the incandescent gas
mantle is made, p. 211—The introduction of acetylene gas, p. 212—Chemistry of acetylene gas, p.
214—Practical gas-making, p. 215—The triumph of electricity, p. 218—Davy and the first electric
light, p. 220—Helpful discoveries in electricity, p. 222—The Jablochkoff candle, p. 223—Defects of
the Jablochkoff candle, p. 225—The improved arc light, p. 226—Edison and the incandescent lamp,
p. 228—Difficulties encountered in finding the proper material for a practical filament, p. 230
—"Parchmentized thread" filament, p. 233—The tungsten lamp, p. 234—The mercury-vapor light of
Peter Cooper Hewitt, p. 236—Advantages and peculiarities of this light, p. 240.

CHAPTER XII
T HE MI NE RAL DE P T HS
Early mining methods, p. 242—Prospecting and locating mines, p. 243—"Booming," p. 246—
Conditions to be considered in mining, p. 248—Dangerous gases in mines, p. 249—Artificial lights
and lighting, p. 251—Ventilation and drainage, p. 252—Electric machinery in mining, p. 253—
Electric drills, p. 254—Traction in mining, p. 256—Various types of electric motors, p. 257
—"Telphers," p. 261—Electric mining pumps, p. 263—Some remarkable demonstrations of
durability of electric pumps, p. 265—Electricity in coal mining, p. 266—Electric lighting in mines, p.
269.

CHAPTER XIII
T HE AGE OF S T E E L
Rapid growth of the iron industry in recent years, p. 271—The Lake Superior mines, p. 272—
Methods of mining, p. 273—"Open-pit" mining, p. 274—Mining with the steam shovel, p. 276—
From mine to furnace, p. 278—Methods of transportation, p. 279—Vessels of special construction, p.
281—The conversion of iron ore into iron and steel, p. 283—Blast furnaces, p. 284—Poisonous
gases and their effect upon the workmen, p. 286—From pig iron to steel, p. 287—Modern methods
of producing pig iron, p. 288—The Bessemer converter, p. 289—Sir Henry Bessemer, p. 291—The
"Bessemer-Mushet" process, p. 293—Open-hearth method, p. 294—Alloy steels, p. 295.

CHAPTER XIV
S OME RE CE NT T RI UMP HS OF AP P L I E D S CI E NCE
The province of electro-chemistry, p. 298—Linking the laboratory with the workshop, p. 299—Soda
manufactories at Niagara Falls, p. 300—Producing aluminum by the electrolytic process, p. 300—
Old and new methods compared, p. 301—Nitrogen from the air, p. 303—What this discovery means
to the food industries of the world, p. 304—Prof. Birkeland's method, p. 307—Another method of
nitrogen fixation, p. 309—Cost of production, p. 312—Electrical energy, p. 313—Production of high
temperatures with the electric arc, p. 314—The production of artificial diamonds by the explosion of
cordite, p. 315—Industrial problems of to-day and to-morrow, p. 316.

ILLUSTRATIONS
A PRIMITIVE USE OF THE ANIMAL MACHINE THAT IS STILL IN VOGUE
Frontispiece
IN MANY EUROPEAN COUNTRIES
HORSE AND CATTLE POWER Facing p. 32
CRANES AND DERRICKS " 38
A BELGIAN MILK-WAGON " 56
TWO APPARATUSES FOR THE UTILIZATION OF ANIMAL POWER " 60
WINDMILLS OF ANCIENT AND MODERN TYPES " 68
WATER WHEELS " 72
HYDRAULIC PRESS AND HYDRAULIC CAPSTAN " 76
THOMAS SAVERY'S STEAM ENGINE " 86
DIAGRAMS OF EARLY ATTEMPTS TO UTILIZE THE POWER OF STEAM " 88
A MODEL OF THE NEWCOMEN ENGINE " 92
WATT'S EARLIEST TYPE OF PUMPING-ENGINE " 96
WATT'S ROTATIVE ENGINE " 100
JAMES WATT " 108
OLD IDEAS AND NEW APPLIED TO BOILER CONSTRUCTION " 114
COMPOUND ENGINES " 118
ROTARY ENGINES " 122
THE ORIGINAL PARSONS' TURBINE ENGINE AND THE RECORD-
" 128
BREAKING SHIP FOR WHICH IT IS RESPONSIBLE
GAS AND OIL ENGINES " 136
AN ELECTRIC TRAIN AND THE DYNAMO THAT PROPELS IT " 174
WILDE'S SEPARATELY EXCITED DYNAMO " 178
THE EVOLUTION OF THE DYNAMO " 180
VIEW IN ONE OF THE POWER HOUSES AT NIAGARA " 186
ELECTRICAL TRANSFORMERS " 198
THOMAS A. EDISON AND THE DYNAMO THAT GENERATED THE FIRST
" 228
COMMERCIAL INCANDESCENT LIGHT
A FLINT-AND-STEEL OUTFIT, AND A MINER'S STEEL MILL " 248
THE LOCOMOTIVE "PUFFING BILLY" AND A MODERN COLLIERY
" 258
TROLLEY

THE CONQUEST OF NATURE

I
n the earlier volumes we have been concerned with the growth of
knowledge. For the most part the scientific delvers whose efforts have
held our attention have been tacitly unmindful, or even explicitly
contemptuous, of the influence upon practical life of the phenomena to
the investigation of which they have devoted their lives. They were and are
obviously seekers of truth for the mere love of truth.
But the phenomena of nature are not dissociated in fact, however much
we may attempt to localize and classify them. And so it chances that even
the most visionary devotee of abstract science is forever being carried into
fields of investigation trenching closely upon the practicalities of every-day
life. A Black investigating the laws of heat is preparing the way explicitly,
however unconsciously, for a Watt with his perfected mechanism of the
steam engine.
Similarly a Davy working at the Royal Institution with his newly
invented batteries, and intent on the discovery of new elements and the
elucidation of new principles, is the direct forerunner of Jablochkoff, Brush,
and Edison with their commercial revolution in the production of artificial
light.
Again Oersted and Faraday, earnestly seeking out the fundamental facts
as to the relations of electricity and magnetism, invent mechanisms which,
though they seem but laboratory toys, are the direct forerunners of the
modern dynamos that take so large a share in the world's work.
In a word, all along the line there is the closest association between what
are commonly called the theoretical sciences and what with only partial
propriety are termed the applied sciences. The linkage of one with the other
must never be forgotten by anyone who would truly apprehend the status of
those practical sciences which have revolutionized the civilization of the
nineteenth and twentieth centuries in its most manifest aspects.
Nevertheless there is, to casual inspection, a somewhat radical distinction
between theoretical and practical aspects of science—just as there are

obvious differences between two sides of a shield. And as the theoretical
aspects of science have largely claimed our attention hitherto, so its
practical aspects will be explicitly put forward in the pages that follow. In
the present volume we are concerned with those primitive applications of
force through which man early learned to add to his working efficiency, and
with the elaborate mechanisms—turbine wheels, steam engines, dynamos—
through which he has been enabled to multiply his powers until it is
scarcely exaggeration to say that he has made all Nature subservient to his
will. It is this view which justifies the title of the volume, which might with
equal propriety have been termed the Story of the World's Work.

THE CONQUEST OF NATURE

I
MAN AND NATURE

"Y
oung men," said a wise physician in addressing a class of
graduates in medicine, "you are about to enter the battle of life.
Note that I say the 'battle' of life. Not a playground, but a
battlefield is before you. It is a hard contest—a battle royal.
Make no mistake as to that. Your studies here have furnished your
equipment; now you must go forth each to fight for himself."
The same words might be said to every neophyte in whatever walk of
life. The pursuit of every trade, every profession is a battle—a struggle for
existence and for supremacy. Partly it is a battle against fellow men; partly
against the contending powers of Nature. The physician meets rivalry from
his brothers; but his chief battle is with disease. In the creative and
manufacturing fields which will chiefly concern us in the following
volumes, it is the powers of Nature that furnish an ever-present antagonism.
No stone can be lifted above another, to make the crudest wall or
dwelling, but Nature—represented by her power of gravitation—strives at
once to pull it down again. No structure is completed before the elements
are at work defacing it, preparing its slow but certain ruin. Summer heat and
winter cold expand and contract materials of every kind; rain and wind
wear and warp and twist; the oxygen of the air gnaws into stone and iron
alike;—in a word, all the elements are at work undoing what man has
accomplished.

THE STRUGGLE FOR EXISTENCE

In the field of the agriculturist it is the same story. The earth which brings
forth its crop of unwholesome weeds so bountifully, resists man's
approaches when he strives to bring it under cultivation. Only by the most
careful attention can useful grains be made to grow where the wildlings
swarmed in profusion. Not only do wind and rain, blighting heat and
withering cold menace the crops; but weeds invade the fields, the germs of

fungoid pests lurk everywhere; and myriad insects attack orchard and
meadow and grain field in devastating legions.
Similarly the beasts which were so rugged and resistant while in the wild
state, become tender and susceptible to disease when made useful by
domestication. Aforetime they roamed at large, braving every temperature
and thriving in all weathers. But now they must be housed and cared for so
tenderly that they become, as Thoreau said, the keepers of men, rather than
kept by men, so much more independent are they than their alleged owners.
Tender of constitution, domesticated beasts must be housed, to protect them
from the blasts in which of yore their forebears revelled; and man must
slave day in and day out to prepare food to meet the requirements of their
pampered appetites.
He must struggle, too, to protect them from disease, and must care for
them in time of illness as sedulously as he cares for his own kith and kin.
Truly the ox is keeper of the man, and the seeming conquest that man has
wrought has cost him dear.
But of course the story has another side. After all, Nature is not so
malevolent as at first glance she seems. She has opposed man at every stage
of his attempted progress; yet at the same time she has supplied him all his
weapons for waging war upon her. Her great power of gravitation opposes
every effort he makes; yet without that same power he could do nothing—
he could not walk or stay upon the earth even; and no structure that he
builds would hold in place for an instant.
So, too, the wind that smites him and tears at his handiwork, may be
made to serve the purposes of turning his windmills and supplying him with
power.
The water will serve a like purpose in turning his mills; and, changed to
steam with the aid of Nature's store of coal, will make his steam engines
and dynamos possible. Even the lightning he will harness and make subject
to his will in the telegraphic currents and dynamos.
And in the fields, the grains which man struggles so arduously to produce
are after all no thing of his creating. They are only adopted products of
Nature, which he has striven to make serve his purpose by growing them
under artificial conditions. So, too, the domesticated beasts are creatures

that belong in the wilds and in distant lands. Man has brought them, in
defiance of Nature, to uncongenial climes, and made them serve as workers
and as food-suppliers where Nature alone could not support them. Turn
loose the cow and the horse to forage for themselves here in the
inhospitable north, and they would starve. They survive because man helps
them to combat the adverse conditions imposed by Nature, yet no one of
them could live for an hour were not the vital capacities supplied by Nature
still in control.
Everywhere, then, it is the opposing of Nature, up to certain limits, with
the aid of Nature's own tools, that constitutes man's work in the world. Just
in proportion as he bends the elements to meet his needs, transforms the
plants and animals, defies and exceeds the limitations of primeval Nature—
just in proportion as he conquers Nature, in a word, is he civilized.
Barbaric man is called a child of Nature with full reason. He must accept
what Nature offers. But civilized man is the child grown to adult stature,
and able in a manner to control, to dominate—if you please to conquer—the
parent.
If we were to seek the means by which developing man has gradually
achieved this conquest, we should find it in the single word, Tools; that is to
say, machines for utilizing the powers of Nature, and, as it were,
multiplying them for man's benefit. So unique is the capacity that man
exerts in this direction, that he has been described as "the tool-making
animal." The description is absolutely accurate; it is inclusive and
exclusive. No non-human animal makes any form of implement to aid it in
performing its daily work; and contrariwise every human tribe, however
low its stage of savagery, makes use of more or less crude forms of
implements. There must have been a time, to be sure, when there existed a
man so low in intelligence that he had not put into execution the idea of
making even the simplest tool. But the period when such a man existed so
vastly antedates all records that it need not here concern us. For the purpose
of classifying all existing men, and all the tribes of men of which history
and pre-historic archæology give us any record, the definition of man as the
tool-making animal is accurate and sufficient.
At first thought it might seem that an equally comprehensive definition
might describe man as the working animal. But a moment's consideration

shows the fallacy of such a suggestion. Man is, to be sure, the animal that
works effectively, thanks to the implements with which he has learned to
provide himself; but he shares with all animate creatures the task of
laboring for his daily necessities. This is indeed a work-a-day world, and no
creature can live in it without taking its share in that perpetual conflict
which bodily necessities make imperative. Most lower animals confine their
work to the mere securing of food, and to the construction of rude
habitations. Some, indeed, go a step farther and lay up stores of food, in
chance burrows or hollow trees; a few even manufacture relatively artistic
and highly effective receptacles, as illustrated by the honeycomb made by
the bees and their allies. Again, certain animals, of which the birds are the
best representatives, construct temporary structures for the purpose of
rearing their young that attain a relatively high degree of artistic perfection.
The Baltimore oriole weaves a cloth of vegetable fibre that is certainly a
wonderful texture to be made with the aid of claws and bill alone. It may be
doubted whether human hands, unaided by implements, could duplicate it.
But it is crude enough compared with even the coarsest cloth which
barbaric races manufacture with the aid of implements.
So it is with any comparison of animal work with the work of man, in
whatever field. The crudest human endeavor is superior to the best non-
human efforts; and the explanation is found always in the fact that the
ingenuity of man has enabled him to find artificial aids that add to his
power of manipulation. So large a share have these artificial aids taken in
man's evolution, that it has long been customary, in studying the
development of civilization, to make the use of various types of implements
a test of varying stages of human progress.

SCIENCE AND CIVILIZATION

The student of primitive life assures us, basing his statements on the
archæological records, that there was a time when the most advanced of
mankind had no tools made of better material than chipped stone. By
common consent that time is spoken of as the Rough Stone Age.
We are told that then in the course of immeasurable centuries man
learned to polish his stone implements, doubtless by rubbing them against
another stone, or perhaps with the aid of sand, thus producing a new type of

implement which has given its name to the Age of Smooth or Polished
Stone.
Then after other long centuries came a time when man had learned to
smelt the softer metals, and the new civilization which now supplanted the
old, and, thanks to the new implements, advanced upon it immeasurably, is
called the Age of Bronze.
At last man learned to accomplish the wonderful feat of smelting the
intractable metal, iron, and in so doing produced implements harder,
sharper, and cheaper than his implements of bronze; and when this
crowning feat had been accomplished, the Age of Iron was ushered in.
By common consent, students of the history of the evolution of society
accept these successive ages, each designated by the type of implements
with which the world's work was accomplished, as representing real and
definite stages of human progress, and as needing no better definition than
that supplied by the different types of implements.
Could the archæologist trace the stream of human progress still farther
back toward its source, he would find doubtless that there were several
great epochal inventions preceding the time of the Rough Stone Age, each
of which was in its way as definitive and as revolutionary in its effects upon
society, as these later inventions which we have just named. To attempt to
define them clearly is to enter the field of uncertainty, but two or three
conjectures may be hazarded that cannot be very wide of the truth.
It is clear, for example, that if we go back in imagination to the very
remotest ancestors of man that can be called human, we must suppose a
vast and revolutionary stage of progress to have been ushered in by the first
race of men that learned to make habitual use of the simplest implement,
such as a mere club. When man had learned to wield a club and to throw a
stone, and to use a stone held in the hand to break the shell of a nut, he had
attained a stage of culture which augured great things for the future. Out of
the idea of wielded club and hurled stone were to grow in time the ideas of
hammer and axe and spear and arrow.
Then there came a time—no one dare guess how many thousands of
years later—when man learned to cover his body with the skin of an
animal, and thus to become in a measure freed from the thraldom of the

weather. He completed his enfranchisement by learning to avail himself of
the heat provided by an artificial fire. Equipped with these two marvelous
inventions he was able to extend the hitherto narrow bounds of his
dwelling-place, passing northward to the regions which at an earlier stage
of his development he dared not penetrate. Under stress of more
exhilarating climatic conditions, he developed new ideals and learned to
overcome new difficulties; developing both a material civilization and the
advanced mentality that is its counterpart, as he doubtless never would have
done had he remained subject to the more pampering conditions of the
tropics.
The most important, perhaps, of the new things which he was taught by
the seemingly adverse conditions of an inhospitable climate, was to provide
for the needs of a wandering life and of varying seasons by domesticating
animals that could afford him an ever-present food supply. In so doing he
ceased to be a mere fisher and hunter, and became a herdsman. One other
step, and he had conceived the idea of providing for himself a supply of
vegetable foods, to take the place of that which nature had provided so
bountifully in his old home in the tropics. When this idea was put into
execution man became an agriculturist, and had entered upon the high road
to civilization.
All these stages of progress had been entered upon prior to the time of
which the oldest known remains of the cave-dweller give us knowledge. It
were idle to conjecture the precise sequence in which these earliest steps
toward civilization were taken, and even more idle to conjecture the length
of time which elapsed between one step and its successor. But all questions
of precise sequence aside, it is clear that here were four or five great ages
succeeding one to another, that marked the onward and upward progress of
our primeval ancestor before he achieved the stage of development that
enabled him to leave permanent records of his existence. And—what is
particularly significant from our present standpoint—it is equally clear that
each of the great ages thus vaguely outlined was dependent upon an
achievement or an invention that facilitated the carrying out of that scheme
of never-ending work which from first to last has been man's portion. How
to labor more efficiently, more productively; how to produce more of the
necessaries and of the luxuries that man's physical and mental being
demands, with less expenditure of toil—that from first to last has been the

ever-insistent problem. And the answer has been found always through the
development of some new species of mechanism, some new labor-saving
device, some ingenious manipulation of the powers of Nature.
If, turning from the hypothetical period of our primitive ancestor, we
consider the sweep of secure and relatively recent history, we shall find that
precisely the same thing holds. If we contrast the civilization of Old Egypt
and Babylonia—the oldest civilizations of which we have any secure record
—with the civilization of to-day, we shall find that the differences between
the one and the other are such as are due to new and improved methods of
accomplishing the world's work.
Indeed, if we view the subject carefully, it will become more and more
evident that the only real progress that the historic period has to show is
such as has grown directly from the development of new mechanical
inventions. The more we study the ancient civilizations the more we shall
be struck with their marvelous resemblance, as regards mental life, to the
civilization of to-day. In their moral and spiritual ideals, the ancient
Egyptians were as brothers to the modern Europeans. In philosophy, in art,
in literature, the Age of Pericles established standards that still remain
unexcelled. In all the subtleties of thought, we feel that the Greeks had
reached intellectual bounds that we have not been able to extend.
But when, on the other hand, we consider the material civilization of the
two epochs, we find contrasts that are altogether startling. The little world
of the Greeks nestled about the Mediterranean, bounded on every side at a
distance of a few hundred leagues by a terra incognita. The philosophers
who had reached the confines of the field of thought, had but the narrowest
knowledge of the geography of our globe. They traversed at best a few petty
miles of its surface on foot or in carts; and they navigated the
Mediterranean Sea, or at most coasted out a little way beyond the Pillars of
Hercules in boats chiefly propelled by oars. By dint of great industry they
produced a really astonishing number of books, but the production of each
one was a long and laborious task, and the aggregate number indited during
the Age of Pericles in all the world was perhaps not greater than an
afternoon's output of a modern printing press.
In a word, these men of the classical period of antiquity, great as were
their mental, artistic, and moral achievements, were as children in those

matters of practical mechanics upon which the outward evidences of
civilization depend. Should we find a race of people to-day in some hitherto
unexplored portion of the earth—did such unexplored portions still exist—
living a life comparable to that of the Age of Pericles, we should marvel no
doubt at their artistic achievements, while at the same time regarding them
as scarcely better than barbarians. Indeed this is more than unsupported
hypothesis; for has it not been difficult for the Western world to admit the
truly civilized condition of the Chinese, simply because that highly
intellectual race of Orientals has not kept abreast of the Occidental changes
in applied mechanics? Say what we will, this is the standard which we of
the Western world apply as the test of civilization.
If, sweeping over in retrospect the history of the world since the time
when the Egyptian and Babylonian civilizations were at their height, we
attempt some such classification of the stages of progress as that which we
a moment ago applied to pre-historic times, we shall be led to some rather
startling conclusions. In the broadest view, it will appear that the age which
ushered in the historic period continued unbroken by the advance of any
great revolutionary invention throughout the long centuries of pre-Christian
antiquity, and well into the so-called Middle Ages of our newer era. Then
came the invention of gunpowder, or at least its introduction to the Western
world—since the Chinaman here lays claim to vague centuries of
precedence. Following hard upon the introduction of gunpowder, with its
capacity to add to the destructive efficiency of man's most sinister form of
labor, came a mechanism no less epoch-making in a far different field—the
printing press.
But even these inventions, great as was their influence upon the progress
of civilization, can scarcely be considered, it seems to me, as taking rank
with the great epochal discoveries that gave their names to the preceding
ages. Nor can any invention of the sixteenth or seventeenth century be
hailed as really ushering in a new era. The invention for which that honor
was reserved was a development of the eighteenth century; and did not
come fully to its heritage until the early days of the nineteenth century. The
invention was the application of steam to the purposes of mechanics. When
this application was made, as wide a gap was crossed as that which
separated the Stone Age from the Age of Metal; then the epoch in which the

world was living when history begins was brought to a close, and a new era,
the Age of Steam, was ushered in.
Scarcely had the world begun to adjust itself to the new conditions of the
Age of Steam, when yet another power was made subservient to man's
needs, and the Age of Steam was supplemented, not to say supplanted, by
the Age of Electricity. Of course the new progressive movements did not
necessarily imply elimination of old conditions; they imply merely the
subordination of old powers to newer and better ones. Stone implements by
no means ceased to have utility at once when metal implements came into
vogue. Bronze long held its own against iron, and still has its utility. And
iron itself finds but an added sphere of usefulness in the Age of Steam and
Electricity.
All great changes are relatively slow. It is only as we look back upon
them and view them in perspective that they seem cataclysmic. Gunpowder
did not at once supplant the crossbow, and the cannon was long held to be
inferior to the catapult. The printed book did not instantly make its way
against the work of the scribe. Neither did the steam engine immediately
supplant water power and the direct application of human labor. But in each
case the new invention virtually rang the death knell of the old method from
the hour of its inauguration, and the end was no less sure because it was
delayed. And it requires no great powers of divination to foretell that in the
coming age, the electric dynamo driven by water power may take the place
of the steam engine. The Age of Steam may pass, with only at most a few
generations of domination. And it is within the possibilities that the Age of
Electricity will scarcely come into its own before it may be displaced by an
Age of Radio-Activity. To press that point, however, would be to enter the
field of prophecy, which is no part of my present purpose.
All that I have wished to point out is that for some thousands of years
after man learned to make implements of iron, the industrial world and the
human civilization that depends upon it, pursued a relatively static course,
like a broad, sluggish current, with no new revolutionary discovery to impel
it into new channels; and that then one revolutionary discovery succeeded
another with bewildering suddenness, so that we of the early days of the
twentieth century are farther removed, in an industrial way, from our
forerunners of two hundred years ago, than those children of the eighteenth
century were from the earliest civilization that ever developed on our globe.

Indeed, this startling contrast would still hold true, were we to consider the
newest era as compassing only the period of a single life. There are men
living to-day who were born in that epoch when the steam engine was for
the first time used to turn the wheels of factories. There are many men who
can well remember the first practical application of steam to railway traffic.
Hosts of men can remember when the first commercial message was
transmitted by electricity along a wire. Even middle-aged men recall the
first cable message that linked the old world with the new. And the
application of the dynamo to the purposes of the world's work is an affair of
but yesterday.
The historian of the future, casting his eye back across the long
perspective of history, will find civilized man pursuing an even and
unbroken course across the ages from the time of the pyramids of Egypt to
about the time of the French Revolution. There will be no dearth of incident
to claim his attention in the way of wars and conquests, and changing
creeds, and the rise and fall of nations, each pursuing virtually the same
course of growth and decay as all the others. But when he comes to the
close of the eighteenth century, it will not be the social paroxysm of a
nation, or the meteoric career of a Napoleon that will claim his attention so
much as the introduction of that new method of utilizing the powers of
Nature which found its expression in the mechanism called the steam
engine.
If the name of any individual stands out as the great and memorable one
of that epoch of transition, at which the static current of previous
civilization changed suddenly to a Niagara-current of progress, it will be the
name of the great scientific inventor, rather than that of the great military
conqueror—the name of James Watt, rather than that of Napoleon.
The military conqueror had his day of surpassing glory and departed, to
leave the world only a little worse than he found it. But the mechanical
inventor left a heritage that was to add day by day to the wealth and
happiness of humanity, supplying millions of artificial hands, and making
possible such beneficent improvements as no previous age had dreamed of.
Tasks that human hands had performed slowly, laboriously, and
inadequately, were now to be performed swiftly, with ease, and well by the
artificial hands provided with the aid of the new power. Where carts drawn
by horses had toiled slowly across the land, and ships driven by the wind

had drifted slowly through the waters, massive trains of cars were to hurtle
to the four corners of the earth with inconceivable speed, and floating
palaces were to course the waters with almost equal defiance to the
limitations of time and space.
And then there came that still weirder conquest of time and space,
wrought by the electric current. The moment when man first spoke with
man from continent to continent in defiance of the oceans, marked the
dawning of that larger day when all mankind shall constitute one
brotherhood and all peoples but a single nation. Within a half century the
sun of that new day has risen well above the horizon, and far sooner than
even the optimist of to-day dare predict with certainty, it seems destined to
reach its zenith.
But here again we verge upon the dangerous field of prophecy. Let us
turn from it and cast an eye back across the most wonderful of centuries,
contrasting the conditions of to-day in each of a half-dozen fields of the
world's work, with the conditions that obtained at the close of the eighteenth
century. Such a brief survey will show us perhaps more vividly than we
could otherwise be shown, how vast has been the progress, how marvelous
the development of civilization, in the short decades that have elapsed since
the coming of the Age of Steam.
Let us pay heed first to the world of the agriculturist. Could we turn back
to the days of our grandparents, we should find farming a very different
employment from what it is to-day. For the most part the farmer operated
but a few small fields; if he had thirty or forty acres of ploughed land, he
found ample employment for his capacities. He ploughed his fields with the
aid of either a yoke of oxen or a team of horses; he sowed his grain by
hand; he cultivated his corn with a hoe; he reaped his oats and wheat with a
cradle—a device but one step removed from a sickle; he threshed his grain
with a flail; he ground such portion of it as he needed for his own use with
the aid of water power at a neighboring mill; and such portion of it as he
sold was transported to market, be it far or near, in wagons that compassed
twenty or thirty miles a day at best. As regards live stock, each farmer
raised a few cattle, sheep, and hogs, and butchered them to supply his own
needs, selling the residue to a local dealer who supplied the non-agricultural
portion of the neighborhood. Any live stock intended for a distant market
was driven on foot across the country to its destination. Each town and city,

therefore, drew almost exclusively for its supply from the immediately
surrounding country.
To-day the small farmer has become almost obsolete, and the farms of
the eastern states that were the nation's chief source of supply a century ago
are largely allowed to lie fallow, it being no longer possible to cultivate
them profitably in competition with the rich farm lands of the middle west.
In that new home of agriculture, the farm that does not comprise two or
three hundred acres is considered small; and large farms are those that
number their acres by thousands. The soil is turned by steam ploughs; the
grain is sown with mechanical seeders and planters; the corn is cultivated
with a horse-drawn machine, having blades that do the work of a dozen
men; harvesters drawn by three or four horses sweep over the fields and
leave the grain mechanically tied in bundles; the steam thresher places the
grain in sacks by hundreds of bushels a day; and this grain is hurried off in
steam cars to distant mills and yet more distant markets.
Meantime the raising of live stock has become a special department, with
which the farmer who deals in cereals often has no concern. The cattle roam
over vast pastures and are herded in the winter for fattening in great droves,
and protected from the cold in barns that, when contrasted with the sheds of
the old-time farmer, seem almost palatial. When in marketable condition,
cattle are no longer slaughtered at the farm, but are transported in cars to
one of the few great centres, chief of which are the stock yards of Chicago
and of Kansas City. At these centres, slaughter houses and meat-packing
houses of stupendous magnitude have been developed, capable of handling
millions of animals in a year. From these centres the meat is transported in
refrigerator cars to the seaboards, and in refrigerator ships to all parts of the
world. Beef that grew on the ranges of the far west may thus be offered for
sale in the markets of New England villages, at a price that prohibits local
competition.
A more radical metamorphosis in agricultural conditions than all this
implies could not well be conceived. And when we recall once more that
the agricultural conditions that obtained at the beginning of the nineteenth
century were closely similar to those that obtained in each successive age
for a hundred preceding centuries, we shall gain a vivid idea of the
revolutionizing effects of new methods of work in the most important of
industries. It is little wonder that in this short time the world has not solved

to the satisfaction of the economists all the new problems thus so suddenly
developed.
Turn now to the manufacturing world. In the days of our great-
grandparents almost every household was a miniature factory where cotton
and wool were spun and the products were woven into cloth. It was not till
toward the close of the eighteenth century—just at the time when Watt was
perfecting the steam engine—that Arkwright developed the spinning-frame,
and his successors elaborated the machinery that made possible the
manufacture of cloth in wholesale quantities; and the nineteenth century
was well under way before the household production of cloth had been
entirely supplanted by factory production. It is nothing less than pitiful to
contemplate in imagination our great-great-grandmothers—and all their
forebears of the long centuries—drudging away day after day, year in and
year out, at the ceaseless task of spinning and weaving—only to produce, as
the output of a lifetime of labor, a quantity of cloth equivalent perhaps to
what our perfected machine, driven by steam, and manipulated by a factory
girl, produces each working hour of every day. Similarly, carpets and quilts
were of home manufacture; so were coats and dresses; and shoes were at
most the product of the local shoemaker around the corner.
In the kitchen, food was cooked over the coals of a great fireplace or in
the brick oven connected with that fireplace. Meat was supplied from a
neighboring farm; eggs were the product of the housewife's own poultry
yard; the son or daughter of the farmer milked the cow and drove her to and
from the pasture; the milk was "set" in pans in the cellar—on a swinging
shelf, preferably, to make it inaccessible to the rats; and twice a week the
cream was made into butter in a primitive churn, the dasher of which was
operated by the vigorous arm of the housewife herself, or by the unwilling
arms of some one of her numerous progeny.
To give variety to the dietary, fruits grown in the local garden or orchard
were preserved, each in its season, by the industrious housewife, and stored
away in the capacious cellar; where also might be found the supply of
home-grown potatoes, turnips, carrots, parsnips, and cabbages to provide
for the needs of the winter. Fuel to supply the household needs, both for
cooking and heating, was cut in the neighboring woodland, and carefully
corded in the door-yard, where it provided most uncongenial employment
for the youth of the family after school hours and of a Saturday afternoon.

The ashes produced when this wood was burned in the various fireplaces,
were not wasted, but were carefully deposited in barrels, from which in due
course lye was extracted by the simple process of pouring water over the
contents of the barrel. Meantime scraps of fat from the table were collected
throughout the winter and preserved with equal care; and in due course on
some leisure day in the springtime—heaven knows how a leisure day was
ever found in such a scheme of domestic economy!—the lye drawn from
the ash-barrels and the scraps of fat were put into a gigantic kettle,
underneath which a fire was kindled; with the result that ultimately a supply
of soft soap was provided the housewife, with which her entire
establishment, progeny included, could be kept in a state of relative
cleanness.
The reader of these pages has but to cast his eye about him in the
household in which he lives, and contrast the conditions just depicted with
those of his every-day life, to realize what change has come over the
aspects of household economy in the course of a short century. Nor need he
be told in each of the various departments of which the activities are here
outlined, that the changes which he observes have been due to the
application of machinery in all the essential lines of work in question. We
need not pause to detail the multitudinous devices for the economy of
household labor which owe their origin to the same agency. There still
remains, to be sure, enough of drudgery in the task of the housewife; yet her
most strenuous day seems a mere playtime in comparison with the average
day of her maternal forebear of three or four generations ago.
But we must not here pause for further outlines of a subject which it is
the purpose of this and succeeding volumes to explicate in detail. All our
succeeding chapters will but make it more clear how marvelous are the
elaborations of method and of mechanism through which the world's work
of to-day is accomplished. We shall consider first the mechanical principles
that underlie work in general, passing on to some of the principal methods
of application through which the powers of Nature are made available. We
shall then take up in succession the different fields of industry. We shall ask
how the work of the agriculturist is done in the modern world; how the
multitudinous lines of manufacture are carried out; how transportation is
effected; we shall examine the modus operandi of the transmission of ideas;
we shall even consider that destructive form of labor which manifests itself

in the production of mechanisms of warfare. As we follow out the stories of
the all-essential industries we shall be led to realize more fully perhaps than
we have done before, the meaning of work in its relations to human
development; and in particular the meaning of modern work, as carried out
with the aid of modern mechanical contrivances, in its relations to modern
civilization.
The full force of these relations may best be permitted to unfold itself as
the story proceeds. There is, however, one fundamental principle which I
would ask the reader to bear constantly in mind, as an aid to the full
appreciation of the importance of our subject. It is that in considering the
output of the worker we have constantly to do with one form or another of
property, and that property is the very foundation-stone of civilization. "It is
impossible," says Morgan, in his work on Ancient Society, "to overestimate
the influence of property in the civilization of mankind. It was the power
that brought the Aryan and Semitic nations out of barbarism into
civilization. The growth of the idea of property in the human mind
commenced in feebleness and ended in becoming its master passion.
Governments and laws are instituted with primary reference to its creation,
protection, and enjoyment. It introduced human slavery in its production;
and, after the experience of several thousand years, it caused the abolition
of slavery upon the discovery that the freeman was a better property-
making machine." If, then, we recall that without labor there is no property,
we shall be in an attitude of mind to appreciate the importance of our
subject; we shall realize, somewhat beyond the bounds of its more tangible
and sordid relations, the essential dignity, the fundamental importance—in a
word, the true meaning—of Work.
Undoubtedly there is a modern tendency to accept this view of the
dignity of physical labor. At any rate, we differ from the savage in thinking
it more fitting that man should toil than that his wife should labor to support
him—though it cannot be denied that even now the number of physical
toilers among women greatly exceeds the number of such toilers among
men. But in whatever measure we admit this attitude of mind, there can be
no question that it is exclusively a modern attitude. Time out of mind,
physical labor has been distasteful to mankind, and it is a later development
of philosophy that appreciates the beneficence of the task so little relished.

The barbarian forces his wife to do most of the work, and glories in his
own freedom. Early civilization kept conquered foes in thraldom,
developing an hereditary body of slaves, whose function it was to do the
physical work.
The Hebrew explained the necessity for labor as a curse imposed upon
Father Adam and Mother Eve. Plato and Aristotle, voicing the spirit of the
Greeks, considered manual toil as degrading.
To-day we hear much of the dignity of labor; but if we would avoid cant
we must admit that now—scarcely less than in all the olden days—the
physical toiler is such because he cannot help himself. Few indeed are the
manual laborers who know any other means of getting their daily bread
than that which they employ. The most strenuous advocates of the strenuous
life are not themselves tillers of the soil or workers in factories or machine
shops.
The farm youth of intelligence does not remain a farmer; he goes to the
city, and we find him presently at the head of a railroad or a bank, or
practising law or medicine. The more intelligent laborer becomes finally a
foreman, and no longer handles the axe or sledge. We should think it
grotesque were we to see a man of intellectual power obstinately following
a pursuit that cost him habitual physical toil. When now and then a Tolstoi
offers an exception to this rule, we feel that he is at least eccentric; and we
may be excused the doubt whether he would follow the manual task
cheerfully if he did not know that he could at any moment abandon it. It is
because he knows that the world understands him to be only a dilettante that
he rejoices in his task.
After all, then, judged by the modern practice, rather than by the
philosopher's precept, the old Hebrew and Greek ideas were not so far
wrong. Using the poetical language which was so native to them, it might
be said that the necessity for physical labor is a curse—a disgrace.
A partial explanation of this may be found in the fact that the most
uncongenial tasks are also the worst paid, while the congenial tasks
command the high emoluments. Generally speaking there is no distinction
between one laborer and another in the same field—except where the
eminently fair method of piece work can be employed. Even the skilled
laborer is usually paid by the day, and the amount he is to receive is

commonly fixed by a Union regardless of his efficiency as compared with
other laborers of the same class. And there is no possibility of his receiving
any such sums as the man who plans the work, but does nothing with his
own hands.
It has always been so. Just as "those who think must govern those that
toil," so the thinker must command the high reward. Partly this is because
man, considered as a mere toiler, is so relatively inefficient a worker. When
he strives to work with his hands, his effort is but a pitiful one; he can by no
possibility compete (as regards mere quantity of labor) with the ox and the
horse. He is impatient of his own puerile efforts. It is only when he brings
the products of ingenuity to his aid that he is able to show his superiority,
and to justify his own egotism. So it is that in every age he has striven to
find means of adding to his feeble powers of body through the use of his
relatively gigantic powers of mind. And in proportion as he thus is able to
"make his head work for his hands" as the saying goes, he verges toward
the heights of civilization. To accomplish this more and more fully has ever
been the task of science as applied to the industries.
It will be our object in the ensuing chapters to inquire how far science
has accomplished the protean task thus set for it. We shall see that much has
been done; but that much still remains to be done. In proportion as the
problems are unsolved, science is reproached for its shortcomings—and
stimulated to new efforts.
In proportion as labor has been minimized and production increased—in
just that proportion has science justified itself; and in the same proportion
has the Conquest of Nature been carried toward completion.

II
HOW WORK IS DONE

T
he word energy implies capacity to do work. Work, considered in the
abstract, consists in the moving of particles of matter against some
opposing force, or in aid of previously acting forces. In the last
analysis, all energy manifests itself either as a push or as a pull. But
there is a modification of push and pull which is familiar to everyone in
practice under the name of prying. Illustrations may be seen on every hand,
as when a workman pries up a stone, or when a housewife pries up a tack
with the aid of a hammer. The principle here involved is that of the lever—a
principle which in its various practical modifications is everywhere utilized
in mechanics. Very seldom indeed is the direct push or pull utilized; since
the modified push or pull, as represented by the lever in its various
modifications of pulley, ratchet-wheel, and the like, has long been known to
meet the needs of practical mechanics.
The very earliest primitive man who came to use any implement
whatever, though it were only a broken stick, must have discovered the
essential principle of the lever, though it is hardly necessary to add that he
did not know his discovery by any such high-sounding title. What he did
know, from practical experience, was that with the aid of a stick he could
pry up stones or logs that were much too heavy to be lifted without this aid.
This practical knowledge no doubt sufficed for a vast number of
generations of men who used the lever habitually, without making specific
study of the relations between the force expended, the lengths of the two
ends of the lever, and the weight raised. Such specific experiments were
made, however, more than two thousand years ago by the famous
Syracusan, Archimedes. He discovered—or if some one else had discovered
it before him, he at least recorded and so gains the credit of discovery—the
specific laws of the lever, and he also pointed out that levers, all acting on
the same principle, may be different as to their practical mechanism in three
ways.

First, the fulcrum may lie between the power and the weight, as in the
case of the balance with which we were just experimenting. This is called a
lever of the first class, and familiar illustrations of it are furnished by the
poker, steelyard, or a pair of scissors. The so-called extensor muscles of the
body—those for example, that cause the arm to extend—act on the bones in
such a way as to make them levers of this first class.
The second type of lever is that in which the weight lies between the
force and the fulcrum, as illustrated by the wheelbarrow, or by an ordinary
door.
In the third class of levers the power is applied between weight and
fulcrum, as illustrated by a pair of tongs, the treadle of a lathe, or by the
flexor muscles of the arm, operating upon the bones of the forearm.
But in each case, let it be repeated, precisely the same principles are
involved, and the same simple law of the relations between positions of
power, weight, and fulcrum are maintained. The practical result is always
that a weight of indefinite size may be moved by a power indefinitely long.
If one arm of the lever is ten times as long as the other, the power of one
pound will lift or balance a ten-pound weight; if the one arm is a thousand
times as long as the other the power of one pound will lift or balance a
thousand pounds. If the long arm of the lever could be made some millions
of miles in length, the power that a man could exert would balance the
earth.
How fully Archimedes realized the possibilities of the lever is illustrated
in the classical remark attributed to him, that, had he but a fulcrum on
which to place his lever, he could move the world. As otherwise quoted, the
remark of Archimedes was that, had he a place on which to stand, he could
move the world, a remark which even more than the other illustrates the full
and acute appreciation of the laws of motion; since, as we have already
pointed out, action and reaction being equal, the most infinitesimal push
must be considered as disturbing even the largest body.
Tremendous as is the pull of gravity by which the earth is held in its
orbit, yet the smallest push, steadily applied from the direction of the sun,
would suffice ultimately to disturb the stability of our earth's motion, and to
push it gradually through a spiral course farther and farther away from its
present line of elliptical flight. Or if, on the other hand, the persistent force

were applied from the side opposite the sun, it would suffice ultimately to
carry the earth in a spiral course until it plunged into the sun itself. Indeed it
has been questioned in modern times whether it may not be possible that
precisely this latter effect is gradually being accomplished, through the
action of meteorites, some millions of which fall out of space into the
earth's atmosphere every day. If these meteorites were uniformly distributed
through space and flying in every direction, the fact that the sun screens the
earth from a certain number of them, would make the average number
falling on the side away from the sun greater, and thus would in the course
of ages produce the result just suggested. All that could save our earth from
such a fate would be the operation of some counteracting force. Such a
counteracting force is perhaps found in solar radiation. It may be added that
the distribution of meteorites in space is probably too irregular to make
their influence on the earth predicable in the present state of science; but the
principle involved is no less sure.

WHEELS AND PULLEYS

Returning from such theoretical applications of the principle of motion,
to the practicalities of every-day mechanisms, we must note some of the
applications through which the principle of the lever is made available. Of
these some of the most familiar are wheels, and the various modifications of
wheels utilized in pulleys and in cogged and bevelled gearings. A moment's
reflection will make it clear that the wheel is a lever of the first class, of
which the axle constitutes the fulcrum. The spokes of the wheel being of
equal length, weights and forces applied to opposite ends of any diameter
are, of course, in equilibrium. It follows that when a wheel is adjusted so
that a rope may be run about it, constituting a simple pulley, a mechanism is
developed which gives no gain in power, but only enables the operator to
change the direction of application of power. In other words, pound weights
at either end of a rope passed about a simple pulley are in equilibrium and
will balance each other, and move through equal distances in opposite
directions.

HORSE AND CATTLE POWER.
The large picture shows a model of a familiar mechanism for
utilizing horse power. The small picture shows a similar apparatus in
actual operation, actuated by cattle, in contemporary Brittany.
If, however, two or more pulley wheels are connected, to make the
familiar apparatus of a compound pulley, we have accomplished by an
interesting mechanism a virtual application of the principle of the long and
short arm of the lever, and the relations between the weight at the loose end
of the rope and the weight attached to the block which constitutes virtually
the short end of the lever, may be varied indefinitely, according to the
number of pulley-wheels that are used. A pound weight may be made to
balance a thousand-pound weight; but, of course, our familiar principle still
holding, the pound weight must move through a distance of a thousand feet
in order to move a thousand-pound weight through a distance of one foot.
Familiar illustrations of the application of this principle may be seen on
every hand; as when, for example, a piano or a safe is raised to the upper
window of a building by the efforts of men whose power, if directly
expended, would be altogether inefficient to stir the weight.

The pulley was doubtless invented at a much later stage of human
progress than the simple lever. It was, however, well known to the ancients.
It was probably brought to its highest state of practical perfection by
Archimedes, whose experiments are famous through the narrative of
Plutarch. It will be recalled that Archimedes amazed the Syracusan general
by constructing an apparatus that enabled him, sitting on shore, to drag a
ponderous galley from the water. Plutarch does not describe in detail the
apparatus with which this was accomplished, but it is obvious from his
description of what took place, that it must have been a system of pulleys.
It will be observed that the pulley is a mechanism that enables the user to
transmit power to a distance. But this indeed is true in a certain sense of
every form of lever. Numberless other contrivances are in use by which
power is transmitted, through utilization of the same principle of the lever,
either through a short or through a relatively long distance. A familiar
illustration is the windlass, which consists of a cylinder rotating on an axis
propelled by a long handle, a rope being wound about the cylinder. This is a
lever of the second class, the axis acting as fulcrum, and the rope operating
about the circumference of the cylinder typifying the weight, which may be
actually at a considerable distance, as in the case of the old-fashioned well
with its windlass and bucket, or of the simple form of derrick sometimes
called a sheerlegs.

OTHER MEANS OF TRANSMITTING POWER

Power is transmitted directly from one part of a machine to another, in
the case of a great variety of machines, with the aid of cogged gearing
wheels of various sizes. The modifications of detail in the application of
these wheels may be almost infinite, but the principle involved is always the
same. The case of two wheels toothed about the circumference, the teeth of
the two wheels fitting into one another, illustrates the principle involved. A
consideration of the mechanism will show that here we have virtually a
lever fixed at both ends, represented by the radii of the two wheels, the
power being applied through the axle of one wheel, and the weight, for
purposes of calculation, being represented by the pressure of the teeth of
one wheel upon those of the other. So this becomes a lever of the second
class, and the relations of power between the two wheels are easily
calculated from the relative lengths of the radii. If, for example, one radius

is twice as long as the other, the transmission of power will be, obviously, in
the proportion of two to one, and meantime the distance traversed by the
circumference of one wheel will be twice as great as that traversed by the
other.
A modification of the toothed wheel is furnished by wheels which may
be separated by a considerable distance, and the circumferences of which
are connected by a belt or by a chain. The principle of action here is
precisely the same, the belt or chain serving merely as a means of
lengthening out our lever. The relative sizes of the wheels, and not the
length of the belt or chain, is the determining factor as regards the relative
forces required to make the wheels revolve.
It is obvious all along, of course, since action and reaction are equal, that
all of the relations in question are reciprocal. When, for example, we speak
of a pound weight on the long end of a lever balancing a ten-pound weight
on the short end, it is equally appropriate to speak of the ten-pound weight
as balancing the one-pound weight. Similarly, when power is applied to the
lever, it may be applied at either end. Ordinarily, to be sure, the power is
applied at the long end, since the object is to lift the heavy weight; but in
complicated machinery it quite as often happens that these conditions are
reversed, and then it becomes desirable to apply strong power to the short
end of the lever, in order that the relatively small weight may be carried
through the long distance. In the inter-relations of gearing wheels, such
conditions very frequently obtain, practical ends being met by a series of
wheels of different sizes. But the single rule, already so often outlined,
everywhere holds—wherever there is gain of power there is loss of
distance, and we can gain distance only by losing power. The words gain
and loss in this application are in a sense misnomers, since, as we have
already seen, gain and loss are only apparent, but their convenience of
application is obvious.
A familiar case in which there is first loss of speed and gain of power,
and then gain of speed at the expense of power in the same mechanism, is
furnished by the bicycle, where (1) the crank shaft turns the sprocket wheel
that constitutes a lever of the second class with gain of power; where (2)
power is further augmented through transmission from the relatively large
sprocket wheel to the small sprocket of the axle; and where (3) there is
great loss of power and corresponding gain of speed in transmitting the

force from the small sprocket wheel at the axle to the rubber rim of the
bicycle proper, this last transmission representing a lever of the third class.
The net gain of speed is tangibly represented by the difference in distance
traversed by the man's feet in revolving the pedals, and the actual distance
covered by the bicycle.

INCLINED PLANES AND DERRICKS

A less obvious application of the principle of reciprocal equivalence of
distance and weight is furnished by the inclined plane, a familiar
mechanism with the aid of which a great gain of power is possible. The
inclined plane, like the lever, has been known from remotest antiquity. Its
utility was probably discovered by almost the earliest builders. Diodorus
Siculus tells us that the great pyramids of Egypt were constructed with the
aid of inclined planes, based on a foundation of earth piled about the
pyramids. Diodorus, living at a period removed by some thousands of years
from the day of the building of the pyramids, may or may not have voiced
and recorded an authentic tradition, but we may well believe that the
principle of the inclined plane was largely drawn upon by the mechanics of
old Egypt, as by later peoples.
The law of the inclined plane is that in order to establish equilibrium
between two weights, the one must be to the other as the height of the
inclined plane is to its length. The steeper the inclined plane, therefore, the
less will be the gain in power; a mechanical principle which familiar
experience or the simplest experiment will readily corroborate.
In its elemental form the inclined plane is not used very largely in
modern machinery, but its modified form of the wedge and the screw have
more utility. The screw, indeed, which is obviously an inclined plane
adjusted spirally about a cylinder or a cone, is familiar to everyone, and is
constantly utilized in applying power.
The crane or derrick furnishes a familiar but relatively elaborate
illustration of a mechanism for the transmission of power, in which all the
various devices hitherto referred to are combined, without the introduction
of any new principle.
Derricks have been employed from a very early day. The battering-rams
of the ancient Egyptians and Babylonians, for example, were virtually

derricks; and no doubt the same people used the device in raising stones to
build their temples and city walls, and in putting into position such massive
sculptures as the obelisks of Egypt and the monster graven bulls and lions
of Nineveh and Babylon.

CRANES AND DERRICKS.

The upper figure shows a floating derrick, the lower right-hand
figure a combined derrick and weighing machine, and the lower left-
hand figure a so-called sheerlegs, which is a simple derrick and
windlass operated by hand or by steam power with the aid of
compound pulleys.
The modern derrick, made of steel, and operated by steam or electricity,
capable of lifting tons, yet absolutely obedient to the hand of the engineer,
is a really wonderful piece of mechanism. A steam-scoop, for example,
excavating a gravel bank, seems almost a thing of intelligence; as it gores
into the bank scooping up perhaps a half ton of earth, its upward sweeping
head reminds one of an angry bull. Then as it swings leisurely about and
discharges its load at just the right spot into an awaiting car, its hinged
bottom swings back and forth two or three times before closing, with
curious resemblance to the jaw of a dog; the similarity being heightened by
the square bull-dog-headed shape of the scoop itself. Yet this remarkable

contrivance, with all its massive steel beams and chains and cog wheels,
employs no other principles than the simple ones of lever and pulley and
inclined plane that we have just examined. The power that must be applied
to produce a given effect may be calculated to a nicety. The capacities of the
machine are fully predetermined in advance of its actual construction. But
of course this is equally true of every other form of power-transmitter with
which the modern mechanical engineer has to deal.

FRICTION

In making such calculations, however, there is an additional element
which the engineer must consider, but which we have hitherto disregarded.
In all methods of transmission of power, and indeed in all cases of the
contact of one substance with another, there is an element of loss through
friction. This is due to the fact that no substance is smooth except in a
relative sense. Even the most highly polished glass or steel, when viewed
under the microscope, presents a surface covered with indentations and
rugosities. This granular surface of even seemingly smooth objects, is easily
visualized through the analogy of numberless substances that are visibly
rough. Yet the vast practical importance of this roughness is seldom
considered by the casual observer. In point of fact, were it not for the
roughened surface of all materials with which we come in contact, it would
be impossible for any animal or man to walk, nor could we hold anything in
our hands. Anyone who has attempted to handle a fish, particularly an eel,
fresh from the water, will recall the difficulty with which its slippery
surface was held; but it may not occur to everyone who has had this
experience that all other objects would similarly slip from the hand, had
their surfaces a similar smoothness. The slippery character of the eel is, of
course, due in large part to the relatively smooth surface of its skin, but
partly also to the lubricant with which it is covered. Any substance may be
rendered somewhat smoother by proper lubrication; it is necessary,
however, that the lubricant should be something which is not absorbed by
the substance. Thus, wood is given increased friction by being moistened
with oil, but, on the other hand, is made slippery if covered with graphite,
soap, or any other fatty substances that it does not absorb.
Recalling the more or less roughened surface of all objects, the source of
friction is readily understood. It depends upon the actual jutting of the

roughened surfaces, one upon the other. It virtually constitutes a force
acting in opposition to the motion of any two surfaces upon each other. As
between any different materials, under given conditions, it varies with the
pressure, in a definite and measurable rate, which is spoken of as the
coefficient of friction for the particular substances. It is very much greater
where the two substances slide over one another than where the one rolls
upon the other, as in the case of the wheel. The latter illustrates what is
called rolling friction, and in practical mechanics it is used constantly to
decrease the loss—as, for example, in the wheels of wagons and cars. The
use of lubricants to decrease friction is equally familiar. Without them, as
everyone knows, it would be impossible to run any wheel continuously
upon an axle at high speed for more than a very brief period, owing to the
great heat developed through friction. Friction is indeed a perpetual
antagonist of the mechanician, and we shall see endless illustrations of the
methods he employs to minimize its influence. On the other hand, we must
recall that were it rendered absolutely nil, his machinery would all be
useless. The car wheel, for example, would revolve indefinitely without
stirring the train, were there absolutely no friction between it and the rail.

AVAILABLE SOURCES OF ENERGY

We have pointed out that every body whatever contains a certain store of
energy, but it has equally been called to our attention that, in the main, these
stores of energy are not available for practical use. There are, however,
various great natural repositories of energy upon which man is able to draw.
The chief of these are, first, the muscular energy of man himself and of
animals; second, the energy of air in motion; third, the energy of water in
motion or at an elevation; and fourth, the molecular and atomic energies
stored in coal, wood, and other combustible materials. To these we should
probably add the energy of radio-active substances—a form of energy only
recently discovered and not as yet available on a large scale, but which may
sometime become so, when new supplies of radio-active materials have
been discovered. It will be the object of succeeding chapters to point out the
practical ways in which these various stores of energy are drawn upon and
made to do work for man's benefit.

III
THE ANIMAL MACHINE

T
he muscular system is not only the oldest machine in existence, but
also the most complex. Moreover, it is otherwise entitled to
precedence, for even to-day, in this so-called age of steam and
electricity, the muscular system remains by far the most important of
all machines. In the United States alone there are some twenty million
horses doing work for man; and of course no machine of any sort is ever put
in motion or continues indefinitely in operation without aid supplied by
human muscles. All in all, then, it is impossible to overestimate the
importance of this muscular machine which is at once the oldest and the
most lasting of all systems of utilizing energy.
The physical laws that govern the animal machine are precisely similar to
those that are applied to other mechanisms. All the laws that have been
called to our attention must therefore be understood as applying fully to the
muscular mechanism. But in addition to these the muscular system has
certain laws or methods of action of its own, some of which are not very
clearly understood.
The prime mystery concerning the muscle is its wonderful property of
contracting. For practical purposes we may say that it has no other property;
the sole function of the muscle is to contract. It can, of course, relax, also,
to make ready for another contraction, but this is the full extent of its
activities. A microscopic examination of the muscle shows that it is
composed of minute fibres, each of which on contraction swells up into a
spindle shape. A mass of such fibres aggregated together constitutes a
muscle, and every muscle is attached at either extremity, by means of a
tendon, to a bone. Both extremities of a muscle are never attached to the
same bone—otherwise the muscle would be absolutely useless. Usually
there is only a single bone between the two ends of a muscle, but in
exceptional cases there may be more. As a rule, the main body of a muscle
lies along the bone to which one end of it is attached, the other end of the
muscle being attached to the contiguous bone placed not far from the point.

The first bone, then, serves as a fulcrum on which the second bone moves
as a lever, and, as already pointed out, the familiar laws of the lever operate
here as fully as in the inanimate world. But a moment's reflection will make
it clear that the object effected by this mechanism is the increase of motion
with relative loss of energy. In other words, the muscular force is applied to
the short end of the lever, and a far greater expenditure of force is required
when the muscle contracts than the power externally manifested would
seem to indicate.
A moment's consideration of the mechanism of the arm, having regard to
the biceps muscle which flexes the elbow, will make this clear. If a weight
is held in the hand it is perhaps twelve inches from the elbow. If, while
holding the weight, you will grasp the elbow with the other hand, you will
feel the point of attachment of the biceps, and discover that it does not seem
to be, roughly speaking, more than about an inch from the joint. Obviously,
then, if you are lifting a pound weight, the actual equivalent of energy
expended by the contracting biceps must be twelve pounds. But, in the
meantime, when the pound weight in your hand moves through the space of
one inch, the muscle has contracted by one-twelfth of an inch; and you may
sweep the weight through a distance of two feet by utilizing the two-inch
contraction, which represents about the capacity of the muscle.
A similar consideration of the muscles of the legs will show how the
muscular system which is susceptible of but trifling variation in size, gives
to the animal great locomotive power. With the aid of a series of levers,
represented by the bones of our thighs, legs, and feet, we are able to stride
along, covering three or four feet at each step, while no set of the muscles
that effect this propulsion varies in length by more than two or three inches.
It appears, then, that the muscular system gives a marvelous illustration of
capacity for storing energy in a compact form and utilizing it for the
development of motion.

THE TWO TYPES OF MUSCLES

The muscles of animals and men alike are divided into two systems, one
called voluntary, the other involuntary. The voluntary muscles, as their
name implies, are subject to the influence of the will, and under ordinary
conditions contract in response to the voluntary nervous impulses. Certain
sets of them, indeed, as those having to do with respiration, have developed

a tendency to rhythmical action through long use, and ordinarily perform
their functions without voluntary guidance. Their function may, however,
become voluntary when attention is directed toward it, and is then subject to
the action of the will within certain bounds. Should a voluntary attempt be
made, however, to prevent their action indefinitely, the so-called reflex
mechanism presently asserts itself. All of which may be easily attested by
anyone who will attempt to stop breathing. All systems of voluntary
muscles are subject to the influence of habit, and may assume activities that
are only partially recognized by consciousness. As an illustration in point,
the muscles involved in walking come, in the case of every adult, to
perform their function without direct guidance of the will. Such was not the
case, however, in the early stage of their development, as the observation of
any child learning to walk will amply demonstrate. In the case of animals,
however, even those muscles are so under the impress of hereditary
tendencies as to perform their functions spontaneously almost from the
moment of birth. These, however, are physiological details that need not
concern us here. It suffices to recall that the voluntary muscles may be
directed by the will, and indeed are always under what may be termed
subconscious direction, even when the conscious attention is not directed to
them.
The strictly involuntary muscles, however, are placed absolutely beyond
control of the will. The most important of these muscles are those that
constitute the heart and the diaphragm, and that enter into the substance of
the walls of blood vessels, and of the abdominal organs. It is obvious that
the functioning of these important organs could not advantageously be left
to the direction of the will; and so, in the long course of evolution they have
learned, as it were, to take care of themselves, and in so doing to take care
of the organism, to the life of which they are so absolutely essential. As the
physiologist views the matter, no organism could have developed which did
not correspondingly develop such involuntary action of the vital organs. It
will be seen that the involuntary muscles differ from the voluntary muscles
in that they are not connected with bones. Instead of being thus attached to
solid levers, they are annular in structure, and in contracting virtually
change the size of the ring which their substance constitutes. Each fibre in
contracting may be thought of as pulling against other fibres, instead of
against a bony surface, and the joint action changes the size of the organ, as
is obvious in the pulsing of the heart.

Though the rhythmical contractions of the involuntary muscles are
independent of voluntary control, it must not be supposed that they are
independent of the control of the central nervous mechanism. On the
contrary, the nerve supply sent out from the brain to the heart and to the
abdominal organs is as plentiful and as important as that sent to the
voluntary muscles. There is a centre in the brain scarcely larger than the
head of a pin, the destruction of which will cause the heart instantly to cease
beating forever. From this centre, then, and from the other centres of the
brain, impulses are constantly sent to the involuntary muscles, which
determine the rate of activity. Nor are these centres absolutely independent
of the seat of consciousness, as anyone will admit who recalls the varied
changes in the heart's action under stress of varying emotions.
That the voluntary muscles are controlled by the central nervous
mechanism needs no proof beyond the appeal to our personal experiences
of every moment. You desire some object that lies on the table in front of
you, and immediately your hand, thanks to the elaborate muscular
mechanism, reaches out and grasps it. And this act is but typical of the
thousand activities that make up our every-day life. Everyone is aware that
the channel of communication between the brain and the muscular system is
found in a system of nerves, which it is natural now-a-days to liken to a
system of telegraph wires. We speak of the impulse generated in the brain
as being transmitted along the nerves to the muscle, causing that to contract.
We are even able to measure the speed of transfer of such an impulse. It is
found to move with relative slowness, compassing only about one hundred
and twelve feet per second, being in this regard very unlike the electric
current with which it is so often compared. But the precise nature of this
impulse is unknown. Its effect, however, is made tangible in the muscular
contraction which it is its sole purpose to produce. The essential influence
of the nerve impulse in the transaction is easily demonstrable; for if the
nerve cord is severed, as often happens in accidents, the muscle supplied by
that nerve immediately loses its power of voluntary contraction. It becomes
paralyzed, as the saying is.

THE NATURE OF MUSCULAR ACTION

Paying heed, now, to the muscle itself, it must be freely admitted that, in
the last analysis, the activities of the substance are as mysterious and as

inexplicable as are those involved in the nervous mechanism. It is easy to
demonstrate that what we have just spoken of as a muscle fibre consists in
reality of a little tube of liquid protoplasm, and that the change in shape of
this protoplasm constitutes the contraction of which we are all along
speaking. But just what molecular and atomic changes are involved in this
change of form of the protoplasm, we cannot say. We know that the power
to contract is the one universal attribute of living protoplasm. This power is
equally wonderful and equally inexplicable, whether manifested in the case
of the muscle cell or in the case of such a formless single-celled creature as
the amœba. When we know more of molecular and atomic force, we may
perhaps be able to form a mental picture of what goes on in the structure of
protoplasm when it thus changes the shape of its mass. Until then, we must
be content to accept the fact as being the vital one upon which all the
movements of animate creatures depend.
But if, here as elsewhere, the ultimate activities of molecules and atoms
lie beyond our ken, we may nevertheless gain an insight into the nature of
the substances involved. We know, for example, that the chief constituents
of all protoplasm are carbon, hydrogen, oxygen, and nitrogen; and that with
these main elements there are traces of various other elements such as iron,
sulphur, phosphorus, and sundry salts. We know that when the muscle
contracts some of these constituents are disarranged through what is spoken
of as chemical decomposition, and that there results a change in the
substance of the protoplasm, accompanied by the excretion of a certain
portion of its constituents, and by the liberation of heat. Carbonic acid gas,
for example, is generated and is swept away from the muscular tissues in
the ever active bloodstreams, to be carried to the lungs and there expelled—
it being a noxious poison, fatal to life if retained in large quantities. Equally
noxious are other substances such as uric acid and its compounds, which are
also results of the breaking down of tissue that attends muscular action. In a
word, there is an incessant formation of waste products, due to muscular
activity, the removal of which requires the constant service of the purifying
streams of blood and of the various excretory organs.
But this constant outflow of waste products from the muscle necessitates,
of course, in accordance with the laws of the conservation of matter and of
energy, an equally constant supply of new matter to take the place of the
old. This supply of what is virtually fuel to be consumed, enabling the

muscle to perform its work, is brought to the muscle through the streams of
blood which flow from the heart in the arterial channels, and in part also
through the lymphatic system. The blood itself gains its supply from the
digestive system and from the lungs. The digestive system supplies water,
that all-essential diluent, and a great variety of compounds elaborated into
the proper pabulum; while the vital function of the lungs is to supply
oxygen, which must be incessantly present in order that the combustion
which attends muscular activity may take place. What virtually happens is
that fuel is sent from the digestive system to be burned in the muscular
system, with the aid of oxygen brought from the lungs.
In this view, the muscular apparatus is a species of heat engine. In point
of fact, it is a curiously delicate one as regards the range of conditions
within which it is able to act. The temperature of any given organism is
almost invariable; the human body, for example, maintains an average
temperature of 98-2/5 degrees, Fahrenheit. The range of variation from this
temperature in conditions of health is rarely more than a fraction of a
degree; and even under stress of the most severe fever the temperature
never rises more than about eight degrees without a fatal result. That an
organism which is producing heat in such varying quantities through its
varying muscular activities should maintain such an equilibrium of
temperature, would seem one of the most marvelous of facts, were it not so
familiar.
The physical means by which the heat thus generated is rapidly given off,
on occasion, to meet the varying conditions of muscular activity, is largely
dependent upon the control of the blood supply, in which involuntary
muscles, similar to those of the heart, are concerned. In times of great
muscular activity, when the production of heat is relatively enormous, the
arterioles that supply the surface of the body are rapidly dilated so that a
preponderance of blood circulates at the surface of the body, where it may
readily radiate its heat into space; the vast system of perspiratory ducts,
with which the skin is everywhere supplied, aiding enormously in
facilitating this result, through the secretion of a film of perspiration, which
in evaporating takes up large quantities of heat.
The flushed, perspiring face of a person who has violently exercised
gives a familiar proof of these physiological changes; and the contrary
condition, in which the peripheral circulation is restricted, and in which the

pores are closed, is equally familiar. Moreover, the same cutaneous
mechanism is efficient in affording the organism protection from the
changes of external temperature; though the human machine, thanks to the
pampering influence of civilization, requires additional protection in the
form of clothing.

APPLICATIONS OF MUSCULAR ENERGY

Having thus outlined the conditions under which the muscular machine
performs its work, we have now to consider briefly the external
mechanisms with the aid of which muscular energy is utilized. Of course,
the simplest application of this power, and the one universally employed in
the animal world is that in which a direct push or pull is given to the
substance, the position of which it is desired to change. We have already
pointed out that there is no essential difference between pushing and
pulling. The fact receives another illustration in considering the muscular
mechanism. We speak of pushing when we propel something away from a
body, of pulling when we draw something toward it, yet, as we have just
seen, each can be accomplished merely through the contraction of a set of
muscles, acting on differently disposed levers. All the bodily activities are
reducible to such muscular contractions, and the diversified movements in
which the organism constantly indulges are merely due to the large number
and elaborate arrangement of the bony levers upon which these muscles are
operated.
We may well suppose that the primitive man continued for a long period
of time to perform all such labors as he undertook without the aid of any
artificial mechanism; that is to say, without having learned to gain any
power beyond that which the natural levers of his body provided. A brief
observation of the actions of a man performing any piece of manual labor
will, however, quickly demonstrate how ingeniously the bodily levers are
employed, and how by shifting positions the worker unconsciously makes
the most of a given expenditure of energy. By bending the arms and
bringing them close to the body, he is able to shorten his levers so that he
can lift a much greater weight than he could possibly raise with the arms
extended. On the other hand, with the extended arm he can strike a much
more powerful blow than with the shorter lever of the flexed arm. But
however ingenious the manipulation of the natural levers, a full utilization

of muscular energy is possible only when they are supplemented with
artificial aids, which constitute primitive pieces of machinery.
These aids are chiefly of three types, namely, inclined planes, friction
reducers, and levers. The use of the inclined plane was very early
discovered and put into practise in chipped implements, which took the
form of the wedge, in such modifications as axes, knives, and spears of
metal. All of these implements, it will be observed, consist essentially of
inclined planes, adapted for piercing relatively soft tissues of wood or flesh,
and hence serving purposes of the greatest practical utility.
The knife-blade is an extremely thin wedge, to be utilized by force of
pushing, without any great aid from acquired momentum. The hatchet, on
the other hand—and its modification the axe—has its blunter blade fastened
to a handle; that the principle of the wedge may be utilized at the long end
of a lever and with the momentum of a swinging blow. Ages before anyone
could have explained the principle involved in such obscuring terms as that,
the implement itself was in use for the same purpose to which it is still
applied. Indeed, there is probably no other implement that has played a
larger part in the history of human industry. Even in the Rough Stone Age it
was in full favor, and the earliest metallurgists produced it in bronze and
then in iron. The blade of to-day is made of the best tempered steel, and the
handle or helve of hickory is given a slight curve that is an improvement on
the straight handle formerly employed; but on the whole it may be said that
the axe is a surviving primitive implement that has held its own and
demonstrated its utility in every generation since the dawn, not of history
only, but of barbarism, perhaps even of savagery.
The saw, consisting essentially of a thin elongated blade, one ragged or
toothed edge, is a scarcely less primitive and an equally useful and familiar
application of the principle of the inclined plane—though it requires a
moment's reflection to see the manner of application. Each tooth, however
minute, is an inclined plane, calculated to slide over the tissue of wood or
stone or iron even, yet to tear at the tissue with its point, and, with the
power of numbers, ultimately wear it away.

THE WHEEL AND AXLE

The primitive friction reducer, which continues in use to the present day
unmodified in principle, is the wheel revolving on an axle. Doubtless man
had reached a very high state of barbarism before he invented such a wheel.
The American Indian, for example, knew no better method than to carry his
heavy burdens on his shoulders, or drag them along the ground, with at
most a pair of parallel poles or runners to modify the friction; every move
representing a very wasteful expenditure of energy. But the pre-historic man
of the old world had made the wonderful discovery that a wheel revolving
on an axle vastly reduces the friction between a weight and the earth, and
thus enables a man or a woman to convey a load that would be far beyond
his or her unaided powers. It is well to use both genders in this illustration,
since among primitive peoples it is usually the woman who is the bearer of
burdens. And indeed to this day one may see the women of Italy and
Germany bearing large burdens on their backs and heads, and dragging
carts about the streets, quite after the primitive method.
The more one considers the mechanism, the more one must marvel at the
ingenuity of the pre-historic man who invented the wheel and axle. Its
utility is sufficiently obvious once the thing has been done. In point of fact,
it so enormously reduces the friction that a man may convey ten times the
burden with its aid that he can without it. But how was the primitive man,
with his small knowledge of mechanics, to predict such a result? In point of
fact, of course, he made no such prediction. Doubtless his attention was first
called to the utility of rolling bodies by a chance observation of dragging a
burden along a pebbly beach, or over rolling stones. The observation of logs
or round stones rolling down a hill might also have stimulated the
imagination of some inventive genius.

A BELGIAN MILK-WAGON.
In many of the countries of Europe the dog plays an important part
as a beast of burden. Stringent laws are enforced in these countries to
prevent possible abuse or neglect of the animals.
Probably logs placed beneath heavy weights, such as are still employed
sometimes in moving houses, were utilized now and again for many
generations before the idea of a narrow section of a log adjusted on an axis
was evolved. But be that as it may, this idea was put into practise before the
historic period begins, and we find the earliest civilized races of which we
have record—those, namely, of Old Egypt and of Old Babylonia—in full
possession of the principle of the wheel as applied to vehicles. Modern
mechanics have, of course, improved the mechanism as regards details, but
the wheels depicted in Old Egyptian and Babylonian inscriptions are
curiously similar to the most modern types. Indeed, the wheel is a striking
illustration of a mechanism which continued century after century to serve
the purposes of the practical worker, with seemingly no prospect of
displacement.

MODIFIED LEVERS

For the rest, the mechanisms which primitive man learned early to use in
adding to his working efficiency, and which are still used by the hand
laborer, are virtually all modifications of our familiar type-implement, the
lever. A moment's reflection will show that the diversified purposes of the
crowbar, hoe, shovel, hammer, drill, chisel, are all accomplished with the
aid of the same principles. The crowbar, for example, enables man to regain
the power which he lost when his members were adapted to locomotion.
His hands, left to themselves, as we have already pointed out, give but
inadequate expression to the power of his muscles. But by grasping the long
end of such a lever as the crowbar, he is enabled to utilize his entire weight
in addition to his muscular strength, and, with the aid of this lever, to lift
many times his weight.
The hoe, on the other hand, becomes virtually a lengthened arm, enabling
a very slight muscular motion to be transformed into the long sweep of the
implement, so that with small expenditure of energy the desired work is
accomplished. Similarly, the sledge and the axe lengthen out the lever of the
arms, so that great momentum is readily acquired, and with the aid of
inertia a relatively enormous force can be applied. It will be observed that a
laborer in raising a heavy sledge brings the head of the implement near his
body, thus shortening the leverage and gaining power at the expense of
speed; but extends his arms to their full length as the sledge falls, having
now the aid of gravitation, to gain the full advantage of the long arm of the
lever in acquiring momentum.
Even such elaborately modified implements as the treadmill and the
rowboat are operated on the principle of the lever. These also are
mechanisms that have come down to us from a high antiquity. Their utility,
however, has been greatly decreased in modern times, by the substitution of
more elaborate and economical mechanisms for accomplishing their
respective purposes. The treadmill, indeed—which might be likened to an
overshot waterwheel in which the human foot supplied the place of the
falling water in giving power—has become obsolete, though a modification
of it, to be driven by animal power, is still sometimes used, as we shall see
in a moment.
All these are illustrations of mechanisms with the aid of which human
labor is made effective. They show the devices by which primitive man
used his ingenuity in making his muscular system a more effective machine

for the performance of work. But perhaps the most ingenious feat of all
which our primitive ancestor accomplished was in learning to utilize the
muscular energy of other animals. Of course the example was always before
him in the observed activity of the animals on every side. Nevertheless, it
was doubtless long before the idea suggested itself, and probably longer
still before it was put into practise, of utilizing this almost inexhaustible
natural supply of working energy.

DOMESTICATED ANIMALS

The first animal domesticated is believed to have been the dog, and this
animal is still used, as everyone knows, as a beast of burden in the far
North, and in some European cities, particularly in those of Germany.
Subsequently the ox was domesticated, but it is probable that for a vast
period of time it was used for food purposes, rather than as a beast of
burden. And lastly the horse, the worker par excellence, was made captive
by some Asiatic tribes having the genius of invention, and in due course this
fleetest of carriers and most efficient of draught animals was introduced
into all civilized nations.
Doubtless for a long time the energy of the horse was utilized in an
uneconomical way, through binding the burden on its back, or causing it to
drag the burden along the ground. But this is inferential, since, as we have
seen, the wheel was invented in pre-historic times, and at the dawn of
history we find the Babylonians driving harnessed horses attached to
wheeled vehicles. From that day to this the method of using horse-power
has not greatly changed. The vast majority of the many millions of horses
that are employed every day in helping on the world's work, use their
strength without gain or loss through leverage, and with only the aid of
rolling friction to increase their capacity as beasts of burden.
To a certain extent horse-power is still used with the aid of the modified
treadmill just referred to—consisting essentially of an inclined plane of
flexible mechanism made into an endless platform, which the horse causes
to revolve as he goes through the movements of walking upon it. In
agricultural districts this form of power is still sometimes used to run
threshing machines, cider mills, wood-saws, and the like. Another
application of horse-power to the same ends is accomplished through
harnessing a horse to a long lever like the spoke of a wheel, fastened to an

axis, which is made to revolve as the horse walks about it. Several horses
are sometimes hitched to such a mechanism, which becomes then a wheel
of several spokes. But this mechanism, which was common enough in
agricultural districts two or three decades ago, has been practically
superseded in recent years by the perambulatory steam engine.

TWO APPARATUSES FOR THE UTILIZATION OF ANIMAL
POWER.

The upper figure shows the type of portable horse-power machine
used for threshing grain in 1851. The lower figure is an inclined-plane
horse-gear. The horse stands on the sloping platform tied to the bar in
front, so that it is compelled to walk as the platform recedes.
It is obvious that the amount of work which a horse can accomplish must
vary greatly with the size and quality of the horse, and with the particular
method by which its energy is applied. For the purposes of comparison,
however, an arbitrary amount of work has been fixed upon as constituting
what is called a horse-power. This amount is the equivalent of raising thirty-
three thousand pounds of weight to the height of one foot in one minute. It
would be hard to say just why this particular standard was fixed upon, since
it certainly represents more than the average capacity of a horse. It is,
however, a standard which long usage (it was first suggested by Watt, of
steam-engine fame) has rendered convenient, and one which the machinist
refers to constantly in speaking of the efficiency of the various types of
artificial machines. All questions of the exact legitimacy of this particular
standard aside, it was highly appropriate that the labor of the horse, which
has made up so large a share of the labor of the past, and which is still so

extensively utilized, should continue to be taken as the measuring standard
of the world's work.

IV
THE WORK OF AIR AND WATER

T
he store of energy contained in the atmosphere and in the waters of
the globe is inexhaustible. Its amount is beyond all calculation; or if
it were vaguely calculated the figures would be quite
incomprehensible from their very magnitude. It is not, however, an
altogether simple matter to make this energy available for the purposes of
useful work. We find that throughout antiquity comparatively little use was
made of either wind or water in their application to machinery.
Doubtless the earliest use of air as a motive power was through the
application of sails to boats. We know that the Phœnicians used a simple
form of sail, and no doubt their example was followed by all the maritime
peoples of subsequent periods. But the use of the sail even by the
Phœnicians was as a comparatively unimportant accessory to the galaxies
of oars, which formed the chief motive power. The elaboration of sails of
various types, adequate in extent to propel large ships, and capable of being
adjusted so as to take advantage of winds blowing from almost any quarter,
was a development of the Middle Ages.
The possibilities of work with the aid of running water were also but little
understood by the ancients. In the days of slave labor it was scarcely worth
while to tax man's ingenuity to invent machines, since so efficient a one
was provided by nature. Yet the properties of both air and water were
studied by various mechanical philosophers, at the head of whom were
Archimedes, whose work has already been referred to, and the famous
Alexandrian, Ctesibius, whose investigations became familiar through the
publications of his pupil, Hero.
Perhaps the most remarkable device invented by Ctesibius was a fire-
engine, consisting of an arrangement of valves constituting a pump, and
operating on the principle which is still in vogue. It is known, however, that
the Egyptians of a much earlier period used buckets having valves in their
bottoms, and these perhaps furnished the foundation for the idea of

Ctesibius. It is unnecessary to give details of this fire-engine. It may be
noted, however, that the principle of the lever is the one employed in its
operation to gain power. A valve consists essentially of any simple hinged
substance, arranged so that it may rise or fall, alternately opening and
closing an aperture. A mere flap of leather, nailed on one edge, serves as a
tolerably effective valve. At least one of the valves used by Ctesibius was a
hinged piece of smooth metal. A piston fitted in a cylinder supplies suction
when the lever is raised, and pressure when it is compressed, alternately
opening the valve and closing the valve through which the water enters the
tube. Meantime a second valve alternating with the first permits the water to
enter the chamber containing air, which through its elasticity and pressure
equalizes the force of the stream that is ejected from the chamber through
the hose.

SUCTION AND PRESSURE

In the construction of this and various other apparatus, Ctesibius and
Hero were led to make careful studies of the phenomena of suction. But in
this they were not alone, since numerous of their predecessors had studied
the subject, and such an apparatus as the surgeon's cupping glass was
familiarly known several centuries before the Christian era. The cupping
glass, as perhaps should be explained to the reader of the present day—
since the apparatus went out of vogue in ordinary medical practise two or
three generations ago—consists of a glass cup in which the air is exhausted,
so as to suck blood from any part of the surface of a body to which it is
applied. Hero describes a method of exhausting air by which such suction
may be facilitated. But neither he nor any other philosopher of his period at
all understood the real nature of this suction, notwithstanding their perfect
familiarity with numerous of its phenomena. It was known, for example,
that when a tube closed at one end is filled with water and inverted with the
open end beneath the surface of the water, the water remains in the tube,
although one might naturally expect that it would obey the impulses of
gravitation and run out, leaving the tube empty. A familiar explanation of
this and allied phenomena throughout antiquity was found in the saying that
"Nature abhors a vacuum." This explanation, which of course amounts to
no explanation at all, is fairly illustrative of the method of metaphysical
word-juggling that served so largely among the earlier philosophers in
explanation of the mysteries of physical science.

The real explanation of the phenomena of suction was not arrived at until
the revival of learning in the seventeenth century. Then Torricelli, the pupil
of Galileo, demonstrated that the word suction, as commonly applied, had
no proper application; and that the phenomena hitherto ascribed to it were
really due to the pressure of the atmosphere. A vacuum is merely an
enclosed space deprived of air, and the "abhorrence" that Nature shows to
such a space is due to the fact that air has weight and presses in every
direction, and hence tends to invade every space to which it can gain access.
It was presently discovered that if the inverted tube in which the water
stands was made high enough, the water will no longer fill it, but will sink
to a certain level. The height at which it will stand is about thirty feet; above
that height a vacuum will be formed, which, for some reason, Nature seems
not to abhor. The reason is that the weight of any given column of water
about thirty feet in height is just balanced by the weight of a corresponding
column of atmosphere. The experiments that gave the proof of this were
made by the famous Englishman, Boyle. He showed that if the heavy liquid,
mercury, is used in place of water, then the suspended column will be only
about thirty inches in height. The weight or pressure of the atmosphere at
sea level, as measured by these experiments, is about fifteen pounds to the
square inch.
Boyle's further experiments with the air and with other gases developed
the fact that the pressure exerted by any given quantity of gas is
proportional to the external pressure to which it is subjected, which, after
all, is only a special application of the law that action and reaction are
equal. The further fact was developed that under pressure a gas decreases at
a fixed rate in bulk. A general law, expressing these facts in the phrase that
density and elasticity vary inversely with the pressure in a precise ratio, was
developed by Boyle and the Frenchman, Mariotte, independently, and bears
the name of both of its discoverers. No immediate application of the law to
the practical purposes of the worker was made, however, and it is only in
recent years that compressed air has been extensively employed as a motive
power. Even now it has not proved a great commercial success, because
other more economical methods of power production are available. In
particular cases, however, it has a certain utility, as a relatively large
available source of energy may be condensed into a very small receptacle.

A very striking experiment illustrating the pressure of the air was made
by a famous contemporary of Boyle and Mariotte, by the name of Otto von
Guericke. He connected an air pump with a large brass sphere, composed of
two hemispheres, the edges of which fitted smoothly, but were not
connected by any mechanism. Under ordinary conditions the hemispheres
would fall apart readily, but von Guericke proved, by a famous public
demonstration, that when the air was exhausted in the sphere, teams of
horses pulling in opposite directions on the hemispheres could not separate
them. This is famous as the experiment of the Magdeburg spheres, and it is
often repeated on a smaller scale in the modern physical laboratory, to the
astonishment of the tyro in physical experiments.
The first question that usually comes to the mind of anyone who has
personally witnessed such an experiment, is the question as to how the
human body can withstand the tremendous force to which it is subjected by
an atmosphere exerting a pressure of fifteen pounds on every square inch of
its surface. The explanation is found in the uniform distribution of the
pressure, the influence of which is thus counteracted, and by the fact that
the tissues themselves contain everywhere a certain amount of air at the
same pressure. The familiar experiment of holding the hand over an
exhausted glass cylinder—which experiment is indeed but a modification of
the use of the cupping glass above referred to—illustrates very forcibly the
insupportable difficulties which the human body would encounter were not
its entire surface uniformly subjected to the atmospheric pressure.

AIR IN MOTION

At about the time when the scientific experiments with the pressure of
gases were being made, practical studies of the effects of masses of air in
motion were undertaken by the Dutch philosopher, Servinus. The use of the
windmill in Holland as a means of generating power doubtless suggested to
Servinus the possibility of attaching a sail to a land vehicle. He made the
experiment, and in the year 1600 constructed a sailing car which, propelled
by the wind, traversed the land to a considerable distance, on one occasion
conveying a company of which Prince Maurice of Orange was a member.
But his experiments have seldom been repeated, and indeed their lack of
practical feasibility scarcely needs demonstration.

The utility of the wind, however, in generating the power in a stationary
mechanism is familiar to everyone. Windmills were constructed at a
comparatively early period, and notwithstanding all the recent progress in
the development of steam and electrical power, this relatively primitive so-
called prime mover still holds its own in agricultural districts, particularly
in its application to pumps. A windmill consists of a series of inclined
planes, each of which forms one of the radii of a circle, or spokes of a
wheel, to the axle of which a gearing is adjusted by which the power
generated is utilized. The wheel is made to face the wind by the wind itself
blowing against a sort of rudder which projects from the axis. The wind
blowing against the inclined surfaces or vanes of the wheel causes each
vane to move in accordance with the law of component forces, thus
revolving the wheel as a whole.

WINDMILLS OF ANCIENT AND MODERN
TYPES.
The smaller figures show Dutch windmills of the
present day, many of which are identical in structure
with the windmills of the middle ages. It will be seen
that the sails can be furled when desired to put the
mill out of operation. In the mill of modern type
(large figure) the same effect is produced by slanting
the slats of the wheel.

It has been affirmed that the Romans had windmills, but "the silence of
Vitruvius, Seneca, and Chrysostom, who have spoken of the advantages of
the wind, makes this opinion questionable." It has been supposed by other
writers that windmills were used in France in the sixth century, while still
others have maintained that this mechanism was unknown in Europe until
the time of the Crusades. All that is tolerably certain is that in the twelfth
century windmills were in use in France and England. It is recorded that
when they began to be somewhat common Pope Celestine III. determined
that the tithes of them belonged to the clergy.

INHERENT DEFECTS OF THE WINDMILL

The mediæval European windmill was supplied with great sails of cloth,
and its picturesque appearance has been made familiar to everyone through
the famous tale of Don Quixote. The modern windmill, acting on precisely
the same principle, is a comparatively small affair, comprising many vanes
of metal, and constituting a far more practical machine. The great defect of
all windmills, however, is found in the fact that of necessity they furnish
such variable power, since the force of the wind is incessantly changing.
Worst of all, there may be protracted periods of atmospheric calm, during
which, of course, the windmill ceases to have any utility whatever. This
uneradicable defect relegates the windmill to a subordinate place among
prime movers, yet on the other hand, its cheapness insures its employment
for a long time to come, and the industry of manufacturing windmills
continues to be an important one, particularly in the United States.

RUNNING WATER

The aggregate amount of work accomplished with the aid of the wind is
but trifling, compared with that which is accomplished with the aid of
water. The supply of water is practically inexhaustible, and this fluid being
much more manageable than air, can be made a far more dependable aid to
the worker. Every stream, whatever its rate of flow, represents an enormous
store of potential energy. A cubic foot of water weighs about sixty-two and
a half pounds. The working capacity of any mass of water is represented by
one-half its weight into the square of its velocity; or, stated otherwise, by its
weight into the distance of its fall. Now, since the interiors of the
continents, where rivers find their sources, are often elevated by some

hundreds or even thousands of feet, it follows that the working energy
expended—and for the most part wasted—by the aggregate water current of
the world is beyond all calculation. Meantime, however, a portion of the
energy which in the aggregate represents an enormous working power is
utilized with the aid of various types of water wheels.
Watermills appear to have been introduced in the time of Mithridates,
Julius Cæsar, and Cicero. Strabo informs us that there was a watermill near
the residence of Mithridates; and we learn from Pomponius Sabinus, that
the first mill seen at Rome was erected on the Tiber, a little before the time
of Augustus. That they existed in the time of Augustus is obvious from the
description given of them by Vitruvius, and the epigram of Antipater, who
is supposed to have lived in the time of Cicero. But though mills driven by
water were introduced at this early period, yet public mills did not appear
till the time of Honorius and Arcadius. They were erected on three canals,
which conveyed water to the city, and the greater number of them lay under
Mount Janiculum. When the Goths besieged Rome in 536, and stopped the
large aqueduct and consequently the mills, Belisarius appears to have
constructed, for the first time, floating mills upon the Tiber. Mills driven by
the tide existed at Venice in the year 1046, or at least in 1078.
The older types of water wheel are exceedingly simple in construction,
consisting merely of vertical wheels revolving on horizontal axes, and so
placed as to receive the weight or pressure of the water on paddles or
buckets at their circumference. The water might be allowed to rush under
the wheel, thus constituting an under-shot wheel; or more commonly it
flows from above, constituting an over-shot wheel. Where the natural fall is
not available, dams are employed to supply an artificial fall.
This primitive type of water wheel has been practically abandoned within
the last generation, its place having been taken by the much more efficient
type of wheel known as the turbine. This consists of a wheel, usually
adjusted on a vertical axis, and acting on what is virtually the principle of a
windmill. To gain a mental picture of the turbine in its simplest form, one
might imagine the propelling screw of a steamship, placed horizontally in a
tube, so that the water could rush against its blades. The tiny windmills
which children often make by twisting pieces of paper illustrate the same
principle. Of course, in its developed form the turbine is somewhat

elaborated, in the aim to utilize as large a proportion of the energy of the
falling water as is possible; but the principle remains the same.
The turbine wheel was invented by a Frenchman named Fourneyron,
about three-quarters of a century ago (1827), but its great popularity, in
America in particular, is a matter of the last twenty or thirty years. To-day it
has virtually supplanted every other type of water wheel. To use any other is
indeed a wasteful extravagance, as the perfected turbine makes available
more than eighty per cent. of the kinetic energy of any mass of falling
water. A turbine wheel two feet in diameter is able to do the work of an
enormous wheel of the old type.
Turbine wheels are of several types, one operating in a closed tube to
which air has no access, and another in an open space in the presence of air.
The water may also be made to enter the turbine at the side or from below,
thus serving to support the weight of the mechanism—a consideration of
great importance in the case of such gigantic turbines as those that are
employed at Niagara Falls, which we shall have occasion to examine in
detail in a later chapter.

WATER WHEELS.
Fig. 1 shows a model of the so-called breast
wheel, a familiar type of water wheel that has
been in use since the time of the Romans. Figs. 2
and 3 show similar wheels as used to-day in
Belgium. Fig. 4 shows a model of Fourneyron's
turbine. This wheel was made in 1837, but the
original turbine was introduced by Fourneyron
in 1827. The turbine wheel has now almost

supplanted the other forms of water wheel
except in rural districts.
The power generated by a revolution of the turbine wheel may, of course,
be utilized directly by belts or gearings attached to its axle, or it may be
transferred to a distance, with the aid of a dynamo generating electricity.
The latter possibility, which has only recently been developed, and which
we shall have occasion to examine in detail in connection with our studies
of the power at Niagara, gives a new field of usefulness to the turbine
wheel, and makes it probable that this form of power will be vastly more
used in the future than it has been in the past. Indeed, it would not be
surprising were it ultimately to become the prime source of working energy
as utilized in every department of the world's work.
Mr. Edward H. Sanborn, in an article on Motive Power Appliances in the
Twelfth Census Report of the United States, comments upon the recent
advances in the use of water wheels as follows:
"One notable advance in turbine construction has been the production of
a type of wheel especially designed for operating under much higher heads
of water than were formerly considered feasible for wheels of this type.
Turbines are now built for heads ranging from 100 to 1,200 feet, and quite a
number of wheels are in operation under heads of from 100 to 200 feet.
This is an encroachment upon the field occupied almost exclusively by
wheels variously known as the 'impulse,' 'impact,' 'tangential,' or 'jet' type,
the principle of which is the impact of a powerful jet of water from a small
nozzle upon a series of buckets mounted upon the periphery of a small
wheel."
"The impact water wheel," Mr. Sanborn continues, "has come largely into
use during the last ten years, principally in the far West, where higher heads
of water are available than can be found in other parts of the country. With
wheels of this type, exceedingly simple in construction and of
comparatively small cost, a large amount of power is developed with great
economy under the great heads that are available. With the tremendous
water pressure developed by heads of 1,000 feet and upward, which in
many cases are used for this purpose, wheels of small diameter develop an
extraordinary amount of power. To the original type of impact wheel which
first led the field have been added several styles embodying practically the

same principle. Considerable study has been given to the designing of
buckets with a view to securing free discharge and the avoidance of any
disturbing eddies, and important improvements have resulted from the
thorough investigation of the action of the water during, and subsequent to,
its impact on the buckets. The impact wheel has been adapted to a wide
range of service with great variation as to the conditions under which it
operates, wheels having been made in California from 30 inches to 30 feet
in diameter, and to work under heads ranging from 35 to 2,100 feet, and at
speeds ranging from 65 to 1,100 revolutions per minute. A number of
wheels of this type have been built with capacities of not less than 1,000
horse-power each."

HYDRAULIC POWER

A few words should be said about the familiar method of transmitting
power with the aid of water, as illustrated by the hydrostatic press. This
does not indeed utilize the energy of the water itself, but it enables the
worker to transmit energy supplied from without, and to gain an indefinite
power to move weights through a short distance, with the expenditure of
very little working energy. The principle on which the hydrostatic press is
based is the one which was familiar to the ancient philosophers under the
name of the hydrostatic paradox. It was observed that if a tube is connected
with a closed receptacle, such as a strong cask, and cask and tube are filled
with water, the cask will presently be burst by the pressure of the water,
provided the tube is raised to a height, even though the actual weight of
water in the tube be comparatively slight. A powerful cask, for example,
may be burst by the water poured into a slender pipe. The result seems
indeed paradoxical, and for a long time no explanation of it was
forthcoming. It remained for Servinus, whose horseless wagon is elsewhere
noticed, to discover that the water at any given level presses equally in all
directions, and that its pressure is proportionate to its depth, quite regardless
of its bulk. Then, supposing the tube in our experiment to have a cross-
section of one square inch, a pressure equal to that in the tube would be
transmitted to each square inch of the surface of the cask; and the pressure
might thus become enormous.
If, instead of a tube lifted to a height, the same tube is connected with a
force pump operated with a lever—an apparatus similar to the fire-engine of

Ctesibius—it is obvious that precisely the same effect may be produced;
whatever pressure is developed in the piston of the force pump, similar
pressure will be transferred to a corresponding area in the surface of the
cask or receptacle with which the force pump connects. In practise this
principle is utilized, where great pressure is desired, by making a receptacle
with an enormous piston connecting with the force pump just described.
An indefinite power may thus be developed, the apparatus constituting
virtually a gigantic lever. But the principle of the equivalence of weight and
distance still holds, precisely as in an actual lever, and while the pressure
that may be exerted with slight expenditure of energy is enormous, the
distance through which this pressure acts is correspondingly small. If, for
example, the piston of the force pump has an area of one square inch, while
the piston of the press has an area of several square feet, the pressure
exerted will be measured in tons, but the distance through which it is
exerted will be almost infinitesimal. The range of utility of the hydrostatic
press is, therefore, limited, but within its sphere, it is an incomparable
transmitter of energy.

HYDRAULIC PRESS AND
HYDRAULIC CAPSTAN.
The upper figure shows Bramah's
original hydraulic pump and press, now
preserved in the South Kensington
Museum, London. The machine was
constructed in 1796 by Joseph Bramah to
demonstrate the principle of his hydraulic
press. The discrepancy in size between the
small lever worked by hand and the

enormous lever carrying a heavy weight
gives a vivid impression of the gain in
power through the use of the apparatus.
The lower figure shows the hydraulic
capstan used on many modern ships, in
which the same principle is utilized.
Moreover, it is possible to reverse the action of the hydraulic apparatus so
as to gain motion at the expense of power. A familiar type of elevator is a
case in point. The essential feature of the hydraulic elevator consists of a
ram attached to the bottom of the elevator and extending down into a
cylinder, slightly longer than the height to which the elevator is to rise. The
ram is fitting into a cylinder with water-tight packing, or a cut leather valve.
Water under high pressure is admitted to the cylinder through the valve at
the bottom, and the pressure thus supplied pushes up the ram, carrying the
elevator with it, of course. Another valve allows the water to escape, so that
ram and elevator may descend, too rapid descent being prevented by the
partial balancing of ram and elevator with weights acting over pulleys. The
ram, to the end of which pressure is thus applied, need be but a few inches
in diameter. Water pressure is secured by bringing water from an elevation.
Such an elevator acts slowly, but is a very safe and in many ways
satisfactory mechanism. Such elevators are still used extensively in Europe,
but have been almost altogether displaced in America by the electric
elevator.
The hydraulic elevator just described is virtually a water engine, the ram
acting as piston. A veritable engine, of small size, to perform any species of
mechanical work, may be constructed on precisely the same principle, the
piston in this case acting in a cylinder similar to that of the ordinary steam
engine. Such an engine operates slowly but with great power. It has special
utility where it is desirable to apply power intermittently, as in various parts
of a dockyard, or in handling guns and ammunition on shipboard. In the
former case in particular, it is often inconvenient to use steam power, as
steam sent from a central boiler condenses in a way to interfere with its
operation. In such a case any number of small water-pressure engines may
be operated from a single tank where water is at a high elevation, or where
the requisite pressure is secured artificially. In the latter case, the water is
kept under pressure by a large piston or ram heavily weighted, the entire

receptacle being, of course, of water-tight construction and adapted to
withstand pressure. The pump that supplies the tank is ordinarily made to
work automatically, ceasing operation as soon as the ram rises to the top of
the receptacle, and beginning again whenever, through use of water, the ram
begins to descend. Such an apparatus is called an accumulator. Such water
engines have come into vogue only in comparatively recent times, being
suggested by the steam engine. As already pointed out, their utility is
restricted, yet the total number of them in actual use to-day is large, and
their share in the world's work is not altogether inconsiderable.

V
CAPTIVE MOLECULES: THE STORY OF THE STEAM ENGINE

W
e come now to that all-important transformer of power, the steam
engine. Everybody knows that steam is a state of water in which,
under the influence of heat, the molecules have broken away
from the mutual attraction of cohesion, and are flying about at
inconceivable speed, rebounding from one another after collision, in virtue
of their elasticity, exerting in the aggregate an enormous pressure in every
direction. It is this consideration of the intimate character of steam that
justifies the title of the present chapter; a title that has further utility as
drawing a contrast between the manner of working with which we are now
to be concerned, and the various types of workers that we have previously
considered.
In speaking of the animal machine and of work accomplished by the air
and the water, we have been concerned primarily with masses of matter,
possessing and transmitting energy. Of course molecules—since they make
up the substance of all matter—could not be altogether ignored, but in the
main we have had to do with molar rather than with molecular motion.
Now, however, we are concerned with a mechanism in which the molecular
activities are directly concerned in performing work.
Even in the aggregate the molecules make up a mere intangible gas,
which requires to be closely confined in order that its energy may be made
available. Once the molecules have performed their work, they are so
changed in their activities that they sink back, as it were, exhausted, into a
relatively quiescent state, which enables their latent cohesive forces to
reduce them again to the state of a liquid. In a word, we are concerned with
the manifestation of energy which depends upon molecular activities in a
way quite different from what has been the case with any of the previously
considered mechanisms. The tangible manifestation of energy which we
term heat is not merely a condition of action and a by-product, as it was in
the case of the animal machine; it is the essential factor upon which all the
efficiency of the mechanism depends.

It should perhaps be stated that this explanation of the action of the steam
engine is a comparatively modern scientific interpretation. The earlier
experimenters brought the steam engine to a high state of efficiency,
without having any such conception as this of the nature of steam itself. For
practical purposes it suffices to note that water when heated takes the form
of steam; that this steam has the property of powerful and indefinite
expansion; and thirdly, that when allowed to escape from a state of
pressure, sudden expansion of the steam cools it sufficiently to cause the
recondensation of part of its substance, thus creating a vacuum.
Stated in few words, the entire action of the steam depends upon these
simple mechanical principles. The principles are practically applied by
permitting the steam to enter the cylinder where it can act on a piston, to
which it gives the thrust that is transmitted to an external mechanism by
means of a rod attached to the piston. When the piston has been driven to
the end of the desired thrust, the valve is opened automatically, permitting
the steam to escape, thus producing a vacuum, and insuring the return thrust
of the piston, which is further facilitated, ordinarily, by the admission of
steam to the other side of the piston. Practical operation of this mechanism
is familiar to everyone, though the marvel of its power and efficiency seems
none the less because of its familiarity.
It is not too much to say that this relatively simple device, in its first
general application, marked one of the most important turning points in the
history of civilization. To its influence, more than to any other single cause,
must be ascribed the revolutionary change that came over the character of
practical life in the nineteenth century. From prehistoric times till well
toward the close of the eighteenth century, there was scarcely any important
change in carrying out the world's work. And in the few generations that
have since elapsed, the entire aspect of the mechanical world has been
changed, the working efficiency of the individual has been largely
increased; mechanical tasks have become easy which hitherto were scarcely
within the range of human capacity.
Before we go on to the detailed study of the machine which has produced
these remarkable results, it is desirable to make inquiry as to the historical
development of so important an invention.

The practical steam engine in its modern form dates, as just mentioned,
from the latter part of the eighteenth century, and was perfected by James
Watt, who is commonly thought of as being its inventor. In point of fact,
however, the history of most inventions is duplicated here, as on
examination it appears that various forerunners of Watt had been on the
track of the steam engine, and some of them, indeed, had produced a
workable machine of no small degree of efficiency.
The very earliest experiments were made away back in the Alexandrian
days in the second century before the Christian era, the experimenter being
the famous Hero, whose work in an allied field was referred to in the
preceding chapter. Hero produced—or at least described and so is credited
with producing, though the actual inventor may have been Ctesibius—a
little toy mechanism, in which a hollow ball was made to revolve on an axis
through the agency of steam, which escaped from two bent tubes placed on
opposite sides of the ball, their orifices pointing in opposite directions. The
apparatus had no practical utility, but it sufficed to establish the principle
that heat, acting through the agency of steam, could be made to do
mechanical work. Had not the age of Hero been a time of mental stasis, it is
highly probable that the principle he had thus demonstrated would have
been applied to some more practical mechanism in succeeding generations.
As it was, however, nothing practical came of his experiment, and the steam
turbine engine was remembered only as a scientific toy.
No other worker continued the experiments, so far as is known, until the
time of the great Italian, Leonardo da Vinci, who, late in the fifteenth
century, gave a new impulse to mechanical invention. Leonardo
experimented with steam, and succeeded in producing what was virtually an
explosion engine, by the agency of which a ball was propelled along the
earth. But this experiment also failed to have practical result.

BEGINNINGS OF MODERN DISCOVERY

Such sporadic experiments as these have no sequential connection with
the story of the evolution of the steam engine. The experiments which led
directly on to practical achievements were not begun until the seventeenth
century. In the very first year of that century, an Italian named Giovanni
Battista della Porta published a treatise on pneumatics, in which the idea of
utilizing steam for the practical purpose of raising water was expressly

stated. The idea of this inventor was put into effect in 1624 by a French
engineer and mathematician, Solomon de Caus. He invented two different
machines, the first of which required a spherical boiler having an internal
tube reaching nearly to the bottom; a fire beneath the boiler produced steam
which would force the water in the boiler to a height proportional to the
pressure obtained. In the other machine, steam is led from the boiler into the
upper part of a closed cistern containing water to be elevated. To the lower
portion of the cistern a delivery pipe was attached so that water was
discharged under a considerable pressure. This arrangement was precisely
similar to the apparatus employed by Hero of Alexandria in various of his
fountains, as regards the principle of expanding gas to propel water. An
important difference, however, consists in the fact that the scheme of della
Porta and of de Caus embodied the idea of generating pressure with the aid
of steam, whereas Hero had depended merely on the expansive property of
air compressed by the water itself.
While these mechanisms contained the germ of an idea of vast
importance, the mechanisms themselves were of trivial utility. It is not even
clear whether their projectors had an idea of the properties of the
condensation of vapor, upon which the working of the practical steam
engine so largely depends. This idea, however, was probably grasped about
half a century later by an Englishman, Edward Somerset, the celebrated
Marquis of Worcester, who in 1663 described in his Century of Inventions
an apparatus for raising water by the expansive force of steam. His own
account of his invention is as follows:
"An admirable and most forcible way to drive up water by fire; not by
drawing or sucking it upwards, for that must be as the philosopher calleth it,
intra sphæram activitatis, which is but at such a distance. But this way hath
no bounder, if the vessel be strong enough: for I have taken a piece of
whole cannon, whereof the end was burst, and filled it three-quarters full of
water, stopping and screwing up the broken end, as also the touch-hole; and
making a constant fire under it, within twenty-four hours it burst and made
a great crack; so that having a way to make my vessels so that they are
strengthened by the force within them, and the one to fill after the other, I
have seen the water run like a constant stream, forty feet high: one vessel of
water, rarefied by fire, driveth up forty of cold water; and the man that tends
the work is but to turn two cocks, that one vessel of water being consumed,

another begins to force and refill with cold water, and so successively; the
fire being tended and kept constant, which the self-same person may
likewise abundantly perform in the interim, between the necessity of
turning the said cocks."
It is unfortunate that the Marquis did not give a more elaborate
description of this remarkable contrivance. The fact that he treats it so
casually is sufficient evidence that he had no conception of the possibilities
of the mechanism; but, on the other hand, his description suffices to prove
that he had gained a clear notion of, and had experimentally demonstrated,
the tremendous power of expansion that resides in steam. No example of his
steam pump has been preserved, and historians of the subject have been left
in doubt as to some details of its construction, and in particular as to
whether it utilized the principle of a vacuum created through condensation
of the steam.

THOMAS SAVERY'S STEAM PUMP

This principle was clearly grasped, however, by another Englishman,
Thomas Savery, a Cornish mine captain, who in 1698 secured a patent for a
steam engine to be applied to the raising of water, etc. A working model of
this machine was produced before the Royal Society in 1699. The
transactions of the Society contain the following: "June 14th, 1699, Mr.
Savery entertained the Royal Society with showing a small model of his
engine for raising water by help of fire, which he set to work before them:
the experiment succeeded according to expectation, and to their
satisfaction."
The following very clear description of Savery's engine is given in the
introduction to Beckmann's History of Inventions:
"This engine, which was used for some time to a considerable extent for
raising water from mines, consisted of a strong iron vessel shaped like an
egg, with a tube or pipe at the bottom, which descended to the place from
which the water was to be drawn, and another at the top, which ascended to
the place to which it was to be elevated. This oval vessel was filled with
steam supplied from a boiler, by which the atmospheric air was first blown
out of it. When the air was thus expelled and nothing but pure steam left in
the vessel, the communication with the boiler was cut off, and cold water

poured on the external surface. The steam within was thus condensed and a
vacuum produced, and the water drawn up from below in the usual way by
suction. The oval vessel was thus filled with water; a cock placed at the
bottom of the lower pipe was then closed, and steam was introduced from
the boiler into the oval vessel above the surface of the water. This steam
being of high pressure, forced the water up the ascending tube, from the top
of which it was discharged, and the oval vessel being thus refilled with
steam, the vacuum was again produced by condensation, and the same
process was repeated. By using two oval steam vessels, which would act
alternately—one drawing water from below, while the other was forcing it
upwards, an uninterrupted discharge of water was produced. Owing to the
danger of explosion, from the high pressure of the steam which was used,
and from the enormous waste of heat by unnecessary condensation, these
engines soon fell into disuse."

THOMAS SAVERY'S STEAM ENGINE.
The principle involved is that of the expansion of
steam exerting a propulsive force and its
subsequent condensation to produce a vacuum.
These are the principles employed in the modern
steam engine, but the only use to which they were
put in Savery's engine was the elevation of water
by suction.

This description makes it obvious that Savery had the clearest conception
of the production of a vacuum by the condensation of steam, and of the
utilization of the suction thus established (which suction, as we know, is
really due to the pressure of outside air) to accomplish useful work. Savery
also arranged this apparatus in duplicate, so that one vessel was filling with
water while the other was forcing water to the delivery pipe. This is credited
with being the first useful apparatus for raising water by the combustion of
fuel. There was a great waste of steam, through imparting heat to the water,
but the feasibility of the all-important principle of accomplishing
mechanical labor with the aid of heat was at last demonstrated.
As yet, however, the experimenters were not on the track of the method
by which power could be advantageously transferred to outside machinery.
An effort in quite another direction to accomplish this had been made as
early as 1629 by Giovanni Branca, an Italian mathematician, who had
proposed to obtain rotary motion by allowing a jet of steam to blow against
the vanes of a fan wheel, capable of turning on an axis. In other words, he
endeavored to utilize the principle of the windmill, the steam taking the
place of moving air. The idea is of course perfectly feasible, being indeed
virtually that which is employed in the modern steam turbine; but to put the
idea into practise requires special detailed arrangements of steam jet and
vanes, which it is not strange the early inventor failed to discover. His
experiments appear not to have been followed up by any immediate
successor, and nothing practical came of them, nor was the principle which
he had attempted to utilize made available until long after a form of steam
engine utilizing another principle for the transmission of power had been
perfected.

DENIS PAPIN INVENTS THE PISTON ENGINE

The principle in question was that of causing expanding steam to press
against a piston working tightly in a cylinder, a principle, in short, with
which everyone is familiar nowadays through its utilization in the ordinary
steam engine. The idea of making use of such a piston appears to have
originated with a Frenchman, Denis Papin, a scientific worker, who, being
banished from his own country, was established as professor of
mathematics at the University of Marburg. He conceived the important idea
of transmitting power by means of a piston as early as 1688, and about two

years later added the idea of producing a vacuum in a cylinder, by cooling
the cylinder,—the latter idea being, as we have just seen, the one which
Savery put into effect.

DIAGRAMS OF EARLY ATTEMPTS TO UTILIZE
THE POWER OF STEAM.

Two attempts to give rotation to a mechanical
apparatus through the action of heated air or steam.
Nothing practical came of either effort, but the
mechanisms depicted are of historical interest.
It will be noted that Papin's invention antedated that of Savery; to the
Frenchman, therefore, must be given the credit of hitting upon two
important principles which made feasible the modern steam engine. Papin
constructed a model consisting of a small cylinder in which a solid piston
worked. In the cylinder beneath the piston was placed a small quantity of
water, which, when the cylinder was heated, was turned into steam, the

elastic force of which raised the piston. The cylinder was then cooled by
removing the fire, when the steam condensed, thus creating a vacuum in the
cylinder, into which the piston was forced by the pressure of the
atmosphere.
Such an apparatus seems crude enough, yet it incorporates the essential
principles, and required but the use of ingenuity in elaborating details of the
mechanism, to make a really efficient steam engine. It would appear,
however, that Papin was chiefly interested in the theoretical, rather than in
the really practical side of the question, and there is no evidence of his
having produced a working machine of practical power, until after such
machines worked by steam had been constructed elsewhere.

THOMAS NEWCOMEN'S IMPROVED ENGINE

As has happened so often in other fields, Englishmen were the first to
make practical use of the new ideas. In 1705 Thomas Newcomen, a
blacksmith or ironmonger, and John Cawley, a plumber and glazier,
patented their atmospheric engine, and five years later, in the year 1710,
namely, Newcomen had on the market an engine which is described in the
Report of the Department of Science and Arts of the South Kensington
Museum, as "the first real pumping engine ever made."
The same report describes the engine as "a vertical steam cylinder
provided with a piston connected at one end of the beam, having a pivot or
bearing in the middle of its length, and at the other end of the beam pump
rods for working the pump. The cylinder was surrounded by a second
cylinder or jacket, open at the top, and cold water could be supplied to this
outer cylinder at pleasure. The single or working cylinder could be supplied
with steam when desired from a boiler below it. There was a drain pipe
from the bottom of the working cylinder, and one from the outer cylinder.
For the working of the engine steam was admitted to the working cylinder,
so as to fill it and expel all the air, the piston then being at the top, owing to
the weight of the pump rods being sufficient to lift it; then the steam was
shut off and the drain cocks closed and cold water admitted to the outer
cylinder, so that the steam in the working cylinder condensed, and, leaving
a partial vacuum of pressure of the atmosphere, forced the piston down and
drew up the pump rods, thus making a stroke of the pump. Then the water
was drawn off from the outer cylinder and steam admitted to the working

cylinder before allowing the piston to return to the top of its stroke, ready
for the next down stroke."
It will be observed that this machine adopts the principle, with only a
change of mechanical details, of the Papin engine just described. A later
improvement made by Newcomen did away with the outer cylinder for
condensing the steam, employing instead an injection of cold water into the
working cylinder itself, thus enabling the engine to work more quickly. It is
said that the superiority of the internal condensing arrangement was
accidentally discovered through the improved working of an engine that
chanced to have an exceptionally leaky piston or cylinder. Many engines
were made on this plan and put into practical use.
Another important improvement was made by a connection from the
beam to the cocks or valves, so that the engine worked automatically,
whereas in the first place it had been necessary to have a boy or man
operate the valves,—a most awkward arrangement, in the light of modern
improvements. As the story is told, the duty of opening and closing the
regulating and condensing valves was intrusted to boys called cock boys. It
is said that one of these boys named Humphrey Potter "wishing to join his
comrades at play without exposing himself to the consequences of
suspending the performance of the engine, contrived, by attaching strings of
proper length to the levers which governed the two cocks, to connect them
with the beam, so that it should open and close the cocks as it moved up and
down with the most perfect regularity."
This story has passed current for almost two centuries, and it has been
used to point many a useful moral. It seems almost a pity to disturb so
interesting a tradition, yet it must have occurred to more than one iconoclast
that the tale is almost too good to be true. And somewhat recently it has
been more than hinted that Desaguliers, with whom the story originated,
drew upon his imagination for it. A print is in existence, made so long ago
as 1719, representing an engine erected by Newcomen at Dudley Castle,
Staffordshire, in 1712, in which an automatic valve gear is clearly shown,
proving that the Newcomen engine was worked automatically at this early
period. That the admirable story of the inventive youth, whose wits gave
him leisure for play, may not be altogether discredited, however, it should
be added that unquestionably some of the early engines had a hand-moved
gear, and that at least one such was still working in England after the middle

of the nineteenth century. It seems probable, then, that the very first engines
were without the automatic valve gear, and there is no inherent reason why
a quick-witted youth may not have been the first to discover and remedy the
defect.
According to the Report of the Department of Science and Arts of the
South Kensington Museum: "The adoption of Newcomen's engine was
rapid, for, commencing in 1711 with the engine at Wolverhampton, of
twenty-three inch diameter and six foot stroke, they were in common use in
English collieries in 1725; and Smeaton found in 1767 that, in the
neighborhood of Newcastle alone there were fifty-seven at work, ranging in
size from twenty-eight inch to seventy-five inch cylinder diameter, and
giving collectively about twelve hundred horse-power. As Newcomen
obtained an evaporation of nearly eight pounds of water per pound of coal,
the increase of boiler efficiency since his time has necessarily been but
slight, although in other requisites of the steam generator great
improvements are noticeable."

A MODEL OF THE NEWCOMEN
ENGINE.
This engine has particular interest not only
because it was a practical pumping engine, but
also because it was while repairing an engine
of this type that Watt was led to the
experiments that resulted in his epoch-making
discovery.

THE COMING OF JAMES WATT

The Newcomen engine had low working efficiency as compared with the
modern engine; nevertheless, some of these engines are still used in a few
collieries where waste coal is available, the pressure enabling the steam to
be generated in boilers unsafe for other purposes. The great importance of
the Newcomen engine, however, is historical; for it was while engaged in
repairing a model of one of these engines that James Watt was led to invent
his plan of condensing the steam, not in the working cylinder itself, but in a
separate vessel,—the principle upon which such vast improvements in the
steam engine were to depend.
It is impossible to overestimate the importance of the work which Watt
accomplished in developing the steam engine. Fully to appreciate it, we
must understand that up to this time the steam engine had a very limited
sphere of usefulness. The Newcomen engine represented the most
developed form, as we have seen; and this, like the others that it had so
largely superseded, was employed solely for the pumping of water. In the
main, its use was confined to mines, which were often rendered unworkable
because of flooding. We have already seen that a considerable number of
engines were in use, yet their power in the aggregate added but a trifle to
man's working efficiency, and the work that they did accomplish was done
in a most uneconomical manner. Indeed the amount of fuel required was so
great as to prohibit their use in many mines, which would have been
valuable could a cheaper means have been found of freeing them from
water. Watt's inventions, as we shall see, accomplished this end, as well as
various others that were not anticipated.
It was through consideration of the wasteful manner of action of the
steam engine that Watt was led to give attention to the subject. The great
inventor was a young man at the University of Glasgow. He had previously
served an apprenticeship of one year with a maker of philosophical
instruments in London, but ill health had prevented him from finishing his
apprenticeship, and he had therefore been prohibited from practising his
would-be profession in Glasgow. Finally, however, he had been permitted to
work under the auspices of the University; and in due course, as a part of
his official duties, he was engaged in repairing a model of the Newcomen
engine. This incident is usually mentioned as having determined the line of
Watt's future activity.

It should be recalled, however, that Watt had become a personal friend of
the celebrated Professor Black, the discoverer of latent heat, and the
foremost authority in the world, in this period, on the study of pneumatics.
Just what share Black had in developing Watt's idea, or in directing his
studies toward the expansive properties of steam, it would perhaps be
difficult to say. It is known, however, that the subject was often under
discussion; and the interest evinced in it by Black is shown by the fact that
he subsequently wrote a history of Watt's inventions.
It is never possible, perhaps, for even the inventor himself to re-live the
history of the growth of an idea in his own mind. Much less is it possible
for him to say precisely what share of his progress has been due to chance
suggestions of others. But it is interesting, at least, to recall this association
of Watt with the greatest experimenter of his age in a closely allied field.
Questions of suggestion aside, it illustrates the technical quality of Watt's
mind, making it obvious that he was no mere ingenious mechanic, who
stumbled upon his invention. He was, in point of fact, a carefully trained
scientific experimenter, fully equipped with all the special knowledge of his
time in its application to the particular branch of pneumatics to which he
gave attention.
The first and most obvious defect in the Newcomen engine was, as Watt
discovered, that the alternating cooling and heating of the cylinder resulted
in an unavoidable waste of energy. The apparatus worked, it will be
recalled, by the introduction of steam into a vertical cylinder beneath the
piston, the cylinder being open above the piston to admit the air. The piston
rod connected with a beam suspended in the middle, which operated the
pump, and which was weighted at one end in order to facilitate the raising
of the piston. The steam, introduced under low pressure, scarcely more than
counteracted the pressure of the air, the raising of the piston being largely
accomplished by the weight in question.
Of course the introduction of the steam heated the cylinder. In order to
condense the steam and produce a vacuum, water was injected, the cylinder
being thereby cooled. A vacuum being thus produced beneath the cylinder,
the pressure of the air from above thrust the cylinder down, this being the
actual working agent. It was for this reason that the Newcomen engine was
called, with much propriety, a pneumatic engine. The action of the engine

was very slow, and it was necessary to employ a very large piston in order
to gain a considerable power.
The first idea that occurred to Watt in connection with the probable
improvement of this mechanism did not look to the alteration of any of the
general features of the structure, as regards size or arrangement of cylinder,
piston, or beam, or the essential principle upon which the engine worked.
His entire attention was fixed on the discovery of a method by which the
loss of heat through periodical cooling of the cylinder could be avoided. We
are told that he contemplated the subject long, and experimented much,
before he reached a satisfactory solution. Naturally enough his attention
was first directed toward the cylinder itself. He queried whether the
cylinder might not be made of wood, which, through its poor conduction of
heat, might better equalize the temperature. Experiments in this direction,
however, produced no satisfactory result.

WATT'S EARLIEST TYPE OF PUMPING ENGINE.

The lower figure shows the ruins of Watt's famous engine "Old
Bess." The upper figure shows a reconstructed model of the "Old
Bess" engine. It will be noted that the walking beam is precisely of the
Newcomen type. In fact, the entire engine is obviously only a
modification of the Newcomen engine. It had, however, certain highly
important improvements, as described in the text.
Then at last an inspiration came to him. Why not connect the cylinder
with another receptacle, in which the condensation of the steam could be
effected? The idea was a brilliant one, but neither its originator nor any
other man of the period could possibly have realized its vast and all-
comprehending importance. For in that idea was contained the germ of all
the future of steam as a motive power. Indeed, it scarcely suffices to speak
of it as the germ merely; the thing itself was there, requiring only the
elaboration of details to bring it to perfection.

Watt immediately set to work to put his brilliant conception of the
separate condenser to the test of experiment. He connected the cylinder of a
Newcomen engine with a receptacle into which the steam could be
discharged after doing its work on the piston. The receptacle was kept
constantly cooled by a jet of water, this water and the water of
condensation, together with any air or uncondensed steam that might
remain in the receptacle, being constantly removed with the aid of an air
pump. The apparatus at once demonstrated its practical efficiency,—and the
modern steam engine had come into existence.
It was in the year 1765, when Watt was twenty-nine years old, that he
made his first revolutionary experiment, but his first patents were not taken
out until 1769, by which time his engine had attained a relatively high
degree of perfection. In furthering his idea of keeping the cylinder at an
even temperature, he had provided a covering for it, which might consist of
wood or other poorly conducting material, or a so-called jacket of steam—
that is to say, a portion of steam admitted into the closed chamber
surrounding the cylinder. Moreover, the cylinder had been closed at the top,
and a portion of steam admitted above the piston, to take the place of the
atmosphere in producing the down stroke. This steam above the piston, it
should be explained, did not connect with the condensing receptacle, so the
engine was still single-acting; that is to say it performed work only during
one stroke of the piston. A description of the mechanism at this stage of its
development may best be given in the words of the inventor himself, as
contained in his specifications in the application for patent on his
improvements in 1769.
"My method of lessening the consumption of steam, and consequently
fuel, in fire-engines, consists of the following principles:
"First, That vessel in which the powers of steam are to be employed to
work the engine, which is called the cylinder in common fire-engines, and
which I call the steam vessel, must, during the whole time the engine is at
work, be kept as hot as the steam that enters it; first by enclosing it in a case
of wood, or any other materials that transmit heat slowly; secondly, by
surrounding it with steam or other heated bodies; and, thirdly, by suffering
neither water nor any other substance colder than the steam to enter or
touch it during that time.

"Secondly, In engines that are to be worked wholly or partially by
condensation of steam, the steam is to be condensed in vessels distinct from
the steam vessels or cylinders, although occasionally communicating with
them; these vessels I call condensers; and, whilst the engines are working,
these condensers ought at least to be kept as cold as the air in the
neighborhood of the engines, by application of water or other cold bodies.
"Thirdly, Whatever air or other elastic vapor is not condensed by the cold
of the condenser, and may impede the working of the engine, is to be drawn
out of the steam vessels or condensers by means of pumps, wrought by the
engines themselves, or otherwise.
"Fourthly, I intend in many cases to employ the expansive force of steam
to press on the pistons, or whatever may be used instead of them, in the
same manner in which the pressure of the atmosphere is now employed in
common fire-engines. In cases where cold water can not be had in plenty,
the engines may be wrought by this force of steam only, by discharging the
steam into the air after it has done its office.
"Sixthly, I intend in some cases to apply a degree of cold not capable of
reducing the steam to water, but of contracting it considerably, so that the
engines shall be worked by the alternate expansion and contraction of the
steam.
"Lastly, Instead of using water to render the pistons and other parts of the
engine air-and steam-tight, I employ oils, wax, resinous bodies, fat of
animals, quicksilver and other metals in their fluid state."

ROTARY MOTION

It must be understood that Watt's engine was at first used exclusively as
an apparatus for pumping. For some time there was no practical attempt to
apply the mechanism to any other purpose. That it might be so applied,
however, was soon manifest, in consideration of the relative speed with
which the piston now acted. It was not until 1781, however, that Watt's
second patent was taken out, in which devices are described calculated to
convert the reciprocating motion of the piston into motion of rotation, in
order that the engine might drive ordinary machinery.

It seems to be conceded that Watt was himself the originator of the idea
of making the application through the medium of a crank and fly-wheel
such as are now universally employed. But the year before Watt took out his
second patent, another inventor named James Picard had patented this
device of crank and connecting rod, having, it is alleged, obtained the idea
from a workman in Watt's employ. Whatever be the truth as to this point,
Picard's patent made it necessary for Watt to find some alternative device,
and after experimenting, he hit upon the so-called sun and planet gearing,
and henceforth this was used on his rotary engines until the time for the
expiration of Picard's patent, after which the simpler and more satisfactory
crank and fly-wheel were adopted.
In the meantime, Watt had associated himself with a business partner
named Boulton, under the firm name of Boulton and Watt. In 1776 a special
act of legislation extending the term of Watt's original patent for a period of
twenty-five years had been secured. All infringements were vigorously
prosecuted, and the inventor, it is gratifying to reflect, shared fully in the
monetary proceeds that accrued from his invention.

WATT'S ROTATIVE ENGINE.

The lower figure shows the earliest type of mechanism through
which Watt applied his engine to other uses than that of pumping. The
so-called sun-and-planet gearing, through which rotary motion was
attained, is seen at the lower right-hand corner of the figure. The
upper figure shows a later and much improved type of the Watt
engine, in which the sun-and-planet gearing has been supplanted by a
simple crank.
Notwithstanding the early recognition of the possibility of securing rotary
motion with Watt's perfected Newcomen engine, it was long before the full
possibilities of the application of this principle were realized, even by the
most practical of machinists. Watt himself apparently appreciated the
possibilities no more fully than the others, as the use of his famous engines

"Beelzebub" and "Old Bess" in the establishment of Boulton and Watt
amply testifies. It appears that Boulton had been an extensive manufacturer
of ornamental metal articles. To drive his machinery at Soho he employed
two large water wheels, twenty-four feet in diameter and six feet wide.
These sufficed for his purpose under ordinary conditions, but in dry weather
from six to ten horses were required to aid in driving the machinery. When
Watt's perfected engine was available, however, this was utilized to pump
water from the tail race back to the head race, that it might be used over and
over. "Old Bess" had a cylinder thirty-three inches in diameter with seven-
foot stroke, operating a pump twenty-four inches in diameter; it therefore
had remarkable efficiency as a pumping apparatus. But of course it utilized,
at best, only a portion of the working energy contained in the steam; and the
water wheels in turn could utilize not more than fifty per cent. of the store
of energy which the pump transferred to the water in raising it. Therefore,
such use of the steam engine involved a most wasteful expenditure of
energy.
It was long, however, before the practical machinists could be made to
believe that the securing of direct rotary power from the piston could be
satisfactorily accomplished. It was only after the introduction of higher
speed and heavier fly-wheels, together with improved governors, that the
speed of rotation was so equalized as to meet satisfactorily the requirements
of the practical engineer, and ultimately to displace the wasteful method of
securing rotary motion indirectly through the aid of pump and water wheel.
It may be added, that the centrifugal governor, with which modern engines
are provided to regulate their speed, was the invention of Watt himself.

FINAL IMPROVEMENTS AND MISSED OPPORTUNITIES

In the year 1782 Watt took out patents which contained specifications for
the two additional improvements that constituted his final contribution to
the production of the steam engine. The first of these provided for the
connection of the cylinder chamber on each side of the piston with the
condenser, so that the engine became double acting. The second introduced
the very important principle,—from the standpoint of economy in the use of
steam—of shutting off the supply of steam from the cylinder while the
piston has only partially traversed its thrust, and allowing the remainder of
the thrust to be accomplished through the expansion of the steam. The

application of the first of these principles obviously adds greatly to the
efficiency of the engine, and in practise it was found that the application of
the second principle produces a very great saving in steam, and thus adds
materially to the economical working of the engine.
All of Watt's engines continued to make use of the walking beam
attached to the piston for the transmission of power; and engineers were
very slow indeed to recognize the fact that in many—in fact in most—cases
this contrivance may advantageously be done away with. The recognition of
this fact constitutes one of the three really important advances that have
been made in the steam engine since the time of Watt. The other two
advances consist of the utilization of steam under high pressure, and of the
introduction of the principle of the compound engine.
Neither of these ideas was unknown to Watt, since the utilization of
steam under high pressure was advocated by his contemporary, Trevithick,
while the compound engine was invented by another contemporary named
Hornblower. Perhaps the very fact that these rival inventors put forward the
ideas in question may have influenced Watt to antagonize them; in
particular since his firm came into legal conflict with each of the other
inventors. At any rate, Watt continued to the end of his life to be an ardent
advocate of low pressure for the steam engine, and his firm even attempted
to have laws passed making it illegal—on the ground of danger to human
life—to utilize high-pressure steam, such as employed by Trevithick.
Possibly the conservatism of increasing age may also have had its share
in rendering Watt antagonistic to the new ideas; for he was similarly
antagonistic to the idea of applying steam to the purposes of locomotion.
Trevithick, among others, had, as we shall see in due course, made such
application with astonishing success, producing a steam automobile which
traversed the highway successfully. In his earlier years Watt had conceived
the same idea, and had openly expressed his opinion that the steam engine
might be used for this purpose. But late in life he was so antipathetic to the
idea that he is said to have put a clause in the lease of his house, providing
that no steam carriage should under any pretext be allowed to approach it.
These incidents have importance as showing—as we shall see illustrated
again and again in other fields—the disastrous influence in retarding
progress that may be exercised by even the greatest of scientific

discoverers, when authority well earned in earlier years is exercised in an
unfortunate direction later in life. But such incidents as these are
inconsequential in determining the position among the world's workers of
the man who was almost solely responsible for the transformation of the
steam engine from an expensive and relatively ineffective pumping
apparatus, to the great central power that has ever since moved the major
part of the world's machinery.

THE SUPREME IMPORTANCE OF WATT

It is speaking well within bounds to say that no other invention within
historical times has had so important an influence upon the production of
property—which, as we have seen, is the gauge of the world's work—as
this invention of the steam engine. We have followed the history of that
invention in some detail, because of its supreme importance. To the reader
who was not previously familiar with that history, it may seem surprising
that after a lapse of a little over a century one name and one alone should be
popularly remembered in connection with the invention; whereas in point of
fact various workers had a share in the achievement, and the man whose
name is remembered was among the last to enter the field. We have seen
that the steam engine existed as a practical working machine several
decades before Watt made his first invention; and that what Watt really
accomplished was merely the perfecting of an apparatus which already had
attained a considerable measure of efficiency.
There would seem, then, to be a certain lack of justice in ascribing
supreme importance to Watt in connection with the steam engine. Yet this
measure of injustice we shall find, as we examine the history of various
inventions, to be meted always by posterity in determining the status of the
men whom it is pleased to honor. One practical rule, and one only, has
always determined to whom the chief share of glory shall be ascribed in
connection with any useful invention.
The question is never asked as to who was the originator of the idea, or
who made the first tentative efforts towards its utilization,—or, if asked by
the historical searcher, it is ignored by the generality of mankind.
So far as the public verdict, which in the last resort determines fame, is
concerned, the one question is, Who perfected the apparatus so that it came

to have general practical utility? It may be, and indeed it usually is the case,
that the man who first accomplished the final elaboration of the idea, made
but a comparatively slight advance upon his predecessors; the early workers
produced a machine that was almost a success; only some little flaw
remained in their plans. Then came the perfecter, who hit upon a device that
would correct this last defect,—and at last the mechanism, which hitherto
had been only a curiosity, became a practical working machine.
In the case of the steam engine, it might be said that even a smaller feat
than this remained to be accomplished when Watt came upon the scene;
since the Newcomen engine was actually a practical working apparatus. But
the all-essential thing to remember is that this Newcomen engine was used
for a single purpose. It supplied power for pumping water, and for nothing
else. Neither did it have possibilities much beyond this, until the all-
essential modification was suggested by Watt, of exhausting its steam into
exterior space.
This modification is in one sense a mere detail, yet it illustrates once
more the force of Michelangelo's famous declaration that trifles make
perfect; for when once it was tested, the whole practical character of the
steam engine was changed. From a wasteful consumer of fuel, capable of
running a pump at great expense, it became at once a relatively economical
user of energy, capable of performing almost any manner of work.
Needless to say, its possibilities in this direction were not immediately
realized, in theory or in practise; yet the conquest that it made of almost the
entire field of labor resulted in the most rapid transformation of industrial
conditions that the world has ever experienced. After all, then, there is but
little injustice in that public verdict which remembers James Watt as the
inventor, rather than as the mere perfecter, of the steam engine.

THE PERSONALITY OF JAMES WATT

The man who occupies this all-important position in the industrial world
demands a few more words as to his personality. His work we have
sufficiently considered, but before we pass on to the work of his successors,
it will be worth our while to learn something more of the estimate placed
upon the man himself. Let us quote, then, from some records written by
men who were of the same generation.

"Independently of his great attainments in mechanics, Mr. Watt was an
extraordinary and in many respects a wonderful man. Perhaps no individual
in his age possessed so much, or remembered what he had read so
accurately and well. He had infinite quickness of apprehension, a
prodigious memory, and a certain rectifying and methodizing power of
understanding which extracted something precious out of all that was
presented to it. His stores of miscellaneous knowledge were immense, and
yet less astonishing than the command he had at all times over them. It
seemed as if every subject that was casually started in conversation had
been that which he had been last occupied in studying and exhausting; such
was the copiousness, the precision, and the admirable clearness of the
information which he poured out upon it without effort or hesitation. Nor
was this promptitude and compass of knowledge confined, in any degree, to
the studies connected with his ordinary pursuits.
"That he should have been minutely and extensively skilled in chemistry,
and the arts, and in most of the branches of physical science, might,
perhaps, have been conjectured; but it could not have been inferred from his
usual occupations, and probably is not generally known, that he was
curiously learned in many branches of antiquity, metaphysics, medicine,
and etymology, and perfectly at home in all the details of architecture,
music, and law. He was well acquainted, too, with most of the modern
languages, and familiar with their most recent literature. Nor was it at all
extraordinary to hear the great mechanician and engineer detailing and
expounding, for hours together, the metaphysical theories of the German
logicians, or criticizing the measures or the matter of the German poetry.
"It is needless to say, that with those vast resources, his conversation was
at all times rich and instructive in no ordinary degree. But it was, if
possible, still more pleasing than wise, and had all the charms of familiarity,
with all the substantial treasures of knowledge. No man could be more
social in his spirit, less assuming or fastidious in his manners, or more kind
and indulgent towards all who approached him. His talk, too, though
overflowing with information, had no resemblance to lecturing, or solemn
discoursing; but, on the contrary, was full of colloquial spirit and pleasantry.
He had a certain quiet and grave humor, which ran through most of his
conversation, and a vein of temperate jocularity, which gave infinite zest
and effect to the condensed and inexhaustible information which formed its

main staple and characteristic. There was a little air of affected testiness,
and a tone of pretended rebuke and contradiction, which he used towards
his younger friends, that was always felt by them as an endearing mark of
his kindness and familiarity, and prized accordingly, far beyond all the
solemn compliments that proceeded from the lips of authority. His voice
was deep and powerful; though he commonly spoke in a low and somewhat
monotonous tone, which harmonized admirably with the weight and brevity
of his observations, and set off to the greatest advantage the pleasant
anecdotes which he delivered with the same grave tone, and the same calm
smile playing soberly on his lips.

JAMES WATT.
"There was nothing of effort, indeed, or of impatience, any more than of
pride or levity, in his demeanor; and there was a finer expression of
reposing strength, and mild self-possession in his manner, than we ever
recollect to have met with in any other person. He had in his character the
utmost abhorrence for all sorts of forwardness, parade, and pretension; and
indeed never failed to put all such impostors out of countenance, by the
manly plainness and honest intrepidity of his language and deportment.
"He was twice married, but has left no issue but one son, associated with
him in his business and studies, and two grandchildren by a daughter who
predeceased him. He was fellow of the Royal Societies both of London and
Edinburgh, and one of the few Englishmen who were elected members of
the National Institute of France. All men of learning and of science were his
cordial friends; and such was the influence of his mild character, and perfect
fairness and liberality, even upon the pretender to these accomplishments,
that he lived to disarm even envy itself, and died, we verily believe, without
a single enemy."

VI
THE MASTER WORKER

W
e have already pointed out at some length that, in the hands of
Watt, the steam engine came at once to be a relatively perfect
apparatus, and that only three really important modifications have
been applied to it since the day of its great perfecter. These
modifications, as already named, are the doing away with the walking
beam, the utilization of high pressure steam, and the development of the
compound engine. Each of these developments requires a few words of
explanation.
The retention of the heavy walking beam for so long a time after the
steam engine of Watt had been applied to the various purposes of
machinery, illustrates the power of a pre-conceived idea. With the
Newcomen engine this beam was an essential, since it was necessary to
have a weight to assist in raising the piston. But with the introduction of
steam rather than air as the actual power to push the piston, and in particular
with the elaboration of the double-chamber cylinder, with steam acting
equally on either side of the piston, the necessity for retaining this
cumbersome contrivance no longer existed. Yet we find all the engines
made by Watt himself, and nearly all those of his contemporaries,
continuing to utilize this means of transmitting the power of the piston.
Even the road locomotive, as illustrated by that first wonderful one of
Trevithick's and such colliery locomotives as "Puffing Billy" and
"Locomotion," utilized the same plan. It was not until almost a generation
later that it became clear to the mechanics that in many cases, indeed in
most cases, this awkward means of transmitting power was really a
needlessly wasteful one, and that with the aid of fly-wheel and crank-shaft
the thrust of the piston might be directly applied to the wheel it was
destined to turn, quite as well as through the intermediary channel of the
additional lever.
The utility of the beam has, indeed, still commended it for certain
purposes, notably for the propulsion of side-wheel steamers, such as the

familiar American ferryboat. But aside from such exceptional uses, the
beam has practically passed out of existence.
There was no new principle involved in effecting this change. It was
merely another illustration of the familiar fact that it is difficult to do things
simply. As a rule, inventors fumble for a long time with roundabout and
complex ways of doing things, before a direct and simple method occurs to
them. In other words, the highest development often passes from the
complex to the simple, illustrating, as it were, an oscillation in the great law
of evolution. So in this case, even so great an inventor as Watt failed to see
the utility of doing away with the cumbersome structure which his own
invention had made no longer a necessity, but rather a hindrance to the
application of the steam engine. However, a new generation, no longer
under the thraldom of the ideas of the great inventor, was enabled to make
the change, gradually, but in the end effectively.

HIGH-PRESSURE STEAM

As regards the use of steam under high pressure, somewhat the same
remarks apply, so far as concerns the conservatism of mankind, and the
influence which a great mind exerts upon its generation. Just why Watt
should have conceived an antagonism to the idea of high-pressure steam is
not altogether clear. It has been suggested, indeed, that this might have been
due to the fact that a predecessor of Watt had invented a high-pressure
engine which did not use the principle of condensation, but exhausted the
steam into open space. As early as 1725, indeed, Leupold in his Theatrum
Machinarum, had described such a non-condensing engine, which, had it
been made practically useful, would have required a high pressure of steam.
Partly through the influence of this work, perhaps, there came to be an
association between the words high pressure and non-condensing, so that
these terms are considered to be virtually synonymous; and since Watt's
great contribution consisted of an application of the idea of condensation,
he was perhaps rendered antagonistic to the idea of high pressure, through
this psychological suggestion. In any event, the antagonism unquestionably
existed in his mind; though it has often enough been pointed out that this
seems the more curious since high-pressure steam would so much better
have facilitated the application of that other famous idea of Watt, the use of
the expansive property of steam.

Curiously enough, however, the influence of Watt led to experiments in
high-pressure steam through an indirect channel. The contemporary
inventor, Trevithick, in connection with his partner, Bull, had made direct-
acting pumping engines with an inverted cylinder, fixed in line with the
pump rod, and actually dispensing with the beam. But as these engines used
a jet of cold water in the exhaust pipe to condense the steam, Boulton and
Watt brought suit successfully for infringement of their patent, and thus
prevented Trevithick from experimenting further in that direction. He was
obliged, therefore, to turn his attention to a different method, and probably,
in part at least, in this way was led to introduce the non-condensing,
relatively high-pressure engine. This was used about the year 1800. At the
same time somewhat similar experiments were made by Oliver Evans in
America.
Both Trevithick and Evans applied their engines to the propulsion of road
vehicles; and Trevithick is credited with being the first man who ran a
steam locomotive on a track,—a feat which he accomplished as early as the
year 1804. We are not here concerned with the details of this
accomplishment, which will demand our attention in a later chapter, when
we come to discuss the entire subject of locomotive transportation. But it is
interesting to recall that the possibilities of the steam engine were thus early
realized, even though another generation elapsed before they were finally
demonstrated to the satisfaction of the public. It is particularly interesting to
note that in his first locomotive engine, Trevithick allowed the steam
exhaust to escape into the funnel of the engine to increase the draught,—an
expedient which was so largely responsible for Stephenson's success with
his locomotive twenty years later, and which retains its utility in the case of
the most highly developed modern locomotive.
Trevithick was, however, entirely subordinated by the great influence of
Watt, and the use of high pressure was in consequence discountenanced by
the leading mechanical engineers of England for some decades. Meantime,
in America, the initiative of Evans led to a much earlier general use of high-
pressure steam. In due course, however, the advantages of steam under high
pressure became evident to engineers everywhere, and its conquest was
finally complete.
The essential feature of super-heated steam is that it contains, as the
name implies, an excess of heat beyond the quantity necessary to produce

mere vaporization, and that the amount of water represented in this vapor is
not the maximum possible under given conditions. In other words, the
vapor is not saturated. It has been already explained that the amount of
vapor that can be taken up in a given space under a given pressure varies
with the temperature of the space. Under normal conditions, when a closed
space exists above a liquid, evaporation occurs from the surface of the
liquid until the space is saturated, and no further evaporation can occur so
long as the temperature and pressure are unchanged. If now the same space
is heated to a higher degree, more vapor will be taken up until again the
point of saturation is attained. But, obviously, if the space were
disconnected with the liquid, and then heated, it would acquire a capacity to
take up more vapor, and so long as this capacity was latent, the vapor
present would exist in a super-heated condition.

OLD IDEAS AND NEW APPLIED TO BOILER
CONSTRUCTION.

The lower figure shows Robert Trevithick's famous boiler, used in
operating his locomotive about the year 1804. The original is
preserved in the South Kensington Museum, London. The upper
figure shows a modern tubular boiler, by way of contrast.
It will be understood from what has been said before, that with all
accessions of heat, the expansive power of the vapor is increased,—its
molecules becoming increasingly active; hence one of the very obvious
advantages of super-heated steam for the purpose of pushing a piston. There
are other advantages, however, which are not at first sight so apparent,
having to do with the properties of condensation. To understand these, we
must pay heed for a few moments to the changes that take place in steam

itself in the course of its passage through the cylinder, where it performs its
work upon the piston.
Many of these changes were not fully understood by the earlier
experimenters, including Watt. Indeed the theory of the steam engine, or
rather the general theory of the heat engine, was not worked out until the
year 1824, when the Frenchman Carnot took the subject in hand, and
performed a series of classical experiments, which led to a nearly complete
theoretical exposition of the subject. It remained, however, for the students
of thermo-dynamics, about the middle of the nineteenth century, with
Clausius and Rankine at their head, to perfect the theory of the steam
engine, and the general subject of the mutual relations of heat and
mechanical work.
We are not here concerned with any elaboration of details, but merely
with a few of the essential principles which enter practically into the
operation of the steam engine. It appears, then, that when steam enters the
cylinder and begins to thrust back the piston of the steam engine, a portion
of the steam is immediately condensed on the walls of the cylinder, owing
to the fact that previous condensation of steam has cooled these walls to a
certain extent. We have already pointed out that Watt endeavored in his
earlier experiments to overcome this difficulty, by equalizing the
temperature of the cylinder walls to the greatest practicable extent.
Notwithstanding his efforts, however, and those of numberless later
experimenters, it still remains true that under ordinary conditions,
particularly if steam enters the cylinder at the saturation point, a very
considerable condensation occurs. Indeed this may amount to from thirty to
fifty per cent. of the entire bulk of water contained in the quantity of steam
that enters the cylinder. This condensation obviously militates against the
expansive or working power of the steam. But now as the steam expands,
pushing forward the cylinder, it becomes correspondingly rarefied, and
immediately a portion of the condensed steam becomes again vaporized,
and in so doing it takes up a certain amount of heat and renders it latent.
This disadvantageous cycle of molecular transformations is very much
modified in the case of super-heated steam, for the obvious reason that such
steam may be very much below the saturation point, and hence requires a
very much greater lowering of temperature in order to produce
condensation of any portion of its mass. Without elaborating details, it

suffices to note that in all highly efficient modern engines, steam is
employed at a relatively high pressure, and that sometimes this pressure
becomes enormous.

COMPOUND ENGINES

As to the compound engine, that also, as has been pointed out, was
invented by a contemporary of Watt, Jonathan Hornblower by name, whose
patent bears date of 1781. In Hornblower's engine, steam was first admitted
to a small cylinder, and then, after performing its work on the piston, was
allowed to escape, not into a condensing receptacle, but into a larger
cylinder where it performed further work upon another piston. This was
obviously an instance of the use of steam expansively, and it has been
pointed out that, in consequence, Hornblower was the first to make use of
this idea in practise, although it is said that Watt's experiments had even at
that time covered this field. The application of the idea to the movement of
the second cylinder, however, appears to have been original with
Hornblower. Certainly it owed nothing to Watt, who refused to accept the
idea, and continued throughout his life to frown upon the compound engine.
Nevertheless, the device had great utility, as subsequent experiments
were very fully to demonstrate. The compound engine was revived by
Woolf in 1804, and his name rather than Hornblower's is commonly
associated with it. The latter experimenter demonstrated that the compound
engine has two important merits as against the simple engine. One of these
is that the sum of the two forces exerted by the joint action results in a more
even and continuous pressure throughout the cycle than could be
accomplished by the action of a single cylinder.
To understand this it must be recalled that when using the expansive
property of steam, the piston thrust could not possibly be uniform, since the
greatest pressure exerted by the steam would be exerted at the moment
before it was shut off from the boiler, and its pressure must then decrease
progressively, as it exerts more and more work upon the piston and
becomes more expanded, thus obviously retaining less elastic energy. The
operation of the fly-wheel largely compensates this difference of pressure in
practise, but it would be obviously advantageous could the pressure be
equalized; and, as just stated, the compound engine tends to produce this
result.

The second, and perhaps the more important merit of the compound
engine is, that it is found in practise to keep the cylinders at a more uniform
temperature. A moment's reflection makes it clear why this should be the
case, since in a single-cylinder engine the exhaust connects with the cool
condenser, whereas in the compound engine the exhaust from the first
cylinder connects with the second cylinder at only slightly lower
temperature.
In many modern engines a third cylinder and sometimes even a fourth is
added, constituting what are called respectively triple-expansion and
quadruple-expansion engines. The triple-expansion system is very generally
employed, especially where it is peculiarly desirable to economize fuel, as,
for example, in the case of ships.

COMPOUND ENGINES.

The lower figure illustrates the use of a modern compound engine,
directly operating the propeller shaft of a steamship. The middle
figure shows a similarly direct application of power to the axes of
paddle wheels. The upper figure shows the application of power
through a walking beam similar in principle to that of the original
Newcomen and Watt engines.

ROTARY ENGINES

All these improvements, it will be observed, have to do with details that
do not greatly modify the steam engine from the original type. The cylinder
with its closely fitting piston, as introduced in the Newcomen engine, is
retained and constitutes the essential mechanism through which the energy
of steam is transferred into mechanical energy. But from a comparatively
remote period the idea has prevailed that it might be possible to utilize a
different principle; that, in short, if the steam instead of being made to press
against a piston were allowed to rush against fan-like blades, adjusted to an
axle, it might cause blades and axle to revolve, precisely as a windmill is
made to revolve by the pressure of the wind, or the turbine wheel by the
pressure of water.
In a word, it has been believed that a turbine engine might be
constructed, which would utilize the energy of the steam as advantageously
as it is utilized in the piston engine, and at the same time would
communicate its power as a direct rotation, instead of as a straight thrust
that must be translated into a rotary motion by means of a crank or other
mechanism.
In point of fact, James Watt himself invented such an engine, and
patented it in 1782, though there is no evidence that he ever constructed
even a working model. His patent specifications show "a piston in the form
of a closely-fitting radial arm, projecting from an axial shaft in a cylinder.
An abutment, arranged as a flap is hinged near a recess in the side of the
cylinder, and swings while remaining in contact with the piston. Steam is
admitted to the chamber on one side of the flap, and so causes an
unbalanced pressure upon the radial arm."
This arrangement has been re-invented several times. Essentially the
same principle is utilized by Joshua Routledge, whose name is well known
in connection with the engineer's slide-rule. A model of this engine is
preserved in the South Kensington Museum, and the apparatus is described
in the catalogue of the Museum as follows:
"The piston revolves on a shaft passing through the centre of the cylinder
casing. The flap or valve hinged to the casing, with its free end resting upon
the piston, acts like the bottom of an ordinary engine cylinder. The steam
inlet port is on one side of the hinge, and the exhaust port on the other. The

admission of steam is controlled by a side valve, actuated by an eccentric
on the fly-wheel shaft, so that the engine could work expansively, and the
steam pressure resisting the lifting of the flap would also be greatly
reduced, so diminishing the knock at this point, which, however, would
always be a serious cause of trouble. The exhaust steam passes down to a
jet condenser, provided with a supply of water from a containing tank, from
which the injection is admitted through a regulating valve. The air pump,
which draws the air and water from the condenser and discharges them
through a pipe passing out at the end of the tank, is a rotary machine
constructed like the engine and driven by spur gearing from the fly-wheel
shaft. Some efforts have been made to prevent leakage by forming grooves
in the sides of the revolving piston and filling them with soft packing."
Sundry other rotary engines, some of them actual working models, are to
be seen at the South Kensington Museum. There is, for example, one
invented by the Rev. Patrick Bell, a gentleman otherwise known to fame as
one of the earliest inventors of a practical reaping machine. In this
apparatus, "A metal disc is secured to a horizontal axis carried in bearings,
and the lower half of the disc is enclosed by a chamber of circular section
having its axis a semi-circle. One end of this chamber is closed and
provided with a pipe through which steam enters, the exhaust taking place
through the open end. The disc is provided with three holes, each fitted with
a circular plate turning on an axis radial to the disc, and these plates when
set at right angles to the disc become pistons in the lower enclosing
chamber. Toothed gearing is arranged to rotate these pistons into the plane
of the disc on leaving the cylinder and back again immediately after
entering, locking levers retaining them in position during the intervals. The
steam pressure upon these pistons forces the disc round, but the engine is
non-expansive, and although some provision for packing has been made,
the leakage must have been considerable and the wear and tear excessive."
It is stated that almost the same arrangement was proposed by Lord
Armstrong in 1838 as a water motor, and that a model subsequently
constructed gave over five horse-power at thirty revolutions per minute,
with an efficiency of ninety-five per cent.
Another working model of a rotary engine shown at the Museum is one
loaned by Messrs. Fielding and Platt in 1888. "The action of this engine

depends upon the oscillating motion which the cross of a universal joint has
relative to the containing jaws when the system is rotated.
"Two shafts are set at an angle of 165 deg. to each other and connected
by a Hooke's joint; one serves as a pivot, the power being taken from the
other. Four curved pistons are arranged on the cross-piece, two pointing
towards one shaft and two towards the other, and on each shaft or jaw are
formed two curved steam cylinders in which the curved pistons work. The
steam enters and leaves the base of each cylinder through ports in the shaft,
which forms a cylindrical valve working in the bearing as a seating.
"On the revolution of the shafts the pistons reciprocate in their cylinders
in much the same way as in an ordinary engine, and the valve arrangement
is such that while each piston is receding from its cylinder the steam
pressure is driving it, and during the in-stroke of each, its cylinder is in
communication with the exhaust. There are thus four single-acting cylinders
making each a double stroke for one revolution of the driving-shaft. The
engine has no dead centres, and has been at 1,000 revolutions per minute."

ROTARY ENGINES.
The three types of rotary engines here shown
are similar in principle, and none of them is of
great practical value, though the upper figure
shows an engine that has met with a certain
measure of commercial success.
It is not necessary to describe other of the rotary engines that have been
made along more or less similar lines by numerous inventors, models of
which are for the most part, as in the case of those just described, to be seen

more commonly in museums than in practical workshops. Reference may
be made, however, to a rotary engine which was invented by a Mr.
Hoffman, of Buffalo, New York, about the beginning of the twentieth
century, an example of which was put into actual operation in running the
machinery of a shop in Buffalo, in 1905.
This engine consists of a solid elliptical shaft of steel, fastened to an axle
at one side of its centre, which axis is also the shaft of the cylinder, which
revolves about the central ellipse in such a way that at one part of the
revolution the cylinder surface fits tightly against the ellipse, while the
opposite side of the cylinder supplies a free chamber between the ellipse
and the cylinder walls. Running the length of the cylinder are two curved
pieces of steel, like longitudinal sections of a tube. These flanges are
adjusted at opposite sides of the cylinder and so arranged that their sides at
all times press against the ellipse, alternately retreating into the substance of
the cylinder, and coming out into the free chamber. Steam is admitted to the
free chamber through one end of the shaft of ellipse and cylinder and
exhausted through the other end. The pressure of the steam against first one
end and then the other of the flanges supplies the motive power. This
pressure acts always in one direction, and the entire apparatus revolves, the
cylinder, however, revolving more rapidly than the central ellipse.
For this engine the extravagant claim is made that there is no limit to its
speed of revolution, within the limit of resistance of steel to centrifugal
force. It has been estimated that a locomotive might be made to run two
hundred or three hundred miles an hour without difficulty, with the
Hoffman engine. Such estimates, however, are theoretical, and it remains to
be seen what the engine can do in practise when applied to a variety of
tasks, and what are its limitations. Certainly the apparatus is at once
ingenious and simple in principle, and there is no obvious theoretical reason
why it should not have an important future.

TURBINE ENGINES

Whatever the future may hold, however, it remains true that the first
practical solution of the problem of securing direct rotary motion from the
action of steam, on a really commercial scale, was solved with an apparatus
very different from any of those just described, the inventor being an
Englishman, Mr. C. A. Parsons, and the apparatus the steam turbine, the

first model of which he constructed in 1884, and which began to attract
general attention in the course of the ensuing decade. Public interest was
fully aroused in 1897, when Mr. Parson's boat, the Turbinia, equipped with
engines of this type, showed a trial speed of 32-3/4 knots per hour, a speed
never hitherto attained by any other species of water craft. More recently, a
torpedo boat, the Viper, equipped with engines developing about ten
thousand horse-power, attained a speed of 35-1/2 knots. The success of
these small boats led to the equipment of large vessels with the turbine, and
on April first, 1905, the first transatlantic liner propelled by this form of
engine steamed into the harbor of Halifax, Nova Scotia.
This first ocean liner equipped with the turbine engine is called the
Victorian. She is a ship five hundred and forty feet long and sixty feet wide,
carrying fifteen hundred passengers. The Victorian had shown a speed of
19-1/2 knots an hour on her trial trip, and it had been hoped that she would
break the transatlantic record. On her first trip, however, she encountered
adverse winds and seas, and did not attain great speed. Her performance
was, however, considered entirely satisfactory and creditable.
In the ensuing half-decade several large ships were equipped with
engines of the same type, the most famous of these being the Cunard liners,
Carmania, Lusitania, and Mauretania. The two last-named ships are sister
craft, and they are the largest boats of any kind hitherto constructed. The
Lusitania was first launched and she entered immediately upon a record-
breaking career, only to be surpassed within a few months by the
Mauretania, which soon acquired all records for speed and endurance.
Fuller details as to the performance of these vessels will be found in
another place. Here we are of course concerned with the Parsons turbine
engine itself rather than with its applications.
This turbine engine constitutes the first really important departure from
the old-type steam engine, thus realizing the dream of the seventeenth-
century Italian, Branca, to which reference was made above. Mr. Parsons'
elaboration of the idea developed a good deal of complexity as regards the
number of parts involved, yet his engine is of the utmost simplicity in
principle. It consists of a large number of series of small blades, each series
arranged about a drum which revolves. Between the rings of revolving
blades are adjusted corresponding rings of fixed blades, which project from

the casing to the cylinder, and by means of which the steam is regulated in
direction, so that it strikes at the proper angle against the revolving blades
of the turbine.
In practise, three series of cylindrical drums are used, each containing a
large number of rings of blades of uniform size; but each successive drum
having longer blades, to accommodate the greater volume of the expanding
steam. The steam is fed against the first series of blades in gusts, which may
be varied in frequency and length to meet the requirements of speed. After
impinging on the first circle of blades, the steam passes to the next under
slightly reduced pressure, and the pressure is thus successively stepped
down from one set of blades to another until it is ultimately reduced from
say two hundred pounds to the square inch, to one pound to the square inch
before it passes to the condenser and ceases to act.
There is thus a fuller utilization of the kinetic energy of the gas, through
carrying it from high to low pressure, than is possible with the old type of
cylinder-and-piston engine. On the other hand, there is a constant loss due
to the fact that the blades of the turbine can not fit with absolute tightness
against the cylinder walls. The net result is that the compound turbine, as at
present developed, appears to have about the same efficiency as the best
engine of the old type.
One capital advantage of the turbine is that it keeps the cylinder walls at
a more uniform temperature than is possible even with a compound engine
of the old type. Another advantage is that the power of the turbine is applied
directly to cause rotation of the shaft, whereas no satisfactory means has
ever been discovered hitherto of making the action of the steam engine
rotary, except with the somewhat disadvantageous crank-shaft. This fact of
adjustment of the turbine blades to the revolving shaft seems to make this
form of engine particularly adapted to use in steamships. It is also highly
adapted to revolving the shaft of a dynamo, and has been largely applied to
this use. Needless to say, however, it may be applied to any other form of
machinery. It would be difficult at the present stage of its development to
predict the extent to which the turbine will ultimately supersede the old type
of engine. Its progress has already been extraordinary, however, as an
engineer pointed out in the London Times of August 14, 1907, in the
following words:

"When the steam turbine was introduced by Mr. Parsons some 25 years
ago, in the form of a little model, which is now in the South Kensington
Museum, and the rotor of which may easily be held stationary by the hand
against the full blast of the steam, who would have been rash enough to
predict, except perhaps the far-seeing inventor himself, that a vessel 760
feet long, loaded to 37,000 tons displacement, drawing 32 ft. 9 in. of water,
and providing accommodation for 2,500 people, could be propelled at a
speed of 24.5 knots per hour, which it is hoped she may maintain over the
3,000 miles of the Atlantic voyage?
"From this small model, which will in time become as historic as the
Rocket of Stephenson, and which is only some few inches in diameter, the
turbine has been developed gradually in size. The cylindrical casings which
take the place of the complicated machinery of the piston engine in the
engine room of the Lusitania contain drums, which in the high-pressure
turbines are 8 feet in diameter and in the low-pressure 11 ft. 8 in., and from
which thousands of curved blades project, the longest of which are 22
inches, and against which the steam impinges in its course from the boiler
to the condenser.
"Not only has the steam turbine justified the confidence of those who
have labored so successfully in its development, but no other great
invention has proceeded from the laboratory stage to such an important
position in the engineering world in such a short space of time. This would
not have happened if some inherent drawback, such as lack of economy in
steam consumption, existed, and as the turbine has been proved to be, for
land purposes, very economical, there seems to be no reason to doubt that
marine turbines, working as they do at full load almost continually, will
show likewise that the coal bill is not increased, but perhaps diminished by
their use.
"The records of the vibrations of the hull which were taken during the
trials by Schlick's instruments showed that the vertical vibration was 60 per
minute on the run, which was due to the propellers, and which may be
further modified. The horizontal vibration was almost unnoticeable, while
the behavior of the ship in the heavy seas she encountered in her long-
distance runs was good, the roll from side to side having a period of 18
seconds. The great length of this ship and the gyrostatic action of the heavy

rotating masses of the machinery ought to render her almost insensible to
the heaviest Atlantic rollers; certainly as far as pitching is concerned."

THE ORIGINAL PARSON'S TURBINE ENGINE AND THE
RECORD-BREAKING SHIP FOR WHICH IT IS RESPONSIBLE.
This small turbine engine, with which Mr. Parson's early
experiments were made in 1884, is preserved in the South Kensington
Museum, London. At the time when it was made it seemed scarcely
more than a toy, and engineers in general doubted that the principle it
employed could ever be made commercially available. Yet within the
lifetime of its inventor engines built on this model have come to be the
most powerful of force transmuters. The "Mauretania," the largest,
and thanks to her turbine engines the speediest, of ships, is here
presented on the same page with the little original turbine model, as
illustrating vividly the practical development of a seemingly visionary
idea.
A more general comment upon the turbine engine, with particular
reference to its use in America, is made by Mr. Edward H. Sanborn in an

article on Motive Power Appliances, in the Twelfth Census Report of the
United States, Vol. X. part IV.
"Apart from its demonstrated economy," says Mr. Sanborn, "other
important advantages are claimed for the steam turbine, some of which are
worthy of brief mention.
"There is an obvious advantage in economy of space as compared with
the reciprocating engine. The largest steam turbine constructed in the
United States is one of 3,000 horse-power, which is installed in the power
house of the Hartford Electric Light Company, Hartford, Conn. The total
weight of this motor is 28,000 pounds, its length over all is 19 feet 8 inches,
and its greatest diameter six feet. With the generator to which it is directly
connected, it occupies a floor space of 33 feet 3 inches long by 8 feet 9
inches wide.
"Friction is reduced to a minimum in the steam turbine, owing to the
absence of sliding parts and the small number of bearings. The absence of
internal lubrication is also an important consideration, especially when it is
desired to use condensers.
"As there are no reciprocating parts in a steam turbine, and as a perfect
balance of its rotating parts is absolutely essential to its successful
operation, vibration is reduced to such a small element that the simplest
foundations will suffice, and it is safe to locate steam turbines on upper
floors of a factory if this be desirable or necessary.
"The perfect balance of the moving parts and the extreme simplicity of
construction tend to minimize the wear and increase the life of a turbine,
and at the same time to reduce the chance of interruption in its operation
through derangement of, or damage to, any of its essential parts.
"Although hardly beyond the stage of its first advent in the motive-power
field, the steam turbine has met with much favor, and there is promise of its
wide use for the purposes to which it is particularly adapted. At present,
however, its uses are restricted to service that is continuous and regular, its
particular adaptability being for the driving of electrical generators, pumps,
ventilating fans, and similar work, especially where starting under load is
not essential.

"Steam turbines are now being built in the United States in all sizes up to
3,000 horse-power. Their use abroad covers a longer period and has become
more general. The largest turbines thus far attempted are those of the
Metropolitan District Electric Traction Company, of London, embracing
four units of 10,000 horse-power each. Several turbines of large size have
been operated successfully in Germany."
It should be added that the compound turbine wheel of Parsons is not the
only turbine wheel that has proved commercially valuable. There is a
turbine consisting of a single ring of revolving blades, the invention of Dr.
Gustav De Laval, which has proved itself capable of competing with the old
type of engine. To make this form of single turbine operate satisfactorily, it
is necessary to have steam under high pressure, and to generate a very high
speed of revolution. In practice, the De Laval machines sometimes attain a
speed of thirty thousand revolutions per minute. This is a much higher rate
of speed than can advantageously be utilized directly in ordinary machinery,
and consequently the shaft of this machine is geared to another shaft in such
a way as to cause the second shaft to revolve much more slowly.

VII
GAS AND OIL ENGINES

J
ust at the time when the type of piston-and-cylinder engine has thus
been challenged, it has chanced that a new motive power has been
applied to the old type of engine, through the medium of heated gas.
The idea of such utilization of a gas other than water vapor is by no
means new, but there have been practical difficulties in the way of the
construction of a commercial engine to make use of the expansive power of
ordinary gases.
The principle involved is based on the familiar fact that a gas expands on
being heated and contracts when cool. Theoretically, then, all that is
necessary is to heat a portion of air confined in a cylinder, to secure the
advantage of its expansion, precisely as the expansion of steam is utilized,
by thrusting forward a piston. Such an apparatus constitutes a so-called
"caloric" or hot-air engine. As long ago as the year 1807 Sir G. Cayley in
England produced a motor of this type, in which the heated air passed
directly from the furnace to the cylinder, where it did work while expanding
until its pressure was not greater than that of the atmosphere, when it was
discharged. The chief mechanical difficulty encountered resulted from the
necessity for the employment of very high temperatures; and for a long time
the engine had no great commercial utility. The idea was revived, however,
about three-quarters of a century later and an engine operated on Cayley's
principle was commercially introduced in England by Mr. Buckett. This
engine has a cold-air cylinder above the crank-shaft and a large hot-air
cylinder below, while the furnace is on one side enclosed in an air-tight
chamber. The fuel is supplied as required through a valve and distributing
cone arranged above the furnace and provided with an air lock in which the
fuel is stored. At about the time when this hot-air engine was introduced,
however, gas and oil engines of another and more important type were
developed, as we shall see in a moment.
Meantime, an interesting effort to utilize the expansive property of heated
air was made by Dr. Stirling in 1826; his engine being one in which heat

was distributed by means of a displacer which moved the mass of air to and
fro between the hot and cold portions of the apparatus. He also compressed
the air before heating it, thus making a distinct advance in the economy and
compactness of the engine. From an engineering standpoint his design has
further interest in that it was a practical attempt to construct an engine
working on the principle of the theoretically perfect heat engine, in which
the cycle of operations is closed, the same mass of air being used
throughout. In the theoretically perfect heat engine, it may be added, the
cycle of operations may be reversed, there being no loss of energy involved;
but in practice, of course, an engine cannot be constructed to meet this ideal
condition, as there is necessarily some loss through dissipation of heat. Dr.
Stirling's practical engine had its uses, but could not compete with the steam
engine in the general field of mechanical operations to which that apparatus
is applied.
Another important practical experimenter in the construction of hot-air
engines was John Ericsson, who in 1824 constructed an engine somewhat
resembling the early one of Cayley, and in 1852 built caloric engines on
such a scale as to be adapted to the propulsion of ships. Notwithstanding the
genius of Ericsson, however, engines of this type did not prove
commercially successful on a large scale, and in subsequent decades the
hot-air motors constructed for practical purposes seldom exceeded one
horse-power. Such small engines as these are comparatively efficient and
absolutely safe, and they are thoroughly adapted for such domestic purposes
as light pumping.
The great difficulty with all these engines operated with heated air has
been, as already suggested, that their efficiency of action is limited by the
difficulties incident to applying high temperatures to large masses of the
gas. There is, however, no objection to the super-heating of small quantities
of gas, and it was early suggested that this might be accomplished by
exploding a gaseous mixture within a cylinder. It was observed by the
experimenters of the seventeenth century that an ordinary gun constitutes
virtually an internal-combustion engine; and such experimenters as the
Dutchman Huyghens, and the Frenchmen Hautefeuille and Papin, attempted
to make practical use of the power set free by the explosion of gunpowder,
their experiments being conducted about the years 1678 to 1689. Their
results, however, were not such as to give them other than an historical

interest. About a century later, in 1794, the Englishman Robert Street
suggested the use of inflammable gases as explosives, and ever since that
time there have been occasional experimenters along that line. In 1823
Samuel Brown introduced a vacuum gas engine for raising water by
atmospheric pressure. The first fairly practical gas engine, however, was
that introduced by J. J. E. Lenoir, who in 1850 proposed an engine working
with a cycle resembling that of a steam engine. His engine patented in 1860
proved to be a fairly successful apparatus. This engine of Lenoir prepared
the way for gas engines that have since become so enormously important.
Its method of action is this:
"To start the engine, the fly-wheel is pulled round, thus moving the
piston, which draws into the cylinder a mixture of gas and air through about
half its stroke; the mixture is then exploded by an electric spark, and
propels the piston to the end of its stroke, the pressure meanwhile falling,
by cooling and expansion, to that of the atmosphere when exhaust takes
place. In the return stroke the process is repeated, the action of the engine
resembling that of the double-acting steam engine, and having a one-stroke
cycle. The cylinder and covers are cooled by circulating water. The firing
electricity was supplied by two Bunsen batteries and an induction coil, the
circuit being completed at the right intervals by contact pieces on an
insulating disc on the crank-shaft; the ignition spark leaped across the space
between two wires carried about one-sixth of an inch apart in a porcelain
holder."
In 1865 Mons. P. Hugon patented an engine similar to that of Lenoir,
except that ignition was accomplished by an external flame instead of by
electricity. The ignition flame was carried to and fro in a cavity inside a
slide valve, moved by a cam so as to get a rapid cut-off, and permanent
lights were maintained at the ends of the valve to re-light the flame-ports
after each explosion. The gas was supplied to the cylinder by rubber
bellows, worked by an eccentric on the crank-shaft. This engine could be
operated satisfactorily, except as to cost, but the heavy gas consumption
made it uneconomical.
An important improvement in this regard was introduced by the
Germans, Herrn. E. Langen and N. A. Otto, who under patents bearing date
of 1866 introduced a so-called "free" piston arrangement—that is to say an
arrangement by which the piston depends for its action partly upon the

momentum of a fly-wheel. This principle had been proposed for a gas
engine as early as 1857, but the first machine to demonstrate its feasibility
was that of Langen and Otto. Their engine greatly decreased the gas
consumption and hence came to be regarded as the first commercially
successful gas engine. It was, however, noisy and limited to small sizes.
The cycle of operations of an engine of this type is described as follows:

GAS AND OIL ENGINES.
Lower right-hand figure, a very early type
of commercially successful gas engine. It has a

"free" piston, an arrangement that was first
proposed for a gas engine in 1857, but only
brought into practical form by Langen & Otto
under their patent of 1866. Upper figure, the
gas engine patented by Lenoir in 1860, one of
the very first practically successful engines.
Lower left-hand figure, a sectional view of a
modern gas engine of the type used as the
motor of the automobile.
"(a) The piston is lifted about one-tenth of its travel by the momentum of
the fly-wheel, thus drawing in a charge of gas and air.
"(b) The charge is ignited by flame carried in by a slide valve.
"(c) Under the impulse of the explosion, the piston shoots upward nearly
to the top of the cylinder, the pressure in which falls by expansion to about
4 lbs. absolute, while absorbing the energy of the piston.
"(d) The piston descends by its own weight and the atmospheric pressure,
and in doing so causes a roller-clutch on a spur-wheel gearing with a rack
on the piston-rod to engage, so that the fly-wheel shaft shall be driven by
the piston; during this down-stroke the pressure increases from 4 lbs.
absolute to that of the atmosphere, and averages 7 lbs. per square inch
effective throughout the stroke.
"(e) When the piston is near the bottom of the cylinder, the pressure rises
above atmospheric, and the stroke is completed by the weight of the piston
and rack, and the products of combustion are expelled.
"(f) The fly-wheel now continues running freely till its speed, as
determined by a centrifugal governor, falls below a certain limit when a trip
gear causes the piston to be lifted the short distance required to
recommence the cycle.
"Ignition is performed by an external gas jet, near a pocket in the slide
valve by which the charge is admitted; this pocket carries flame to the
charge, thus igniting it without allowing any escape. The valve also
connects the interior of the cylinder with the exhaust pipe, and a valve in
the latter controlled by the governor throttles the discharge, and so defers
the next stroke until the speed has fallen below normal. To run the engine

empty about four explosions per minute are necessary, and at full power 30
to 35 are made, so that about 28 explosions per minute are available for
useful work under the control of the governor."
The definitive improvement in this gas engine was introduced in 1876 by
Dr. N. A. Otto, when he compressed the explosive mixture in the working
cylinder before igniting it. This expedient—so all-important in its results—
had been suggested by William Barnett in 1838, but at that time gas engines
were not sufficiently developed to make use of the idea. Now, however, Dr.
Otto demonstrated that by compressing the gas before exploding it a much
more diluted mixture can be fired, and that this gives a quieter explosion,
and a more sustained pressure during the working stroke, while as the
engine runs at a high speed the fly-wheel action is generally sufficient to
correct the fluctuations arising from there being but one explosion for four
strokes of the piston.
In this perfected engine, then, the method of operation is as follows:
The piston is pulled forward with the application of some outside force,
which in practice is supplied by the inertia of the fly-wheel, or in starting
the engine by the action of a crank with which every user of an automobile
is familiar. In being pulled forward, the piston draws gas into the cylinder;
as the piston returns, this gas is compressed; the compressed gas,
constituting an explosive mixture, is then ignited by a piece of incandescent
metal or by an electric spark; the exploding gas expands, pushing the piston
forward, this being the only thrust during which work is done; the returning
piston expels the expanded gas, completing the cycle. Thus there are three
ineffective piston thrusts to one effective thrust. Nevertheless, the engine
has proved a useful one for many purposes.
This so-called Otto cycle has been adopted in almost all gas and oil
engines, the later improvements being in the direction of still higher
compression, and in the substitution of lift for slide valves. There has been a
steady increase in the size and power of such engines, the large ones usually
introducing two or more working cylinders so as to secure uniform driving.
Cheap forms of gas have been employed such as those made by
decomposing water by incandescent fuel, and it has been proved possible
thus to operate gas-power plants on a commercial scale in competition with
the most economical steam installations.

A practical modification of vast importance was introduced when it was
suggested that a volatile oil be employed to supply the gas for operation in
an internal combustion engine. There was no new principle involved in this
idea, and the Otto cycle was still employed as before; but the use of the
volatile oil—either a petroleum product or alcohol—made possible the
compact portable engine with which everyone is nowadays familiar through
its use in automobiles and motor boats. The oil commonly used is gasoline
which is supplied to the cylinder through a so-called carburettor in which
the vapors of gasoline are combined with ordinary air to make an explosive
mixture. The introduction of this now familiar type of motor is to a large
extent due to Herr G. Daimler, who in 1884 brought out a light and compact
high-speed oil engine. About ten years later Messrs. Panhard and Levassor
devised the form of motor which has since been generally adopted. Few
other forms of mechanisms are better known to the general public than the
oil engine with its two, four, six, or even eight cylinders, as used in the
modern automobile. As everyone is aware, it furnishes the favorite type of
motor, combining extraordinary power with relative lightness, and making
it feasible to carry fuel for a long journey in a receptacle of small compass.
With the gas engines a complication arises precisely opposite to that
which is met with in the case of the cylinder of the steam engine—the
tendency, namely, to overheating of the cylinder. To obviate this it is
customary to have the cylinder surrounded by a water jacket, though air
cooling is used in certain types of machines. About fifty per cent. of the
total heat otherwise available is lost through this unavoidable expedient.
The rapid introduction of the gas engine in recent years suggests that this
type of engine may have a most important future. It has even been predicted
that within a few years most trans-Atlantic steamers will be equipped with
this type of engine, producing their own gas in transit. It is possible, then,
that through this medium the old piston-and-cylinder engine may retain its
supremacy, as against the turbine. For the moment, at any rate, the gas
engine is gaining popularity, not merely in its application to the automobile,
but for numerous types of small stationary engines as well.
In this connection it will be interesting to quote the report of the Special
Agent of the Twelfth Census of the United States, as showing the status of
gas engines and steam engines in the year 1902.

"The decade between 1890 and 1900," he says, "was a period of marked
development in the use of gas engines, using that term to denote all forms
of internal combustible engines, in which the propelling force is the
explosion of gaseous or vaporous fuel in direct contact with a piston within
a closed cylinder. This group embraces those engines using ordinary
illuminating gas, natural gas, and gas made in special producers installed as
a part of the power plant, and also vaporised gasoline or kerosene. This
form of power for the first time is an item of consequence in the returns of
the present census, and the very large increase in the horse-power in 1900
as compared with 1890 indicates the growing popularity of this class of
motive power.
"In 1890 the number of gas engines in use in manufacturing plants was
not reported, but their total power amounted to only 8,930 horse-power, or
one-tenth of one per cent of the total power utilized in manufacturing
operations. In 1900, however, 14,884 gas engines were reported, with a
total of 143,850 horse-power, or 1.3 per cent of the total power used for
manufacturing purposes. This increase from 8,930 horse-power to 143,850
horse-power, a gain of 134,920 horse-power, is proportionately the largest
increase in any form of primary power shown by a comparison of the
figures of the Eleventh and Twelfth censuses, amounting to 1,510.9 per
cent.
"Within the past decade, and more particularly during the past five years,
there has been a marked increase in the use of this power in industrial
establishments for driving machinery, for generating electricity, and for
other kindred uses. At the same time, internal-combustion engines have
increased in popularity for uses apart from manufacturing, and the amount
of this kind of power in use for all purposes in 1900 was, doubtless, very
much larger than indicated by the figures relating to manufacturing plants
alone.
"The average horse-power per gas engine in 1900 was 9.7 horse-power.
There are no available statistics upon which to base a comparison of this
average with the average for 1890, but it is doubtful if there has been any
very material change in ten years; for while gas engines are built in much
larger sizes than ever before, there has been also a great increase in the
number of small engines for various purposes.

"The large increase in the use of internal-combustion engines has been
due to the rapid improvements that have been made in them, their increased
efficiency and economy, their decreased cost, and the wider range of
adaptability that has been made practicable.
"Steam still continues to be preeminently the power of greatest
importance, and the census returns indicate that the proportion of steam to
the total of all powers has increased very largely in the past thirty years. In
1870 steam furnished 1,215,711 horse-power, or 51.8 per cent of a total of
2,346,142; in 1880 the amount of steam power used was 2,185,458 horse-
power out of a total of 3,410,837, or 64.1 per cent; in 1890 out of an
aggregate of 5,954,655 horse-power, 4,581,595, or 76.9 per cent was steam;
while in 1900 steam figured to the extent of 8,742,416 horse-power, or 77.4
per cent, in a total of 11,300,081. This increase in thirty years, from 51.8
per cent to 77.4 per cent of the total power, shows how much more rapidly
the use of steam power has increased than other primary sources of power.
"The tendency toward larger units in the use of steam power is shown
inadequately by the increase in the average horse-power per engine from 39
horse-power in 1880, to 51 horse-power in 1890, and 56 horse-power in
1900.
"The tendency toward great operations which has been such a
conspicuous feature of industrial progress during the past ten years, has
shown itself strikingly in the use of units of larger capacity in nearly every
form of machinery, and nowhere has this tendency been more marked than
in the motive power by which the machinery is driven. At the same time
there has been an increase in the use of small units, which tends to destroy
the true tendency in steam engineering in these statistics. For example, a
steam plant consisting of one or more units of several thousand horse-power
may also embrace a number of small engines of only a few horse-power
each, the use of which is necessitated by the magnitude of the plant, for the
operation of mechanical stokers, the driving of draft fans, coal and ash
conveyors, and other work requiring power in small units. On this account
the average horse-power of steam engines in use at different census periods
fails to afford a true basis for measuring progress toward larger units during
the past ten years.

"Developments of the past few years in the distribution of power by the
use of electric motors have served to accelerate the tendency toward larger
steam units and the elimination of small engines in large plants and to
change completely the conditions just described. For example: In one of the
largest power plants in the world, which is now being installed, all the
stokers, blowers, conveyors, and other auxiliary machinery are to be driven
by electric motors. Such rapidly changing conditions tend to invalidate any
comparisons of statistical averages deduced from figures for periods even
but a few years apart.
"Comparison of two important industries will illustrate the foregoing.
The average horse-power of the steam engine used in the cotton mills of the
United States in 1890 was 198, and in 1900 it was 300.
"In the iron and steel industry the average horse-power per engine in
1890 was 171, and in 1900 it was 235. In the cotton mills the use of single
large units of motive power, with few auxiliary engines of small capacity,
gives the largest horse-power per engine of any industry; while in the iron
and steel industry the average of the motive power proper, although
probably larger than in the manufacture of cotton goods, is reduced by the
large number of small engines which are used for auxiliary purposes in
every iron and steel plant."
It will be understood that the object of exploding the mixed gases in the
oil engine is to produce sudden heating of the entire gas. There is no reason
whatever for introducing the gasoline beyond this. Could a better method of
heating air be devised, the oil might be entirely dispensed with, and the
safety of the apparatus enhanced, as well as the economy of operation.
Efforts have been made for fifty years to construct a hot-air engine that
would compete with steam successfully. In the early fifties, as already
noted, Ericsson showed the feasibility of substituting hot air for steam, but
although he constructed large engines, their power was so slight that he was
obliged to give up the idea of competing with steam, and to use his engines
for pumping where very small power was required.
The great difficulty was that it was not found practicable to heat the air
rapidly. All subsequent experimenters have met with the same difficulty
until somewhat recently. It is now claimed, however, that a means has been
found of rapidly heating the air, and it is even predicted that the hot-air

engine will in due course entirely supersede the steam engine. Mr. G. Emil
Hesse, in an article in The American Inventor, for April 15, 1905, describes
a Svea caloric engine as having successfully solved the problem of rapidly
heating air. The methods consist in breaking up the air into thin layers and
passing it over hot plates, where it rapidly absorbs heat. It passes from the
heater to the power cylinder which resembles the cylinder of a steam
engine; thence after expanding and doing its work it is exhausted into the
atmosphere. Large engines may use the same air over and over again under
pressure of one hundred pounds per square inch, alternately heating and
cooling it. A six horse-power engine of this type is said to have a cylinder
four and one-half inches in diameter and a stroke of four and seven-eighth
inches, and makes four hundred and fifty revolutions per minute. The heater
is twenty inches in diameter, sixteen inches long, and has a heating surface
of sixty square feet. The total weight of heater and engine complete is four
hundred pounds for a half horse-power Ericsson engine.
"The Svea heater," says Mr. Hesse, "absorbs the heat as perfectly as an
ordinary steam boiler, and the heat-radiating surface of both heater and
engine is not larger than that of a steam plant of the same power, thereby
placing the two motors on the same basis, as far as the utilization of the heat
in the fuel itself is concerned.
"The advantage which every hot-air engine has over the steam engine is
the amount of heat saved in the vaporization of the water. It is now well
known that one gas is as efficient as another for the conversion of heat into
power. Air and steam at 100° C. are consequently on the same footing and
ready to be superheated. The amount of heat required to bring the two gases
to this temperature is, however, very different.
"With an initial temperature of 10° C. for both air and water, we find that
one kilogram of steam requires 90 + 537 = 627 thermal units, and one
kilogram of air 0.24 × 90 = 21.6 thermal units. Some heat is recovered if the
feed water is heated and the steam condensed, but the difference is still so
great as to altogether exclude steam as a competitor, provided air can be as
readily handled.
"Having now the means to rapidly heat the air, the outlook for the
external-combustion engine is certainly very promising.

"The saving of more than half the coal now used by the steam engine will
be of tremendous importance to the whole world."
To what extent this optimistic prediction will be verified is a problem for
the future to decide.

VIII
THE SMALLEST WORKERS

I
n our studies of the steam engine and gas engine we have been
concerned with workers of infinitesimal size. Yet, if we are to believe
the reports of the modern investigator, the molecules of steam or of
ignited gas are small only in a relative sense, and there is a legion of
workers compared with which the molecules are really gigantic in size.
These workers are the atoms, and the yet more minute particles of which,
according to the most recent theories, they are themselves composed.
These smallest conceivable particles, the constituents of the atoms, are
called electrons. They are a discovery of the physicists of the most recent
generation. According to the newest theories they account for most—
perhaps for all—of the inter-molecular and inter-atomic forces; they are
indeed the ultimate repositories of those stores of energy which are known
to be contained in all matter. The theories are not quite as fully developed as
could be wished, but it would appear that these minutest particles, the
electrons, are the essential constituents of the familiar yet wonderful carrier
of energy which we term electricity. In considering the share of electricity
in the world's work, therefore, we shall do well at the outset to put ourselves
in touch with recent views as to the nature of this most remarkable of
workers.
On every side in this modern world we are confronted by this strange
agent, electricity. The word stares us in the face on every printed page. The
thing itself is manifest in all departments of our every-day life. You go to
your business in an electric car; ascend to your office in an electric elevator;
utilize electric call-bells; receive and transmit messages about the world and
beneath the sea by electric telegraph. Your doctor treats you with an electric
battery. Your dentist employs electric drills and electric furnaces. You ride
in electric cabs; eat food cooked on electric stoves; and read with the aid of
electric light. In a word, the manifestations of electricity are so obvious on
every side that there can be no challenge to the phrasing which has
christened this the Age of Electricity.

But what, then, is this strange power that has produced all these
multifarious results? It would be hard to propound a scientific query that
has been more variously answered. Ever since the first primitive man
observed the strange effect produced by rubbing a piece of amber,
thoughtful minds must have striven to explain that effect. Ever since the
eighteenth-century scientist began his more elaborate studies of electricity,
theories in abundance have been propounded. And yet we are not quite sure
that even the science of to-day can give a correct answer as to the nature of
electricity. At the very least, however, it is able to give some interesting
suggestions which seem to show that we are in a fair way to solve this
world-old mystery. And, curiously enough, the very newest explanations are
not so very far away from some eighteenth-century theories which for a
long time were looked at askance if not altogether discarded. In particular,
the theory of Benjamin Franklin, which considered electricity as an
immaterial fluid bearing certain curious relations to tangible matter, is
found to serve singularly well as an aid to the interpretation of the very
newest experiments.

FRANKLIN'S ONE-FLUID THEORY

Such being the case, we must consider this theory of Franklin's somewhat
in detail. Perhaps we cannot do better than state the theory in the words of
the celebrated physicist, Dr. Thomas Young, as given in his work on natural
philosophy, published in 1807. By quoting from this old work we shall
make sure that we are not reading any modern interpretations into the
theory. "It is supposed," says Young, "that a peculiar ethereal fluid pervades
the pores, if not the actual substance of the earth and of all other material
bodies, passing through them with more or less facility, according to their
different powers of conducting it; that particles of this fluid repel each
other, and are attracted by particles of common matter; that particles of
common matter also repel each other; and that these attractions and
repulsions are equal among themselves, and vary inversely as to squares of
the distances of the particles. The effects of this fluid are distinguished from
those of all other substances by an attractive or repulsive quality, which it
appears to communicate to different bodies, and which differs in general
from other attractions and repulsions by its immediate diminution or
cessation when the bodies, acting on each other, come into contact, or are
touched by other bodies.... In general, a body is said to be electrified when

it contains, either as a whole or in any of its parts, more or less of the
electric fluid than is natural to it.... In this common neutral state of all
bodies, the electrical fluid, which is everywhere present, is so distributed
that the various forces hold each other exactly in equilibrium and the
separate results are destroyed, unless we choose to consider gravitation
itself as arising from a comparatively slight inequality between the
electrical attractions and repulsions."
The salient and striking feature of this theory, it will be observed, is that
the electrical fluid, under normal conditions, is supposed to be incorporated
everywhere with the substance of every material in the world. It will be
observed that nothing whatever is postulated as to the nature or properties
of this fluid beyond the fact that its particles repel each other and are
attracted by the particles of common matter; it being also postulated that the
particles of common matter likewise repel each other under normal
conditions.
At the time when Franklin propounded his theory, there was a rival
theory before the world, which has continued more or less popular ever
since, and which is known as the two-fluid theory of electricity. According
to this theory, there are two uncreated and indestructible fluids which
produce electrical effects. One fluid may be called positive, the other
negative. The particles of the positive fluid are mutually repellent, as also
are the particles of the negative fluid, but, on the other hand, positive
particles attract and are attracted by negative particles. We need not further
elaborate the details of this two-fluid theory, because the best modern
opinion considers it less satisfactory than Franklin's one-fluid theory.
Meantime, it will be observed that the two theories have much in common;
in particular they agree in the essential feature of postulating an invisible
something which is not matter, and which has strange properties of
attraction and repulsion.
These properties of attraction and repulsion constituted in the early day
the only known manifestations of electricity; and the same properties
continue to hold an important place in modern studies of the subject.
Electricity is so named simply because amber—the Latin electrum—was
the substance which, in the experience of the ancients, showed most
conspicuously the strange property of attracting small bodies after being
rubbed. Modern methods of developing electricity are extremely

diversified, and most of them are quite unsuggestive of the rubbing of
amber; yet nearly all the varied manifestations of electricity are reducible,
in the last analysis, to attractions and repulsions among the particles of
matter.
As to the alleged immaterial fluids which, according to the theories just
mentioned, make up the real substance of electricity, it was perfectly natural
that they should be invented by the physicists of the elder day. All the
conceptions of the human mind are developed through contact with the
material world; and it is extremely difficult to get away, even in theory,
from tangible realities. When the rubbed amber acquires the property of
drawing the pith ball to it, we naturally assume that some change has taken
place in the condition of the amber; and since the visible particles of amber
appear to be unchanged—since its color, weight, and friability are
unmodified—it seems as if some immaterial quality must have been added
to, or taken from it. And it was natural for the eighteenth-century physicist
to think of this immaterial something as a fluid, because he was accustomed
to think of light, heat, and magnetism as being also immaterial fluids. He
did not know, as we now do, that what we call heat is merely the
manifestation of varying "modes" of motion among the particles of matter,
and that what we call light is not a thing sui generis, but is merely our
recognition of waves of certain length in the all-pervading ether. The wave
theory of light had, indeed, been propounded here and there by a
philosopher, but the theory which regarded light as a corpuscular emanation
had the support of no less an authority than Sir Isaac Newton, and he was a
bold theorist that dared challenge it. When Franklin propounded his theory
of electricity, therefore, his assumption of the immaterial fluid was
thoroughly in accord with the physical doctrines of the time.

MODERN VIEWS

But about the beginning of the nineteenth century the doctrine of
imponderable fluids as applied to light and heat was actively challenged by
Young and Fresnel and by Count Rumford and Humphry Davy and their
followers, and in due course the new doctrines of light and heat were
thoroughly established. In the light of the new knowledge, the theory of the
electric fluid or fluids seemed, therefore, much less plausible. Whereas the
earlier physicists had merely disputed as to whether we must assume the

existence of two electrical fluids or of only one, it now began to be
questioned whether we need assume the existence of any electrical fluid
whatever. The physicists of about the middle of the nineteenth century
developed the wonderful doctrine of conservation of energy, according to
which one form of force may be transformed into another, but without the
possibility of adding to, or subtracting from, the original sum total of energy
in the universe. It became evident that electrical force must conform to this
law. Finally, Clerk-Maxwell developed his wonderful electromagnetic
theory, according to which waves of light are of electrical origin. The work
of Maxwell was followed up by the German Hertz, whose experiments
produced those electromagnetic waves which, differing in no respect except
in their length from the waves of light, have become familiar to everyone
through their use in wireless telegraphy. All these experiments showed a
close relation between electrical phenomena, and the phenomena of light
and of radiant heat, and a long step seemed to be taken toward the
explanation of the nature of electricity.
The new studies associated electricity with the ether, rather than with the
material substance of the electrified body. Many experiments seemed to
show that electricity in motion traverses chiefly the surface of the
conductor, and it came to be believed that the essential feature of the
"current" consists of a condition of strain or stress in the ether surrounding a
conductor, rather than of any change in the conductor itself. This idea,
which is still considered valid, has the merit of doing away with the thought
of action at a distance—the idea that was so repugnant to the mind of
Faraday.
So far so good. But what determines the ether strain? There is surely
something that is not matter and is not ether. What is this something? The
efforts of many of the most distinguished experimenters have in recent
years been directed toward the solution of that question; and these efforts,
thanks to the new methods and new discoveries, have met with a
considerable measure of success. I must not attempt here to follow out the
channels of discovery, but must content myself with stating briefly the
results. We shall have occasion to consider some further details as to the
methods in a later chapter.
Briefly, then, it is now generally accepted, at least as a working
hypothesis, that every atom of matter—be it oxygen, hydrogen, gold, iron,

or what not—carries a charge of electricity, which is probably responsible
for all the phenomena that the atom manifests. This charge of electricity
may be positive or negative, or it may be neutral, by which is meant that the
positive and negative charges may just balance. If the positive charge has
definite carriers, these are unknown except in association with the atom
itself; but the negative charge, on the other hand, is carried by minute
particles to which the name electron (or corpuscle) has been given, each of
which is about one thousand times smaller than a hydrogen atom, and each
of which carries uniformly a unit charge of negative electricity.
Electrons are combined, in what may be called planetary systems, in the
substance of the atom; indeed, it is not certain that the atom consists of
anything else but such combinations of electrons, held together by the
inscrutable force of positive electricity. Some, at least, of the electrons
within the atom are violently active—perhaps whirling in planetary orbits,
—and from time to time one or more electrons may escape from the atomic
system. In thus escaping an electron takes away its charge of negative
electricity, and the previously neutral atom becomes positively electrified.
Meanwhile the free electron may hurtle about with its charge of negative
electricity, or may combine with some neutral atom and thus give to that
neutral atom a negative charge. Under certain conditions myriads of these
electrons, escaped thus from their atomic systems, may exist in the free
state. For example, the so-called beta (ß) rays of radium and its allies
consist of such electrons, which are being hurtled off into space with
approximately the speed of light. The cathode rays, of which we have heard
so much in recent years, also consist of free electrons.
But, for that matter, all currents of electricity whatever, according to this
newest theory, consist simply of aggregations of free electrons. According
to theory, if the electrons are in uniform motion they produce the
phenomena of constant currents of electricity; if they move non-uniformly
they produce electromagnetic phenomena (for example, the waves used in
wireless telegraphy); if they move with periodic motion they produce the
waves of light. Meanwhile stationary aggregations of electrons produce the
so-called electrostatic phenomena. All the various ether waves are thus
believed to be produced by changes in the motions of the electrons. A very
sudden stoppage, such as is produced when the cathode ray meets an
impassable barrier, produces the X-ray.

With these explanations in mind, it will be obvious how closely this
newest interpretation of electricity corresponds in its general features with
the old one-fluid theory of Franklin. The efforts of the present-day physicist
have resulted essentially in an analysis of Franklin's fluid, which gives to
this fluid an atomic structure. The new theory takes a step beyond the old in
suggesting the idea that the same particles which make up the electric fluid
enter also into the composition—perhaps are the sole physical constituents
—of every material substance as well. But while the new theory thus
extends the bounds of our vision, we must not claim that it fully solves the
mystery. We can visualize the ultimate constituent of electricity as an
electron one thousand times smaller than the hydrogen atom, which has
mass and inertia, and which possesses powers of attraction and repulsion.
But as to the actual nature of this ultimate particle we are still in the dark.
There are, however, some interesting theories as to its character, which
should claim at least incidental attention.
We have all along spoken of the electron as an exceedingly minute
particle, stating indeed, that in actual size it is believed to be about one
thousand times smaller than the hydrogen atom, which hitherto had been
considered the smallest thing known to science. But we have now to offer a
seemingly paradoxical modification of this statement. It is true that in mass
or weight the electron is a thousand times smaller than the hydrogen atom,
yet at the same time it may be conceived that the limits of space which the
electron occupies are indefinitely large. In a word, it is conceived (by
Professor J. J. Thomson, who is the chief path-breaker in this field) that the
electron is in reality a sort of infinitesimal magnet, having two poles joined
by lines or tubes of magnetic force (the so-called Faraday tube), which lines
or tubes are of indefinite number and extent; precisely as, on a large scale,
our terrestrial globe is such a magnet supplied with such an indefinite
magnetic field. That the mass of the electron is so infinitesimally small is
explained on the assumption that this mass is due to a certain amount of
universal ether which is bound up with the tubes where they are thickest;
close to the point in space from which they radiate, which point in space
constitutes the focus of the tangible electron.
It will require some close thinking on the part of the reader to gain a clear
mental picture of this conception of the electron; but the result is worth the
effort. When you can clearly conceive all matter as composed of electrons,

each one of which cobwebs space with its system of magnetic tubes, you
will at least have a tangible picture in mind of a possible explanation of the
forces of cohesion and gravitation—in fact, of all the observed cases of
seeming action at a distance. If at first blush the conception of space as
filled with an interminable meshwork of lines of force seems to involve us
in a hopeless mental tangle, it should be recalled that the existence of an
infinity of such magnetic lines joining the poles of the earth may be
demonstrated at any time by the observation of a compass, yet that these do
not in any way interfere with the play of other familiar forces. There is
nothing unthinkable, then, in the supposition that there are myriads of minor
magnetic centres exerting lesser degrees of force throughout the same
space.
All that can be suggested as to the actual nature of the Faraday tubes is
that they perhaps represent a condition of the ether. This, obviously, is
heaping hypothesis upon hypothesis. Yet it should be understood that the
hypothesis of the magnetic electron as the basis of matter, has received an
amount of experimental support that has raised it at least to the level of a
working theory. Should that theory be demonstrated to be true, we shall
apparently be forced to conclude not merely that electricity is present
everywhere in nature, but that, in the last analysis, there is absolutely no
tangible thing other than electricity in all the universe.

HOW ELECTRICITY IS DEVELOPED

Turning from this very startling theoretical conclusion to the
practicalities, let us inquire how electricity—which apparently exists, as it
were, in embryo everywhere—can be made manifest. In so doing we shall
discover that there are varying types of electricity, yet that these have a
singular uniformity as to their essential properties. As usually divided—and
the classification answers particularly well from the standpoint of the
worker—electricity is spoken of as either statical or dynamical. The words
themselves are suggestive of the essential difference between the two types.
Statical electricity produces very striking manifestations. We have already
spoken of it as theoretically due to the conditions of the electrons at rest. It
must be understood, however, that the statical electricity will, if given
opportunity, seek to escape from any given location to another location,
under certain conditions, somewhat as water which is stored up in a

reservoir will, when opportunity offers, flow down to a lower level. The
pent-up static electricity has, like the water in the reservoir, a store of
potential energy. The physicist speaks of it as having high tension. In
passing to a condition of lower tension, the statical electricity may give up a
large portion of its energy.
If, for example, on a winter day in a cold climate, you walk briskly along
a wool carpet, the friction of your feet with the carpet generates a store of
statical electricity, which immediately passes over the entire surface of your
body. If now you touch another person or a metal conductor, such as a
steam radiator or a gas pipe, a brilliant spark jumps from your finger, and
you experience what is spoken of as an electrical shock. If the day is very
cold, and the air consequently very dry, and if you will take pains to rub
your feet vigorously or slide along the carpet, you may light a gas jet with
the spark which will spring from your finger to the tip of the jet, provided
the latter is of metal or other conducting substance; and even if you attempt
to avoid the friction between your feet and the carpet as much as possible,
you may be constantly annoyed by receiving a shock whenever you touch
any conductor, since, in spite of your efforts, the necessary amount of
friction sufficed to generate a store of statical electricity.
An illustration of the development of this same form of electricity, on a
large scale, is supplied by the familiar statical machine, which consists of a
large circle of glass, so adjusted that it may be revolved rapidly against a
suitable friction producer. With such a machine a powerful statical current
is produced, capable of generating a spark that may be many inches or even
several feet in length,—a veritable flash of lightning. It is with such a
supply of electricity conducted through a vacuum tube that the cathode ray
and the Roentgen ray are produced.
Such effects as this suggest considerable capacity for doing work. Yet in
reality, notwithstanding the very sporadical character of the result, the
quantity of electricity involved in such a statical current may be very slight
indeed. Even a lightning flash is held to represent a comparatively small
amount of electricity. Faraday calculated that the amount of electricity that
could be generated from a single drop of water, through chemical
manipulation, would suffice to supply the lightning for a fair-sized thunder-
storm. Nevertheless the destructive work that may be done by a flash of
lightning may be considerable, as everyone is aware. But, on the other

hand, while the visible effect of a stroke of lightning on a tree trunk, for
example, makes it seem a powerful agency, yet the actual capacity to do
work—the power to move considerable masses of matter—is extremely
limited. The effect on a tree trunk, it will be recalled, usually consists of
nothing more than the stripping off of a channel of bark. In other words, the
working energy contained in a seemingly powerful supply of statical
electricity commonly plays but an insignificant part.
The working agent, and therefore the form of electricity which concerns
us in the present connection, is the dynamical current. This may be
generated in various ways, but in practice these are chiefly reducible to two.
One of these depends upon chemical action, the other upon the inter-
relations of mechanical motion and magnetic lines of force. A common
illustration of the former is supplied by the familiar voltaic or galvanic
battery. The electromagnetic form has been rendered even more familiar in
recent times by the dynamo. This newest and most powerful of workers will
claim our attention in detail in the succeeding chapter. Our present
consideration will be directed to the older method of generating the electric
current as represented by the voltaic cell.

THE WORK OF THE DYNAMICAL CURRENT

Let us draw our illustration from a familiar source. Even should your
household otherwise lack electrical appliances, you are sure to have an
electric call-bell. The generator of the electric current, which is stored away
in some out-of-the-way corner, is probably a small so-called "dry-cell"
which you could readily carry around in your pocket; or it may consist of a
receptacle holding a pint or two of liquid in which some metal plates are
immersed. Such an apparatus seems scarcely more than a toy when we
contrast it with the gigantic dynamos of the power-house; yet, within the
limits of its capacities, one is as surely a generator of electricity as the other.
If we are to accept the latest theory, the electrical current which flows from
this tiny cell is precisely the same in kind as that which flows from the five-
thousand-horse-power dynamo. The difference is only one of quantity.
To understand the operation of this common household appliance we
must bear in mind two or three familiar experimental facts in reference to
the action of the voltaic cell. Briefly, such a cell consists of two plates of
metal—for example, one of copper and the other of zinc—with a

connecting medium, which is usually a liquid, but which may be a piece of
moistened cloth or blotting-paper. So long as the two plates of metal are not
otherwise connected there is no electricity in evidence, but when the two
are joined by any metal conductor, as, for example, a piece of wire—thus,
in common parlance, "completing the circuit"—a current of electricity
flows about this circuit, passing from the first metal plate to the second,
through the liquid and back from the second plate to the first through the
piece of wire. The wire may be of any length. In the case of your call-bell,
for example, the wire circuit extends to your door, and is there broken,
shutting off the current.
When you press the button you connect the broken ends of the wire, thus
closing the circuit, as the saying is, and the re-established current, acting
through a little electromagnet, rings the bell. In another case, the wire may
be hundreds of miles in length, to serve the purposes of the telegrapher, who
transmits his message by opening and closing the circuit, precisely as you
operate your door-bell. For long-distance telegraphy, of course, large cells
are required, and numbers of them are linked together to give a cumulative
effect, making a strong current; but there is no new principle involved.
The simplest study of this interesting mechanism makes it clear that the
cell is the apparatus primarily involved in generating the electric current;
yet it is equally obvious that the connecting wire plays an important part,
since, as we have seen, when the wire is broken there is no current in
evidence. Now, according to the electron theory, as previously outlined, the
electric current consists of an actual flow along the wire of carriers of
electricity which are unable to make their way except where a course is
provided for them by what is called a conductor. Dry air, for example, is,
under ordinary circumstances, quite impervious to them. This means, then,
that the electrons flow freely along the wire when it is continuous, but that
they are powerless to proceed when the wire is cut. When you push the
button of your call-bell, therefore, you are virtually closing the switch
which enables the electrons to proceed on their interrupted journey.

THEORIES OF ELECTRICAL ACTION

But all this, of course, leaves quite untouched the question of the origin
of the electrons themselves. That these go hurtling from one plate or pole of
the battery to the other, along the wire, we can understand at least as a

working theory; that, furthermore, the electrons have their origin either in
the metal plates or in the liquid that connects them, seems equally obvious;
but how shall we account for their development? It is here that the chemist
with his atomic theory of matter comes to our aid. He assures us that all
matter consists in the last analysis of excessively minute particles, and that
these particles are perpetually in motion. They unite with one another to
form so-called molecules, but they are perpetually breaking away from such
unions, even though they re-establish them again. Such activities of the
atoms take place even in solids, but they are greatly enhanced when any
substance passes from the solid into the liquid state.
When, for example, a lump of salt is dissolved in water, the atoms of
sodium and of chlorine which joined together make up the molecules of salt
are held in much looser bondage than they were while the salt was in a dry
or crystalline form. Could we magnify the infinitesimal particles
sufficiently to make them visible we should probably see large numbers of
the molecules being dissociated, the liberated atoms moving about freely
for an instant and then reuniting with other atoms. Thus at any given instant
our solution of salt would contain numerous free atoms of sodium and of
chlorine, although we are justified in thinking of this substance as a whole
as composed of sodium-chlorine molecules. It is only by thus visualizing
the activity of the atoms in a solution that we are able to provide even a
thinkable hypothesis as to the development of electricity in the voltaic cell.
What puts us on the track of the explanation we are seeking is the fact
that the diverse atoms are known to have different electrical properties. In
our voltaic cell, for example, sodium atoms would collect at one pole and
chlorine atoms at the other. Humphry Davy discovered this fact in the early
days of electro-chemistry, just about a century ago. He spoke of the sodium
atom as electro-positive, and of the chlorine atom as electro-negative, and
he attempted to explain all chemical affinity as merely due to the mutual
attraction between positively and negatively electrified atoms. The modern
theorist goes one step farther, and explains the negative properties of the
chlorine atom by assuming the presence of one negative electron or
electricity in excess of the neutralizing charge. The assumption is, that the
sodium atom has lost this negative electron and thus has become positively
electrified. The chlorine atom, harboring the fugitive electron, becomes

negatively electrified. Hence the two atoms are attracted toward opposite
poles of the cell.
This disunion of atoms, be it understood, must be supposed to take place
in the case of any solution of common salt, whether it rests in an ordinary
cup or forms a part of the ocean. Here we have, then, material for the
generation of the electrical current, if some means could be found to induce
the chlorine atom to give up the surplus electron which from time to time it
carries. And this means is provided when two pieces of metal of different
kinds, united with a metal conductor, are immersed in the liquid. Then it
comes to pass that the electrons associated with the chlorine atoms that
chance to lie in contact with one of these plates of metal, find in this metal
an avenue of escape. They rush off eagerly along the metal and the
connecting wire, and in so doing establish a current which acts—if we may
venture a graphic analogy from an allied field of physics—as a sort of
suction, attracting other chlorine atoms from the body of the liquid against
the metal plate that they also may discharge their electrons. In other words,
the electrical current passes through the liquid as well as through the
outside wire, thus completing the circuit.
According to this theory, then, the electrical energy in evidence in the
current from the voltaic cell, is drawn from a store of potential energy in the
atoms of matter composing the liquid in the cell. In practice, as is well
known, the liquid used is one that affects one of the metal poles more
actively than the other, insuring vigorous chemical activity. But the
principle of atomic and electrical dissociation just outlined is the one
involved, according to theory, in every voltaic cell, whatever the particular
combination of metals and liquids of which it is composed. It should be
added, however, that while we are thus supplied with a thinkable
explanation of the origin of this manifestation of electrical energy, no
explanation is forthcoming, here any more than in the case of the dynamo,
as to why the electrons rush off in a particular direction and thus establish
an electrical current. Perhaps we should recall that the very existence of this
current has at times been doubted. Quite recently, indeed, it has been held
that the seeming current consists merely of a condition of strain or
displacement of the ether. But we are here chiefly concerned with the
electron theory, according to which, as we have all along noted, the seeming

current is an actual current; the ether strain, if such exists, being due to the
passage of the electrons.

PRACTICAL USES OF ELECTRICITY

Various effects of the current of electrons have been hinted at above.
Considered in detail, the possible ways in which these currents may be
utilized are multifarious. Yet, they may be all roughly classified into three
divisions as follows:
First, cases in which the current of electricity is used to transmit energy
from one place to another, and reproduce it in the form of molar motion.
The dynamo, in its endless applications, illustrates one phase of such
transportation of energy; and the call-bell, the telegraph, and the telephone
represent another phase. In one case a relatively large quantity of electricity
is necessary, in the other case a small quantity; but the principle involved—
that of electric and magnetic induction—is the same in each.
The second method is that in which the current, generated by either a
dynamo or a battery of voltaic cells, is made to encounter a relatively
resistant medium in the course of its flow along the conducting circuit. Such
resistance leads to the production of active vibrations among the particles of
the resisting medium, producing the phenomena of heat and, if the activity
is sufficient, the phenomena of light also. It will thus appear that in this
class of cases, as in the other, there is an actual re-transformation of
electrical energy into the energy of motion, only in this case the motion is
that of molecules and not of larger bodies. The principle is utilized in the
electrical heater, with which our electric street-cars are commonly provided,
and which is making its way in the household for purposes of general
heating and of cooking. It is utilized also in various factories, where the
very high degree of heat attainable with the electrical furnace is employed
to produce chemical dissociation and facilitate chemical combinations. By
this means, for example, a compound of carbon and silicon, which is said to
be the hardest known substance, except the diamond, is produced in
commercial quantities. A familiar household illustration of the use of this
principle is furnished by the electric light. The carbon filament in the
electric bulb furnishes such resistance to the electric current that its particles
are set violently aquiver. Under ordinary conditions the oxygen of the air
would immediately unite with the carbon particles, volatilizing them, and

thus instantly destroying the filament; but the vacuum bulb excludes the air,
and thus gives relative permanency to the fragile thread.
The third class of cases in which the electric current is commercially
utilized is that in which the transformations it effects are produced in
solutions comparable to those of the voltaic cell, the principles involved
being those pointed out in the earlier part of the present chapter. By this
means a metal may be deposited in a pure state upon the surface of another
metal made to act as a pole to the battery; as, for example, when forks,
spoons, and other utensils of cheap metals are placed in a solution of a
silver compound, and thus electroplated with silver. To produce the
powerful effects necessary in the various commercial applications of this
principle, the poles of the voltaic cell—which cell may become in practice a
large tank—are connected with the current supplied by a dynamo. Various
chemical plants at Niagara utilize portions of the currents from the great
generators there in this way. Another familiar illustration of the principle is
furnished by the copper electroplates from which most modern books are
printed.
It appears, then, that all the multifarious uses of electricity in modern life
are reducible to a few simple principles of action, just as electricity itself is
reduced, according to the analysis of the modern physicist, to the activities
of the elementary electron. There is nothing anomalous in this, however, for
in the last analysis the mechanical principles involved in doing all the
world's work are few and relatively simple, however ingenious and
relatively complex may be the appliances through which these principles
are made available.

IX
MAN'S NEWEST CO-LABORER: THE DYNAMO

A
s you stand waiting for your train at elevated or subway station you
must have noticed the third rail. To outward appearance it is not
different from the other rails. It seems a mere inert piece of steel.
Yet you are well aware that a strange power abides there unseen—a
power that pulls the train, and that lurks in hiding to strike a death-blow to
any chance unfortunate whose foot or hand comes in contact with the rail.
As the heavy train dashes up, dragged by this unseen power, probably you,
in common with the rest of the world, have been led to remark, "Is it not
marvelous?"
Marvelous it surely seems. Yet the cause of our astonishment is to be
sought in the relative newness of the phenomena rather than in the nature of
the phenomena themselves. At first glance it may seem that the intangible
character of the electrical power gives it a unique claim on our wonderment.
But a moment's reflection dispels this illusion. After all, electricity is no
more intangible than heat. Neither the one nor the other can be seen or
heard, but each alike may be felt. Yet we observe without astonishment a
locomotive propelled by the power of heat—simply because the locomotive
has become an old story. Again, electricity is far less intangible than
gravitation. Not merely may electricity be felt, but it may be generated
through transformation of other forms of energy; it may be stored away and
measured; may be conducted at will through tortuous channels, or
obstructed in its flight by the intervention of non-conductors. But
gravitation submits to no such restrictions. It eludes all of our senses, and it
absolutely disregards all barriers. To its catholic taste all substances are
alike. It holds in bondage every particle of matter in the universe, and can
enforce its influence over every kind of atom with an impartiality that is as
astounding as it is inexorable. Moreover, this weird force, gravitation, has
thus far evaded all man's efforts to classify or label it. No man has the
slightest inkling as to what gravitation really is. If, as you glance at these
lines, you should chance to release your hold and allow the volume to drop

to the floor, you will have performed a miracle which no scientist in the
world can even vaguely explain.
As regards our electric train, then, the fact that it stands there firmly, held
fast to the rails by gravitation, is in reality as great and as inexplicable a
marvel as the fact that the electric current gives it propulsion. Not only so,
but the fact that the train goes forward of its own inertia, as we say, for a
time after the current is shut off, presents to us yet another inexplicable
marvel. It is a fundamental property of matter, we say, when once in motion
to continue in motion until stopped by some counter-force; but that
phrasing, expressive though it be of a fact upon which so many physical
phenomena depend, is in no proper sense of the word an explanation.
Once for all, then, there is nothing unique, nothing preternaturally
marvelous, about the phenomena of electricity. And indeed, it is interesting
to note how quickly we become accustomed to these phenomena, and how
little wonder they excite so soon as they cease to be novel. Even
imaginative people have long since ceased to give thought to the trolley car;
and within a week of the opening of New York's subway the average man
came to regard it as much as a matter of course as if he had been
accustomed to it from boyhood.
And yet, in another sense of the word, the electric motor is a wonderful
contrivance. As an example of what man's ingenuity can accomplish toward
transforming the powers of nature and adapting them to his own use, it is
fully entitled to be called a marvel. Moreover, in the last analysis, we are as
helpless to explain the nature of electricity as we are to explain the nature of
gravitation. It is only the proximal phenomena of the electric current that
can be explained. These phenomena, however, are full of interest. Let us
examine them somewhat in detail, allowing them to lead us back from
electric train to power-house and dynamo, and from dynamo as far toward
the mystery of electric energy as present-day science can guide us.

THE MECHANISM OF THE DYNAMO

If we could look into the interior of a mechanism in connection with the
trucks beneath the car, we should find an apparatus consisting essentially of
coils of wire adjusted compactly about an axis, and closely fitted between
the poles of a powerful electromagnet. These coils of wire constitute what is

called an armature. When the current is switched on it passes through this
armature, as well as through the electromagnet, and the mutual attractions
and repulsions between the magnetic poles and the electric current in the
coils of wire, cause the armature to revolve with such tremendous energy as
to move the train—the motion of its axis being transmitted to the axle of the
car-wheels by a simple gearing.
All this is simple enough if we regard only the how and not the why of
the phenomena. Ignoring the why for the moment, let us seek the origin of
the current which, by being conducted through the armature, has produced
the striking effect we have just witnessed. This current reaches the car
through an overhead or underground wire. All that is essential is that some
conducting medium, such as an iron rail, or a copper wire, shall form an
unbroken connection between the motor apparatus and the central dynamo
where the power is generated—the return circuit being made either by
another wire or by the ordinary rails.
The central dynamo in question will be found, if we visit the power-
house, to be a ponderous affair, suggestive to the untechnical mind of
impenetrable mysteries. Yet in reality it is a device essentially the same in
construction as the motor which drives the train. That is to say, its unit of
construction consists of a wire-wound armature revolving on an axis and
fitted between the poles of an electromagnet. Here, however, the sequence
of phenomena is reversed, for the armature, instead of receiving a current of
electricity, is made to revolve by a belt adjusted to its axis and driven by a
steam engine. The wire coils of the armature thus made to revolve cut
across the so-called lines of magnetic force which connect the two poles of
the magnet, and in so doing generate a current of induced electricity, which
flows away to reach in due course the third rail or the trolley-wire, and
ultimately to propel the motor.

AN ELECTRIC TRAIN AND THE DYNAMO THAT PROPELS
IT.

Lower figure copyrighted by N. Y. Edison Co.
The lower figure gives an interior view of a power house of the
Manhattan Elevated Railway Company. The upper figure shows one
of the electric engines operating on the New York Central Lines just
outside of New York. The power is conveyed to the engine by a third
rail clearly shown in the picture.
It is hardly necessary to state that in actual practice this generating
dynamo is a complex structure. The armature is a complex series of coils of
wire; the electromagnets surrounding the armature are several or many; and
there is an elaborate system of so-called commutators through which the
currents of electricity—which would otherwise oscillate as the revolving
coil cuts the lines of magnetic force in opposite directions—are made to
flow in one direction. But details aside, the foundation facts upon which
everything depends are (1) that a coil of wire when forced to move so that it

cuts across the lines of force in any magnetic field develops a so-called
induced current of electricity; and (2) that such an induced current
possesses power of magnetic attraction and repulsion. These facts were
discovered more than sixty years ago, and carefully studied by Michael
Faraday, Joseph Henry, and others. Faraday found that such an induced
current could be produced not merely with the aid of an iron magnet, but
even by causing a wire to cut the lines of force that everywhere connect the
north and south poles of the earth,—the earth being indeed, as William
Gilbert long ago demonstrated, veritably a gigantic magnet. Moreover,
these relations are reciprocal; so that if a wire through which a current of
electricity is passing is placed across a magnetic field, the wire is impelled
to move in a plane at right angles to the direction of the lines of force. It is
forcibly thrust aside. This side-thrust acting on coils of wire is what
produces the revolution of the armature of the electric motor.

THE ORIGIN OF THE DYNAMO

The very first studies that had to do with the mutual relations of
electricity and magnetism were made by Hans Christian Oersted, the Dane,
as early as 1815. He discovered that a magnetic needle is influenced by the
passage near it of a current of electricity, demonstrating, therefore, that the
electric current in some way invades the medium surrounding any
conductor along which it is passing. Oersted's experiments were repeated,
and some new phenomena observed by the Frenchman André Marie
Ampère and Dominique François Arago. Arago constructed an interesting
device, in which a metal disk was made to revolve in the presence of a
current of electricity; but neither he nor anyone else at the time was able to
explain the phenomenon.
In 1824 an advance was made through the construction of the first
electric magnet by Sturgeon. Hitherto it had not been known that a magnet
could be made artificially, except by contact with a previously existing
magnet. Sturgeon showed that any core of iron may be rendered magnetic if
wound with a conducting wire, through which a current of electricity is
passed. The experiments thus inaugurated were followed up in America by
Joseph Henry of Albany who made enormous electromagnets, capable of
sustaining great weights. One of his magnets, operated by a single cell, was
able to lift six hundred and fifty pounds of metal.

It was this apparatus which was subsequently to make possible the
utilization of electricity as a working force, but as yet no one suspected its
possibilities in this direction.
It remained for Michael Faraday, in 1831, to make the final experiment
which laid the secure foundation for the new science of electrodynamics.
Faraday constructed a tiny apparatus, consisting of a magnet between the
poles of which a metal disk was placed in such a way that it could revolve
on an axis, the disk being connected with a wire conveying an electric
current.
The details as to this most ingenious mechanism need not be given here.
Suffice it that Faraday demonstrated the interrelations of magnetism and
electricity and the possibility of causing a metal disk to revolve through this
mutual interaction. In so doing he constructed the first dynamo-electric
machine. In his hands it was a mere laboratory toy, but the principles
involved were fully elaborated by the original experimenter, and stated in
precise language which modern investigators have not been able to improve
upon.
Several decades elapsed after Faraday's initial experiment before the
phenomena of magneto-electricity were proved to have any considerable
commercial significance. A vast amount of ingenuity was required to devise
a mechanism which could advantageously utilize the principle in question
for commercial purposes. Indeed the early experimenters did not at once get
upon the right track, as their efforts were influenced disadvantageously by
an attempt to follow the principle of the steam engine. Some interesting
mechanisms were devised whereby the motion of an armature in being
drawn toward an electromagnet could be translated into rotary motion
through the use of crank-shafts and even of beams, precisely comparable to
those employed in the steam engine. Such devices worked with a
comparatively low degree of efficiency and were totally abandoned so soon
as the idea of getting rotary motion directly from the magnet or armature
was made feasible. The names of Saxton, Clarke, Woolrich, Wheatstone,
and Werner Siemens are intimately connected with the early efforts at
utilization of magneto-electric power. The shuttle-wound armature of
Siemens, invented in 1854, marked an important progressive step.

PERFECTING THE DYNAMO

The first separately excited dynamos were constructed by Dr. Henry
Wilde, F.R.S., between 1863 and 1865, and this invention paved the way for
rapid progress. In 1866-7 Varley, Siemens, Wheatstone, and Ladd
constructed machines with several iron electromagnets, self-excited, which
were described as dynamo-electric machines, a term afterward contracted to
dynamos. In 1867 Dr. Wilde improved the armature by introducing several
coils arranged around a cylinder; the current from a few of the coils was
rectified and used to excite the field magnet, while the main current as
given off by the rest of the coils was taken off by ring-contacts, the machine
being a self-exciting, alternating-current dynamo.

WILDE'S SEPARATELY EXCITED
DYNAMO.
Dr. Wilde invented and patented (1863-5) the
first separately excited dynamo, with which he
demonstrated that the feeble current from a
small magneto-electric machine would, by the
expenditure of mechanical power, produce
currents of great strength from a large
dynamo.
The Italian, Picnotti, in 1864 invented a ring armature which, although
provided with teeth was wound with coils in such a way as to obtain a very
uniform current; but the practical introduction of the continuous-current
machines dates from 1870, when Gramme re-invented the ring and gave it
the form which is still in vogue. Von Alteneck in 1873 converted the
Siemens shuttle armature along the same lines and so introduced the drum
arrangement which has since been very extensively adopted.
Thus through the efforts of a great number of workers the idea of
utilizing electromagnetic energy for the purposes of the practical worker
came to be a reality. Numberless machines have been made differing only
as to details that need not detain us here. Everyone is familiar with sundry
applications of the dynamo to the purposes of to-day's applied science. It
must be understood, of course, that the amount of electricity generated in
any dynamo is precisely measurable, and that by no possibility could the
energy thus developed exceed the energy required to move the coils of wire.
Were it otherwise the great law of the conservation of energy would be
overthrown. In actual practice, of course, there is loss of energy in the
transaction. The current of electricity that flows from the very best dynamo
represents considerably less working power than is expended by the steam
engine in forcibly revolving the armature. In the early days of experiments
the loss was so great as to be commercially prohibitive. With the perfected
modern dynamo the loss is not greater than fifteen per cent; but even this, it
will be noted, makes electricity a relatively expensive power as compared
with steam,—except, indeed, where some natural power, like the Falls of
Niagara, can be utilized to drive the armature.

A MYSTERIOUS MECHANISM

The efficiency of the modern dynamo is due largely to the fact that when
the poles of the magnet are made to face each other, the lines of magnetic
force passing between these poles are concentrated into a narrow compass.
With the ordinary bar magnet, as everyone is aware, these lines of force
circle out in every direction from the poles in an almost infinite number of
loops, all converging at the poles, and becoming relatively separated at the
equator in a manner which may be graphically illustrated by the lines of
longitude drawn on an ordinary globe.
It is obvious that with a magnet of such construction only a small
proportion of the lines of magnetic force could be utilized in generating
electricity. But, as already mentioned, when the magnet is so curved that its
poles face each other, the lines of force, instead of widely diverging, pass
from pole to pole almost in a direct stream. The strength of this magnetic
stream may be increased almost indefinitely by winding the iron core of the
magnet with the coil of wire through which the electric current is passed,
thus constituting the electromagnet which has replaced the old permanent
magnet in all modern commercial dynamos.

THE EVOLUTION OF THE DYNAMO.
Fig. 1.—A small example of the original
commercial form of the drum armature machine,
patented in 1873 by Dr. Werner Siemens and F. Von
Hefner Alteneck. The armature is a development of
the Siemens shuttle form of 1856, and gives a
nearly continuous current. Fig. 2.—An early
experimental dynamo. Fig. 3.—Ferranti's original
dynamo, patented in 1882-1883. The field magnets
are stationary and consist of two sets of electro-

magnets each with 16 projecting pull pieces,
between which the armature revolves. Fig. 4.—The
gigantic rotary converters of the Manhattan
Elevated Railway.
An electromagnet may be sufficiently powerful to lift tons of iron. The
force it exerts, therefore, is very tangible in its results. Yet it seems
mysterious, because so many substances are unaffected by it. You may
place your head, for example, between the poles of the most powerful
magnet without experiencing any sensation or being in any obvious way
affected. You may wave your hand across the lines of force as freely as you
may wave it anywhere else in space. Apparently nothing is there. But were
you to attempt to pass a dumb-bell or a bar of iron across the same space,
the unseen magnetic force would wrench it from your grasp with a power so
irresistible as to be awe-inspiring.
Similarly, the armature, when its coils of wire are adjusted between the
poles of the magnet, is held in a vise-like grip by the invisible but potent
lines of magnetic force which tend to make it revolve. It requires a
tremendous expenditure of energy—supplied by the steam-engine or by
water power—to enable the coiled wires of the generating armature to stem
the current of magnetic force, which is virtually what is done when the
armature revolves in such a way as to produce electrical energy. Part of the
mechanical energy thus expended is transformed into heat and dissipated
into space; but the main portion is carried off, as we have seen, through the
coiled wires of the armature in the form of what we term the current of
electricity, to be re-transformed in due course into the mechanical energy
that moves the car.
It appears, then, that the phenomena of the electric dynamo depend upon
the curious relations that exist between magnetism and electricity. Granted
the essential facts of magneto-electric induction, all the phenomena of the
dynamo are explicable. But how explain these facts themselves? Why is an
electric current generated in a coil of wire moving in a magnetic field? And
why is a wire carrying a current of electricity, when placed across a
magnetic field, impelled to move at right angles to the lines of magnetic
force? No thoughtful person can consider the subject without asking these
questions. But as yet no definitive answer is forthcoming. Some suggestive
half-explanations, based on an assumed condition of torsion or strain in the

ether, have been attempted, but they can hardly be called more than
scientific guesses.
Meanwhile, it may be understood that the mutual relations of the
magnetic and electrical forces just referred to are not at all dependent upon
the manner in which the electric current is generated. The magneto-electric
motor may be operated as well with a chemical battery as with such a
mechanical generating dynamo as has just been described. The storage-
batteries which have been employed in some street railways and those
which propel the electric cabs about our city streets furnish cases in point.
The only reason these are not more generally employed is that the storage
battery has not yet been perfected so that it can produce a large supply of
electricity in proportion to its weight, and produce it economically.

X
NIAGARA IN HARNESS

"H
arnessing Niagara"—the phrase has been a commonplace for a
generation; but until very recently indeed it was nothing more
than a phrase. Almost since the time when the Falls were first
viewed by a white man the idea of utilizing their powers has
been dreamed of. But until our own day—until the last decade—science
had not shown a way in which the great current could be economically
shackled. A few puny mill-wheels have indeed revolved for thirty years or
so, but these were of no greater significance than the thousands of others
driven by mountain streams or by the currents of ordinary rivers. But about
a decade ago the engineering skill of the world was placed in commission,
and to-day Niagara is fairly in harness.
If you have ever seen Niagara—and who has not seen it?-you must have
been struck with the metamorphosis that comes over the stream about half a
mile above the falls. Above this point the river flows with a smooth
sluggish current. Only fifteen feet have the waters sunk in their placid
flowing since they left Lake Erie. But now in the course of half a mile they
are pitched down more than two hundred feet. If you follow the stream
toward this decline you shall see it undergo a marvelous change. Of a
sudden the placid waters seem to feel the beckoning of a new impulse.
Caught with the witchery of a new motion, they go swirling ahead with
unwonted lilt and plunge, calling out with ribald voices that come to the ear
in an inchoate chorus of strident, high-pitched murmurings. Each wavelet
seems eager to hurry on to the full fruition of the cataract. It lashes with
angry foam each chance obstruction, and gurgles its disapproval in ever-
changing measures. Even to the most thoughtless observer the mighty
current thus unchained attests the sublimity of almost irresistible power.
Could a mighty mill-wheel be adjusted in that dizzy current, what labors
might it not perform? Five million tons of water rush down this decline
each hour, we are told; and the force that thus goes to waste is as if three
million unbridled horses exhausted their strength in ceaseless plunging.

This estimate may be only a guess, but it matters not whether it be high or
low; all estimates are futile, all comparisons inadequate to convey even a
vague conception of the majesty of power with which the mighty waters
rush on to their final plunge into the abysm.
It is here, you might well suppose, where the appalling force of the
current is made so tangible, that man would place the fetters of his harness,
making the madcap current subject to his will. You will perhaps more than
half expect to see gigantic mechanisms of man's construction built out over
the rapids or across the face of the cataract—so much has been said of
æstheticism versus commercialism in connection with the attempt to utilize
Niagara's power. But whatever your fears in this regard, they will not be
realized. Inspect the rapids and the falls as you may, you will see no
evidence that man has tampered with their pristine freedom. Subtler means
have been employed to tame the wild steed. The mad waves that go dashing
down the rapids are as free and untrammeled to-day as they were when the
wild Indian was the only witness of their tempestuous activity. Such
portions of the current as reach the rapids have full license to pass on
untrammeled, paying no toll to man. The water which is made to pay tribute
is drawn from the stream up there above the rapids, where it lies placid and
as yet unstirred by the beckoning incline. To see Niagara in harness, then,
you must leave the cataract and the rapids and pass a full mile up the stream
where the great river looks as calm as the Hudson or the Mississippi, and
where, under ordinary conditions, not even the sound of the falls comes to
your ear.
Prosaic enough it seems to observe here nothing more startling than a
broad cul de sac of stagnant water, like the beginning of a broad canal,
extending in for a few hundred yards only from the main stream; its waters
silent, currentless, seemingly impotent. This stagnant pool, then, not the
whirling current below, is to furnish the water whose reserve force of
energy of position is drawn upon to serve man's greedy purpose. Coming
from the rapids and cataract to this stagnant canal, you seem to step from
the realm of poetic beauty to the sordid realities of the work-a-day world.
Of a truth it would seem that "harnessing Niagara" is but a far-fetched
metaphor.

WITHIN THE POWER-HOUSE

And yet if you will turn aside from the canal and enter one of the long,
low buildings that flank it on either side, you will soon be made to feel that
the metaphor was amply justified. Little as there was exteriorly to suggest
it, you are entering a fairyland of applied science, and within these plain
walls you shall witness evidences of the ingenuity of man that should
appeal scarcely less to your imagination than the sight of the cataract itself
in all its sublimity of power.
For within these walls, by a miracle of modern science, the potential
energy which resides in the water of the canal is transformed into an
electrical current which is sent out over a network of wires to distant cities
to perform a thousand necromantic tasks,—propelling a street car in one
place, effecting chemical decompositions in another; turning the wheels of a
factory here and lighting the streets of a city there; in short, subserving the
practical needs of man in devious and wonderful ways.
Even as you gazed disdainfully at the stagnant canal, its waters,
miraculously transformed, were propelling the trolley cars along the brink
of the cliff over there on the Canadian shore, and at the same time were
turning the wheels in many a factory in the distant city of Buffalo. After all,
then, the quiet pool of water was not so prosaic as it seemed.
As you stand in the building where this wonderful transformation of
power is effected, the noble simplicity of the vista heightens the mystery.
The most significant thing that strikes the eye is a row of great mushroom-
like affairs, for all the world like giant tops, that stand spinning—and
spinning. These great tops are about a dozen feet in diameter. They are
whirling, so we are told, at a rate of two hundred and fifty revolutions per
minute. Hour after hour they spin on, never varying in speed, never
faltering; day and night are alike to them, and one day is like another. They
are as ceaselessly active, as unwearying as Niagara itself, whose power they
symbolize; and, like the great Falls, they murmur exultingly as they work.

VIEW IN ONE OF THE POWER HOUSES AT
NIAGARA.
Each of the top-like dynamos generates 5000
horse-power.
The giant tops which thus seem to bid defiance to the laws of motion are
in reality electric dynamos, no different in principle from the electric
generators with which some visit to a street-car power-house has doubtless
made you familiar. The anomalous feature of these dynamos—in addition to
their size—is found in the fact that they revolve on a vertical shaft which

extends down into a hole in the earth for more than a hundred feet, and at
the other end of which is adjusted a gigantic turbine water-wheel. Water
from the canal is supplied this great turbine wheel through a steel tube or
penstock, seven feet in diameter. As the turbine revolves under stress of this
mighty column of water, the long shaft revolves with it, thus turning the
electric generator at the other end of the shaft—the generator at which we
are looking, and which we have likened to a giant top—without the
interposition of any form of gearing whatever.
To gain a vivid mental picture of the apparatus, we must take an elevator
and descend to the lower regions where the turbine wheel is in operation.
As we pass down and down, our eyes all the time fixed on the vertical
revolving shaft, which is visible through a network of bars and gratings, it
becomes increasingly obvious that to speak of this shaft as standing in "a
hole in the ground" is to do the situation very scant justice. A much truer
picture will be conceived if we think of the entire power-house as a monster
building, about two hundred feet high, all but the top story being
underground. What corresponds to the ground floor of the ordinary building
is located one hundred and fifty feet below the earth's surface; and it is the
top story which we entered from the street level, thus precisely reversing
the ordinary conditions.

PENSTOCKS AND TURBINES

As we descend now and reach at last the lowest floor of the building, we
step out into a long narrow room, the main surface of which is taken up
with a series of gigantic turnip-shaped mechanisms, each one having a
revolving shaft at its axis; while from its side projects outward and then
upward a seven-foot steel tube, for all the world like the funnel of a
steamship. This seeming funnel—technically termed a penstock—is in
reality the great tube through which the massive column of water finds
access to the turbine wheel, which of course is incased within the turnip-
shaped mechanism at its base.
As you stand there beside this great steel mechanism a sense of
wonderment and of utter helplessness takes possession of you. As you
glance down the hall at this series of great water conduits, and strain your
eyes upward in the endeavor to follow the great funnel to its very end, an
oppressive sense of the irresistible weight of the great column of water it

supports comes to you, and you can scarcely avoid a feeling of
apprehension. Suppose one of the great tubes were to burst?—we should all
be drowned like rats in a hole. There is small danger, to be sure, of such a
contingency; but it is well worth while to have stood thus away down here
at the heart of the great power-house to have gained an awed sense of what
man can accomplish toward rivaling the wonders of nature. To have stood
an hour ago on the ice bridge at the foot of the most tremendous cataract in
the world, where Nature exhausts her powers amidst the mad rush and roar
of seething waters; and now to stand beneath this other column of water
which effects a no less wonderful transformation of energy, serenely,
silently,—is to have run such a gamut of emotions as few other hours in all
your life can have in store for you.

A MIRACULOUS TRANSFORMATION OF ENERGY

There are eleven of these great turbine mechanisms, each with a
supplying funnel of water and a revolving shaft extending upward to its
companion dynamo, in the room in which we stand. Energy representing
fifty-five thousand horse-power is incessantly transformed and made
available for man's use in the subterranean building in which we stand. And
there is not a pound of coal, not a lick of flame, not an atom of steam
involved in the transformation. There are no dust-grimed laborers; there is
no glare of furnace, no glow of heat, no stifling odor of burning fuel;—there
is only the restful hum of the machinery that responds to the ceaseless flow
of the silent and invisible waters. Day and night the mighty river here pulls
away at its turbine harness; and man, having once adjusted that harness,
may take his ease and enjoy the fruits of his ingenuity.
As we return now to the top of the building, we shall view the spinning
dynamos with renewed interest, and a few facts regarding their output of
energy may well claim our attention. In their principle of action, as we have
seen, all dynamos are alike,—depending upon the mutual relations between
the wire-wound armature and a magnetic field. In the present case the
magnets are made to revolve and the armatures are stationary, but this is a
mere detail. There is one feature of these dynamos, however, which is of
greater importance,—the fact namely that they operate without
commutators, and therefore produce alternating currents. This fact has an
important bearing upon the distribution of the current. Each of the dynamos

before us generates the equivalent of five thousand horse-power of energy.
There are eleven such dynamos here before us; there are ten more in the
power-house on the other side of the canal, giving a total of one hundred
and five thousand horse-power for this single plant; and there are five such
plants now in existence or in course of construction to utilize the waters of
Niagara, three being on the Canadian shore. When in full operation the
aggregate output of these plants will be six or seven hundred thousand
horse-power.

SUBTERRANEAN TAIL-RACES

As we step from the door of the power-house and stand again beside the
canal whose waters produce the wonderful effects we have witnessed in
imagination, one question remains to be answered: What becomes of the
water after it has passed through the turbine wheels down there in the
depths? The answer is simple: All the water from the various turbines flows
away into a great subterranean canal which passes down beneath the city of
Niagara Falls, and discharges finally at the level of the rapids a few hundred
yards below the Falls. The construction of this subterranean canal would in
itself have been considered a great engineering feat a few decades ago; but
of late years mountain tunnels, such subterranean railways as the London
"tube system" and tunnels beneath rivers have robbed such structures of
their mystery. It may be added that another such subterranean canal, to
serve as a tail-race for one of the new Canadian plants, extends beneath the
cataract itself, discharging not far from the centre of the Horseshoe Falls.
Another of the power companies utilizes the water of the old surface canal
which extends to the brink of the gorge some distance below the Falls. Yet
another company on the Canadian side conveys water from far above the
rapids in a gigantic closed tube to the brink of the gorge just below the
Canadian Falls, above the point where their power-house is located.
But the principle involved is everywhere the same. The idea is merely to
utilize the weight of falling water. The water of Niagara River is of course
no different from any other body of water of equal size. It is merely that its
unique position gives the engineer an easy opportunity to utilize the
potential energy that resides in any body of water—or, for that matter, in
any other physical substance—lying at a high level. In due course,
doubtless, other bodies of water, such as mountain lakes and mountain

streams will be similarly put into electrical harness. The electrical feature is
of course the one that most appeals to the imagination. But it may be well to
recall that the ultimate source of all the power in question is gravitation.
People fond of philosophical gymnastics may reflect with interest that,
according to the newest theory, gravitation itself is, in the last analysis, an
electrical phenomenon—a reflection which, it will be noted, leads the mind
through a very curious cycle.

THE EFFECT ON THE FALLS

Much solicitude has been expressed as to the possible effect, upon the
Falls themselves, of this withdrawal of water. For the present, it is admitted,
there is no visible effect; and to the casual observer it may seem that almost
any quantity of water the power-houses are likely to need might be
withdrawn without seriously marring the wonderful cataract. But the
statistics supplied by the power companies, taken in connection with
estimates as to the bulk of water that passes over the Falls, do not support
this optimistic view. Taking what seems to be a reasonable estimate for a
basis of computation it would appear that when the power-houses now
rapidly approaching completion are in full operation, the total withdrawal of
water from the stream will represent a very appreciable fraction of its entire
bulk—one-twenty-fifth at the very least, perhaps as much as one-tenth.
Such a diminution as this will by no means ruin the Falls, yet it would seem
as if it must sensibly affect them, particularly at some places near Goat
Island, where the water flows at present in a very shallow stream. Be that as
it may, however, the power-houses are there, and it is probable that their
number will be added to as years go on. Whether commercialism or
æstheticism will win in the end, it remains for the legislators of the future to
decide.
Meanwhile, it is gratifying to reflect that for the present the Falls retain
their pristine beauty, even though part of the water that is their normal due
is turned aside and made to do service for man in another way. There is only
one reason why the Falls have escaped desecration so long as they have;
that reason being the very practical one that until quite recently man has not
known how to utilize their powers to advantage. The effort was indeed
made, a full generation ago, through the construction of the canal leading
from the upper river to the bluffs overlooking the gorge below the cataract.

Here a few mill-wheels were set whirling, and a tiny fraction of the
potential energy of the water was utilized. There was no mechanical
difficulty involved in the utilization of this power. Mill-wheels are a
familiar old-time device, and even the turbine wheel is modern only in a
relative sense of the word. And it must be understood that the turbine water-
wheel utilizes the greatest proportion of the power of falling water of any
contrivance as yet known to mechanics. It was possible, then, to utilize the
water of Niagara with full effectiveness fifty years ago, so far as the direct
action of the water-wheel upon machinery near at hand was concerned. The
sole difficulty lay in the fact that only a small amount of machinery can be
placed in any one location. The real problem was not how to produce the
power, but how to transmit it to a distance.

THE TRANSMISSION OF POWER

For fifty years mechanical engineers have looked enviously upon
unshackled Niagara, and have striven to solve the problem of transmitting
its power. It were easy enough to harness the great Fall, but futile to do so,
so long as the power generated must be used in the immediate vicinity. So,
many schemes for transmitting power were tried one after another, and as
often laid aside. There was one objection to even the best of them—the
cost. At one time it was thought that compressed air might solve the
problem. But repeated experiments did not justify the hope. Then it was
believed that the storage battery might be made available. The storage
battery, it might be explained, does not really store electricity in the sense in
which the Leyden jar, for example, stores it. Rather is it to be likened to an
ordinary voltaic cell, the chemical ingredients of which have been rendered
active by the passage of the electric current. The active ingredients of the
storage battery are usually lead compounds, which through action of the
electric currents have been decomposed and placed in a state of chemical
instability. The dissociated molecule of the lead compound, when permitted
to reunite with the atoms with which it was formerly associated, will give
up electrical energy.
Such a storage battery might readily be charged with electricity generated
at Niagara Falls. It might then be conveyed to any part of the world, and, its
poles being connected, the charge of electricity would be made available.
Such storage batteries are in common use in connection with electric

automobiles, as we have seen. But the great difficulty is that they are
enormously heavy in proportion to the amount of electricity that they can
generate; therefore, their transportation is difficult and expensive. In
practice it is cheaper to produce electricity through the operation of a steam
engine in a distant city than to transmit the electricity with the aid of a
storage battery from Niagara. So the storage battery served as little as
compressed air to solve the engineer's problem.
When the electric dynamo became a commercial success for such
purposes as the operation of trolley lines it seemed as if the Niagara
problem was on the verge of solution. And so, in point of fact, it really was,
though more time was required for it than at first seemed needed. The
power generated by the dynamo could, indeed, be transmitted along a wire,
but not without great loss. Sir William Siemens, in 1877, had pointed out in
connection with this very subject of the wasted power of Niagara, that a
thousand horse-power might be transmitted a distance of, say, thirty miles
over a copper rod three inches in diameter. But a copper rod three inches in
diameter is enormously expensive, and when Siemens further stated that
sixty per cent of the power involved would be lost in transmission, it was
obvious that the method was far too wasteful to be commercially
practicable.
For a time the experimenters with the transmission of electricity along a
wire were on the wrong track. They were experimenting with a continuous
current which, as we have seen, is produced from an ordinary dynamo with
the aid of a commutator. But hosts of experiments finally made it clear that
this form of current, no matter how powerful it might be, is unable to
traverse considerable distance without great loss, being frittered away in the
form of heat.
But the very term "continuous current" implies the existence of a current
that is not continuous. In point of fact, we have already seen that a dynamo,
if not supplied with a commutator, will produce what is called an alternating
current, and such a current has long been known to possess properties
peculiar to itself. It is, in effect, an interrupted current, and it is sometimes
spoken of as if it really consisted of an alternation of currents which move
first in one direction and then in another. Such a conception is not really
justifiable. The more plausible explanation is that the alternating current is
one in which the electrons are not evenly distributed and move with

irregular motion. Perhaps we may think of the individual electrons of such a
current as oscillating in their flight, and, as it were, boring their way into the
resisting medium. In any event, experience shows that such a current, under
proper conditions, may be able to traverse a conducting wire for a long
distance with relatively small loss.
It must be understood, however, that the mere fact that a current
alternates is not in itself sufficient to make feasible its transmission to a
remote distance. To meet all the requirements a current must be of very high
voltage. This means, in so far as we can represent the conditions of one
form of energy in the terms of another, that it shall be under high pressure.
Fortunately a relatively simple apparatus enables the electrician to
transform a current from low to high voltage without difficulty. And so at
last the problem of transmitting power to a distance of many miles has been
solved. Electrical currents representing thousands of horse-power are to-day
transmitted from Niagara Falls to the city of Buffalo over ordinary wires,
with a loss that is relatively insignificant. A plant is in process of
construction that will similarly transmit the power to Toronto; and it is
predicted that in the near future the powers of Niagara will be drawn upon
by the factories of cities even as far distant as New York and Chicago.
Practical difficulties still stand in the way of such very distant transmission,
to be sure, but these are matters of detail, and are almost certain to be
overcome in the near future.
All this being explained, it will be understood that the sole reason why
the new power-houses at Niagara generate electricity is that electricity is the
one readily transportable carrier of energy. We have already explained that
there is loss of energy when the steam engine operates the dynamo. At
Niagara, of course, no steam is involved; it is the energy of falling water
that is transformed into the energy of the electrical current. Moreover, the
revolving dynamo is attached to the same shaft with the turbine water-
wheel, so that there is no loss through the interposition of gearing. Yet even
so, the electric current that flows from the dynamo represents somewhat
less of energy than the water current that flows into the turbine. This loss,
however, is compensated a thousandfold by the fact that the energy of the
electric current may now be distributed in obedience to man's will.

"STEP UP" AND "STEP DOWN" TRANSFORMERS

The dynamos in operation at Niagara do not differ in principle from those
in the street-car power-house, except in the fact that they are not supplied
with commutators. We have seen that these dynamos are of enormous size.
Those already in operation generate five thousand horse-power; others in
process of construction will develop ten thousand. The generator which
produces this enormous current is about eleven feet in diameter, and it
makes two hundred and fifty revolutions per minute. The armatures are so
wound that the result is an alternating current of electricity of twenty-two
hundred volts. This current represents, it has been said, raw material which
is to be variously transformed as it is supplied to different uses. To factories
near at hand, indeed, the current of twenty-two hundred volts is supplied
unchanged; but for more distant consumption it is raised to ten thousand
volts; and that portion which is sent away to the factories of Buffalo and
other equally distant places is raised to twenty-two thousand volts.

ELECTRICAL TRANSFORMERS.
The upper figure shows Ferranti's
experimental transformer built in 1888. It
has a closed iron circuit, built up of thin
strips filling the interior of the coil and
having their ends bent over and
overlapping outside. The lower figure
shows a simple transformer known as
Sturgeon's induction coil. The middle
figure gives a view of the series of

converters in the power house of the
Manhattan Elevated Railway.
The transformation from a relatively low voltage to the high one is
effected by means of what is called a step-up transformer. This is an
apparatus which brings into play a principle of electric induction not very
different from that which was responsible for the generation of the current
of electricity in the dynamo. The principle is that evidenced in the familiar
laboratory apparatus known as the Ruhmkorff coil. The transformer consists
essentially of a primary coil of relatively large wire, surrounded by, but
insulated from, a secondary coil of relatively fine wire. When the
interrupted current is sent through the primary coil of such an apparatus, an
induced counter-current is generated in the secondary coil. Of course there
is no gain in the actual quantity of electricity, but the voltage of the current
generated in the finer wire is greatly increased. For example, as we have
seen, the current that came from the dynamo at twenty-two hundred volts is
raised to ten thousand or twenty-two thousand volts. These proportions may
be varied indefinitely by varying the relative sizes and lengths of the
primary and secondary coils.
How shall we picture to ourselves the actual change in the current
represented by this difference in voltage? We might prove, readily enough,
that the difference is a real one, since a wire carrying a current of low
voltage may be handled with impunity, while a similar wire carrying a
current of high voltage may not safely be touched. But when we attempt to
visualize the difference in the two currents we are all at sea. We may
suppose, of course, that electrons spread out over a long stretch of the
secondary coil must be more widely scattered. One can conceive that the
electrons, thus relatively unimpeded, may acquire a momentum, and hence
a penetrative power, which they retain after they are crowded together in a
straight conductor. But this suggestion at best merely hazards a guess.
Arrived at the other end of its journey, the current which travels under
this high voltage is retransformed into a low-voltage current by means of an
apparatus which simply reverses the conditions of the step-up transformer,
and which, therefore, is called a step-down transformer. The electricity
which came to Buffalo as a twenty-two-thousand-volt current is thus
reduced by any desired amount before it is applied to the practical purposes
for which it is designed. It may, for example, be "stepped-down" to two

thousand volts to supply the main wires of an electric-lighting plant; and
then again "stepped-down" to two hundred volts to supply the electric
lamps of an individual house.
Who that reads by the light of one of these electric lamps, let us say in
Buffalo, and realizes that he is reading by the transformed energy of
Niagara River, dare affirm that in our day there is nothing new under the
sun?

XI
THE BANISHMENT OF NIGHT

O
ne great fundamental advantage that man has won over the other
animals is that although by nature a diurnal animal he has made
night almost equally subject to his dominion through the use of
artificial light. He thus establishes an average day of sixteen or
eighteen hours in place of the twelve-hour day within which his activities
would otherwise be restricted. Of course this conquest of the night began at
an early stage of the human development, since a certain familiarity with
the uses of fire was attained long before man came out of the ages of
savagery. But when the transition had been made from the primitive torch to
the simplest type of lamp, there was for many centuries a cessation of
progress in this direction, and it remained for comparatively recent
generations to provide more efficient methods of lighting. Indeed, the
culminating achievements are matters which make the most recent history.
It is the purpose of the ensuing pages to narrate the story of the successive
practical achievements through which man has been enabled virtually to
turn night into day.

PRIMITIVE TORCH AND OPEN LAMP

To moderns, in an age when even the time-honored gas jets and kerosene
lamps are regarded as obsolescent, that ancient form of illuminant, the
candle, seems about the most primitive form of light-producing apparatus.
In point of fact, however, the candle holds no such place in the
chronological order of lighting-device discovery, being a relatively late
innovation. Indeed, lamps of various kinds, even those burning petroleum,
were used thousands of years before the relatively clean and effective
candle was invented.
The camp fires of primitive man must have suggested the use of a fire-
brand for lighting purposes almost as soon as the discovery of fire itself; but
the development of any means of lighting his caves or rude huts, even in the
form of torches, was probably a slow process. For our earliest ancestors

were not the nocturnal creatures their descendants became early in the
history of civilization. To them the period of darkness was the time for
sleeping, and their waking hours were those between dawn and dusk. It was
only when man had reached a relatively high plane above the other
members of the animal kingdom, therefore, that he would wish to prolong
the daylight, and then the use of the torch made of some resinous wood
would naturally suggest itself.
Just when the ancient lamp was invented in the form of a vessel filled
with oil into which some kind of wick was dipped, cannot be ascertained,
but its invention certainly antedated the Christian Era by several centuries.
And it is equally certain that once this smoky, foul-smelling lamp had been
discovered, it remained in use, practically without change or improvement,
until the end of the twelfth century, the date of the invention of the candle.
Such lamps were used by the Greeks and Romans, great quantities of them
being still preserved. They were simply shallow, saucer-like vessels for
holding the oil, into which the wick was laid, so arranged that the upper end
rested against the edge of the vessel. Here the oil burned and smoked,
capillarity supplying oil to the burning end of the wick, which was pulled
up from time to time as it became shortened by burning, either with pincers
made for the purpose, or perhaps more frequently by the ever useful hairpin
of the matron.
As the thick wick did not allow the air to penetrate to burn the carbon of
the oil completely, a nauseous smoke was given off constantly which was
stifling when a draught of air prevented its escape through the hole in the
roof—the only chimney used by the Greeks. And since this was the only
kind of lamp known at the time, the palace of the Roman Emperor and hut
of the Roman peasant were necessarily alike in their methods of lighting if
in little else. The Emperor's lamps might be modeled of gold and set with
precious stones, while those of the peasant were of rudely modeled clay; but
each must have evoked, along with its dim light, an unwholesome modicum
of smoke and malodor.
It was this form of lamp, practically unaltered except occasionally in
design, that remained in common use during the Middle Ages; and when, at
the close of the twelfth century, the "tallow candle" was invented, that now
despised device must have been almost as revolutionary in its effect as the
incandescent burner and the electric bulb were destined to be in a more

recent generation. It burned with dazzling brilliancy in comparison with the
oil lamp; it gave off no smoke and little smell; it needed no care, and it
occupied little space. Then for the first time in the history of the world
reasonably good house illumination became possible. Several additional
centuries elapsed, however, before the idea was developed of placing a
candle in a covered glass-sided receptacle, to form a lantern or a street
lamp.
For generations the candle held supreme place, though its cost made it
something of a luxury; doubly so if wax was substituted for tallow in its
composition. But toward the close of the eighteenth century, when the
action of combustion had begun to be better understood, attempts were
made to improve the wicks and burners of oil lamps. In 1783, an inventor
named Leger, of Paris, produced a burner using a broad, flat, ribbonlike
wick in which practically every part of the oil supply was brought into
contact with the air, producing, therefore, a steady flame relatively free
from smoke. The flame, while broad, was extremely thin, and its light was
consequently radiated very unevenly. Portions of a room lying in the
direction of the long axis of the flame were but poorly lighted. To overcome
this difficulty, a curved form of burner was adopted; and this led eventually
to the invention of the circular Argand burner, the prototype of the best
modern lamp-burners.

TALLOW CANDLE AND PERFECTED OIL LAMP

Stated in scientific terms, the problem of the ideal lamp-wick resolves
itself into a question of how to supply oxygen to every portion of the flame
in sufficient quantities to bring all the carbon particles to a temperature at
which they are luminous. It occurred to Argand that this could be done by
giving the wick a circular form like a cylindrical tube, giving the air free
access to the centre of the tube as well as to its outer surface. In his lamp
the reservoir of oil was placed at a little distance from, and slightly above,
the tube holding the burner, connected with it by a small tube much as the
tank of the modern "student lamp" connects with the burner. In this manner
a fairly good lamp was produced,—a decided improvement over any made
heretofore,—and when, in 1765, Quinquet added a glass chimney to this
lamp a new epoch of artificial lighting was inaugurated. "This date is of as
much importance in artificial lighting as is 1789 in politics," says one

writer. "Between the ancient lamps and the lamps of Quinquet there is as
much difference as between the chimney-place of our parlors and the
fireplaces of our original Aryan ancestors, formed by a hole dug in the
ground in the centre of their cabins."
A little later Carcel still further improved the Quinquet lamp by adapting
a clock movement that forced the oil to rise to the wick, so that it was no
longer necessary to have the burner and the reservoir separated by a tube.
This was still further improved upon by substituting a spring for the
clockwork, the result being a lamp of great simplicity, yet one which gave
such results that it replaced the candle as a unit for measuring the
illuminating power of different sources of light.
These various burners should not be confused with the modern burners of
the ordinary kerosene lamps. Mineral oils had not as yet come into use for
illuminating purposes, except as torches or in simple lamps like those of the
Romans, as refining processes had not been perfected, and the smoke and
odors from crude petroleum were absolutely intolerable in closed rooms.
Many other substances were tried in place of the heavy oils, such as the
volatile hydrocarbons and alcohols, but with no great success. Early in the
nineteenth century a lamp burning turpentine, under the name of
"camphine," was invented that gave a good light and was smokeless; but
like most others of its type, it was dangerous owing to its liability to
explode. And it was not until methods of refining petroleum had been
improved that "mineral-oil lamps"—the predecessors of the modern type of
lamps—came into use.
The invention of this type of lamp was a relatively easy task—a simple
transition and adaptation as processes of refining the oil were perfected. The
principle of combustion was, of course, the same as in the Argand type of
lamps burning animal and vegetable oils; but mineral oils are of such
consistency that capillarity causes an abundant supply of oil to rise in the
wick, so that clockwork and spring devices, such as were used in the Carcel
lamps, could be dispensed with.

GAS LIGHTING

While the rivalry between the candle and the new forms of lamps was at
its height, and just as the lamp was gaining complete supremacy, a new

method of artificial illumination was discovered that was destined to eclipse
all others for half a century, and then finally to succumb to a still better
form. As early as the beginning of the eighteenth century the Rev. Joseph
Clayton, in England, had made experiments in the distillation of coal,
producing a gas that was inflammable. A little later Dr. Stephen Hales
published his work on Vegetable Staticks, in which he described the process
of distilling coal in which a definite amount of gas could be obtained from a
given quantity of coal.
No practical use was made of this discovery, however, until over half a
century later. But just at the close of the century a Scot, William Murdoch,
became interested in the possibilities of gases as illuminants, and finally
demonstrated that coal gas could be put to practical use. In 1798, being
employed in the workshops of Boulton and Watt in Birmingham, he fitted
up an apparatus in which he manufactured gas, lighting the workshops by
means of jets connected by tubes with this primitive plant. Shortly after
this, a Frenchman, M. Lebon, lighted his house in Paris with gas distilled
from wood, and the Parisians soon became interested in the new illuminant.
England seems to have been the first country to use it extensively in public
buildings, however, the London Lyceum Theatre being lighted with gas in
1803. By 1810 the great Gas-Light and Coke Company was formed, and
within the next five years gas street-lamps had become familiar objects in
the streets of London, and house illumination by this means a common
thing among the wealthier classes.
In the early days of gas-lighting the results were frequently
disappointing, because no suitable and efficient type of burner had been
devised; but in 1820 Neilson of Glasgow discovered the principle of the
now familiar flat burner, of which more examples still remain in use the
world over than of all other kinds combined. Indeed, this simple, but as we
now regard it, inefficient burner, would probably have remained the best-
known type for many years longer than it did had not the possibilities of
lighting by electricity aroused persons interested in the great gas-plants to
the fact that the new illuminant was jeopardizing their enormous
investments; making it clear that they must bestir themselves and improve
their flat burners if they would arrest disaster. To be sure, several
modifications of the round Argand burner had been introduced from time to
time, some of them being a distinct improvement over the flat burner, but

these did not by any means seriously compete with electric light. And it was
not until the incandescent mantle was perfected that gas as a brilliant
illuminant was able to make a stand against its new competitor.

THE INCANDESCENT GAS MANTLE

It has been known almost since the beginnings of civilization that all
solids can be made to emit light when heated to certain temperatures. Some
substances were known to be peculiarly adapted to this purpose, such as
lumps of lime, and for many years the calcium light or "lime-light" as it is
popularly called, had been in use for special purposes, and was the most
intense light known. This light is made by heating a block of lime to the
highest practicable temperature by means of a blast of oxygen and coal gas;
but such lights were too complicated and expensive for general purposes. It
had been determined even as early as the beginning of the nineteenth
century, however, that the high temperature necessary for producing this
light was due in part at least to the fact that such a large amount of material
had to be raised to incandescence. It was evident, therefore, that if a small
amount of some such substance as lime and magnesia could be spread out
so as to present a large surface in a small space, such as is represented by
basket-work, sufficient heat for making it incandescent might be obtained
from an ordinary gas-and-air blowpipe.
Here then was the germ of the "mantle" idea; and such an apparatus,
known as the Clamond mantle, which was made of threads of calcined
magnesia, was shown at the Crystal Palace Exhibition, in London, in 1882.
Curiously enough, this mantle and burner worked in an inverted position,
the mantle being suspended bottom upwards below the burner through
which the blast of gas was forced. The light given by this mantle was most
brilliant—little short of the older calcium light, in fact—but the device itself
was too complicated to be of service for ordinary lighting purposes. The
principle was correct, but the construction of the mantle was defective.
Meanwhile a German scientist, Dr. Auer von Welsbach, who had become
famous in the scientific world for his researches on rare metals, was
experimenting with certain oxides of different metals, and developing a
method of handling them that finally resulted in the perfected incandescent
burner in use at present. His process, which in theory at least was not
entirely original with him, was to dip an open fabric of cotton into a

solution of the nitrates of the metals to be used, drying it, and converting
the nitrates into oxides by burning; the cotton fabric disappearing but
leaving the skeleton of the oxide, which retained its original shape.
At the same time corresponding improvements were made in the type of
burner, which is quite as essential to success as the mantle itself. It had been
found that it was absolutely essential for such a burner to give a practically
non-luminous flame, as otherwise the deposit of carbon particles will ruin
the mantle. Two ways of obtaining this are possible; one by mixing a certain
quantity of air with the gas before combustion, the other to burn the gas in
so thin a flame that the air permeates it freely. Several burners of both types
were used at first, but gradually the burners in which the air is mixed with
the gas became the more popular, and most of the incandescent burners now
on the market are of this type.
In the construction of mantles at the present time, while the principle of
their use remains the same as that of the lime-light, lime itself is not used,
the oxides of certain other metals having proved better adapted for the
purpose. Thus the Welsbach patent of 1886 covered the use of thoria, either
alone or mixed with other substances such as zirconia, alumina, magnesia,
etc.; thoria being considered as having a very high power of light emission.
Later it was discovered that pure thoria emits very little light by itself,
although it possesses a refractory nature that gives a stability to the mantle
unequalled by any other material as yet discovered. When combined with a
small trace of the oxides of certain rare metals, however, such as uranium,
terbium, or cerium, thoria mantles have a very high power of light emission,
most modern mantles being composed of about ninety-nine per cent. thoria
with one per cent. cerium.
In the ordinary method of manufacturing such mantles, a cotton-net
cylinder about eight inches long, more or less according to the size of
mantle required, is made, one end being contracted by an asbestos thread. A
loop of the same material, or in some cases a platinum wire, is fastened
across the opening, to be used for suspending the mantle when in use. The
cotton-thread cylinder is soaked in a solution of the nitrates of the metals
thorium and cerium, and is then wrung out to remove the excess, stretched
on a conical mold, and dried. The flame of an atmospheric burner being
applied to the upper part at the constricted position, the burning extends
downward, converting the nitrates into oxides, and removing the organic

matter. Considerable skill is required in this part of the process, as the
regular shape of the mantle is largely dependent upon the regularity of the
burning. As a finishing process a flame is applied to the inside of the mantle
after it has cooled, to remove all traces of carbon that may remain.
The mantle is now ready for use, but is so fragile that it can scarcely be
touched without breaking, and such handling as would be necessary for
shipment would be out of the question. It is therefore strengthened
temporarily by being dipped into a mixture of collodion and castor oil,
which, when dry, forms a firm but elastic jacket surrounding all parts. It is
this collodion jacket that is burned away when the new mantle is placed on
the burner before the gas is turned on.
Quite recently the method of manufacturing mantles used by Clamond
has been revived. In this method the cotton thread is dispensed with, the
thread used being made from a paste containing the mantle material itself.
The paste is placed in a proper receptacle the bottom of which is perforated
with minute openings, and subjected to pressure, squeezing out the material
in long filaments. When dry these are wound on bobbins, and, after being
treated by certain chemical processes, are ready for weaving into mantles. It
is claimed for mantles made on this principle that they last much longer and
retain their light-emitting power more uniformly than mantles made by the
older process.

THE INTRODUCTION OF ACETYLENE GAS

When the incandescent mantle had been perfected so as to be an
economical as well an as efficient light-giver, the position of coal gas as an
illuminant seemed again secured against the encroachments of its rivals, the
arc and incandescent electric lights. But just at this time another rival
appeared in the field that not only menaced the mantle lamp but the arc and
incandescent light as well. Curiously enough, this new rival, acetylene gas,
had been brought into existence commercially by the electric arc itself. For
although it had been known as a possible illuminant for many years, the
calcium carbide for producing it could not be manufactured economically
until the advent of the electric furnace, itself the outcome of Davy's arc
light.

Even as early as 1836 an English chemist had made the discovery that
one of the by-products of the manufacture of metallic potassium would
decompose water and evolve a gas containing acetylene; and this was later
observed independently from time to time by several chemists in different
countries. No importance was attached to these discoveries, however, and
nothing was done with acetylene as an illuminant until the last decade of the
nineteenth century. By this time electric furnaces had come into general use,
and it was while working with one of these furnaces in 1892 that Mr.
Thomas F. Wilson, in preparing metallic calcium from a mixture of lime
and coal, produced a peculiar mass of dark-colored material, calcium
carbide, which, when thrown into water, evolved a gas with an extremely
disagreeable odor. When lighted, this gas burned with astonishing
brilliancy, and, as its cost of production was extremely small, the idea of
utilizing it for illuminating was at once conceived and put into practice.
The secret of the cheap manufacture of the carbide lies in the fact that the
extremely high temperature required—about 4500° Fahrenheit—can be
obtained economically in the electric furnace, but not otherwise. Thus
electricity created its own greatest rival as an illuminant. It followed
naturally that the ideal place for manufacturing the carbide would be at the
source of the cheapest supply of electricity, and as the "harnessed" Niagara
Falls represented the cheapest source of electric supply, this place soon
became the centre of the carbide industry. Here the process of manufacture
is carried out on an enormous scale. In practice, lime and ground coke are
thoroughly mixed in the proportion of about fifty-six parts of lime to thirty-
six parts of coke. When this mixture has been subjected to the heat of the
electric furnace for a short time an ingot of pure calcium carbide is formed,
surrounded by a crust of less pure material. The ingot and crust together
represent sixty-four parts of the original ninety-two parts of lime and coke,
the remaining twenty-eight parts being liberated as carbon-monoxide gas.
Calcium carbide as produced by this process is a dark-brown crystalline
substance which may be heated to redness without danger or change. It will
not burn except when heated in oxygen, and will keep indefinitely if sealed
from the air. Chemically it consists of one atom of lime combined with two
atoms of carbon (CaC2); and to produce acetylene gas, which is a
combination of carbon and hydrogen (C2H2) it is only necessary to bring it
into contact with water, acetylene gas and slaked lime being formed. One

pound of pure carbide will produce five and one half cubic feet of gas of
greater illuminating power than any other known gas. The flame is
absolutely white and of blinding brilliancy, giving a spectrum closely
approximating that of sunlight. The light is so strongly actinic that it is
excellent for photography.
Here was a gas that could be made in any desired quantities simply by
adding water to a substance costing only about three cents a pound; its cost
of production, therefore, representing only about one sixth of the dollar-per-
thousand-feet rate usually charged for illuminating gas in our cities. It could
be used in lamps and lanterns made with special burners and with the
simple mechanism of a small water tank which allowed water to drip into a
receptacle holding the carbide; or—reversing the process—an apparatus
that dropped pieces of carbide into the water tanks. It was, in short, the
cheapest illuminant known, generated by an apparatus that was simplicity
itself.
There were, however, two defects in this gas: its odor was intolerable—
the "smell of decayed garlic," it has been aptly called—and when mixed
with air it was highly explosive. The first of these defects could be
overcome easily; when the burner consumed all the gas there was no odor.
The second, the explosive quality, presented greater difficulties. These were
emphasized and magnified by the number of defective lamps that soon
flooded the market, many of these being so badly constructed that
explosions were inevitable. As a result a strong prejudice quickly arose
against the gas, some countries passing laws prohibiting its use.
But further inquiry into the cause of the frequent disasters revealed the
fact that when the burner of a lamp was constructed so that the air for
combustion was supplied after the gas issued from the jet, there was no
danger of explosion. And as lamps carefully constructed on this principle
replaced the early ones of faulty construction, confidence in acetylene was
restored. Methods were devised for supplying the gas for house-
illumination like ordinary gas, and the occupants of country houses were
afforded a means of lighting their houses on a scale of brilliancy hitherto
unapproached, yet with economy and relative safety.
It was found also that the brilliancy of the acetylene flame was of such
intensity that it could be used, like the electric arc light, as a search-light. It

thus furnished a simple means of supplying small boats and vehicles with
such lights, which they could not otherwise have had. It also supplied army
signal-corps with an apparatus for flashing messages—an apparatus that
was ideal on account of its simplicity and small size.
At the Pan-American Exhibition at Buffalo the various illuminating
exhibits were among the most conspicuous and attractive features. But even
amid the dazzling electrical displays the Acetylene Building was a
noteworthy object. "It was the most brilliantly and beautifully lighted
building in the grounds," declared one observer. "It sparkled like a diamond,
and was the admiration of all visitors. In it were generators of all types—
most of them supplying the gas for their own exhibits—several being the
latest exponents of the art, so simple that they can be safely managed by
unskilled labor; in fact, 'the brains are in the machines,' and when the
attendant has charged them with carbide and filled them with water—given
them food and drink—they will work steadily until they need another
meal." Indeed, these exhibits at the Pan-American Exhibition demonstrated
conclusively that acetylene gas occupies a field by itself as a practical
illuminant.
At the same exposition a standard was established for good stationary
acetylene generators for house-lighting, and the fact that a large number of
generators fulfilled the requirements of the set of rules laid down showed
how thoroughly the problem of handling this gas has been solved. Some of
these rules used as tests are instructive to anyone interested in the subject,
and a few of them are given here. They specified, for example, that—
"The carbide should be dropped into the water," the reverse process of
letting the water drip on the carbide, as was done in most of the early
generators, being condemned. "There must be no possibility of mixing air
with the acetylene gas. Construction must be such that an addition to the
charge of carbide can be made at any time without affecting the lights.
Generators must be entirely automatic in their action—that is to say: after a
generator has been charged, it must need no further attention until the
carbide has been entirely exhausted. The various operations of discharging
the refuse, filling with fresh water, charging with carbide, and starting the
generator must be so simple that the generator can be tended by an
unskilled workman without danger of accident. When the lights are out, the

generation of gas should cease. The carbide should be fed automatically
into the water in proportion to the gas consumed."
Perhaps the most significant thing, showing the stage of progress that has
been made in overcoming the danger of explosions from acetylene gas, is
that the use of generators meeting some such requirements as the above is
not prohibited by fire underwriters. This in itself is very convincing
evidence of their safety.

THE TRIUMPH OF ELECTRICITY

Throughout the ages primitive man had had constantly before him two
sources of light other than that of the sun, moon, and stars. One of these, the
fire of ordinary combustion, he could understand and utilize; the other,
more powerful and more terrible, which flashed across the heavens at times,
he could not even vaguely understand, and, naturally, did not attempt to
utilize. But early in the seventeenth century some scientific discoveries
were made which, although their destination was not even imagined at the
time, pointed the way that eventually led to man's imitating in the most
striking manner Nature's electrical illumination.
About this time Otto von Guericke, the burgomaster-philosopher of
Magdeburg, in the course of his numerous experiments, had discovered
some of the properties of electricity, by rubbing a sulphur ball, and among
other things had noticed that when the ball was rubbed in a darkened room,
a faint glow of light was produced. He was aware, also, that in some way
this was connected with the generation of electricity, but in what manner he
had no conception. In the opening years of the following century Francis
Hauksbee obtained somewhat similar results with glass globes and tubes,
and made several important discoveries as to the properties of electricity
that stimulated an interest in the subject among the philosophers of the time.
Gray in England, and Dufay in France, who became enthusiastic workers in
the field, soon established important facts regarding conduction and
insulation, and by the middle of the eighteenth century the production of an
electric spark had become a commonplace demonstration.
But until this time it had not been demonstrated that this electric spark
was actual fire, although there was no disputing the fact that it produced
light. In 1744, however, this point was settled definitely by the German,

Christian Friedrich Ludolff, who projected a spark from a rubbed glass rod
upon the surface of a bowl of ether, causing the liquid to burst into flame. A
few years later Benjamin Franklin demonstrated with his kite and key that
lightning is a manifestation of electricity.
But neither the galvanic cell nor the dynamo had been invented at that
time, and there was no possibility of producing anything like a sustained
artificial light with the static electrical machines then in use. It was not until
the classic discovery of Galvani and the resulting invention of the voltaic,
or galvanic, cell shortly after, that the electric light, in the sense of a
sustained light, became possible. And even then, as we shall see in a
moment, such a light was too expensive to be of any use commercially.

DAVY AND THE FIRST ELECTRIC LIGHT

As soon as Volta's great invention was made known a new wave of
enthusiasm in the field of electricity swept over the world, for the constant
and relatively tractable current of the galvanic battery suggested
possibilities not conceivable with the older friction machines. Batteries
containing large numbers of cells were devised; one having two thousand
such elements being constructed for Sir Humphry Davy at the Royal
Institution, of London. By bringing two points of carbon, representing the
two poles of the battery, close together, Davy caused a jet of flame to play
between them—not a momentary spark, but a continuous light—a true
voltaic arc, like that seen in the modern street-light to-day.
"When pieces of charcoal about an inch long and one-sixth of an inch in
diameter were brought near each other (within the thirtieth or fortieth of an
inch)," wrote Davy in describing this experiment, "a bright spark was
produced, and more than half the volume of charcoal became ignited to
whiteness; and, by withdrawing the points from each other, a constant
discharge took place through the heated air, in a space equal to at least four
inches, producing a most brilliant ascending arch of light, broad and conical
in form in the middle. When any substance was introduced into this arch, it
instantly became ignited; platina melted in it as readily as wax in a common
candle; quartz, the sapphire, magnesia, lime, all entered into fusion;
fragments of diamond and points of charcoal and plumbago seemed to
evaporate in it, even when the connection was made in the receiver of an
air-pump; but there was no evidence of their having previously undergone

fusion. When the communication between the points positively and
negatively electrified was made in the air rarefied in the receiver of the air-
pump, the distance at which the discharge took place increased as the
exhaustion was made; and when the atmosphere in the vessel supported
only one-fourth of an inch of mercury in the barometrical gauge, the sparks
passed through a space of nearly half an inch; and, by withdrawing the
points from each other, the discharge was made through six or seven inches,
producing a most brilliant coruscation of purple light; the charcoal became
intensely ignited, and some platina wire attached to it fused with brilliant
scintillations and fell in large globules upon the plate of the pump. All the
phenomena of chemical decomposition were produced with intense rapidity
by this combination."
It will be seen from this that as far as the actual lighting-part of Davy's
apparatus was concerned, it was completely successful. But the source of
the current—the most essential part of the apparatus—was such that even
the wealthy could hardly afford to indulge in it as a luxury. The initial cost
of two thousand cells was only a small item of expense compared with the
cost of maintaining them in working order, and paying skilled operators to
care for them. So that for the moment no practical results came from this
demonstration, conclusive though it was, and the introduction of a
commercial electric light was of necessity deferred until a cheaper method
of generating electricity should be discovered.
This discovery was not made for another generation, but then, as seems
entirely fitting, it was made by Davy's successor and former assistant at the
Royal Institution, Sir Michael Faraday. His discovery of electromagnetic
induction in 1831 for the first time made possible the electric dynamo,
although still another generation passed before this invention took practical
form. In the meantime, however, the magneto-electric machine of Nollet
was used for generating an electric current for illuminating purposes as
early as 1863; and when finally the dynamo-electric machine was produced
by Gramme in 1870, engineers and inventors had at their disposal
everything necessary for producing a practical electric illuminant.
It must not be supposed, however, that inventors stood by patiently with
folded hands waiting for the coming of a machine that would furnish them
with an adequate current without attempting to produce electric lamps. On
the contrary, they were constantly wrestling with the problem, in some

instances being fairly successful, even before the invention of the magneto-
electric machine. Great advances had been made in batteries and cell
construction over the primitive cells of the time of Davy, and for exhibition
purposes, and even for lighting factories and large buildings, fairly good
electric lights had been used before 1863.
The first practical application of electric lighting seems to have been
made in France in 1849. During the production of the opera "The Prophet"
the sun was to appear, and for this purpose an electric arc light was used.
The success of this effort—an artificial sun being produced that seemed
almost as dazzling to the astonished audience as Old Sol himself—
stimulated further efforts in the same direction. The previous year W. E.
Staite in England made experiments along similar lines in the large hall of
the hotel of Sunderland. He generated a light "resembling the sun, or the
light of day, and making candles appear as obscure as they do by daylight,"
according to the Times of the following morning. The electric light was
therefore proved to be a practical illuminator, although it was not until the
introduction of the Gramme dynamo-electric machine that its great
economic utility was demonstrated.

THE JABLOCHKOFF CANDLE

In Sir Humphry Davy's experiments with his arc light he was led to
believe that the light between the two points of carbon would be produced
even in an absolute vacuum, if it were possible to create one. Several
scientists at the time disputed this contention, and M. Masson, Professor of
Physics in the École Centrale des Arts et Manufactures in Paris was
particularly active in combatting the idea, maintaining that the arc had the
same cause as the electric spark—the transport by electricity of the
incandescent particles of the electrodes through the atmosphere. It was
certain, at any rate, that no light was produced when the opposing carbons
were brought into contact with each other, or were, on the other hand,
separated too widely; and since there was a constant wearing away and
shortening of the points, and thus a constantly increasing space between
them, the great difficulty in making a practical lamp lay in regulating this
distance automatically. It was finally accomplished, however, by the
invention of a Russian officer, M. Jablochkoff, in 1876. The "Jablochkoff
candle," as his lamp was called, marked an epoch in the history of electric

lighting. One great merit of this invention was its simplicity, and while it
has long since gone out of use, having been superseded by still simpler and
better devices, it must always be recalled as an important stepping-stone in
the progress of artificial illumination.
The name "candle" for Jablochkoff's lamp was suggested by the fact that
the two carbons were placed side by side, instead of point to point, the light
at the top thus suggesting a candle. Between these two carbons, and
extending their whole length except at the very tips, was an insulating
material that the arc could not pierce, but which burned away at a rate
commensurate with the shortening of the carbons. In this manner the points
were kept constantly at the proper distance without regulating-machinery of
any kind. This ingenious apparatus had the additional advantage that it
could be placed on any kind of a bracket or chandelier that was properly
wired, thus dispensing with the cumbersome frames and machines of the
point-to-point carbon arc lights then being introduced.
One difficulty at first encountered in using the Jablochkoff candle was
the starting of the voltaic arc. In doing this it was necessary that contact be
made between two carbon points, whether they lie parallel or point to point,
and the necessary slight separation for producing the light effected later. To
accomplish this Jablochkoff joined the tips of the carbons of his candle with
a thin strip of carbon, which quickly burned away when the current was
turned on, leaving the necessary space between the points for the arc.
There was one difficulty with the "candle" that seemed insurmountable
for a time—the wasting of the two carbons was unequal, as in any arc light,
the points thus gradually drawing apart until the passage of the current was
no longer possible. To overcome this the rapidly wasting positive carbon
was made double the thickness of its mate; but while this answered fairly
well the thinner negative carbon gradually became heated by the increased
resistance, and burned up too rapidly. The difficulty was finally overcome
by the simple expedient of alternating the flow of the current, so that each
carbon was alternately a positive and a negative pole. As the magneto-
electric machines then in use produced alternating currents it was only
necessary to use such machines for generating the current to produce an
equal destruction of both carbons.

The simplicity and excellence of the light of these "candles" brought
them at once into general popularity, not only in the large cities of Europe,
but in many out-of-the-way places. Greece, Portugal, and other obscure
European countries adopted them, and even Brazil, La Plata, and Mexico
installed many plants. But stranger still, they were soon used for
illuminating the palaces of the Shah of Persia and the King of Cambodia,
and a little later were introduced into the residence of the savage King of
Burma. In short, their use became universal almost immediately.

THE IMPROVED ARC LIGHT

About the time that Jablochkoff's candles were making such a sensation
in Europe, Charles F. Brush, of Cleveland, Ohio, invented an arc light in
which the carbons were set point to point, the distance being maintained
and the necessary feed produced automatically in much the same manner as
in the lamps used at present. Other inventions soon followed, some of the
lamps being regulated by clockwork, some by electricity and magnetism.
The advantage of this type of arc lamp over the candle type—an
advantage that led to its general adoption—was largely that of efficiency, a
far greater amount of light being obtainable from the same expenditure of
power by the point-to-point type of lamp.
In this lamp it is necessary that the points of carbon shall come in contact
when the current is off, but be drawn apart a moment after the current is
turned on, and remain at this fixed distance. To accomplish this, the lower
carbon is usually made stationary, the feeding being regulated by the
position of the upper carbon. In the usual type of modern lamp the passage
of the current causes the points to separate the required distance through the
action of an electromagnet the coils of which are traversed by the current. A
clutch holds the carbon in place, the position of this being also determined
by an electromagnet. The action is regulated by the difference in the
resistance to the passage of the current caused by the increase in the
separation of the points.
In the older type of arc lamp it was necessary to "trim" the lights by
replacing the carbons every day; but recently lamps have been perfected in
which the carbons last from one hundred to one hundred and twenty hours.
In these the arc is enclosed in a glass globe which is made as nearly air-tight

as possible with the necessary feed devices. This closed chamber is fitted
with a valve opening outward, which allows the air to be forced out by the
heat of the lamp, but does not admit a return current. In this manner a
rarefied chamber is produced in which the carbons are oxidized very
slowly; yet there is no diminution in the brilliancy of the light.
Early in the history of electric lighting it became apparent that the proper
construction of the carbon electrodes was a highly important item in the
manufacture of a lighting apparatus. The value of carbons depends largely
upon their purity and freedom from ash in burning, and it required a
countless number of experiments to develop the highly efficient carbons
now in general use. Davy made use of pieces of wood charcoal in his
experiments, but these were too fragile to be of practical value, even if their
other qualities had been ideal. Later experimenters tried various
compounds, and in 1876 Carré in France produced excellent carbons made
of coke, lampblack, and syrup. From these were developed the present
carbons, usually made by mixing some finely divided form of carbon, such
as soot or lampblack made from burning paraffin or tar, with gum or syrup
to form a paste. Rods of proper size and shape are made by forcing this
paste through dies by hydraulic pressure, subsequently baking them at a
high temperature. Sometimes they are given a coating of copper, a thin
layer of the metal being deposited upon them by electrolysis.

EDISON AND THE INCANDESCENT LAMP

The familiar incandescent electric-light bulb seems such a simple
apparatus to-day, being nothing apparently but a small wire enclosed in an
ordinary glass bulb, that it is almost impossible to realize what an enormous
amount of money, energy, and that particular quality of mentality which we
call "genius" has been required to produce it. First and foremost among the
names of the men of genius who finally evolved this lamp is that of Thomas
A. Edison; and only second to this foremost name are those of Swan, Lane-
Fox, and Hiram Maxim. But Edison's name must stand preeminent; and
there are probably very few, even among Europeans, who would attempt or
wish to deny him the enviable place as the actual perfecter of the
incandescent-light bulb.

THOMAS A. EDISON AND THE DYNAMO
THAT GENERATED THE FIRST COMMERCIAL
ELECTRIC LIGHT.
It is said that Edison first conceived the idea of an incandescent electric
light while on a trip to the Rocky Mountains in company with Draper, in
1878. Be this as it may, he certainly set to work immediately after
completing this journey, and never relaxed or ceased his efforts until a
practical incandescent lamp had been produced. His idea was to perfect a
lamp that would do everything that gas could do, and more; a lamp that

would give a clear, steady light, without odor, or excessive heat such as was
given by the arc lights—in short, a household lamp.
Early in his experiments he abandoned the voltaic arc, deciding that a
successful lamp must be one in which incandescence is produced by a
strong current in a conductor, the heat caused by the resistance to the
current producing the glow and light. But when search was made for a
suitable substance possessing the necessary properties to be the
incandescent material, the inventor was confronted by a vast array of
difficulties. It was of course essential that the substance must remain
incandescent without burning, and at the same time offer a resistance to the
passage of the current precisely such as would bring about the heating that
produced incandescence. It should be infusible even under this high degree
of heat, or otherwise it would soon disappear; and it must not be readily
oxidizable, or it would be destroyed as by ordinary combustion. It should
also be of material reducible to a filament as fine as hair, but capable of
preserving a rigid form. These, among others, were the qualities to be
considered in selecting this apparently simple filament for the incandescent
lamp. It was not a task for the tyro, therefore, that Edison undertook when
he began his experiments for producing an "ideal lamp."
The substance in nature that seemed to possess most of the necessary
qualities just enumerated was the metal platinum, and Edison began at once
experimenting with this. He made a small spiral of very fine platinum wire,
which he enclosed in a glass globe about the size of an ordinary baseball.
The two ends of the wires connected with outside conducting wires, which
were sealed into the base of the bulb. The air in the bulb had to be
exhausted and a vacuum maintained to diminish the loss of heat and of
electricity and to prevent the oxidation of the platinum. But when the
current was passed through the spiral wire in this vacuum a peculiar change
took place in the platinum itself. The gases retained in the pores of the
metal at once escaped, and the wire took on such peculiar physical
properties that it was supposed for a time by some physicists that a new
metal had been produced. The metal acquired a very high degree of
elasticity and became susceptible of a high polish like silver, at the same
time becoming almost as hard as steel. It also acquired a greater calorific
capacity so that it could be made much more luminous without fusing. To
diminish the loss of heat the wire was coated with some metallic oxide, and

the slope of the spiral also aided in this as each turn of the spiral radiated
heat upon its neighbor, thus utilizing a certain amount that would otherwise
have been lost. But despite all this, Edison found, after tedious
experimenting, that platinum did not fulfil the requirements of a practical
filament for his lamp; it either melted or disintegrated in a short time and
became useless; and the other experimenters had met with the same
obstacles to its use, and were forced to the same conclusion.
Some other substance must be found. The use of carbon for arc lights and
Edison's own experiments with carbon in his work on the telephone
naturally suggested this substance as a possibility. It is said that this idea
was brought forcibly to the inventor's attention by noticing the delicate
spiral of vegetable carbon left in his hand after using a twisted bit of paper,
one day, for lighting a cigar. This spiral of carbon was, of course, too fragile
to be of use in its ordinary form. But it occurred to Edison that if a means of
consolidating it could be found, there was reason to hope that it would
answer the purpose. Experiments were begun at once, therefore, not only
with processes of consolidation but also with various kinds of paper, and
neither effort nor expense was spared to test every known variety of paper.
Moreover, many new varieties of paper were manufactured at great expense
from substances having peculiar fibres. One of these, made from a delicate
cotton grown on some little islands off South Carolina, gave a carbon free
from ash, and seemed to promise good results; but later it was found that
the current of electricity did not circulate through this substance with
sufficient regularity to get protracted and uniform effects. Nevertheless,
since many things pointed to this fibre carbon as the ideal substance, Edison
set about determining the cause of the irregularity in the circulation of the
current in the filament, and a number of other experimenters soon became
interested in the problem.
It was soon determined that the arrangement of the fibres themselves
were directly responsible for the difficulty. In ordinary paper the fibres are
pressed together without any special arrangement, like wool fibres in
felting. In passing through such a substance, therefore, the current cannot
travel along a continuous fibre, but must jump from fibre to fibre, "like a
man crossing a brook on stepping-stones." Each piece of fibre constitutes a
lamp or miniature voltaic arc, so that the current is no longer a continuous
one; and the little interior sparks thus generated quickly destroy the

filament. This discovery made it apparent that such an artificial, feltlike
substance as paper could not be made to answer the purpose, and Edison set
about searching for some natural substance having fibres sufficiently long
to give the necessary homogeneity for the passage of the current.
For this purpose specimens of all the woods and fibre-substances of all
countries were examined. Special agents were sent to India, China, Japan,
South America, in quest of peculiar fibrous substances. The various woods
thus secured were despatched to the Edison plant at Menlo Park and there
carefully examined and tested. Without dwelling on the endless details of
this tedious task, it may be said at once that only three substances out of all
the mass withstood the tests reasonably well. Of these, a species of
Japanese bamboo was found to answer the purpose best. Thus the practical
incandescent lamp, which had cost so much time, ingenuity, and money,
came into existence, fulfilling the expectation of the most sanguine dream
of its inventor.
In using these bamboo carbon filaments the original spiral form of
filament was abandoned, the now familiar elongated horseshoe being
adopted, as the carbon could not be bent into the tortuous shapes possible
with platinum. Later various modifications in the shape of the filament were
made, usually as adaptations to changes in the shape of the bulbs.
At the same time that Edison was succeeding with his bamboo carbon
filaments, J. W. Swan had been almost as successful with a filament formed
by treating cotton thread with sulphuric acid, thus producing a
"parchmentized thread," which was afterwards carbonized. A modification
of this process eventually supplanted the Edison bamboo filament; and the
filament now in common use—the successor of the "parchmentized
thread"—is made of a form of soluble cellulose prepared by dissolving
purified cotton wool in a solution of zinc chloride, and then pressing the
material out into long threads by pressing it through a die.
The long thread so obtained is a semi-transparent substance, resembling
catgut, which when carbonized at a high temperature forms a very elastic
form of carbon filament. To prepare the filament the cellulose threads are
cut into the proper lengths, bent into horseshoe shape, double loops, or any
desired form, and then folded round carbon formers and immersed in
plumbago crucibles. On heating these crucibles to a high temperature the

organic matter of the filaments is destroyed, the carbon filaments
remaining. These filaments are then ready for attachment to the platinum
leading-in wires, which is accomplished either by means of a carbon
cement or by a carbon-depositing process. They are then placed in the glass
bulbs and the wires hermetically sealed, after which the bulbs are
exhausted, tested, fitted with the familiar brass collars, and are ready for
use.
The combined discoveries of all experimenters had made it evident that
certain conditions were necessary to success, regardless of the structure of
the carbon filament. It was essential that the vessel containing the filament
should be entirely of glass; that the current should be conveyed in and out
this by means of platinum wires hermetically sealed through the glass; and
that the glass globe must be as thoroughly exhausted as possible. This last
requirement proved a difficult one for a time, but by improved methods it
finally became possible to produce almost a perfect vacuum in the bulbs,
with a corresponding increase in the efficiency of the lamps.

THE TUNGSTEN LAMP

For twenty years the carbon-filament lamp stood without a rival. But
meanwhile the science of chemistry was making rapid strides and putting at
the disposal of practical inventors many substances hitherto unknown, or
not available in commercial quantities. Among these were three metals,
osmium, tantalum, and tungsten, and these metals soon menaced the
apparently secure position of the highly satisfactory, although expensive,
Edison lamp.
It will be recalled that the early experimenters had used two metals,
platinum and iridium, for lamp filaments; and that these two, although
unsatisfactory, were the only ones that had given even a promise of success.
But in 1898 Dr. Auer von Welsbach took out patents, and in 1903 produced
a lamp using an osmium filament. Its advent marked the beginning of the
return to metal-filament lamps, although the lamp itself did not prove to be
very satisfactory and was quickly displaced by a lamp invented by Messrs.
Siemens and Halske, having a tantalum filament. On account of its ease to
manufacture, its brilliant light, and relatively low consumption of power,
this lamp gained great popularity at once, and for a single year was
practically without a rival. Then, in 1904, patents were taken out by Just

and Hanaman, Kuzel, and Welsbach, for lamps using filaments of tungsten,
and the superiority of these lamps over the tantalum lamps gave them an
immediate popularity never attained by either of the other metal-filament
lamps.
Needless to say there is good ground for this popularity, which may be
explained by the simple statement that the tungsten lamp gives more light
with much less consumption of power per candle power than any of its
predecessors. Unlike the carbon filament, which projects in the familiar
elongated horse-shoe loop, or double loop, into the exhausted bulb, the
tungsten filament is wound on a frame, so that several filaments (usually
eight or more) are used for producing the light in each bulb. The chief
defect of this lamp is the fragility of the filament, which breaks easily when
subjected to mechanical vibration. On the other hand, tungsten lamps can be
used in places at a long distance from the central generating plant, where
the electric current is too weak for carbon-filament lamps.

THE MERCURY-VAPOR LIGHT OF PETER COOPER HEWITT

"On an evening in January, 1902, a great crowd was attracted to the
entrance of the Engineers' Club in New York city. Over the doorway a
narrow glass tube gleamed with a strange blue-green light of such intensity
that print was easily readable across the street, and yet so softly radiant that
one could look directly at it without the sensation of blinding discomfort
which accompanies nearly all brilliant artificial lights. The hall within,
where Mr. Hewitt was making the first public announcement of his great
discovery, was also illuminated by the wonderful new tubes. The light was
different from anything ever seen before, grateful to the eyes, much like
daylight, only giving the face a curious, pale-green, unearthly appearance.
The cause of this phenomenon was soon evident; the tubes were seen to
give forth all the rays except red,—orange, yellow, green, blue, violet,—so
that under its illumination the room and the street without, the faces of the
spectators, the clothing of the women, lost all their shades of red; indeed,
changing the face of the world to a pale green-blue.
"The extraordinary appearance of this lamp and its profound significance
as a scientific discovery at once awakened a wide public interest, especially
among electricians who best understood its importance. Here was an
entirely new sort of electric light. The familiar incandescent lamp, though

the best of all methods of illumination, is also the most expensive. Mr.
Hewitt's lamp, though not yet adapted to all the purposes served by the
Edison lamp, on account of its peculiar color, produces eight times as much
light with the same amount of power. It is also practically indestructible,
there being no filament to burn out; and it requires no special wiring. By
means of this invention electricity, instead of being the most costly means
of illumination becomes the cheapest—cheaper even than kerosene. No
further explanation than this is necessary to show the enormous importance
of this invention."
As just stated, the defect of the Edison incandescent lamp is its cost, due
to its utilizing only a small fraction of the power used in producing the
incandescence, and, of much less importance, the relatively short life of the
filament itself. Only about three per cent. of the actual power is utilized by
the light, the remaining ninety-seven per cent. being absolutely wasted; and
it was this enormous waste of energy that first attracted the attention of Mr.
Hewitt, and led him to direct his energies to finding a substitute that would
be more economical. A large part of the waste in the Edison bulb is known
to be due to the conversion of the energy into useless heat, instead of light,
as shown by the heated glass. Mr. Hewitt attempted to produce a light that
would use up the power in light alone—to produce a cool light, in short.
Instead of directing his efforts to the solids, Mr. Hewitt turned his
attention to gaseous bodies, believing that an incandescent gas would prove
the more nearly ideal substance for a cool light. The field of the passage of
electricity through gases was by no means a virgin one, but was
nevertheless relatively unexplored: and Mr. Hewitt was, therefore, for the
most part obliged to depend upon his own researches and experiments. In
these experiments hundreds of gases were examined, some of them giving
encouraging results, but most of them presenting insurmountable
difficulties. Finally mercury vapor was tried, with the result that the light
just referred to was produced.
The possibilities of mercury-vapor gas had long been vaguely suspected
—suspected, in fact, since the early days of electrical investigation, two
centuries before. The English philosopher, Francis Hauksbee, as early as
1705 had shown that light could be produced by passing air through
mercury in an exhausted receiver. He had discovered that when a blast of
air was driven up against the sides of the glass receiver, it appeared "all

round like a body of fire, consisting of an abundance of glowing globules,"
and continuing until the receiver was about half full of air. Hauksbee called
this his "mercurial fountain," and although he was unable to account for the
production of this peculiar light, which he remarked "resembled lightning,"
he attributed it to the action of electricity.
Between Hauksbee's "mercurial fountain" and Hewitt's mercury-vapor
light, however, there is a wide gap, and, as it happened, this gap is
practically unbridged by intermediate experiments, for Mr. Hewitt had
never chanced to hear anything of Hauksbee's early experiments, or of any
of the tentative ones of later scientists. But this, on the whole, may have
been rather advantageous than otherwise, as, being ignorant, he was perhaps
in a more receptive state of mind than if hampered by false or prejudicial
conceptions. Be this as it may, he began experimenting with mercury
confined in a glass tube from which the air had been exhausted, the mercury
being vaporized either by heating, or by a current of electricity. No results
of any importance came of his numerous experiments for a time, but at last
he made the all-important discovery that once the high resistance of the
cold mercury was overcome, a comparatively weak current would then be
conducted, producing a brilliant light from the glow of the mercury vapor.
Here, then, was the secret of the use of mercury vapor for lighting—a
powerful current of electricity for a fraction of a second passed through the
vapor to overcome the initial resistance, and then the passage of an ordinary
current to produce the light.
In practice this apparent difficulty in overcoming the initial resistance
with a strong current is easily overcome by the use of a "boosting coil,"
which supplies the strong current for an instant, and is then shut off
automatically, the ordinary current continuing for producing the light. The
mechanism is hardly more complex than that of the ordinary incandescent
light, but the current of ordinary strength produces an illumination about
eight times as intense as the ordinary incandescent bulb of equal candle-
power.
The form of lamp used is that of a long, horizontal tube suspended
overhead in the room, a brilliant light being diffused, which, lacking the red
rays of ordinary lights, gives a bluish-green tone to objects, and a
particularly ghastly and unpleasant appearance to faces and hands, as
referred to a moment ago. In many ways this feature of the light is really a

peculiarity rather than a defect, and for practical purposes in work requiring
continued eye-strain the absence of the red rays is frequently advantageous.
In such close work as that of pen-drawing, for example, some artists find it
advantageous to use globes filled with water tinted a faint green color,
placed between the lamps and their paper, the effect produced being
somewhat the same as that of the mercury-vapor light. For such work the
absence of the red rays of the Hewitt light would not be considered a defect;
and in workshops and offices where Mr. Hewitt's lamps are used the
workmen have become enthusiastic over them.
On the other hand, the fact that the color-values of objects are so
completely changed makes this light objectionable for ordinary use; so
much so, in fact, that the inventor was led to take up the problem of
introducing red rays in some manner so as to produce a pure white light. He
has partly accomplished this by means of pink cloth colored with rhodium
thrown around the glass; but this causes a distinct loss of brilliancy.
The most natural method of introducing the red rays, it would seem,
would be to use globes of red glass; but a moment's reflection will show
that this would not solve the difficulty. Red glass does not change light
waves, but simply suppresses all but the red rays; and since there are no red
rays in the mercury-vapor light the result of the red globe would be to
suppress all the light. Obviously, therefore, this apparently simple method
does not solve the difficulty; but those familiar with Mr. Hewitt's work will
not be surprised any day to hear that he has finally overcome all obstacles,
and produced a perfectly white light. In the meantime the relatively
expensive arc light and the incandescent bulb with its filament of carbon or
metal hold unchallenged supremacy in the commercial field.

XII
THE MINERAL DEPTHS

A
ges before the dawn of civilization, primitive man had learned to
extract certain ores and metals from the earth by subterranean
mining. Such nations as the Egyptians, for example, understood
mining in most of its phases, and worked their mines in practically
the same manner as all succeeding nations before the time of the
introduction of the steam engine. The early Britons were good miners and
the products of their mines were carried to the Orient by the Phœnicians
many centuries before the Christian era. The Romans were, of course, great
miners, and remains of the Roman mines are still in existence, particularly
good examples being found in Spain.
Even the aborigines of North America possessed some knowledge of
mining, as attested by the ancient copper mines in the Lake Superior region,
although by the time of the discovery of America, and probably many
centuries before, the interloping races of Indians who had driven out or
exterminated the Lake Superior copper mines had forgotten the art of
mining, if indeed they had ever learned it. But the fact that their
predecessors had worked the copper mines is shown by the number of stone
mining implements found in the ancient excavations about Lake Superior,
these implements being found literally by cart loads in some places.
The great progress in mining methods, however, as in the case of most
other mechanical arts, began with the introduction of steam as a means of
utilizing energy; and another revolution is in rapid progress owing to the
perfection of electrical apparatus for furnishing power, heat, and light.
Methods of mining a hundred years ago were undoubtedly somewhat in
advance of the methods used by the ancients; but the gap was not a wide
one, and the progress made by decades after the introduction of steam has
been infinitely greater than the progress made by centuries previous to that
time.

This progress, of course, applies to all kinds of mines and all phases of
mining; but steam and electricity are not alone responsible for the great
nineteenth-century progress. Geology, an unknown science a century ago,
has played a most active and important part; and chemistry, whose birth as a
science dates from the opening years of the nineteenth century, is
responsible for many of the great advances.
Obviously a very important feature of any mine must be its location, and
the determination of this must always constitute the principal hazard in
practical mining. Prospecting, or exploring for suitable mining sites, has
been an important occupation for many years, and has in fact become a
scientific one recently. Formerly mines were frequently stumbled upon by
accident, but such accidental discoveries are becoming less and less
frequent. The prospector now draws largely upon the knowledge of the
scientist to aid him in his search. Geology, for example, assists him in
determining the region in which his mines may be found, if it cannot
actually point out the location for sinking his shaft; and at least a rough
knowledge of botany and chemistry is an invaluable aid to him. It is
obvious that it would be useless to prospect for coal in a region where no
strata of rocks formed during the Carboniferous or coal-forming age are to
be found within a workable distance below the surface of the earth. The
prospector must, therefore, direct his efforts within "geological confines" if
he would hope to be successful, and in this he is now greatly aided by the
geological surveys which have been made of almost every region in the
United States and Europe.
An example of what science has done in this direction was shown a few
years ago in a western American town during one of the "oil booms" that
excited so many communities at that time. In the neighborhood of this town
evidences of oil had been found from time to time—some of them under
peculiar and suspicious circumstances, to be sure—and the members of the
community were in an intense state of excitement over the possibility of oil
being found on their lands. Prices of land jumped to fabulous figures, and
the few land-owners that could be induced to part with their farms became
opulent by the transactions. An "oil expert" appeared upon the scene about
this time—just "happening to drop in"—who declared, after an
examination, that the entire region abounded in oil. He backed up his
assertion by offering to stake his experience against the capital of a

company which was formed at his suggestion. Before any wells were
actually started, however, a prudent member of the company consulted the
State geologist on the subject, receiving the assurance that no oil would be
found in the neighborhood. Strangely enough the word of the man of
science triumphed over that of the "oil expert," and although some tentative
borings were made on a minor scale, no great amount of money was sunk.
It developed afterwards that the evidences of oil found from time to time
had been the secret work of the "expert."
In general, prospecting for oil differs pretty radically from prospecting
for most other minerals. A very common way of locating an ore-mine is by
the nature of the out-crop,—that is, the broken edges of strata of rocks
protruding from hillsides, or tilted at an angle on level areas. If the ore-
bearing vein is harder than the surrounding strata it will be found as a
jutting edge, protruding beyond the surface of the other layers of rocks
which, being softer, are more easily worn away. On the other hand, if this
stratum is soft or decomposable it will show as a depression, or "sag" as it is
called. Of course such protrusions and depressions may only be seen and
examined where the rocks themselves are exposed; vegetation, drift, and
snow preventing such observations. But the vegetation may in itself serve
as a guide to the experienced prospector in determining the location of a
mine, peculiar mineral conditions being conducive to the growth of certain
forms of vegetation, or to the arrangement of such growth. Alterations in
the color of the rocks on a hillside are also important guides, as such
discolorations frequently indicate that oxidizable minerals are located
above.
In hilly or mountainous regions, where the underlying rocks are covered
with earth, portions of these surfaces are sometimes uncovered by the
method known as "booming." In using this method the prospector selects a
convenient depression near the top of a hill and builds a temporary dam
across the point corresponding to the lowest outlet. When snow and rain
have turned the basin so formed into a lake, the dam is burst and the water
rushing down the hillside cuts away the overlying dirt, exposing the rocks
beneath. This method is effective and inexpensive.
The beds of streams, particularly those in hilly and mountainous regions,
are fertile fields for prospecting, particularly for precious metals. Stones
and pebbles found in the bed are likely to reveal the ore-foundations along

the course of the stream, and the shape of these pebbles helps in
determining the approximate location of such foundations. An ore-bearing
pebble, well worn and rounded, has probably traveled some little distance
from its original source, being rounded and worn in its passage down the
stream. On the other hand, if it is still angular it has come a much shorter
distance, and the prospector will be guided accordingly in his search for the
ore-vein.
But prospecting is not limited to these simple surface methods. In
enterprises undertaken on a large scale, borings are frequently made in
regions where there are perhaps no specific surface indications. In such
regions a shaft may be sunk or a tunnel may be dug, and the condition of
the underlying strata thus definitely determined. This last is, of course, a
most expensive method, the simpler and more usual way being that of
making borings to certain depths. The difficulty with such borings is that
rich veins may be passed by the borer without detection; or, on the other
hand, a small vein happening to lie in the same plane as the drill may give a
wrong impression as to the extent of the vein.
One of the most satisfactory ways of making borings is by means of the
diamond drill. This drill is made in the form of a long metal tube, the lower
edge of which is made into a cutting implement by black diamonds fixed in
the edge of the metal. By rotating this tube a ring is cut through the layers
of rock, the solid cylinder or core of rock remaining in the hollow centre of
the drill. This can be removed from time to time, the nature and thickness of
the geological formation through which the drill is passing being thus
definitely determined.

CONDITIONS TO BE CONSIDERED IN MINING

Three great problems always confront the mine operator—light, power,
and ventilation. Of these ventilation is the most important from the
workman's standpoint, although the problem of light is scarcely less so.
Obviously a cavity of the earth where hundreds of men are constantly
consuming the atmosphere and vitiating it, and where thousands of lights
are burning, would become like the black hole of Calcutta in a few minutes
if some means were not adopted to relieve this condition. But besides this
vitiation of the atmosphere caused by the respiration of the men and the
burning of lamps there are likely to be accumulations of poisonous gases in

mines, that are even more dangerous. Of the two classes of dangerous gases
—those that asphyxiate and those that explode or burn—it may be said in a
general way that the suffocating or poisonous gases, such as carbonic acid,
which is known as black damp, or choke damp, are more likely to occur in
ore mines, while the explosive gases are found more frequently in coal
mines.
Choke damp, which is a gas considerably heavier than the atmosphere, is
usually found near the bottom of mines, running along declines and falling
into holes in much the same manner as a liquid. It kills by suffocation, and,
as it will not support combustion, it may be detected by lowering a lighted
candle into a suspected cavity, the light being extinguished at once if the
gas is present. To rid the cavity of it, forced ventilation is used where
possible, the gas being scattered by draughts of fresh air. If this is
impracticable, and the cavity small, the choke damp may be dipped out with
buckets.
But the problem of the mining engineer is not so much to rid cavities of
gas as to prevent its accumulation. In modern mining, with proper
ventilation and drainage, there is comparatively little danger of extensive
accumulation of this gas.

A FLINT-AND-STEEL OUTFIT, AND A MINER'S STEEL MILL.

The upper picture shows a flint-and-steel outfit, the implements for
lighting a fire before the days of matches. The lower picture shows a
miner's steel mill, which was used for giving light in mines before the
day of the safety-lamp. It consists of a steel disk which is rotated
rapidly against a piece of flint, producing a stream of sparks. It was
thought that such sparks would not ignite fire-damp—a belief which
is now known to be erroneous.
The danger from this choke damp, therefore, is one that concerns the
individual workman rather than large bodies of men or the structure of the
mine itself. With fire damp, however, the case is different, as an explosion
of this gas may destroy the mine itself and all the workmen in it. It is,
therefore, the most dreaded factor in mining, and is the one to which more
attention has been directed than to almost any other problem.
This fire damp is a mixture of carbonic oxide and marsh gas which, being
lighter than air, tends to rise to the upper part of the mines. For this reason

explosions are more likely to occur near the openings of the mine,
frequently entombing the workmen in a remote part of the mine even when
not actually killing them by the explosion. As this gas is poisonous as well
as explosive the miners who survive the explosion may succumb eventually
to suffocation.
Previous to the year 1816 no means had been devised for averting the
explosions of fire damp except the uncertain one of watching the flame of
the candle with which the miner was working. On coming in contact with
air mildly contaminated with fire damp the candle flame takes on a blue tint
and assumes a peculiarly elongated shape which may be instantly detected
by a watchful workman. But miners were, and still are, a proverbially
careless class of men even where a matter of life and death is concerned,
and too frequently gave no heed to the warning flame. But in 1816 Sir
Humphrey Davy invented his safety lamp, a device that has been the means
of saving thousands of lives, and which has not as yet been entirely
supplanted by any modern invention.
In making his numerous experiments, Davy had observed that iron-wire
gauze is such a good conductor of heat that a flame enclosed in such gauze
could not pass readily through meshes to ignite a gas on the outside. He
found by experiment that a considerable quantity of explosive gas might be
brought into contact with the gauze surrounding a flame, and no explosion
occur. At the same time this gas would give warning of its presence by
changing the color of the flame. When a lamp was made with a surrounding
gauze having seven hundred and eighty meshes to the square inch, it was
found to give sufficient light and at the same time to be practically non-
explosive in the presence of ordinary quantities of gas.
One would suppose that such a life-saving invention would have been
eagerly adopted by the men whose lives it protected; but, as a matter of fact,
owing to certain inconveniences of Davy's lamps, many miners refused to
use them until forced to do so by the mine-owners. One of these
disadvantages was that this safety lamp gave a poor light overhead. This is
particularly annoying to the miner, who wishes always to watch the
condition of the ceiling under which he is working. When not under
constant observation, therefore, a miner would frequently remove the gauze
of the lamp and work by the open flame, regardless of consequences. Or
again, he would sometimes forgetfully use the flame for lighting his pipe.

To overcome the possibility of such forgetfulness or wilful disobedience, it
was found necessary to equip safety lamps with locking devices, so that the
miner had no means of access to the open flame of his lamp once it had
been lighted.
Since the time of the first Davy safety lamp there have been numerous
improvements in mechanical details, although the general principle remains
unchanged. One of these improvements is a device whereby the lamp, when
accidentally extinguished, may be relighted without opening it, and without
the use of matches. This is done by means of little strips of paper containing
patches of a fulminating substance which is ignited by friction, working on
the same principle as the paper percussion caps used on toy pistols.
But even the improved safety lamp seems likely to disappear from mines
within the next few years, now that electricity has come into such general
use. As yet, however, no satisfactory portable electric lamp or lantern has
been perfected, such lamps being as a rule too heavy, expensive, and
unreliable. Even if these defects were remedied, the advantage would still
lie with the Davy lamp, since the electric lamp, being enclosed, cannot be
used for the detection of fire damp. But this advantage of the safety lamp is
becoming less important, since well-regulated mines are now more
thoroughly ventilated, and the danger from fire damp correspondingly
lessened.
In some Continental mines the experiment has been tried of constantly
consuming the fire damp, before it has had time to accumulate in explosive
quantities, by means of numerous open lights kept constantly burning. This
method is effective, but since the numerous lights consume the precious
oxygen of the air as well as the damp, the method has never become
popular. Obviously, then, the question of mine ventilation is closely
associated with that of lighting.
Probably the simplest method of properly ventilating a mine is that of
having two openings at the surface, one on a much higher level than the
other if the mine is on a hillside, the lower one corresponding to the lowest
portion of the mine where possible. By such an arrangement natural
currents will be established, and may be controlled and distributed through
the mine by doors or permanent partitions, or aided by fans. But of course

only a comparatively small number of mines are so situated that this system
can be used.
It is possible, of course, to ventilate a mine from a single shaft or opening
by use of double sets of pipes, one for admitting air and the other for
expelling it; but this system is obviously not an ideal one, and is prohibited
by law in most mining districts. Such laws usually stipulate that there must
be at least two openings situated at some distance from each other.
The older method of creating air currents was by means of furnaces, but
this method, while very effective, is expensive and dangerous. In using this
system a furnace is built near the outlet of the air shaft, the combustion of
the fuel creating the necessary draught. But in the nature of things this
furnace is a constant menace to the mine, besides being an extremely
wasteful expenditure of energy. The modern method of ventilating is by
means of rotary fans, the electric fan having practically solved the problem.
The air currents established by such fans are controlled either by the doors
in the passages, or by means of auxiliary fans. In addition, jets of
compressed air are sometimes used, and have become very popular.
Another important problem that constantly confronts the mining engineer
is that of drainage. Mines are, of course, great reservoirs for the
accumulation of water, which must be drained or pumped out continually;
and as the shafts are sunk deeper and deeper it becomes increasingly
difficult to raise the water to the surface. Special means and machinery are
employed for this purpose which will be considered more in detail in a
moment.

ELECTRIC MACHINERY IN MINING

Electricity is, of course, the great revolutionary factor in modern mining.
There is scarcely a department of mining in which electric power has not
wrought revolutionary changes in recent years; and the subject has become
so important and so thoroughly specialized as to "create a literature and a
technology of its own." From the electric drill, working hundreds of feet
below the surface of the earth, to the delicate testing-instruments in the
laboratory of the assaying offices, the effect of this electrical revolution is
being felt progressively more and more every year.

Moreover, electricity, on account of its transmutability, has made
accessible many important mining sites hitherto unworkable. Rich mines
are now in operation on an economical basis which, thirty years ago, were
worthless on account of their isolation. When such mines were situated in
mountainous regions where there was no coal supply at hand for creating
steam power, and where the only available water power was perhaps several
miles away, operations on a paying basis were out of the question before the
era of electric power.
At present, however, the question of distance of the seat of power has
been practically eliminated by the possibilities of electric conduction. A
stream, situated miles away, when harnessed to a turbine and electric
motors may afford a source of power more economical than could be
furnished a few years ago by a power plant supplied with fuel at the very
door of the mine. We need not enter into the details of this transmission of
power, however, since the subject has been discussed in a general way in
another place. Our subject here is rather to deal with the application of
electricity to certain mining implements of special importance.
One of the most useful acquisitions to the equipment of the modern
miner is a portable mechanical drill, which makes it possible for him to
dispense with the time-honored pick, hammer, and hand-drill. But it is only
recently that inventors have been able to produce this implement. The great
difficulty has lain in the fact that a reciprocating motion, which is essential
for certain kinds of drilling, is not readily secured with electric power. The
use of steam or compressed air for operating such reciprocating drills
presents no mechanical difficulties, and the fact that power of this kind can
be transmitted long distances by the use of flexible tubes made such drills
popular for several years. But the cost of operating such drills is so much
greater than that of the new electric drills that they are rapidly being
replaced in mining work.
The first attempts to produce an electric drill with a reciprocating motion
were so unsuccessful that inventors turned their attention to perfecting some
rotary device. This proved more successful, and rotary drills, operating long
augers and acting like ordinary wood-boring machines, are now used
extensively for certain kinds of drilling. The more recent forms perform the
same amount of work as the air drill, with a consumption of about one-tenth
the power. Moreover, none of the energy is lost at high altitudes as in the

case of air drills, and they are not affected by low temperatures which
sometimes render the air drill inoperable. On the other hand, the air drill is a
hardy implement, capable of withstanding very rough usage, whereas the
electric drill is probably the more economical, as well as the more
convenient drill of the two.
In certain kinds of mining, such as in the potash mines of Europe and the
coal mines of America, these electric drills operating their long augers have
been found particularly useful. The ordinary type of drill is so arranged that
it can be operated at any angle, vertically or horizontally. The lighter forms
are mounted on upright stands, with screws at the ends for fastening to the
floor and roof, although the heavier types are sometimes mounted on trucks.
The motor, which is not much larger or heavier than an ordinary fan motor,
is fastened to the upright and is from four to six horse-power. This connects
with a flexible wire which transmits the power from the generating station,
frequently several miles away. The auger, which is about the largest part of
the machine and entirely out of proportion to the little motor that drives it,
is simply a long bar of steel, twisted spirally at the cutting-end like an
ordinary wood auger.
From the workman's standpoint these rotary drills are infinitely superior
to reciprocating or percussion drills, where the constant jarring of the
machine, besides being extremely tiresome, sometimes produces the serious
disease known as neuritis. Various means have been attempted to prevent
this, such as by overcoming the jar in a measure by flexible levers which do
not transmit the vibrations to the hands and arms; but such attempts are only
partially successful, and a certain amount of jarring cannot be avoided. In
the rotary electric drills there is none of this, the workmen simply
controlling the drill and the motor with levers, and receiving at most only a
slight jar from the vibrations of the auger.

TRACTION IN MINING

In recent years electric traction engines for use in mines have been
rapidly replacing horse-and mule-power, and have become important
economic factors in mining operations. The pioneer of this type of
locomotive seems to have been one built by Mr. W. M. Schlessinger for one
of the collieries of the Pennsylvania Railroad about 1882, and which has
remained in active use ever since. The total weight of this locomotive was

five tons and it was equipped with thirty-two horse-power electric motors.
The current was supplied through a trolley pole which took the current from
a T-shaped rail placed above and at one side of the track. The train hauled
by this locomotive consisted of fifteen cars, carrying from two to three tons
of coal each.
Following this first mining-locomotive a great number were quickly
produced. In Pennsylvania alone something like four hundred are now in
use, and in Illinois two million tons of coal were hauled in this manner in
twelve mines in 1901. It was estimated at the beginning of the present
century that some 3,000 electric locomotives specially built for mining were
in use in the United States alone.
The earlier types of mining-locomotives were much higher and bulkier
than those of more recent construction, the motors being mounted above the
trucks and geared downward. Very soon, however, the "turtle-back" or
"terrapin-back" type was developed, with the motors brought close to the
ground, so that even quite a heavy locomotive might not be much higher
than the diameter of its driving-wheels. When these queer-looking machines
were boxed in so that even the wheels were covered, they lost all
resemblance to locomotives or vehicles of any kind, appearing like low,
rectangular metal boxes placed upon the car tracks, that glided along the
rails in some mysterious manner. The presence of the trolley pole helped to
dispel this illusion, but in some instances this is wanting, the power being
taken from a third rail.
With these locomotives, some of them not more than two and a half feet
high, it was possible to haul trains even in very low and narrow passages—
much lower, in fact, than could be entered by the little mules used in former
years. This in itself was revolutionary in its effects, as many thin veins were
thus made workable.
This type of low locomotive is the one that has come into general use
throughout the world. Such locomotives range in size from two to twenty
tons, with wheel gauges from a foot and a half wide to the standard railway
gauge of four feet, eight and a half inches. Locomotives weighing more
than twenty tons are not in general use on account of the small size of the
mine entrances.

In the ordinary types the motorman sits in front, controlling the
locomotive with levers and mechanical brakes placed within easy reach, but
sunk as low as possible. As a rule, the motors are geared to the truck axles,
either inside or outside the locomotive frame. An overhead copper wire
supplies the current by contact with a grooved trolley wheel mounted on the
end of the regulation trolley pole. An electric headlight is used, and the
ordinary speed attained by the compact motors is from six to ten miles an
hour.
The amount of work that can be performed by one of these little, flat,
box-like locomotives is entirely out of proportion to its size. A 10-ton
locomotive in a Pennsylvania mine hauled about 150,000 tons of coal in a
year at a cost of less than one-tenth of a cent per ton for repairs. The usual
train was made up of thirty-five cars, each loaded with about 3,700 pounds
of coal, which was hauled up a three-per-cent grade. The cost of such
haulage was only about 2.76 cents per ton, as against 7.15 cents when
hauled by mule-power. These figures may be considered representative, as
other mines show similar results.

THE LOCOMOTIVE "PUFFING BILLY" AND A MODERN
COLLIERY TROLLEY.

This locomotive was constructed in 1813 at Wylam Colliery,
England, by William Hedley. It was entirely successful, and was in
operation for almost half a century, up to the time of its removal in
1862 to the South Kensington Museum. The vertical cylinders and
arrangement of walking beams for transmitting power are
particularly interesting. The power was transmitted through cogged
wheels to the rear axle, as is done with modern automobiles.
A particular advantage has been gained by the use of electric locomotives
over older methods in the process of "gathering" the cars. In many coal
mines, even when the main hauling is done by electricity, the gathering or
collecting of cars from the working faces of the rooms was formerly done
either by mule-power or by hand. In some low-veined mines, hand power
alone was used, on account of the low roof.

In such places, low, compressed-air locomotives were sometimes used;
but these were very expensive. These have now been very generally
replaced by "turtle-back" electric locomotives, operated at a distance from
the main trolley wire by means of long, flexible cables, so geared that they
can be paid out or coiled as desired.
On the main line these locomotives take the current from the trolley wire
by means of the trolley pole, but when the place for gathering is reached,
the connection is made by means of the flexible cable, and the trolley pole
fastened down so as not to be in the way. This allows the locomotive to
push the little cars into the rooms far removed from the main line, with
passages too low and narrow to allow the use of the trolley pole. By the
time the last cars have been delivered the first cars of the train have been
filled, and the process of gathering may be begun at once, and the loaded
train made up for the return trip. With such a locomotive two men can
distribute and gather up from one hundred to one hundred and twenty cars
in an ordinary eight-hour working-day, hauling from three hundred to three
hundred and fifty tons of coal.
In certain regions, a system of third-rail current-supply is used, this rail
being also a tooth rail with which a cog on the locomotive works
frictionally. For climbing steep grades this system of cogged rails has many
advantages over other systems.
Another type of electric locomotive used in some mines is a self-
propelling or automobile one equipped with storage batteries. Such
locomotives do away with the inconvenience and dangers of contact rails or
trolley wires, but are heavy and expensive. A compromise locomotive,
particularly useful for gathering, is one equipped with both trolley pole and
storage batteries. This locomotive is so made that the storage batteries are
charged while it is running with the trolley connection, so that no time is
lost in the charging process. Such locomotives have been found very
satisfactory for many purposes, and but for the imperfections common to all
storage batteries would be ideal in many ways. They can be worked over
any improvised track, regardless of distance, which is an advantage over the
flexible-cable system where distances are limited by the length of cable;
and the first cost of the battery is no more than the outlay on trolley wires
and supports. It is also claimed that the cost of maintenance is relatively

low, but it is doubtful if it equals the trolley or third-rail systems in this
respect.
Closely allied to the systems of traction by electric locomotives, is the
modern electric telpherage system. Until quite recently the haulage of ores
and other raw materials used in mining, when done aerially, has been by
means of travelling rope or cable. When distances to be travelled in this
manner are short, such as across streams or valleys, where no supports are
used, the term "cableway" is generally applied; but where the distance is so
long that supports are necessary, the term "tramway cable" is used. It is to
these longer systems that electric telpherage is particularly applicable.
The advantage of such an electric system over the older method is the
same as the advantages of the trolley road over the cable, all ropes and
cables being stationary, the electric motor, or "telpher," travelling along on
one cable and taking its current by means of a trolley pole from a wire
above. For heavier work metal rails supported between posts are employed
in place of a flexible cable, and over such systems loads of several tons can
be hauled.
Such an electric telpher system is used in one of the Cuban limestone
quarries, the telpher and cars travelling a long distance upon cables, except
at some of the curves, where solid rails are substituted, hauling a load of a
thousand pounds at a speed of from twelve to fifteen miles an hour. The
current comes from a distant source, and the telpher is so arranged that it
travels automatically when the current is turned on, stopping when the
current is cut off. This is quite a common arrangement for smaller telphers,
but in the larger ones a man travels with the telpher and load, controlling
the train just as in the case of the ordinary trolley system.
The various processes of hoisting in mines by electricity is closely akin
to that of traction, since, after all, "an elevator is virtually a railway with a
100-per-cent grade." As such work is done spasmodically, long periods of
rest intervening between actual periods of work, a great deal of energy is
wasted by steam hoisting engines, where a certain pressure of steam in the
boiler must be maintained at all times. For this reason electrical energy for
hoisting has come rapidly into popularity in recent years. "The throttling of
steam to control speed," said Mr. F. O. Blackwell in addressing the
American Institute of Mining Engineers, "the necessity for reversing the

engine, the variation in steam pressure, the absence of condensing
apparatus, the cooling and large clearance of cylinders, and the
condensation and leakage of steam pipes when doing no work, are all
against the steam hoisting engine. One of the largest hoisting engines in the
world was recently tested and found to take sixty pounds of steam per
indicated horse-power per hour. The electric motor, on the other hand, is
ideal for intermittent work. It wastes absolutely no energy when at rest,
there being no leakage or condensation. Its efficiency is high, from one-
quarter load to twice full load."
There seems to be practically no difference as far as the element of
danger is concerned between steam and electric hoists. The difference is
largely one of economy. The importance of this is shown by the recent
comparisons in a gold mine which has replaced its steam apparatus by
electricity. In this mine the hoist moves through the shaft at a rate of over
twelve hundred feet per minute, elevating five hundred tons of ore daily on
double-decked cages. It is estimated that this system shows an efficiency of
75 per cent, taking into account losses of all kinds, with a resulting
reduction of cost of from seven to twenty dollars per horse-power per
month.
Results comparing very favorably with these have been obtained also in
some of the mines in Germany and Bohemia, where electricity has been
introduced extensively in mining. In one of these mines the daily hoisting
capacity is twenty-seven hundred tons from a depth of over sixteen hundred
feet, at a speed of over fifty-two feet per second. In the Comstock mine, at
Virginia City, Nev., electric hoists are used which obtain their power from a
plant situated on the Truchee River thirty-two miles away.

ELECTRIC MINING PUMPS

In pumping, which is always one of the important items in mining, the
use of electric power has been found quite as advantageous as in the other
fields of its application. No special features are embodied in most of the
types of mining pumps over the rotary and reciprocating types used for
ordinary purposes, except perhaps a type of pump known as the sinking
pump. This is a movable pump that can be easily lowered from one place to
another, and has proved to be a great time-saver over steam or air pumps
used for similar purposes.

For some time the question of the durability of electric pumps was in
dispute, but developments in quite recent years seem to prove that, in some
instances at least, such pumps are practically indestructible.
"The question of what would happen to an electric motor in a mine if
pumps and motors get flooded has often come up. From tests made recently
at the University of Liège, Belgium, it appears that a suitably designed
polyphase alternating-current motor of a type largely used on the continent
of Europe was completely submerged in water. It was run for a quarter of an
hour; it was then stopped and allowed to remain submerged, under official
seal, for twenty-four hours, at the end of which time it was again run for a
few minutes. It was next removed from the water, again put under seal, and
left to dry for twenty-four hours. The insulation was then tested, and the
motor was found to be in perfect order. It would be hard to imagine a test
more severe than this.
"As bearing upon this question it is interesting to note that among the
pumps in use around Johannesburg, South Africa, at the beginning of the
Anglo-Boer War, there were twelve of a well-known American make, each
of which was operated by a 50-horse-power induction motor of American
construction with three 15-kilowatt transformers. When the mines were shut
down, upon the breaking out of the war, the water rose so rapidly that it was
impossible to remove the pumps, motors, transformers, etc., and
consequently they remained under 500 to 1,000 feet of water. Two and a
half years later, when peace was declared in South Africa, the water in the
shaft was pumped out and the electrical apparatus was removed to the
surface. Three of the motors were stripped and completely rewound, but to
the general surprise of the experts the condition of the insulation indicated
that the rewinding might not be absolutely necessary. Accordingly the other
nine motors were thoroughly dried in an oven and then soaked in oil. After
this treatment they were rigidly tested, proved to be all right, and were at
once restored to regular service in the mine. The transformers were treated
in the same manner as the motors, with equally gratifying results.
"An interesting illustration of the flexibility and adaptability of electric
motors for pumping purposes is furnished by the Gneisenau mine, near
Dortmund, Germany, where a very large electric mining plant was installed
in 1903. In this instance the pump is located more than 1,200 feet below the
surface, and the difficulties of installing the apparatus were so great, on

account of the small cross section of the shaft, that it was necessary to build
up the motor in the pumping chamber, the material being transported
through the wet shaft and the winding of the coils being performed in situ.
"An interesting use of the electric pump associated with the telephone in
connection with mining is noted by Mr. W. B. Clarke. In one coal mine,
where an electric pump is located in a worked-out portion of the mine, the
circuits are so arranged that the pump is started from the power house, some
distance away. Near the pump is placed a telephone transmitter connected to
a receiver in the power house. To start the motors, or to ascertain whether
the pumps are working properly, the engineer merely listens at the
telephone receiver, without leaving his post."

ELECTRICITY IN COAL MINING

In coal mining the effect of the use of electrical machinery has been
revolutionary in recent years, particularly in the development of electric
coal cutters. The old method of picking out coal by hand, where the miner
labored with the heavy pick, working in all manner of cramped and
dangerous positions, was supplanted a few years ago by the "puncher"
machine, worked by steam or compressed air. With these machines the coal
was picked out just as in the case of the hand method, except that the energy
was derived from some power other than muscular. So that while these
machines worked more rapidly than the hand picks, they utilized the same
general principle in applying their energy.
Within recent years, however, various coal-cutting machines have been
devised, with which the coal was actually cut, or sawed out, these machines
being peculiarly well adapted to using the electric current. The most
practical and popular form of machine is one in which the sawing is done
by an endless chain, the links of which are provided with a cutting blade.
These have been very generally replacing the compressed-air or pick type
of machine, and their popularity accounts largely for the enormous increase
in the use of coal-mining machinery during the past decade. Thus in 1898
there were 2,622 coal-mining machines in use in the United States. Four
years later this number had more than doubled, the increase being due
largely to the adoption of chain machines.

Like electric locomotives, and for similar reasons, the coal-cutting
machines are low, broad, flat machines, from eighteen to twenty-eight
inches high. They rest upon a flat shoeboard that can be moved easily along
the face of the coal. An ordinary machine weighs in the neighborhood of a
ton, and requires two men to operate. The apparatus is described briefly as
follows:
"On an outside frame, consisting of two steel channel bars and two angle
irons riveted to steel cross ties, rests a sliding frame consisting of a heavy
channel or centre rail, to which is bolted the cutter head. The cutter head is
made entirely of two milled steel plates, which bolt together, forming the
front guide for the cutter chain. This chain, which is made of solid cast steel
links connected by drop forge straps, is carried around idlers or sprockets
placed at each end of the cutter head and along the chain guides at the side
to the rear of the machine, where it engages with and receives its power
from a third sprocket, under the motor. The electric motor, which is of
ironclad multipolar type, rests upon a steel carriage, which forms the
bearing for the main shaft.... A reversing switch is provided, so that the
truck can travel in either direction, and when the machine has reached its
stopping point, either forward or backward, it is checked by an automatic
cut-off. The return travel is made in about one-fourth of the time required to
make the cut."
In veins of coal of a thickness from twenty-eight to thirty inches, such a
machine will cut about one hundred tons of coal in a day. The cost of
production with such machines has been estimated at about sixty-three
cents a ton, as against ninety cents as the cost of pick mining in rooms,—a
saving of about twenty-seven cents a ton. Since it is estimated that for a cost
of $10,000 an electrical equipment can be installed capable of working four
such machines besides affording power for lighting, pumping, ventilation of
the mine, etc., thus saving something like $100 a day for the operator, the
great popularity of these machines is readily understood.
After such a machine has been placed in position, a cut some four feet
wide, four or five inches high, and six feet deep can be made in five
minutes, with the expenditure of very little energy on the part of the
workmen. One of the largest cuttings ever recorded by one of these
machines is 1,700 square feet in nine and one-half hours, although this may
have been exceeded and not recorded.

Among the several advantages claimed for the chain machine over the
older pick machines is the small amount of slack coal produced, and the
absence of the racking vibrations that exhaust the workmen, and, like the air
drills, sometimes cause serious diseases. On the other hand the advocates of
the pick machines point out that they can be used in mines too narrow for
the introduction of chain machines. They show also that there is a constant
element of danger from motor-driven machines in mines where the quantity
of gas present makes it necessary to use safety lamps, on account of the
sparking of the machines which may produce explosions. Both these claims
are valid, but apply only to special cases, or to certain mines, and do not
affect the general popularity of the chain machines.
There are several different types of chain cutting machines, such as
"long-wall machines," and "shearing machines," but these need not be
considered in detail here. The general principle upon which they work is the
same as the ordinary chain machine, the difference being in the method of
applying it for use in special situations.

ELECTRIC LIGHTING OF MINES

For many obvious reasons the ideal light for mining purposes is one in
which the danger from the open flame is avoided, particularly in well-
ventilated mines, or mines under careful supervision, where the danger
from inflammable gases is slight. The incandescent electric light, therefore,
has become practically indispensable in modern mining operations. For
certain purposes and in certain locations where an intense light is desirable
and where there is no danger from combustible gases, arc lights are used to
a limited extent. But there is constant danger from the open flame in using
such lights, and also from the connecting wires leading to them.
Furthermore, such intense light is not usually necessary in the narrow
passages of the mine.
To be sure, there is a certain element of danger even with incandescent
lights on account of the possibility of breakage of the globes, and of short-
circuiting where improper wiring has been done. To overcome as much as
possible the dangers from these sources, special precautions are taken in
wiring mines, and special bulbs are used. In general the incandescent lamps
as used in mining are made of stout round bulbs of thick glass which are not
likely to crack from the effects of water dripping upon them while heated.

As a further protection it is customary to enclose the bulbs in wire cages. It
is also customary to use low-current lamps with a rather high voltage,
although this must be limited, as excessive voltage may in itself become a
source of danger.

XIII
THE AGE OF STEEL

T
he iron industry has of late years become more and more merged
into the steel industry, as steel has been gradually replacing the
parent metal in nearly every field of its former usefulness. Steel is so
much superior to iron for almost every purpose and the process of
making it has been so simplified by Bessemer's discovery that it may justly
be said that civilization has emerged from the Iron Age, and entered the Age
of Steel. While iron is mined more extensively now than at any time in the
history of the world, the ultimate object of most of this mining is to produce
material for manufacturing steel. We still speak of boiler iron, railroad iron,
iron ships, etc., but these names are reminiscent, for in the construction of
modern boilers and modern ships, steel is used exclusively. In the past
decade it is probable that no railroad rails even for the smallest and cheapest
of tracks have been made of anything but steel.
The last half of the nineteenth century has been one of triumph of steel
manufacture and production in America, and at the present time the United
States stands head and shoulders above any other nation in this industry. In
the middle of the century both Germany and England were greater
producers than America; but by the close of the century the annual output in
the United States was above fifteen million tons as against England's ten
and Germany's seven; and since 1900 this lead has been greatly increased.
The steel industry has become so great, in fact, that it is "a sort of barometer
of trade and national progress."
The great advances in the quantity of steel produced have been made
possible by corresponding advances in methods of winning the iron ore
from the earth. Mining machinery has been revolutionized at least twice
during the last half century, first by improved machines driven by steam,
and again by electricity and compressed air. Ore is still mined to a limited
extent by men with picks and shovels, but these implements now play so
insignificant a part in the process that they cannot be considered as
important factors. Steam shovels, automatic loaders and unloaders,

dynamite and blasting powder, have taken the place of brawn and muscle,
which is now mostly expended in directing and guiding mining machinery
rather than in actually handling the ore.

THE LAKE SUPERIOR MINES

At the present time the greatest iron-ore fields lie in the Lake Superior
region, and it is in this region that the greatest progress in mining methods
has been made in recent years. There are, of course, extensive mines in
other sections of the United States, but at least three-quarters of all the iron
produced in America comes from the Lake Superior mines, and the systems
of mining pursued there may be considered as representative of the most
advanced modern methods.
Where the iron ore of these mines is found near the surface of the earth,
the great system of "open-pit" mining is practised; but as only a relatively
small portion of the ore is so situated, modifications of older mining
methods are still employed. Of these the three most important are known as
"overhead scooping," "caving," and "milling."
In the overhead method a shaft is sunk into the earth to a depth of several
hundred feet, according to the depth of the ore, this shaft being lined with
timbers for support. From this shaft horizontal tunnels are made in all
directions in the ore deposits, and through these tunnels the ore is conveyed
to the shaft and thence to the surface. As the ore is removed and the earth
thus honeycombed in all directions, supports of various kinds must be made
to prevent caving. For this purpose columns of the ore itself may be left, or
supports of masonry or wood or steel may be introduced. Under certain
circumstances, however, these supports are not employed, the earth being
allowed gradually to cave in at the surface as the ore is removed, this being
the method of mining known as "caving."
Where the ore deposit occurs in a favorable hillside the "milling" system
is frequently employed. In working this system a large horizontal tunnel,
twenty or more feet in diameter, is dug into the hillside. Perpendicular
shafts are then sunk from the top of the hill, connected with openings
leading directly into the top of the main horizontal shaft. By this
arrangement the ore, when loosened in these perpendicular shafts, falls
directly into the bins placed for its reception about the openings, or into the

rows of cars in waiting to receive it. In this method dynamite and powder
take the place of hand labor, the main mass of ore being dislodged and
thrown into the shaft by blasting, instead of by hand labor.
But all these methods are overshadowed in magnitude by the great "open
pit" systems, where the ore is taken from the surface and handled entirely
by machinery, the only part played by the miner's pick being that of
assisting in loosing certain fragments so that they may be more easily
seized by the machines. Indeed, this system of mining partakes of the nature
of quarrying rather than that of mining in the ordinary sense, the ore being
scooped from the surface of the ground. One naturally thinks of a mine as
being subterranean; but in the great open-pit mines in the Lake Superior
region, which are the largest mines in the world, all the mining is done at
the surface of the earth.
It should not be understood, however, that in such mines nature has left
the red iron ore exposed at the surface in any great quantities. On the
contrary, it is usually covered by a layer of earth ranging from a yard to ten
or more yards in depth, and this, of course, must be removed before open-
pit methods can be practised. Prospecting for such deposits is therefore just
as necessary as in cases where the deposit is situated much deeper in the
earth; and the business of prospecting by "test pit" men is as important an
industry as ever.
When an available open-pit mine of sufficient extent has been located the
gigantic task of "stripping" or removing the overlying layer of earth begins.
Immense areas of land have been thus stripped in some of these
undertakings, no difficulties being considered insurmountable. If a small
river-bed lies in an unfavorable position, the course of the river is changed
regardless of expense. Farms and farm houses are purchased and literally
carted away, neither land nor houses representing values worth considering
when compared with the stratum of ore beneath them. The single contract
for stripping one area in the Lake Superior region was let for a sum
amounting to half a million dollars.
As soon as a sufficiently large area has been stripped, railroads are
constructed into the pit, steam shovels are run into place, and the actual
work of mining begins. Five shovels full make a car-load, and under
ordinary circumstances the five loads may be delivered in as many minutes.

The number of men required to manipulate one of these steam shovels is
from ten to twelve. The ore itself is frequently so hard that the scoop of the
shovel could not penetrate it until loosened and broken up, and it is the
business of the gang of workmen to do this and slide the ore down within
easy working distance of the shovel. This is mostly done by blasting with
dynamite and powder, little of the actual labor being performed by hand. In
blasting, a deep hole is first drilled into the ore near the top of the
embankment, and into this hole a stick of dynamite is dropped and
exploded. This enlarges the cavity sufficiently so that a quantity of blasting
powder may be poured in and set off, tumbling the ore down within reach
of the shovel.
This ore is frequently almost as hard as iron itself, many of the pieces
thus dislodged being too large for convenient handling, either by the steam
shovel or in the chutes at the wharves, and must be still further broken up.
This is sometimes done by the men with picks; but in mining on a large
scale, where the deposit is all of a very hard nature, crushing machines are
used.
In this manner the steam shovel is kept constantly supplied with ore for
the waiting train of cars. These trains are arranged on a track running
parallel with the track from which the steam shovel operates, and at such a
distance that the centre of the car will be directly under the opening in the
bottom of the shovel when it is swung around on its crane. The engineer in
charge of the locomotive drawing the train stops it in a position so that the
first shovelful of ore will be dumped into the forward end of the first car. As
each successive shovelful is deposited, representing about one-fifth of a car-
load, the train is pulled or backed along the track about one-fifth of a car-
length. In this manner it is only necessary for the steam shovel to be swung
into the same position and dumped at the same point each time to insure the
proper loading of the cars.
From what has been said it will be seen that in this open-pit mining the
steam engine and steam locomotive still play a conspicuous part; but in the
other forms of iron mining, electric or compressed-air motors are used, as
much better adapted for underground work. In the Lake Superior region,
where everything is done by the most modern methods, the use of horses
and mules for hauling purposes is practically unknown.

The cars used for hauling the ore are of peculiar construction. The latest
types are built of steel with a carrying capacity of fifty tons of ore, and are
so made that by simply knocking loose a few pins their bottoms open and
discharge the ore into the receiving bins on the wharves, or into the chutes
leading to the waiting boats.
A perennial problem in iron mining, whether surface or subterranean, just
as in all other kinds of mining, is the removal of accumulations of water,
some of these mines filling at the rate of from twenty-five to thirty thousand
gallons an hour. But an equally important problem is that of removing
moisture from the ore itself. Obviously every additional pound of moisture
adds to the cost and difficulty in handling, and inasmuch as this ore must be
transported a distance of something like a thousand miles, necessitating
three or four handlings in the process, the aggregate amount of wasted
energy caused by each ton of water is enormous. It has been found that at
least ten per cent of the moisture may be dried out of the ore before
shipping, and that the ore does not tend to absorb moisture again under
ordinary circumstances once it has been dried. This is of course of great
advantage where it is found necessary to store it in heaps some little time
before shipping.

FROM MINE TO FURNACE

In most industries, particularly where the percentage of waste products is
large, it is found advantageous and economical to establish factories as near
the source of supply of raw material as possible. But the iron ore mined in
the Lake Superior region is transported something like a thousand miles
before being delivered to the factories. The question naturally arises, Why
is not the ore turned into pig iron or steel ingots at once as near the mouths
of the mines as possible, and sent in this condensed form to the factories,
thus saving more than half the cost of transportation? The answer is simple:
the coal mines and steel factories lie in the East, one established by nature,
the other by man many years before iron ore was found in the Lake region.
And it is found just as cheap and easy to transport the iron to the coal
regions as it would be to transport the coal to the ore regions. Furthermore,
the factories in the neighborhood of Pittsburg and along the southern shores
of Lake Erie and Lake Ontario are near the great centres of civilization, and

are accessible the year round; while the Lake Superior region is "frozen in"
for at least three months in the year.
And so, in place of a great traffic of coal westward to the Lake Superior
regions, there is a great eastward traffic of ore, by rail and water, passing
from the mines to furnaces and factories a thousand miles away. Indeed,
this is probably the greatest and most remarkable system of transportation
in the world. Specially constructed trains, wharves, boats, and machinery,
used for this single purpose, and not duplicated either in design or extent,
make this stupendous enterprise a unique, as well as a purely American one.
The transportation begins with the train loads of ore that run from the
mines to the lake shore and out upon the wharves built to receive them.
These wharves are enormous structures, sometimes half a mile in length,
built up to about the height of the masts of ore boats. On the sides and in the
centres of these towering structures are huge bins for holding the ore, these
bins communicating directly with the holds of the ore steamers tied up
alongside. Four tracks are frequently laid on the top of the wharves, and are
so arranged that trains four abreast can dump the ore into the bins, or
waiting ships, at the same time. If the bins are empty and boats waiting to
receive a cargo, the ore is discharged by long chutes into the holds from the
cars. Otherwise the bins are filled, the trains returning to the mines as
quickly as possible for fresh loads.
The boats for receiving this cargo are of special design, many of them
differing very greatly in appearance from ordinary ocean liners of
corresponding size. This is particularly true of the "whale-backs" which
have little in common in appearance with ordinary steamers except in the
matter of funnels; and even these are misplaced sternwards to a distance
quite out of drawing with the length of the hull. Their shape is that of the
ordinary type of submarine boat—that is, cigar-shaped—this effect being
obtained by a curved deck completely covering the place ordinarily
occupied by a flat deck. A wheel-house, like a battle-ship's conning-tower,
is placed well forward, supported on steel beams some distance above the
curved deck for observation purposes; and engines, boilers, and coal
bunkers occupy a small space in the stern. The boat, therefore, is mostly
hold.

But the "whale-backs" form only a small portion of the ore-fleet. The
ordinary type of boat conforms more nearly to the shape of ocean boats,
except that the bridge, wheel-house, and engines are located as in the
whale-backs. The bows of these boats are blunt, the desideratum in such
craft being hull-capacity rather than speed. For sea-worthiness they are
equal to any ocean boats, as the battering waves of Lake Superior are quite
as powerful and even more treacherous than those of the Atlantic or Pacific.
Some of these boats are five hundred feet long, equal to all but the largest
ocean vessels. Their coal-carrying capacity is relatively small, since coaling
stations are numerous at various points on the journey, and every available
inch of space is utilized for the precious iron ore.
In order to facilitate loading, the decks are literally honey-combed with
hatches, some boats having fifteen or sixteen openings extending the width
of the deck. By this arrangement the time of loading is reduced to a matter
of a few hours, as a dozen chutes, each discharging several tons of ore per
minute, soon fill the yawning compartments with the necessary six, eight,
or nine thousand tons, that make up the cargo.
Quite recently lake-navigators have learned, what rivermen have long
known, that cheap transportation may be effected on a large scale by barges
and towing. Before the outbreak of the Civil War forty years ago, the
Mississippi river swarmed with great cargo-carrying steamers, employing
armies of men and consuming enormous quantities of fuel. But after the war
the experiment was tried of hauling the cargoes on barges towed by tug
boats, and this proved to be so much cheaper that the fleet of great river
boats soon disappeared. In somewhat the same way the barge has come into
use of late years in the ore-traffic, and the great ore-steamers now tow
behind them one or two barges equal in carrying capacity to themselves. In
this way three ships' cargoes of ore are transported a thousand miles by a
score of men, a dozen on the steamer and three or four on each of the
barges. The barges themselves are rigged as ships, and if necessary can shift
for themselves by means of sails attached to their stubby masts. But these
are used only on special and unusual occasions, as in case of accidental
parting of the hawsers during a storm.
The problem of loading the ships at the ore wharves is a simple one as
compared with the equally important one of transferring the ore from the
hold to trains of cars in waiting at the eastern end of the water route. For

four handlings of the ore are necessary before it is finally deposited in the
furnaces in the east. The first of these is from the mine to cars; the second
from the cars to the boats; the third from the boats to cars; and the fourth
from the cars to the blast furnaces.
For many years about the only hand work done in any of these processes
was that of transferring from the boats to the ore-trains, and even here
"automatic unloaders" are now rapidly supplanting the tedious hand
method. By the older methods a travelling crane, or swinging derrick,
dropped a bucket into the hold of the ore-vessel, where workmen shovelled
it full of the red ore. It was then lifted out by machinery and the contents
dumped into cars in much the same manner as that of the steam shovel in
the mines. Recently, however, a machine has been perfected which scoops
up the ore from the ship's hold and transfers it to the cars without the aid of
shovellers. The only human aid given this gigantic machine is to guide it by
means of controlling levers—to furnish brains for it, in short—the "muscle"
being furnished by steam power. The great arm of this automatic unloader,
resembling the sweep of the old-fashioned well in principle, moves up and
down, burying the jaws of the shovel into the ore in the hold, and pulling
them out again filled with ore, with monotonous regularity, quickly
emptying the vessel under the guidance of half a dozen men, and
performing the labor of hundreds.
Thus the last field of activity for the laborer and his shovel, in the iron-
ore industry, has been usurped by mechanical devices. From the time the
ore is taken from the mine until it appears as molten metal from the
furnaces, it is not touched except by mechanisms driven by steam,
compressed air, or electricity. And yet, so rapid is the growth of the iron and
steel industry that there is almost always a demand for more workmen.
For this reason, and perhaps because of the "American spirit" among
workmen, innovations in the way of labor-saving machinery are not resisted
among the mine laborers. The American workman seldom resists or attacks
machinery on the ground that it "throws him out of a job," as does his
English cousin. It would be unjust to attribute this attitude to superior
acumen on the part of the American workman, and it is probably a
difference in conditions and surroundings that accounts for the
diametrically opposite views held by laborers on the two sides of the
Atlantic. But after all, results must speak for themselves, and the advantage

all lies in favor of the progressive attitude of the western laborer, if we may
judge by the relative social status and financial standing of European and
American workmen.

THE CONVERSION OF IRON ORE INTO IRON AND STEEL

Since steel is a compound substance composed essentially of two
elementary substances in varying proportions, it appears that the name
"steel," like wood, refers to a class of which there are several varieties.
This, of course, is the case, but for the moment we may consider steel as a
single substance composed chiefly of iron and containing a certain
percentage of carbon. In this respect it resembles cast iron, steel having a
smaller amount of carbon. Wrought iron, on the other hand, contains no
carbon at all, or at least only a trace of it. But whatever the ultimate destiny
of iron ore—whether it is to become aristocratic manganese steel, or
plebeian cast iron—it must first pass through certain processes before being
"converted."
To extract the pure iron from the iron ore it is necessary to heat the ore in
a furnace containing a certain quantity of coal, coke, or charcoal, and
limestone. The furnaces used in this process are known as blast-furnaces,
and in these about one ton of iron is extracted for every two tons of Lake
Superior ore, one and a quarter tons of coke, and half a ton of limestone
used. These quantities are by no means constant, of course, but they may be
taken as representing roughly the relative amounts of material that must be
fed into the furnaces.
Like everything else in the world of iron and steel, these blast-furnaces
have undergone revolutionary improvements during the past quarter of a
century. From being most dangerous and destructive structures causing
frightful loss of life and producing only about one ton of iron a day for
every man working about them, as formerly, they have now become
relatively harmless monsters, capable of turning out six times that quantity
of ore for each man employed.
The older blast-furnace was a huge, chimney-like structure, perhaps a
hundred feet high, into which the ore, coal, and limestone were poured.
Most of the work about these furnaces was done by manual labor, or at least
manual labor was an active assistant to the machinery used in manipulating

the furnaces. The top of the furnace was closed in by a great movable lid, or
"bell," and the material for charging it was hauled up the sides by elevators
and dumped in at the top. About the top of the furnace was constructed a
staging upon which the workmen stood, an elevator shaft connecting the
staging with the ground. The ore and other materials were brought to the
foot of the shaft on cars from which it was shovelled into peculiarly
designed wheelbarrows, trundled to the elevator, and hauled to the top.
In order to dump the wheelbarrow loads into the furnaces it was
necessary to raise the bell. This was always dangerous, and frequently
resulted in the suffocation or injury of the workmen on the staging. For
when the bell was raised there was an escape of poisonous gases, which
might flare out in a sheet of flame, with the possibility of burning or
suffocating the workmen. The fumes from these gases, if inhaled in small
quantities, might simply cause coughing, hiccoughing, or dizziness; but
when inhaled in large quantities they struck down a man like the fumes of
chloroform, suffocating him in a few seconds if he was not removed at once
into a purer atmosphere. Indeed, the likelihood of this was so great that at
many of these furnaces a special workman was detailed to take the position
on the staging, well out of range of the gas, his sole duty being to rescue
any of the men who might be overcome, and hurry them as quickly as
possible down the elevator shaft into the pure atmosphere below. It was not
an uncommon thing in the neighborhood of these older furnaces to see
stretched about on the ground at the base several workmen in various stages
of suffocation. Fortunately, by use of precautionary measures, fatal
accidents were rather unusual, the men being overcome only temporarily,
and usually recovering quickly and returning to work.
But the poisonous gas coming from the top of the furnace was not the
only, nor the worst, danger constantly menacing the men on the staging.
Their greatest dread was the possibility of explosions occurring in the
furnace, which might hurl the bell into the air and deluge the upper
structure with molten metal. Against this possibility there was no safeguard
in the older furnaces, explosions occurring without warning and frequently
with terrible effects. But fortunately these older types of furnaces are being
rapidly replaced by the newer forms in which the danger to life, at least
from gas and explosions, is minimized. And even in the older furnaces,

improvements in the structure of the bell and in methods of filling have
greatly lessened the dangers.
In the modern type of blast-furnace the work at the top formerly
performed by men on the staging is accomplished entirely by machinery.
The general appearance of these furnaces is that of huge iron pipes or
kettles mounted on several iron legs. The outer structure, or shaft, is
constructed of plate iron, but this is lined with fire brick of considerable
thickness, and may have a water jacket interposed between these bricks and
the shaft. About this large kettle are smaller kettles of somewhat similar
shape having pipes leading from their tops to the larger structure. These
smaller kettles are the "stoves" used in producing the hot air for the furnace.
The working capacity of some of these furnaces is in the neighborhood of
a thousand tons of iron a day, although the average furnace produces only
about half that quantity. The powerful machinery used for charging these
monster caldrons hauls the ore and other charging materials to the top and
dumps it in car-load lots.
In the older methods of manufacturing steel, the contents of the blast-
furnaces were first drawn off into molds and allowed to cool into what is
known as pig-iron. It was then necessary to re-heat this iron and treat it by
the various methods for producing the kind of steel desired. By the newer
methods, however, time and money are saved by converting the liquid iron
from the blast-furnace directly into steel without going through the
transitional stage of cooling it into pigs. Pigs of iron are still made in
enormous quantities, to be sure, but mostly for shipment to distant places or
for stores as stock material. For statistical purposes, however, the entire
product of the blast-furnace, whether liquid or solid, is known as "pig iron."
The older method of removing the iron from the blast furnaces was by
tapping at the opening near the bottom, the stream of liquid iron being
allowed to flow into a connected series of sand molds, each mold being
about three feet long by three or four inches wide. The bottom of these
molds was flat but as the metal cooled in them the upper surface became
round in shape, assuming a fanciful resemblance to a pig's back. In this
molding a great amount of time was wasted in the slow process of cooling,
and a large expenditure of energy wasted in this handling and re-handling of
the metal.

In modern smelting works, however, pigs are no longer cast in sand
molds, the molten metal from the furnace being discharged directly into
iron molds attached to an endless chain. These molds are long, narrow, and
shallow, having the general shape of sand molds. Each mold as it passes
beneath the opening in the furnace remains just long enough to receive the
requisite amount of metal to fill it, and then moves on to a point where it is
either sprayed with water, or cooled by actually passing through a tank of
water, emerging from this bath with the metal sufficiently solidified so that
it may be dropped into a waiting car at the turning point of the endless
chain. In this manner the charge from the blast-furnace may be drawn,
cooled, and converted into pigs, loaded into cars, and hauled away without
extra handlings or loss of time, the whole process occupying practically no
more time than the initial step of tapping by the older method.
Where the contents of the blast-furnace are to be converted into steel at
once, the molten metal is run off into movable tanks which carry it directly
to the steel furnaces. These tanks, holding perhaps twenty tons of metal, are
made of thick iron lined with fire brick, and arranged on low, flat cars
designed specially for the purpose. These tanks are run under the spout of
the furnace, filled with molten metal, and drawn to the steel works, possibly
five miles away. As a rule, the distance is much less, but as far as the
condition of the metal is concerned distance seems to make little difference,
as even at the extreme distance there is no apparent cooling of the seething
mass. The intense heat given off by these trains necessitates specially
constructed cars, tracks, bridges, and crossings.
The destination of this train load of iron pots is the "mixer"—a great 200-
ton kettle in which the products from the various furnaces are mixed and
rendered uniform in quality. On the arrival of the train at the mixer, Titanic
machinery seizes the twenty-ton pots and dumps their contents bodily into
the glowing pool in the great crucible. Like the filling process, this
operation occupies only a few minutes.
From the mixer the metal is poured out into ladles and transferred
immediately to the "converter"—the important development of Sir Henry
Bessemer's discovery that has made possible the modern steel industry. This
converter resembles in shape some of the old mortars used in the American
Civil War—barrel-shaped structures suspended vertically by trunnions at
the middle and having an opening at the top. Into this opening at the top the

metal from the mixer is poured and when the converter has been sufficiently
charged a blast of cooled air is blown in at the bottom through the molten
metal. This blast emerges at the top as a long roaring flame, of a red color at
first but gradually changing into white, and then faint blue. These changes
in color are indicative of the changes that are taking place in the metal, and
the appearance of a certain shade of color indicates that the conversion into
steel is complete, and that it is time for shutting off the blast of air. Any
mistake in this matter—even the variation of thirty seconds' time—means a
loss of thousands of dollars in the quality of steel produced. The man whose
duty it is to determine this important point, therefore, holds an exceptionally
delicate and responsible position, and receives pay accordingly.
In deciding the exact moment when the blast shall be turned off, this
workman is guided entirely by the sense of sight. Mounted on a platform
commanding the best possible view of the mouth of the converter and
wearing green glass goggles of special construction, this man watches the
change of color in the flame until a certain shade is reached—a shade that
to the ordinary untrained observer does not differ in appearance from that of
a moment before—when he gives the signal to shut off the blast. When this
signal is given the contents of the converter is no longer common-place cast
iron, but steel, ready to be molded into rails, boilers, or a thousand and one
other useful things.
The contents of the converter may now be drawn off as liquid steel into
molds of any desired shape and size, and when cooled will be ready for
shipment. But in the great steel factories the metal is not ordinarily allowed
to cool completely before being sent to the rolling mills, being drawn off
into molds placed along the surface of small, flat cars. These molds are
rectangular, ordinarily four or five feet high by less than two feet in
diameter. The metal is poured into openings in the top of each mold, and
allowed to cool, solidify, and to contract enough to permit the outer casings
of the molds to be pulled off by machinery, leaving the glowing "ingots" of
steel ready for molding by machinery in the mills.
The process just described is the one by which "Bessemer steel" is made.
There is another important process in use, the "open hearth" method, which
differs considerably from this; but before considering this process
something more should be said of the man whose discoveries made possible
the modern steel industry.

SIR HENRY BESSEMER

In the history of the progress of science and invention some one great
name is usually pre-eminently associated with epoch-marking advances,
although there may be a cluster of important but minor associates. This is
true in the history of the modern steel industry, and the central name here is
that of Sir Henry Bessemer.
Bessemer was born at Charlton, England, on Jan. 19, 1813. Always of an
inventive turn of mind, his attention was first directed to improving the
methods then in use for the manufacture of steel, while experimenting with
the manufacture of guns. After several years of experimenting in his little
iron works near London, he reached some definite results which he
announced to the British Association in 1856. In this paper he described a
process of converting cast iron into steel by removing the excess of carbon
in the molten metal by a blast of air driven through it. This paper, in short,
described the general principles still employed in the Bessemer process of
manufacturing steel. And although the first simple process described by
Bessemer has been modified and supplemented in recent years, it was in
this paper that the process which placed steel upon the market as a
comparatively cheap, and infinitely superior, substitute for ordinary iron,
was first disclosed.
This famous paper before the British Association aroused great interest
among the English ironmasters, and applications for licenses to use the new
process were made at once by several firms. But the success attained by
these firms was anything but satisfactory, although Bessemer himself was
soon able to manufacture an entirely satisfactory product. The disappointed
ironmasters, therefore, returned to the earlier processes, the inventor
himself being about the only practical ironmaster who persisted in using it.
Recognizing the defects in his process, Bessemer set about overcoming
them, and at the end of two years he had so succeeded in perfecting his
methods that his product, equal in every respect to that of the older process,
could be manufactured at a great saving of time and money. But the
ironmasters were now skeptical, and refused to be again inveigled into
applying for licenses. Bessemer, therefore, with the aid of friends, erected
extensive steel works of his own at Sheffield, and began manufacturing
steel in open competition with the other steel operators. The price at which

he was able to sell his product and realize a profit was so much below the
actual cost of manufacture by the older process, that there was soon
consternation in the ranks of his rivals. For when it became known that the
firm of Henry Bessemer & Co. was selling steel at a price something like
one hundred dollars a ton less than the ordinary market price, there was but
one thing left for the ironmasters to do—surrender, and apply for licenses to
be allowed to use the new process.
By this means, and through the profits of his own establishment,
Bessemer eventually amassed a well-earned fortune. Moreover, he was
honored in due course by a fellowship in the Royal Society, and knighted
by his government.
One other name is usually associated with that of Bessemer in the
practical development of the inventor's original idea. That is the name of
Robert Mushet, and the "Bessemer-Mushet" process is still in use. Mushet's
improvement over Bessemer's original process was that of adding a certain
quantity of spiegeleisen, or iron containing manganese, which, for some
reason not well understood, simplifies the process of steel making. Mushet,
therefore, must be considered as the discoverer of a useful, though not an
absolutely essential, accessory to the Bessemer process.

OPEN-HEARTH METHOD

In the open-hearth method the metal from the blast-furnaces is not sent to
the converter, but is poured into oven-like structures built of fire brick, and
in these heated to a terrific temperature. This heat has the same effect upon
the metal as the blast of air in the Bessemer converter, and this open-hearth
process has become very popular for manufacturing certain kinds of steel.
While in the method of application this process differs greatly from that of
Bessemer, it differs largely in the fact that the oxygen necessary to burn off
the carbonic oxide, silicon, etc., is made to play over the molten mass
instead of passing through it.
It has been noted that the old type of blast-furnace gave off great
quantities of combustible gases which became waste products. Even gases
containing something like 20 or 25 per cent. of carbonic acid may be highly
inflammable, and thus an enormous quantity of valuable fuel was constantly
wasted. In some furnaces, to be sure, they were put to practical use for

heating the blast, but as the quantities given off were greatly in excess of
the amount necessary for this purpose, there was a constant loss even with
such furnaces.
Quite recently it has been found that the gases can be used directly in gas
engines, developing three or four times as much energy in this way as if
they were used as fuel under ordinary steam boilers. These engines are now
used for operating the rolling-mill machinery, and the machinery of shops
adjoining the furnaces, which, however, must not be situated at any very
great distances from the furnaces. This accounts partly for the grouping
together of blast-furnaces, rolling mills, and machine shops, the economical
feature of this arrangement being so great that segregated establishments
find it next to impossible to compete in the open market with such
"communities" under the conditions prevailing in the steel industry.

ALLOY STEELS

The introduction of Krupp steel, or nickel, for armor plates, a few years
ago, called attention in a popular way to the fact that for certain purposes
pure steel—that is, iron plus a certain quantity of carbon—was not as useful
as an alloy of steel with some other metal. An alloy was a great
improvement over ordinary steel or iron plates used in warfare; but in the
more peaceful pursuits, as well as in warfare, certain alloyed steels, such as
chrome steel, tungsten steel, and manganese steel play a very important
part.
Chrome steel, for example, in the form of projectiles, is the most dreaded
enemy of nickel-steel armor plates, because of the hardness and elasticity of
armor-piercing projectiles made of it. Such a steel contains about two per
cent. of chromium with about one or two per cent. of carbon, which when
suddenly cooled is extremely hard and tough. This kind of steel and
manganese steel are the best guards against the burglar and safe-blower, as
they resist even very highly tempered and hardened drills. As this steel is
relatively cheap to manufacture, it is frequently used in the construction of
safes and burglar-proof gratings. For this purpose, however, it is sometimes
combined in alternate layers with soft wrought iron, the steel resisting the
point of the drill, while the iron furnishes the necessary elasticity to resist
the blows of the sledge. The bars used in modern jails and prisons are often
made in a similar manner of alternate sheaths of iron and chrome steel.

Against the time-honored "hack-saw," the bugbear of prison officials for
generations, such bars an inch and a quarter in diameter offer an almost
insurmountable obstacle; and they are equally effective against a heavy
sledge hammer.
At least one case is recorded in which the use of these "composite" bars
resulted in a disastrous fire in a prison. A small blaze having started in the
basement of this prison, attempts to reach it with a stream of water were
defeated by the bars of the steel gratings at the windows, which would not
admit the nozzle of the hose. A corps of men armed with hack-saws, crow-
bars, and sledges attacked this grating, which, if made of ordinary steel,
could have been readily broken. But against these composite bars they
produced no appreciable effect. Meanwhile the fire gained rapidly,
threatening the building and its eight hundred inmates, and was only
checked after holes had been made through fire-proof floors and ceilings for
admitting the nozzle.
Manganese steel is peculiar in becoming ductile by sudden cooling, and
brittle on cooling slowly—precisely the reverse of ordinary steel. It contains
about 1.50 per cent. of carbon, and about 12 per cent. of manganese. If a
small quantity of manganese, that is, 1 or 2 per cent., is used the steel is
very brittle, and becomes more so as greater quantities of the manganese are
used, up to about 5 per cent. From that point, however, it becomes more
ductile as the quantity of manganese is increased, until at about 12 per cent.
it reaches an ideal state. When used for safes and money vaults this steel
has one great advantage over chrome steel—it is not affected by heat. By
using a blow-pipe and heating a limited area of steel, the burglar is able to
"draw the temper" of ordinary steel to a sufficient depth so that he can drill
a hole to admit a charge of dynamite; but manganese steel retains its temper
under the blow-pipe no matter how long it may be applied. Against attacks
of the sledge, however, it is probably inferior to chrome steel.
Like manganese steel, tungsten steel retains its temper even when heated
to high temperatures. For this reason it is used frequently in making tools
for metal-lathe work where thick slices of iron are to be cut, as even at red
heat such a tool continues to cut off metal chips as readily as when kept at a
lower temperature. This steel contains from 6 to 10 per cent. of tungsten, a
metallic element with which we have previously made acquaintance in our
studies of the incandescent lamp.

XIV
SOME RECENT TRIUMPHS OF APPLIED SCIENCE

N
ot long ago a little company of men met in a lecture hall of
Columbia University to discuss certain questions in applied science.
It was a small gathering, and its proceedings were so unspectacular
as to be esteemed worth only a few lines of newspaper space. The
very name—"Society of Electro-Chemistry"—seemed to mark it as having
to do with things that are caviare to the general. The name seems to smack
of fumes of the laboratory, far removed from the interests of the man in the
street. Yet Professor Chandler said in his address of welcome to the
members of the society, that though theirs was the very youngest of
scientific organizations, he could confidently predict for it a future position
outranking that of all its sister societies; and his prediction was based on the
belief that electro-chemistry is destined to revolutionize vast and important
departments of modern industry. A majority of the heat-using methods of
mechanics will owe their future development to the new science.
In a word, then, despite its repellent name, the society in question has to
do with affairs that are of the utmost importance to the man in the street.
Though its members may sometimes deal in occult formulas and abstruse
calculations, yet the final goal of their studies has to do not with
abstractions but with practicalities,—with the saving of fuel, the smelting of
metals, the manufacture of commodities. But theory in the main must
precede practice—the child creeps before it walks. "The later developments
of industrial chemistry," says Sir William Ramsey, "owe their success
entirely to the growth of chemical theory; and it is obvious," he adds
significantly, "that that nation which possesses the most competent
chemists, theoretical and practical, is destined to succeed in the competition
with other nations for commercial supremacy and all its concomitant
advantages."
Fortunately this interdependence of science and industry is not a mere
matter of prophecy—for the future tense is never quite so satisfying as the
present. Vastly important changes have already been accomplished; old

industries have been revolutionized, and new industries created. The
commercial world of to-day owes vast debts to the new science. Professor
Chandler outlined the character of one or two of these in the address just
referred to. He cited in some detail, for example, the difference between old
methods and new in such an industry as the manufacture of caustic soda. He
painted a vivid word picture of the distressing conditions under which soda
was produced in the old-time factories. Salt and sulphuric acid were
combined to produce sulphate of soda, which was mixed with lime and coal
and heated in a reverberatory furnace. Each phase of the process was
laborious. The workmen operating the furnaces sweltered all day long in an
almost unbearable atmosphere—stripped to the waist, dripping with
perspiration, sometimes overcome with heat. Their task was one of the most
trying to which a man could be subjected.
But to-day, in such establishments as the soda manufactories at Niagara
Falls, all this is changed. A salt solution circulates continuously in retorts
where it can be acted upon by electricity supplied from dynamos operated
by the waters of the Niagara River. The workmen, comfortably dressed and
moving about in a normal temperature, have really nothing to do but refill
the retorts now and then and remove the finished product. "It almost
seems," Professor Chandler added with a smile, "as if workmen ought to be
glad to pay for the privilege of participating in so pleasant an occupation. At
all events it is, in all seriousness, a pleasure for the visitor who knows
nothing of old practices to witness this triumph of a modern scientific
method."
Even more interesting, said Professor Chandler, are the processes
employed in the modern method of producing the metal aluminum by the
electrolytic process. The process is based on the discovery made by Mr.
Charles M. Hall while he was a student working in a college laboratory, that
the mineral cryolite will absorb alumina to the extent of twenty-five per
cent. of its bulk, as a sponge absorbs water. The solution of this compound
is then acted on by electricity, and the aluminum is deposited as pure metal.
A curiously interesting practical detail of the process is based on the fact
that pulverized coke remains perfectly dry and rises to the surface when
stirred into a crucible containing the hot alumina solution: moreover, it rises
to the surface and remains there as a shield to protect the workmen against
the heat of the solution. It serves yet another purpose, as the powdered

alumina may be sifted upon it and left there to dry before being stirred into
the crucible. A most ingenious yet simple device tells the workman when
any particular crucible is in need of replenishing. A small, ordinary,
incandescent electric-light bulb is placed in circuit between the poles that
convey the electric current through the alumina solution. So long as the
crucible contains alumina, the bulb does not glow, because twenty volts of
electricity are required to make it incandescent, whereas seven volts pass
through the solution. But so soon as the alumina becomes exhausted,
resistance to the current rises in the cryolite solution and, as it were, dams
back the electric current until it overflows into the wire at sufficient
pressure to start the signal lamp. Then it is necessary merely for a workman
to stir into the solution the dry alumina resting on the surface, along with
the coke that supports it. This, of course, reestablishes the electrolytic
process; the lamp goes out and the coke, unaffected by its bath, rises to the
surface to support a fresh supply of alumina.
Such a process as this, contrasted with the usual methods of smelting
metals in fiercely heated furnaces, seems altogether wonderful. Here a pure
metal is extracted from the clayey earth of which it formed a part, without
being melted or subjected to any of the familiar processes of the
picturesque, but costly, laborious, and even dangerous, blast-furnaces.
There is no glare and roar of fires; there are no showers of sparks; there is
no gush of fiery streams of molten metal. A silent and invisible electric
current, generated by the fall of distant waters, does the work more
expeditiously, more efficiently, and more cheaply than it could be done by
any other method as yet discovered.
Fully to appreciate the importance of the method just outlined, we must
reflect that aluminum is a metal combining in some measure the properties
of silver, copper, and iron. It rivals copper as a conductor of electricity; like
silver it is white in color and little subject to tarnishing; like iron it has great
hardness and tensile strength. True, it does not fully compete with the more
familiar metals in their respective fields; but it combines many valuable
qualities in fair degree; and it has an added property of extreme lightness
that is all its own. Add to this the fact that aluminum is extremely abundant
everywhere in nature—it is a constituent of nearly all soils and is computed
to form about the twelfth part of the entire crust of the earth—whereas the
other valuable metals are relatively rare, and it will appear that aluminum

must be destined to play an important part in the mechanics of the future.
There is every indication that the iron beds will begin to give out at no
immeasurably distant day; but the supply of aluminum is absolutely
inexhaustible. Until now there has been no means known of extracting it
cheaply from the clay of which it forms so important a constituent. But at
last electro-chemistry has solved the problem; and aluminum is sure to take
an important place among the industrial metals, even should it fall short of
the preeminent position as "the metal of the future" that was once
prematurely predicted for it.

NITROGEN FROM THE AIR

There is a curious suggestiveness about this finding of aluminum at our
very door, so to speak, some scores of centuries after the relatively rare and
inaccessible metals had been known and utilized by man. But there is
another yet more striking instance of an abundant element which man
needed, but knew not how to obtain until the science of our own day solved
the problem of making it available. This is the case of the nitrogen of the
air. As every one knows, this gas forms more than three-fourths of the bulk
of the atmosphere. But, unlike the other chief constituent, oxygen, it is not
directly available for the use of plants and animals. Yet nitrogen is an
absolutely essential constituent of the tissues of every living organism,
vegetable and animal. Any living thing from which it is withheld must die
of starvation, though every other constituent of food be supplied without
stint; and the fact that the starving organism is bathed perpetually in an
inexhaustible sea of atmosphere chiefly composed of nitrogen would not
abate by one jot the certainty of its doom.
To be made available as food for plants (and thus indirectly as food for
animals) nitrogen must be combined with some other element, to form a
soluble salt. But unfortunately the atoms of nitrogen are very little prone to
enter into such combinations; under all ordinary conditions they prefer a
celibate existence. In every thunder-storm, however, a certain quantity of
nitrogen is, through the agency of lightning, made to combine with the
hydrogen of dissociated water-vapor, to form ammonia; and this ammonia,
washed to the earth dissolved in rain drops, will in due course combine with
constituents of the soil and become available as plant food. Once made
captive in this manner, the nitrogen atom may pass through many changes

and vicissitudes before it is again freed and returned to the atmosphere. It
may, for example, pass from the tissues of a plant to the tissues of a
herbivorous animal and thence to help make up the substance of a
carnivorous animal. As animal excreta or as residue of decaying flesh it
may return to the soil, to form the chief constituent of a guano bed, or of a
nitrate bed,—in which latter case it has combined with lime or sodium to
form a rocky stratum of the earth's crust that may not be disturbed for
untold ages.
A moment's reflection on the conditions that govern vegetable and animal
life in a state of nature will make it clear that a soil once supplied with
soluble nitrates is likely to be replenished almost perpetually through the
decay of vegetation. But it is equally clear that when the same soil is tilled
by man, the balance of nature is likely to be at once disturbed. Every pound
of grain or of meat shipped to a distant market removes a portion of
nitrogen; and unless the deficit is artificially supplied, the soil becomes
presently impoverished.
But an artificial supply of nitrogen is not easily secured—though
something like twenty-five million tons of pure nitrogen are weighing down
impartially upon every square mile of the earth's surface. In the midst of
this tantalizing sea of plenty, the farmer has been obliged to take his choice
between seeing his land become yearly more and more sterile and sending
to far-off nitrate beds for material to take the place of that removed by his
successive crops. The most important of the nitrate beds are situated in
Chili, and have been in operation since the year 1830. The draft upon these
beds has increased enormously in recent years, with the increasing needs of
the world's population. In the year 1870, for example, only 150,000 tons of
nitrate were shipped from the Chili beds; but in 1890 the annual output had
grown to 800,000 tons; and it now exceeds a million and a half.
Conservative estimates predict that at the present rate of increased output
the entire supply will be exhausted in less than twenty years. And for some
years back scientists and economists have been asking themselves, What
then?
But now electro-chemistry has found an answer—even while the
alarmists were predicting dire disaster. Means have been found to extract
the nitrogen from the atmosphere, in a form available as plant food, and at a
cost that enables the new synthetic product to compete in the market with

the Chili nitrate. So all danger of a nitrogen famine is now at an end,—and
applied science has placed to its credit another triumph, second to none,
perhaps, among all its conquests. The author of this truly remarkable feat is
a Swedish scientist, Christian Birkeland by name, Professor of Physics in
the University of Christiania. His experiments were begun only about the
year 1903, and the practical machinery for commercializing the results—in
which enterprise Professor Birkeland has had the co-operation of a practical
engineer, Mr. S. Eyde—is still in a sense in the experimental stage,—albeit
a large factory was put in successful operation in 1905 at Notodden,
Norway.
Professor Birkeland has thus accomplished what many investigators in
various parts of the world have been striving after for years. The
significance of his accomplishment consists in the fact that he has
demonstrated the possibility of making nitrogen combine with oxygen in
large quantities and at a relatively low expense. The mere fact of the
combination, as a laboratory possibility, had been demonstrated in an elder
generation by Cavendish, and more recently by such workers as Sir William
Crookes, and Lord Rayleigh in England and Professors W. Mutjmaan and
H. Hofer in Germany. Moreover, the experiments of Messrs. Bradley and
Lovejoy, conducted on a commercial scale at Niagara Falls, had seemed to
give promise of a complete solution of the problem; had, indeed, produced
a nitrogen compound from the air in commercial quantity, but not,
unfortunately, at a cost that made competition with the Chili nitrate
possible. Equally unsuccessful in solving this important part of the problem
had been the experiments, conducted on a large scale, of Professors
Kowalski and Moscicki, at Freiburg.
All these experimenters had adopted the same agent as the means of, so
to say, forcing the transformation—namely, electricity. The American
investigators employed a current of ten thousand volts; the German workers
carried the current to fifty thousand volts. The flame of the electric arc thus
produced ignited the nitrogen with which it came in contact readily enough;
but the difficulty was that it came in contact with so little. Despite ingenious
arrangements of multiple poles, the burning-surface of the multiple arc
remained so small in proportion to the expenditure of energy that the cost of
the operation far exceeded the commercial value of the product. Such, at

least, must be the inference from the fact that the establishments in question
did not attain commercial success.
The peculiarity of Professor Birkeland's method is based upon the
curious fact that when the electric arc is made to pass through a magnetic
field, its line of flame spreads out into a large disk—"like a flaming sun."
The sheet of flame thus produced represents no greater expenditure of
energy than the lightning flash of light that the same current would produce
outside the magnetic field; but it obviously adds enormously to the arc-light
surface that comes in contact with the air, and hence in like proportion to
the amount of nitrogen that will be ignited. In point of fact, this burning of
nitrogen takes place so rapidly in laboratory experiments as to vitiate the air
of the room very quickly. In the commercial operation, with powerful
electro-magnets and a current of five thousand volts, operating, of course,
in closed chambers, the ratio between energy expended and result achieved
is highly satisfactory from a business standpoint, and will doubtless become
still more so as the apparatus is further perfected.
To the casual reader, unaccustomed to chemical methods, there may seem
a puzzle in the explanation just outlined. He may be disposed to say, "You
speak of the nitrogen as being ignited and burned; but if it is burned and
thus consumed, how can it be of service?" Such a thought is natural enough
to one who thinks of burning as applied to ordinary fuel, which seems to
disappear when it is burned. But, of course, even the tyro in chemistry
knows that the fuel has not really disappeared except in a very crude visual
sense; it has merely changed its form. In the main its solid substance has
become gaseous, but every atom of it is still just as real, if not quite so
tangible, as before; and the chemist could, under proper conditions, collect
and weigh and measure the transformed gases, and even retransform them
into solids.
In the case of the atmospheric nitrogen, as in the case of ordinary fuel, a
burning "consists essentially in the union of nitrogen atoms with atoms of
oxygen." The province of the electric current is to produce the high
temperature at which alone such union will take place. The portion of
nitrogen that has been thus "burned" is still gaseous, but is no longer in the
state of pure nitrogen; its atoms are united with oxygen atoms to form
nitrous oxide gas. This gas, mixed with the atmosphere in which it has been
generated, may now be passed through a reservoir of water, and the new gas

combines with a portion of water to form nitric acid, each molecule of
which is a compound of one atom of hydrogen, one atom of nitrogen, and
three atoms of oxygen; and nitric acid, as everyone knows, is a very active
substance, as marked in its eagerness to unite with other substances as pure
nitrogen is in its aloofness.
In the commercial nitrogen-plant at Notodden, the transformed nitrogen
compound is brought into contact with a solution of milk of lime, with the
resulting formation of nitrate of lime (calcium nitrate), a substance identical
in composition—except that it is of greater purity—with the product of the
nitrate beds of Chili. Stored in closed cans as a milky fluid, the transformed
atmosphere is now ready for the market. A certain amount of it will be used
in other manufactories for the production of various nitrogenous chemicals;
but the bulk of it will be shipped to agricultural districts to be spread over
the soil as fertilizer, and in due course to be absorbed into the tissues of
plants to form the food of animals and man.

ANOTHER METHOD OF NITROGEN FIXATION

Just at the time when the Scandinavian experimenters were solving the
problem of securing nitrogen from the air, other experimenters in Italy,
operating along totally different lines, reached the same important result.
The process employed by these investigators is known as the Frank and
Caro process, and it bids fair to rival the Norwegian method as a
commercial enterprise. The process is described as follows by an
engineering correspondent of the London Times in the Engineering
Supplement of that periodical for January 22, 1908:
"This process is based upon the absorption of nitrogen by calcium
carbide, when this gas, in the pure form, is passed over the carbide heated to
a temperature of 1,100 degrees centigrade in retorts of special form and
design. The calcium carbide required as raw material for the cyanamide
manufacture is produced in the usual manner by heating lime and coke to a
temperature of 2,500 degrees centigrade in electric furnaces of the
resistance type.
"The European patent rights of the Frank and Caro process have been
purchased by the Societa Generale per la Cianamide of Rome, and the
various subsidiary companies promoting the manufacture in Italy, France,

Switzerland, Norway, and elsewhere, are working under arrangement with
the parent company as regards sharing of profits.
"The first large installation of a plant for carrying out this process was
erected at Piano d'Orta, in Central Italy, and was put into operation in
December, 1905. The power for this factory is developed by an independent
company, and is obtained by taking water from the river Pescara and
leading it to a point above the generating station at Tramonti. A head of 90
feet, equivalent to 8,400 horse-power, is here made available for the
industries of the district. The power of the cyanamide factory is transmitted
a distance of 6-1/4 miles at 6,000 volts. An aluminum and chemical works
are also dependent upon the same power station.
"The Piano d'Orta works contains six furnaces for the manufacture of
cyanamide, each furnace containing five retorts for absorption of the
nitrogen by the carbide. A retort is capable of working off three charges of
100 kilograms (220 pounds) of carbide per day of 24 hours, the weight of
the charge increasing to 125 kilograms by the nitrogen absorbed. The
present carbide consumption of the Piano d'Orta factory is, therefore, at the
rate of about 3,000 tons per annum, and the output of calcium cyanamide is
about 3,750 tons per annum. The company controlling the manufacture at
Piano d'Orta is named the Societa Italiana per la Fabbricazione di Prodotti
Azotati. Extensions of the factory at this place to a capacity of 10,000 tons
per annum are already in progress. Another company is also planning the
erection of similar works at Fiume and at Sebenico, on the eastern borders
of the Adriatic Sea. The additional electric power required will be obtained
by carrying out the second portion of the power development scheme on the
river Pescara. A fall of 235 feet, equivalent to 22,000 horse-power, is
available at the new power station, which is being erected at Piano d'Orta."
After stating that companies to operate the Frank and Caro process have
been organized in France, in Switzerland, in Germany, in England, and in
America,—the last-named plant being at Muscle Shoals, Tennessee River,
in Northern Alabama—the writer continues:
"These facts prove that the manufacture of the new nitrogenous manure
will soon be carried on in all the more important countries on both sides of
the Atlantic. If the financial results come up to the promoter's expectations