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Title: Scientific American Supplement, No. 460, October 25, 1884

Author: Various

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*** START OF THE PROJECT GUTENBERG EBOOK SCIENTIFIC
AMERICAN SUPPLEMENT, NO. 460, OCTOBER 25, 1884 ***

SCIENTIFIC AMERICAN
SUPPLEMENT NO. 460

NEW YORK, OCTOBER 25, 1884
Scientific American Supplement. Vol. XVIII, No. 460.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

TABLE OF CONTENTS.
I. CHEMISTRY. ETC.—Wolpert's Method of Estimating the Amount
of Carbonic Acid in the Air.—7 Figures.
Japanese Camphor.—Its preparation, experiments, and analysis of the
camphor oil.—By H. OISHI.
II. ENGINEERING AND MECHANICS.—Links in the History of the
Locomotive.—With two engravings of the Rocket.
The Flow of Water through Turbines and Screw Propellers.—By
ARTHUR RIGG.—Experimental researches.—Impact on level plate.
—Impact and reaction in confined channels.—4 figures.
Improved Textile Machinery.—The Textile Exhibition at Islington.—
5 figures.
Endless Rope Haulage.—2 figures.
III. TECHNOLOGY.—A Reliable Water Filter.—With engraving.
Simple Devices for Distilling Water.—4 figures.
Improved Fire Damp Detecter.—With full description and engraving.
Camera Attachment for Paper Photo Negatives.—2 figures.
Instantaneous Photo Shutter.—1 figure.

Sulphurous Acid.—Easy method of preparation for photographic
purposes.
IV. PHYSICS. ELECTRICITY, ETC.—Steps toward a Kinetic Theory of
Matter.—Address by Sir Wm. THOMSON at the Montreal meeting
of the British Association.
Application of Electricity to Tramways.—By M. HOLROYD
SMITH.—7 figures.
The Sunshine Recorder.—1 figure.
V. ARCHITECTURE AND ART.—The National Monument at Rome.
—With full page engraving.
On the Evolution of Forms of Art.—From a paper by Prof.
JACOBSTHAL.—Plant Forms the archetypes of cashmere patterns.
—Ornamental representations of plants of two kinds.—Architectural
forms of different ages.—20 figures.
VI. NATURAL HISTORY.—The Latest Knowledge about Gapes.—How
to keep poultry free from them.
The Voyage of the Vettor Pisani.—Shark fishing In the Gulf of
Panama.—Capture of Rhinodon typicus, the largest fish in existence.
VII. HORTICULTURE, ETC.—The Proper Time for Cutting Timber.
Raising Ferns from Spores.—1 figure.
The Life History of Vaucheria.—Growth of alga vaucheria under the
microscope.—4 figures.
VIII. MISCELLANEOUS.—Fires in London and New York.
The Greely Arctic Expedition.—With engraving.
The Nile Expedition.—1 figure.

LINKS IN THE HISTORY OF THE
LOCOMOTIVE.
It is, perhaps, more difficult to write accurate history than anything else, and
this is true not only of nations, kings, politicians, or wars, but of events and
things witnessed or called into existence in every-day life. In The Engineer
for September 17, 1880, we did our best to place a true statement of the facts
concerning the Rocket before our readers. In many respects this was the
most remarkable steam engine ever built, and about it there ought to be no
difficulty, one would imagine, in arriving at the truth. It was for a
considerable period the cynosure of all eyes. Engineers all over the world
were interested in its performance. Drawings were made of it; accounts were
written of it, descriptions of it abounded. Little more than half a century has
elapsed since it startled the world by its performance at Rainhill, and yet it is
not too much to say that the truth—the whole truth, that is to say—can never
now be written. We are, however, able to put some facts before our readers
now which have never before been published, which are sufficiently
startling, and while supplying a missing link in the history of the locomotive,
go far to show that much that has hitherto been held to be true is not true at
all.

When the Liverpool and Manchester Railway was opened on the 15th of
September, 1830, among those present was James Nasmyth, subsequently
the inventor of the steam hammer. Mr. Nasmyth was a good freehand
draughtsman, and he sketched the Rocket as it stood on the line. The sketch
is still in existence. Mr. Nasmyth has placed this sketch at our disposal, thus
earning the gratitude of our readers, and we have reproduced as nearly as
possible, but to a somewhat enlarged scale, this invaluable link in the history
of the locomotive. Mr. Nasmyth writes concerning it, July 26, 1884: "This
slight and hasty sketch of the Rocket was made the day before the opening
of the Manchester and Liverpool Railway, September 12, 1830. I availed
myself of the opportunity of a short pause in the experimental runs with the
Rocket, of three or four miles between Liverpool and Rainhill, George
Stephenson acting as engine driver and his son Robert as stoker. The limited

time I had for making my sketch prevented me from making a more
elaborate one, but such as it is, all the important and characteristic details are
given; but the pencil lines, after the lapse of fifty-four years, have become
somewhat indistinct." The pencil drawing, more than fifty years old, has
become so faint that its reproduction has become a difficult task. Enough
remains, however, to show very clearly what manner of engine this Rocket
was. For the sake of comparison we reproduce an engraving of the Rocket of
1829. A glance will show that an astonishing transformation had taken place
in the eleven months which had elapsed between the Rainhill trials and the
opening of the Liverpool and Manchester Railway. We may indicate a few of
the alterations. In 1829 the cylinders were set at a steep angle; in 1830 they
were nearly horizontal. In 1829 the driving wheels were of wood; in 1830
they were of cast iron. In 1829 there was no smoke-box proper, and a
towering chimney; in 1830 there was a smoke-box and a comparatively short
chimney. In 1829 a cask and a truck constituted the tender; in 1830 there was
a neatly designed tender, not very different in style from that still in use on
the Great Western broad gauge. All these things may perhaps be termed
concomitants, or changes in detail. But there is a radical difference yet to be
considered. In 1829 the fire-box was a kind of separate chamber tacked on to
the back of the barrel of the boiler, and communicating with it by three
tubes; one on each side united the water spaces, and one at the top the steam
spaces. In 1830 all this had disappeared, and we find in Mr. Nasmyth's
sketch a regular fire-box, such as is used to this moment. In one word, the
Rocket of 1829 is different from the Rocket of 1830 in almost every
conceivable respect; and we are driven perforce to the conclusion that the
Rocket of 1829 never worked at all on the Liverpool and Manchester
Railway; the engine of 1830 was an entirely new engine. We see no possible
way of escaping from this conclusion. The most that can be said against it is
that the engine underwent many alterations. The alterations must, however,
have been so numerous that they were tantamount to the construction of a
new engine. It is difficult, indeed, to see what part of the old engine could
exist in the new one; some plates of the boiler shell might, perhaps, have
been retained, but we doubt it. It may, perhaps, disturb some hitherto well
rooted beliefs to say so, but it seems to us indisputable that the Rocket of
1829 and 1830 were totally different engines.

FIG. 1. THE ROCKET, 1829. THE ROCKET, 1830.

Our engraving, Fig. 1, is copied from a drawing made by Mr. Phipps,
M.I.C.E., who was employed by Messrs. Stephenson to compile a drawing
of the Rocket from such drawings and documents as could be found. This
gentleman had made the original drawings of the Rocket of 1829, under
Messrs. G. & R. Stephenson's direction. Mr. Phipps is quite silent about the
history of the engine during the eleven months between the Rainhill trials
and the opening of the railway. In this respect he is like every one else. This
period is a perfect blank. It is assumed that from Rainhill the engine went
back to Messrs. Stephenson's works; but there is nothing on the subject in
print, so far as we are aware. Mr. G.R. Stephenson lent us in 1880 a working
model of the Rocket. An engraving of this will be found in The Engineer for
September 17, 1880. The difference between it and the engraving below,
prepared from Mr. Phipps' drawing, is, it will be seen, very small—one of
proportions more than anything else. Mr. Stephenson says of his model: "I
can say that it is a very fair representation of what the engine was before she
was altered." Hitherto it has always been taken for granted that the alteration
consisted mainly in reducing the angle at which the cylinders were set. The

Nasmyth drawing alters the whole aspect of the question, and we are now
left to speculate as to what became of the original Rocket. We are told that
after "it" left the railway it was employed by Lord Dundonald to supply
steam to a rotary engine; then it propelled a steamboat; next it drove small
machinery in a shop in Manchester; then it was employed in a brickyard;
eventually it was purchased as a curiosity by Mr. Thomson, of Kirkhouse,
near Carlisle, who sent it to Messrs. Stephenson to take care of. With them it
remained for years. Then Messrs. Stephenson put it into something like its
original shape, and it went to South Kensington Museum, where "it" is now.
The question is, What engine is this? Was it the Rocket of 1829 or the
Rocket of 1830, or neither? It could not be the last, as will be understood
from Mr. Nasmyth's drawing; if we bear in mind that the so-called fire-box
on the South Kensington engine is only a sham made of thin sheet iron
without water space, while the fire-box shown in Mr. Nasmyth's engine is an
integral part of the whole, which could not have been cut off. That is to say,
Messrs. Stephenson, in getting the engine put in order for the Patent Office
Museum, certainly did not cut off the fire-box shown in Mr. Nasmyth's
sketch, and replace it with the sham box now on the boiler. If our readers
will turn to our impression for the 30th of June, 1876, they will find a very
accurate engraving of the South Kensington engine, which they can compare
with Mr. Nasmyth's sketch, and not fail to perceive that the differences are
radical.

In "Wood on Railroads," second edition, 1832, page 377, we are told that
"after those experiments"—the Rainhill trials—"were concluded, the
Novelty underwent considerable alterations;" and on page 399, "Mr.
Stephenson had also improved the working of the Rocket engine, and by
applying the steam more powerfully in the chimney to increase the draught,
was enabled to raise a much greater quantity of steam than before." Nothing
is said as to where the new experiments took place, nor their precise date.
But it seems that the Meteor and the Arrow—Stephenson engines—were
tried at the same time; and this is really the only hint Wood gives as to what
was done to the Rocket between the 6th of October, 1829, and the 15th of
September, 1830.

There are men still alive who no doubt could clear up the question at issue,
and it is much to be hoped that they will do so. As the matter now stands, it
will be seen that we do not so much question that the Rocket in South

Kensington Museum is, in part perhaps, the original Rocket of Rainhill
celebrity, as that it ever ran in regular service on the Liverpool and
Manchester Railway. Yet, if not, then we may ask, what became of the
Rocket of 1830? It is not at all improbable that the first Rocket was cast on
one side, until it was bought by Lord Dundonald, and that its history is set
out with fair accuracy above. But the Rocket of the Manchester and
Liverpool Railway is hardly less worthy of attention than its immediate
predecessor, and concerning it information is needed. Any scrap of
information, however apparently trifling, that can be thrown on this subject
by our readers will be highly valued, and given an appropriate place in our
pages.—The Engineer.

The largest grain elevator in the world, says the Nashville American, is that
just constructed at Newport News under the auspices of the Chesapeake &
Ohio Railway Co. It is 90 ft. wide, 386 ft. long, and about 164 ft. high, with
engine and boiler rooms 40 × 100 ft. and 40 ft. high. In its construction there
were used about 3,000 piles, 100,000 ft. of white-oak timber, 82,000 cu. ft.
of stone, 800,000 brick, 6,000,000 ft. of pine and spruce lumber, 4,500 kegs
of nails, 6 large boilers, 2 large engines, 200 tons of machinery, 20 large
hopper-scales, and 17,200 ft. of rubber belts, from 8 to 48 in. wide and 50 to
1,700 ft. long; in addition, there were 8,000 elevator buckets, and other
material. The storage capacity is 1,600,000 bushels, with a receiving
capacity of 30,000, and a shipping capacity of 20,000 bushels per hour.

THE FLOW OF WATER THROUGH TURBINES
AND SCREW PROPELLERS.1
By Mr. ARTHUR RIGG, C.E.

Literature relating to turbines probably stands unrivaled among all that
concerns questions of hydraulic engineering, not so much in its voluminous
character as in the extent to which purely theoretical writers have ignored
facts, or practical writers have relied upon empirical rules rather than upon
any sound theory. In relation to this view, it may suffice to note that
theoretical deductions have frequently been based upon a generalization that
"streams of water must enter the buckets of a turbine without shock, and
leave them without velocity." Both these assumed conditions are misleading,
and it is now well known that in every good turbine both are carefully
disobeyed. So-called practical writers, as a rule, fail to give much useful
information, and their task seems rather in praise of one description of
turbine above another. But generally, it is of no consequence whatever how a
stream of water may be led through the buckets of any form of turbine, so
long as its velocity gradually becomes reduced to the smallest amount that
will carry it freely clear of the machine.

The character of theoretical information imparted by some Chicago Journal
of Commerce, dated 20th February, 1884. There we are informed that "the
height of the fall is one of the most important considerations, as the same
stream of water will furnish five times the horse power at ten ft. that it will at
five ft. fall." By general consent twice two are four, but it has been reserved
for this imaginative writer to make the useful discovery that sometimes
twice two are ten. Not until after the translation of Captain Morris' work on
turbines by Mr. E. Morris in 1844, was attention in America directed to the
advantages which these motors possessed over the gravity wheels then in
use. A duty of 75 per cent. was then obtained, and a further study of the
subject by a most acute and practical engineer, Mr. Boyden, led to various
improvements upon Mr. Fauneyron's model, by which his experiments
indicated the high duty of 88 per cent. The most conspicuous addition made

by Mr. Boyden was the diffuser. The ingenious contrivance had the effect of
transforming part of whatever velocity remained in the stream after passing
out of a turbine into an atmospheric pressure, by which the corresponding
lost head became effective, and added about 3 per cent. to the duty obtained.
It may be worth noticing that, by an accidental application of these
principles to some inward flow turbines, there is obtained most, if not all, of
whatever advantage they are supposed to possess, but oddly enough this
genuine advantage is never mentioned by any of the writers who are
interested in their introduction or sale. The well-known experiments of Mr.
James B. Francis in 1857, and his elaborate report, gave to hydraulic
engineers a vast store of useful data, and since that period much progress has
been made in the construction of turbines, and literature on the subject has
become very complete.

In the limits of a short paper it is impossible to do justice to more than one
aspect of the considerations relating to turbines, and it is now proposed to
bring before the Mechanical Section of the British Association some
conclusions drawn from the behavior of jets of water discharged under
pressure, more particularly in the hope that, as water power is extremely
abundant in Canada, any remarks relating to the subject may not fail to prove
interesting.

Between the action of turbines and that of screw propellers exists an exact
parallelism, although in one case water imparts motion to the buckets of a
turbine, while in the other case blades of a screw give spiral movement to a
column of water driven aft from the vessel it propels forward. Turbines have
been driven sometimes by impact alone, sometimes by reaction above,
though generally by a combination of impact and reaction, and it is by the
last named system that the best results are now known to be obtained.

The ordinary paddles of a steamer impel a mass of water horizontally
backward by impact alone, but screw propellers use reaction somewhat
disguised, and only to a limited extent. The full use and advantages of
reaction for screw propellers were not generally known until after the
publication of papers by the present writer in the "Proceedings" of the
Institution of Naval Architects for 1867 and 1868, and more fully in the
"Transactions" of the Society of Engineers for 1868. Since that time, by the
author of these investigations then described, by the English Admiralty, and

by private firms, further experiments have been carried out, some on a
considerable scale, and all corroborative of the results published in 1868.
But nothing further has been done in utilizing these discoveries until the
recent exigencies of modern naval warfare have led foreign nations to place
a high value upon speed. Some makers of torpedo boats have thus been
induced to slacken the trammels of an older theory and to apply a somewhat
incomplete form of the author's reaction propeller for gaining some portion
of the notable performance of these hornets of the deep. Just as in turbines a
combination of impact and reaction produces the maximum practical result,
so in screw propellers does a corresponding gain accompany the same
construction.

FIG. 1.

FIG. 2.

Turbines.—While studying those effects produced by jets of water
impinging upon plain or concave surfaces corresponding to buckets of
turbines, it simplifies matters to separate these results due to impact from
others due to reaction. And it will be well at the outset to draw a distinction
between the nature of these two pressures, and to remind ourselves of the
laws which lie at the root and govern the whole question under present
consideration. Water obeys the laws of gravity, exactly like every other
body; and the velocity with which any quantity may be falling is an
expression of the full amount of work it contains. By a sufficiently accurate
practical rule this velocity is eight times the square root of the head or
vertical column measured in feet. Velocity per second = 8 sqrt (head in feet),
therefore, for a head of 100 ft. as an example, V = 8 sqrt (100) = 80 ft. per
second. The graphic method of showing velocities or pressures has many
advantages, and is used in all the following diagrams. Beginning with purely
theoretical considerations, we must first recollect that there is no such thing
as absolute motion. All movements are relative to something else, and what
we have to do with a stream of water in a turbine is to reduce its velocity
relatively to the earth, quite a different thing to its velocity in relation to the
turbine; for while the one may be zero, the other may be anything we please.
ABCD in Fig. 1 represents a parallelogram of velocities, wherein AC gives
the direction of a jet of water starting at A, and arriving at C at the end of
one second or any other division of time. At a scale of 1/40 in. to 1 ft., AC
represents 80 ft., the fall due to 100 ft. head, or at a scale of 1 in. to 1 ft., AC
gives 2 ft., or the distance traveled by the same stream in 1/40 of a second.
The velocity AC may be resolved into two others, namely, AB and AD, or
BC, which are found to be 69.28 ft. and 40 ft. respectively, when the angle
BAC—generally called x in treatises on turbines—is 30 deg. If, however,
AC is taken at 2 ft., then A B will be found = 20.78 in., and BC = 12 in. for a
time of 1/40 or 0.025 of a second. Supposing now a flat plate, BC = 12 in.
wide move from DA to CB during 0.025 second, it will be readily seen that a
drop of water starting from A will have arrived at C in 0.025 second, having
been flowing along the surface BC from B to C without either friction or loss
of velocity. If now, instead of a straight plate, BC, we substitute one having a
concave surface, such as BK in Fig. 2, it will be found necessary to move it
from A to L in 0.025 second, in order to allow a stream to arrive at C, that is
K, without, in transit, friction or loss of velocity. This concave surface may

represent one bucket of a turbine. Supposing now a resistance to be applied
to that it can only move from A to B instead of to L. Then, as we have
already resolved the velocity A C into AB and BC, so far as the former (AB)
is concerned, no alteration occurs whether BK be straight or curved. But the
other portion, BC, pressing vertically against the concave surface, BK,
becomes gradually diminished in its velocity in relation to the earth, and
produces and effect known as "reaction." A combined operation of impact
and reaction occurs by further diminishing the distance which the bucket is
allowed to travel, as, for examples, to EF. Here the jet is impelled against the
lower edge of the bucket, B, and gives a pressure by its impact; then
following the curve BK, with a diminishing velocity, it is finally discharged
at K, retaining only sufficient movement to carry the water clear out of the
machine. Thus far we have considered the movement of jets and buckets
along AB as straight lines, but this can only occur, so far as buckets are
concerned, when their radius in infinite. In practice these latter movements
are always curves of more or less complicated form, which effect a
considerable modification in the forms of buckets, etc., but not in the general
principles, and it is the duty of the designer of any form of turbine to give
this consideration its due importance. Having thus cleared away any
ambiguity from the terms "impact," and "reaction," and shown how they can
act independently or together, we shall be able to follow the course and
behavior of streams in a turbine, and by treating their effects as arising from
two separate causes, we shall be able to regard the problem without that
inevitable confusion which arises when they are considered as acting
conjointly. Turbines, though driven by vast volumes of water, are in reality
impelled by countless isolated jets, or streams, all acting together, and a clear
understanding of the behavior of any one of these facilitates and concludes a
solution of the whole problem.

Experimental researches.—All experiments referred to in this paper were
made by jets of water under an actual vertical head of 45 ft., but as the
supply came through a considerable length of ½ in. bore lead piping, and
many bends, a large and constant loss occurred through friction and bends,
so that the actual working head was only known by measuring the velocity
of discharge. This was easily done by allowing all the water to flow into a
tank of known capacity. The stop cock had a clear circular passage through
it, and two different jets were used. One oblong measured 0.5 in. by 0.15 in.,
giving an area of 0.075 square inch. The other jet was circular, and just so

much larger than ¼ in. to be 0.05 of a square inch area, and the stream
flowed with a velocity of 40 ft. per second, corresponding to a head of 25 ft.
Either nozzle could be attached to the same universal joint, and directed at
any desired inclination upon the horizontal surface of a special well-adjusted
compound weighing machine, or into various bent tubes and other
attachments, so that all pressures, whether vertical or horizontal, could be
accurately ascertained and reduced to the unit, which was the quarter of an
ounce. The vertical component p of any pressure P may be ascertained by the
formula—
p = P sin alpha,

where alpha is the angle made by a jet against a surface; and in order to test
the accuracy of the simple machinery employed for these researches, the
oblong jet which gave 71 unit when impinging vertically upon a circular
plate, was directed at 60 deg. and 45 deg. thereon, with results shown in
Table I., and these, it will be observed, are sufficiently close to theory to
warrant reliance being placed on data obtained from the simple weighing
machinery used in the experiment.
Table I.—Impact on Level Plate.
--------------+--------------------+----------+----------+------
----
| Inclination of jet | | |
Distance. | to the horizonal. | 90 deg. | 60 deg. | 45
deg.
--------------+--------------------+----------+----------+------
----
| | Pressure | Pressure |
Pressure
| | | |
/ | Experiment \ | / | 61.00 |
49.00
1½ in. < | > | 71.00 < | |
\ | Theory / | \ | 61.48 |
50.10
| | | |
| | | |
/ | Experiment \ | / | 55.00 |
45.00
1 in. < | > | 63.00 < | |
\ | Theory / | \ | 54.00 |
45.00

| | | |
--------------+--------------------+----------+----------+------
----
In each case the unit of pressure is ¼ oz.

In the first trial there was a distance of 1½ in. between the jet and point of its
contact with the plate, while in the second trial this space was diminished to
½ in. It will be noticed that as this distance increases we have augmented
pressures, and these are not due, as might be supposed, to increase of head,
which is practically nothing, but they are due to the recoil of a portion of the
stream, which occurs increasingly as it becomes more and more broken up.
These alterations in pressure can only be eliminated when care is taken to
measure that only due to impact, without at the same time adding the effect
of an imperfect reaction. Any stream that can run off at all points from a
smooth surface gives the minimum of pressure thereon, for then the least
resistance is offered to the destruction of the vertical element of its velocity,
but this freedom becomes lost when a stream is diverted into a confined
channel. As pressure is an indication and measure of lost velocity, we may
then reasonably look for greater pressure on the scale when a stream is
confined after impact than when it discharges freely in every direction.
Experimentally this is shown to be the case, for when the same oblong jet,
discharged under the same conditions, impinged vertically upon a smooth
plate, and gave a pressure of 71 units, gave 87 units when discharged into a
confined right-angled channel. This result emphasizes the necessity for
confining streams of water whenever it is desired to receive the greatest
pressure by arresting their velocity. Such streams will always endeavor to
escape in the directions of least resistance, and, therefore, in a turbine means
should be provided to prevent any lateral deviation of the streams while
passing through their buckets. So with screw propellers the great mass of
surrounding water may be regarded as acting like a channel with elastic
sides, which permits the area enlarging as the velocity of a current passing
diminishes. The experiments thus far described have been made with jets of
an oblong shape, and they give results differing in some degree from those
obtained with circular jets. Yet as the general conclusions from both are
found the same, it will avoid unnecessary prolixity by using the data from
experiments made with a circular jet of 0.05 square inch area, discharging a
stream at the rate of 40 ft. per second. This amounts to 52 lb. of water per
minute with an available head of 25 ft., or 1,300 foot-pounds per minute.
The tubes which received and directed the course of this jet were generally

of lead, having a perfectly smooth internal surface, for it was found that with
a rougher surface the flow of water is retarded, and changes occur in the data
obtained. Any stream having its course changed presses against the body
causing such change, this pressure increasing in proportion to the angle
through which the change is made, and also according to the radius of a
curve around which it flows. This fact has long been known to hydraulic
engineers, and formulæ exist by which such pressures can be determined;
nevertheless, it will be useful to study these relations from a somewhat
different point of view than has been hitherto adopted, more particularly as
they bear upon the construction of screw propellers and turbines; and by
directing the stream, AB, Fig. 3, vertically into a tube 3/8 in. internal
diameter and bent so as to turn the jet horizontally, and placing the whole
arrangement upon a compound weighing machine, it is easy to ascertain the
downward pressure, AB, due to impact, and the horizontal pressures, CB,
due to reaction. In theoretical investigations it may be convenient to assume
both these pressures exactly equal, and this has been done in the paper "On
Screw Propellers" already referred to; but this brings in an error of no
importance so far as general principles are involved, but one which destroys
much of the value such researches might, otherwise possess for those who
are engaged in the practical construction of screw propellers or turbines. The
downward impact pressure, AB, is always somewhat greater than the
horizontal reaction, BC, and any proportions between these two can only be
accurately ascertained by trials. In these particular experiments the jet of
water flowed 40 ft. per second through an orifice of 0.05 square inch area,
and in every case its course was bent to a right angle. The pressures for
impact and reaction were weighed coincidently, with results given by
columns 1 and 2, Table II.

FIG. 3

FIG. 4
Table II.—Impact and Reaction in Confined Channels.

-----------------------------+-------+---------+----------+-----
--
Number of column. | 1 | 2 | 3 | 4
-----------------------------+-------+---------+----------+-----
--
Description of experiments. |Impact.|Reaction.|Resultant.|
Angles
| | | |
ABS.
-----------------------------+-------+---------+----------+-----
--
Smooth London tube, 1¾ in. | 71 | 62 | 94.25 |
49°
mean radius. | | | |
| | | |
Rough wrought iron tube, | 78 | 52 | 98.75 |
56.5°
1¾ in. | | | |
| | | |
Smooth leaden tube bent to a | 71 | 40 | 81.5 | 60
sharp right angle. | | | |
-----------------------------+-------+---------+----------+-----
-

The third column is obtained by constructing a parallelogram of forces,
where impact and reaction form the measures of opposing sides, and it
furnishes the resultant due to both forces. The fourth column gives the
inclination ABS, at which the line of impact must incline toward a plane
surface RS, Fig. 3, so as to produce this maximum resultant perpendicularly
upon it; as the resultant given in column 3 indicates the full practical effect
of impact and reaction. When a stream has its direction changed to one at
right angles to its original course, and as such a changed direction is all that
can be hoped for by ordinary screw propellers, the figures in column 3
should bear some relationship to such cases. Therefore, it becomes an
inquiry of some interest as to what angle of impact has been found best in
those screw propellers which have given the best results in practical work.
Taking one of the most improved propellers made by the late Mr. Robert
Griffiths, its blades do not conform to the lines of a true screw, but it is an
oblique paddle, where the acting portions of its blades were set at 48 deg. to

the keel of the ship or 42 deg. to the plane of rotation. Again, taking a screw
tug boat on the river Thames, with blades of a totally different form to those
used by Mr. Griffiths, we still find them set at the same angle, namely, 48
deg. to the keel or 42 deg. to the plane of rotation. An examination of other
screws tends only to confirm these figures, and they justify the conclusion
that the inclinations of blades found out by practice ought to be arrived at, or
at any rate approached, by any sound and reliable theory; and that blades of
whatever form must not transgress far from this inclination if they are to
develop any considerable efficiency. Indeed, many favorable results obtained
by propellers are not due to their peculiarities, but only to the fact that they
have been made with an inclination of blade not far from 42 deg. to the plan
of rotation. Referring to column 4, and accepting the case of water flowing
through a smooth tube as analogous to that of a current flowing within a
large body of water, it appears that the inclination necessary to give the
highest resultant pressure is an angle of 49 deg., and this corresponds closely
enough with the angle which practical constructors of screw propellers have
found to give the best results. Until, therefore, we can deal with currents
after they have been discharged from the blades of a propeller, it seems
unlikely that anything can be done by alterations in the pitch of a propeller.
So far as concerns theory, the older turbines were restricted to such
imperfect results of impact and reaction as might be obtained by turning a
stream at right angles to its original course; and the more scientific of
modern turbine constructors may fairly claim credit for an innovation by
which practice gave better results than theory seemed to warrant; and the
consideration of this aspect of the question will form the concluding subject
of the present paper. Referring again to Fig. 3, when a current passes round
such a curve as the quadrant of a circle, its horizontal reaction appears as a
pressure along c B, which is the result of the natural integration of all the
horizontal components of pressures, all of which act perpendicularly to each
element of the concave surface along which the current flows. If, now, we
add another quadrant of a circle to the curve, and so turn the stream through
two right angles, or 180 deg., as shown by Fig. 4, then such a complete
reversal of the original direction represents the carrying of it back again to
the highest point; it means the entire destruction of its velocity, and it gives
the maximum pressure obtainable from a jet of water impinging upon a
surface of any form whatsoever. The reaction noticed in Fig. 3 as acting
along c B is now confronted by an impact of the now horizontal stream as it
is turned round the second 90 deg. of curvature, and reacts also vertically

downward. It would almost seem as if the first reaction from B to F should
be exactly neutralized by the second impact from F to D. But such is not the
case, as experiment shows an excess of the second impact over the first
reaction amounting to six units, and shows also that the behavior of the
stream through its second quadrant is precisely similar in kind to the first,
only less in degree. Also the impact takes place vertically in one case and
horizontally in the other. The total downward pressure given by the stream
when turned 180 deg. is found by experiment thus: Total impact and reaction
from 180 deg. change in direction of current = 132 units; and by deducting
the impact 71 units, as previously measured, the new reaction corresponds
with an increase of 61 units above the first impact. It also shows an increase
of 37.75 units above the greatest resultant obtained by the same stream
turned through 90 deg. only. Therefore, in designing a screw propeller or
turbine, it would seem from these experiments desirable to aim at changing
the direction of the stream, so far as possible, into one at 180 deg. to its
original course, and it is by carrying out this view, so far as the necessities of
construction will permit, that the scientifically designed modern turbine has
attained to that prominence which it holds at present over all hydraulic
motors. Much more might be written to extend and amplify the conclusions
that can be drawn from the experiments described in the present paper, and
from many others made by the writer, but the exigencies of time and your
patience alike preclude further consideration of this interesting and
important subject.

[1]
Paper read before the British Association at Montreal.

IMPROVED TEXTILE MACHINERY.

THE TEXTILE EXHIBITION, ISLINGTON.

In the recent textile exhibition at Islington, one of the most extensive
exhibits was that, of Messrs. James Farmer and Sons, of Salford. The exhibit
consists of a Universal calender, drying machines, patent creasing,
measuring, and marking machines, and apparatus for bleaching, washing,
chloring, scouring, soaping, dunging, and dyeing woven fabrics. The
purpose of the Universal calender is, says the Engineer, to enable limited
quantities of goods to be finished in various ways without requiring different
machines. The machine consists of suitable framing, to which is attached all
the requisite stave rails, batching apparatus, compound levers, top and
bottom adjusting screws, and level setting down gear, also Stanley roller
with all its adjustments. It is furthermore supplied with chasing arrangement
and four bowls; the bottom one is of cast iron, with wrought iron center; the

next is of paper or cotton; the third of chilled iron fitted for heating by steam
or gas, and the top of paper or cotton. By this machine are given such
finishes as are known as "chasing finish" when the thready surface is
wanted; "frictioning," or what is termed "glazing finish," "swigging finish,"
and "embossing finish;" the later is done by substituting a steel or copper
engraved roller in place of the friction bowl. This machine is also made to I
produce the "Moire luster" finish. The drying machine consists of nineteen
cylinders, arranged with stave rails and plaiting down apparatus. These
cylinders are driven by bevel wheels, so that each one is independent of its
neighbor, and should any accident occur to one or more of the cylinders or
wheels, the remaining ones can be run until a favorable opportunity arrives
to repair the damage. A small separate double cylinder diagonal engine is
fitted to this machine, the speed of which can be adjusted for any texture of
cloth, and being of the design it is, will start at once on steam being turned
one. The machine cylinders are rolled by a special machine for that purpose,
and are perfectly true on the face. Their insides are fitted with patent
buckets, which remove all the condensed water. In the machine exhibited,
which is designed for the bleaching, washing, chloring, and dyeing, the cloth
is supported by hollow metallic cylinders perforated with holes and
corrugated to allow the liquor used to pass freely through as much of the
cloth as possible; the open ends of the cylinders are so arranged that nearly
all of their area is open to the action of the pump. The liquor, which is drawn
through the cloth into the inside of the cylinders by the centrifugal pumps, is
discharged back into the cistern by a specially constructed discharge pipe, so
devised that the liquor, which is sent into it with great force by the pump, is
diverted so as to pour straight down in order to prevent any eddies which
could cause the cloth to wander from its course. The cloth is supported to
and from the cylinders by flat perforated plates in such a manner that the
force of the liquor cannot bag or displace the threads of the cloth, and by this
means also the liquor has a further tendency to penetrate the fibers of the
cloth. Means are provided for readily and expeditiously cleansing the entire
machine. The next machine which we have to notice in this exhibit is
Farmer's patent marking and measuring machine, the purpose of which is to
stamp on the cloths the lengths of the same at regular distances. It is very
desirable that drapers should have some simple means of discovering at a
glance what amount of material they have in stock without the necessity of
unrolling their cloth to measure it, and this machine seems to perfectly meet
the demands of the case. The arrangement for effecting the printing and

inking is shown in our engraving at A. It is contained within a small disk,
which can be moved at will, so that it can be adapted to various widths of
cloth or other material. A measuring roller runs beside the printing disk, and
on this is stamped the required figures by a simple contrivance at the desired
distances, say every five yards. The types are linked together into a roller
chain which is carried by the disk, A, and they ink themselves automatically
from a flannel pad. The machine works in this way: The end of the piece to
be measured is brought down until it touches the surface of the table, the
marker is turned to zero, and also the finger of the dial on the end of the
measuring roller. The machine is then started, and the lengths are printed at
the required distances until it becomes necessary to cut out the first piecing
or joint in the fabric. The dial registers the total length of the piece.

ENDLESS ROPE HAULAGE.
In the North of England Report, the endless rope systems are classified as
No. 1 and No 2 systems. No. 1, which has the rope under the tubs, is said to
be in operation in the Midland counties. To give motion to the rope a single
wheel is used, and friction for driving the rope is supplied either by clip
pulleys or by taking the rope over several wheels. The diagram shows an
arrangement for a tightening arrangement. One driving wheel is used, says
The Colliery Guardian, and the rope is kept constantly tight by passing it
round a pulley fixed upon a tram to which a heavy weight is attached. Either
one or two lines of rails are used. When a single line is adopted the rope
works backward and forward, only one part being on the wagon way and the
other running by the side of the way. When two lines are used the ropes
move always in one direction, the full tubs coming out on one line and the
empties going in on the other. The rope passes under the tubs, and the
connection is made by means of a clamp or by sockets in the rope, to which
the set is attached by a short chain. The rope runs at a moderately high
speed.

TIGHTENING ARRANGEMENT—ENDLESS ROPE HAULAGE.

No. 2 system was peculiar to Wigan. A double line of rails is always used.
The rope rests upon the tubs, which are attached to the rope either singly or
in sets varying in number from two to twelve. The other engraving shows a
mode of connection between the tubs and the rope by a rope loop as shown.

ATTACHMENT TO ENDLESS ROPE "OVER."

The tubs are placed at a regular distance apart, and the rope works slowly.
Motion is given to the rope by large driving pulleys, and friction is obtained
by taking the rope several times round the driving pulley.

A RELIABLE WATER FILTER.
Opinions are so firmly fixed at present that water is capable of carrying the
germs of disease that, in cases of epidemics, the recommendation is made to
drink natural mineral waters, or to boil ordinary water. This is a wise
measure, assuredly; but mineral waters are expensive, and, moreover, many
persons cannot get used to them. As for boiled water, that is a beverage
which has no longer a normal composition; a portion of its salts has become
precipitated, and its dissolved gases have been given off. In spite of the
aeration that it is afterward made to undergo, it preserves an insipid taste,
and I believe that it is not very digestible. I have thought, then, that it would
be important, from a hygienic standpoint, to have a filter that should
effectually rid water of all the microbes or germs that it contains, while at
the same time preserving the salts or gases that it holds in solution. I have
reached such a result, and, although it is always delicate to speak of things
that one has himself done, I think the question is too important to allow me
to hold back my opinion in regard to the apparatus. It is a question of general
hygiene before which my own personality must disappear completely.

In Mr. Pasteur's laboratory, we filter the liquids in which microbes have been
cultivated, so as to separate them from the medium in which they exist. For
this purpose we employ a small unglazed porcelain tube that we have had
especially constructed therefor. The liquid traverses the porous sides of this
under the influence of atmospheric pressure, since we cause a vacuum
around the tube by means of an air-pump. We collect in this way, after
several hours, a few cubic inches of a liquid which is absolutely pure, since
animals may be inoculated with it without danger to them, while the smallest
quantity of the same liquid, when not filtered, infallibly causes death.

This is the process that I have applied to the filtration of water. I have
introduced into it merely such modifications as are necessary to render the
apparatus entirely practical. My apparatus consists of an unglazed porcelain
tube inverted upon a ring of enameled porcelain, forming a part thereof, and
provided with an aperture for the outflow of the liquid. This tube is placed
within a metallic one, which is directly attached to a cock that is soldered to

the service pipe. A nut at the base that can be maneuvered by hand permits,
through the intermedium of a rubber washer resting upon the enameled ring,
of the tube being hermetically closed.

Under these circumstances, when the cock is turned on, the water fills the
space between the two tubes and slowly filters, under the influence of
pressure, through the sides of the porous one, and is freed from all solid
matter, including the microbes and germs, that it contains. It flows out
thoroughly purified, through the lower aperture, into a vessel placed there to
receive it.

I have directly ascertained that water thus filtered is deprived of all its
germs. For this purpose I have added some of it (with the necessary
precautions against introducing foreign organisms) to very changeable
liquids, such as veal broth, blood, and milk, and have found that there was
no alteration. Such water, then, is incapable of transmitting the germs of
disease.

CHAMBERLAND'S WATER FILTER.

With an apparatus like the one here figured, and in which the filtering tube is
eight inches in length by about one inch in diameter, about four and a half
gallons of water per day may be obtained when the pressure is two
atmospheres—the mean pressure in Mr. Pasteur's laboratory, where my
experiments were made. Naturally, the discharge is greater or less according
to the pressure. A discharge of three and a half to four and a half gallons of
water seems to me to be sufficient for the needs of an ordinary household.
For schools, hospitals, barracks, etc., it is easy to obtain the necessary
volume of water by associating the tubes in series. The discharge will be
multiplied by the number of tubes.

In the country, or in towns that have no water mains, it will be easy to devise
an arrangement for giving the necessary pressure. An increase in the porosity
of the filtering tube is not to be thought of, as this would allow very small
germs to pass. This filter being a perfect one, we must expect to see it soil
quickly. Filters that do not get foul are just the ones that do not filter. But
with the arrangement that I have adopted the solid matters deposit upon the
external surface of the filter, while the inner surface always remains
perfectly clean. In order to clean the tube, it is only necessary to take it out
and wash it vigorously. As the tube is entirely of porcelain, it may likewise
be plunged into boiling water so as to destroy the germs that may have
entered the sides or, better yet, it may be heated over a gas burner or in an
ordinary oven. In this way all the organic matter will be burned, and the tube
will resume its former porosity.—M. Chamberland, La Nature.

SIMPLE DEVICES FOR DISTILLING WATER.
The alchemists dreamed and talked of that universal solvent which they so
long and vainly endeavored to discover; still, for all this, not only the
alchemist of old, but his more immediate successor, the chemist of to-day,
has found no solvent so universal as water. No liquid has nearly so wide a
range of dissolving powers, and, taking things all round, no liquid exercises
so slight an action upon the bodies dissolved—evaporate the water away,
and the dissolved substance is obtained in an unchanged condition; at any
rate, this is the general rule.

The function of water in nature is essentially that of a solvent or a medium
of circulation; it is not, in any sense, a food, yet without it no food can be
assimilated by an animal. Without water the solid materials of the globe
would be unable to come together so closely as to interchange their
elements; and unless the temperatures were sufficiently high to establish an
igneous fluidity, such as undoubtedly exists in the sun, there would be no
circulation of matter to speak of, and the earth would be, as it were, locked
up or dead.

When we look upon water as the nearest approach to a universal solvent that
even the astute scientist of to-day has been able to discover, who can wonder
that it is never found absolutely pure in nature? For wherever it accumulates
it dissolves something from its surroundings. Still, in a rain-drop just formed
we have very nearly pure water; but even this contains dissolved air to the
extent of about one-fiftieth of its volume, and as the drop falls downward it
takes up such impurities as may be floating in the atmosphere; so that if our
rain-drop is falling immediately after a long drought, it becomes charged
with nitrate or nitrite of ammonia and various organic matters—perhaps also
the spores or germs of disease. Thus it will be seen that rain tends to
wonderfully clear or wash the atmosphere, and we all know how much a first
rain is appreciated as an air purifier, and how it carries down with it valuable
food for plants. The rain-water, in percolating through or over the land,
flows mainly toward the rivers, and in doing so it becomes more or less
charged with mineral matter, lime salts and common salt being the chief of

them; while some of that water which has penetrated more deeply into the
earth takes up far more solid matter than is ordinarily found in river water.
The bulk of this more or less impure water tends toward the ocean, taking
with it its load of salt and lime. Constant evaporation, of course, takes place
from the surface of the sea, so that the salt and lime accumulate, this latter
being, however, ultimately deposited as shells, coral, and chalk, while nearly
pure or naturally distilled water once more condenses in the form of clouds.
This process, by which a constant supply of purified water is kept up in the
natural economy, is imitated on a small scale when water is converted into
steam by the action of heat, and this vapor is cooled so as to reproduce liquid
water, the operation in question being known as distillation.

For this purpose an apparatus known as a still is required; and although by
law one must pay an annual license fee for the right to use a still, it is not
usual for the government authorities to enforce the law when a still is merely
used for purifying water.

One of the best forms of still for the photographer to employ consists of a tin
can or bottle in which the water is boiled, and to this a tin tube is adapted by
means of a cork, one end of this tin tube terminating in a coil passing
through a tub or other vessel of cold water. A gas burner, as shown, is a
convenient source of heat, and in order to insure a complete condensation of
the vapor, the water in the cooling tub must be changed now and again.

Sometimes the vapor is condensed by being allowed to play against the
inside of a conical cover which is adapted to a saucepan, and is kept cool by
the external application of cold water; and in this case the still takes the form
represented by the subjoined diagrams; such compact and portable stills
being largely employed in Ireland for the private manufacture of whisky.

It is scarcely necessary to say that the condensed water trickles down on the
inside of the cone, and flows out at the spout.

An extemporized arrangement of a similar character may be made by
passing a tobacco pipe through the side of a tin saucepan as shown below,
and inverting the lid of the saucepan; if the lid is now kept cool by frequent
changes of water inside it, and the pipe is properly adjusted so as to catch the
drippings from the convex side of the lid, a considerable quantity of distilled
water may be collected in an hour or so.

The proportion of solid impurities present in water as ordinarily met with is
extremely variable: rain water which has been collected toward the end of a
storm contains only a minute fraction of a grain per gallon, while river or
spring water may contain from less than thirty grains per gallon or so and
upward. Ordinary sea water generally contains from three to four per cent. of
saline matter, but that of the Dead Sea contains nearly one-fourth of its
weight of salts.

The three impurities of water which most interest the photographer are lime
or magnesia salts, which give the so-called hardness; chlorides (as, for
example, chloride of sodium or common salt), which throw down silver
salts; and organic matter, which may overturn the balance of photographic
operations by causing premature reduction of the sensitive silver
compounds. To test for them is easy. Hardness is easily recognizable by
washing one's hands in the water, the soap being curdled; but in many cases
one must rather seek for a hard water than avoid it, as the tendency of
gelatine plates to frill is far less in hard water than in soft water. It is, indeed,
a common and useful practice to harden the water used for washing by
adding half an ounce or an ounce of Epsom salts (sulphate of magnesia) to
each bucket of water. Chlorides—chloride of sodium or common salt being
that usually met with—may be detected by adding a drop or two of nitrate of
silver to half a wineglassful of the water, a few drops of nitric acid being
then added. A slight cloudiness indicates a trace of chlorides, and a decided
milkiness shows the presence of a larger quantity. If it is wished to get a
somewhat more definite idea of the amount, it is easy to make up a series of
standards for comparison, by dissolving known weights of common salt in
distilled or rain water, and testing samples of them side by side with the
water to be examined.

Organic matters may be detected by adding a little nitrate of silver to the
water, filtering off from any precipitate of chloride of silver, and exposing
the clear liquid to sunlight; a clean stoppered bottle being the most
convenient vessel to use. The extent to which a blackening takes place may
be regarded as approximately proportionate to the amount of organic matter
present.

Filtration on a small scale is not altogether a satisfactory mode of purifying
water, as organic impurities often accumulate in the filter, and enter into
active putrefaction when hot weather sets in.—Photo. News.

IMPROVED FIRE-DAMP DETECTER.
According to the London Mining Journal, Mr. W.E. Garforth, of Normanton,
has introduced an ingenious invention, the object of which is to detect fire-
damp in collieries with the least possible degree of risk to those engaged in
the work. Mr. Garforth's invention, which is illustrated in the diagram given
below, consists in the use of a small India rubber hand ball, without a valve
of any description; but by the ordinary action of compressing the ball, and
then allowing it to expand, a sample of the suspected atmosphere is drawn
from the roof, or any part of the mine, without the great risk which now
attends the operation of testing for gas should the gauze of the lamp be
defective. The sample thus obtained is then forced through a small protected
tube on to the flame, when if gas is present it is shown by the well-known
blue cap and elongated flame. From this description, and from the fact that
the ball is so small that it can be carried in the coat pocket, or, if necessary,
in the waistcoat pocket, it will be apparent what a valuable adjunct Mr.
Garforth's invention will prove to the safety-lamp. It has been supposed by
some persons that explosions have been caused by the fire-trier himself, but
owing to his own death in most cases the cause has remained undiscovered.
This danger will now be altogether avoided. It is well known that the
favorite form of lamp with the firemen is the Davy, because it shows more
readily the presence of small quantities of gas; but the Davy was some years
ago condemned, and is now strictly prohibited in all Belgian and many
English mines. Recent experience, gained by repeated experiments with
costly apparatus, has resulted in not only proving the Davy and some other
descriptions of lamps to be unsafe, but some of our Government Inspectors
and our most experienced mining engineers go so far as to say that "no lamp
in a strong current of explosive gas is safe unless protected by a tin shield."

If such is the case, Mr. Garforth seems to have struck the key-note when, in
the recent paper read before the Midland Institute of Mining and Civil
Engineers, and which we have now before us, he says: "It would seem from
the foregoing remarks that in any existing safety-lamp where one
qualification is increased another is proportionately reduced; so it is doubtful
whether all the necessary requirements of sensitiveness, resistance to strong
currents, satisfactory light, self-extinction, perfect combustion, etc., can ever
be combined in one lamp."

The nearest approach to Mr. Garforth's invention which we have ever heard
of is that of a workman at a colliery in the north of England, who, more than
twenty years ago, to avoid the trouble of getting to the highest part of the
roof, used a kind of air pump, seven or eight feet long, to extract the gas
from the breaks; and some five years ago Mr. Jones, of Ebbw Vale, had a
similar idea. It appears that these appliances were so cumbersome, besides
requiring too great length or height for most mines, and necessitating the use
of both hands, that they did not come into general use. The ideas, however,
are totally different, and the causes which have most likely led to the
invention of the ball and protected tube were probably never thought of until

recently; indeed, Mr. Garforth writes that he has only learned about them
since his paper was read before the Midland Institute, and some weeks after
his patent was taken out.

No one, says Mr. Garforth, in his paper read before the Midland Institute,
will, I presume, deny that the Davy is more sensitive than the tin shield
lamp, inasmuch as in the former the surrounding atmosphere or explosive
mixture has only one thickness of gauze to pass through, and that on a level
with the flame; while the latter has a number of small holes and two or three
thicknesses of gauze (according to the construction of the lamp), which the
gas must penetrate before it reaches the flame. Moreover, the tin shield lamp,
when inclined to one side, is extinguished (though not so easily as the
Mueseler); and as the inlet holes are 6 inches from the top, it does not show
a thin stratum of fire-damp near the roof as perceptibly as the Davy, which
admits of being put in almost a horizontal position. Although the Davy lamp
was, nearly fifty years ago, pronounced unsafe, by reason of its inability to
resist an ordinary velocity of eight feet per second, yet it is still kept in use
on account of its sensitiveness. Its advocates maintain that a mine can be
kept safer by using the Davy, which detects small quantities of gas, and
thereby shows the real state of the mine, than by a lamp which, though able
to resist a greater velocity, is not so sensitive, and consequently is apt to
deceive. Assuming the Davy lamp to be condemned (as it has already been
in Belgium and in some English mines), the Stephenson and some of the
more recently invented lamps pronounced unsafe, then if greater shielding is
recommended the question is, what means have we for detecting small
quantities of fire-damp?

It would seem from the foregoing remarks that in any existing safety-lamp,
where one qualification is increased another is proportionately reduced; so it
is doubtful whether all the necessary requirements of sensitiveness,
resistance to strong currents, satisfactory light, self-extinction, perfect
combustion, etc., can ever be combined in one lamp. The object of the
present paper is to show that with the assistance of the fire-damp detecter,
the tin shield, or any other description of lamp, is made as sensitive as the
Davy, while its other advantages of resisting velocity, etc., are not in any
way interfered with. As a proof of this I may mention that a deputy of
experience recently visited a working place to make his inspection. He
reported the stall to be free from gas, but when the manager and steward

visited it with the detecter, which they applied to the roof (where it would
have been difficult to put even a small Davy), it drew a sample of the
atmosphere which, on being put to the test tube in the tin-shield lamp, at
once showed the presence of fire-damp. Out of twenty-eight tests in a mine
working a long-wall face the Davy showed gas only eleven times, while the
detecter showed it in every case. The detecter, as will be perceived from the
one exhibited, and the accompanying sectional drawing, consists simply of
an oval-shaped India rubber ball, fitted with a mouthpiece. The diameter is
about 2¼ inches by 3 inches, its weight is two ounces, and it is so small that
it can be carried without any inconvenience in the coat or even in the
waistcoat pocket. Its capacity is such that all the air within it may be
expelled by the compression of one hand.

The mouthpiece is made to fit a tube in the bottom of the lamp, and when
pressed against the India rubber ring on the ball-flange, a perfectly tight joint
is made, which prevents the admission of any external air. The tube in the
bottom of the lamp is carried within a short distance of the height of the
wick-holder. It is covered at the upper end with gauze, besides being fitted
with other thicknesses of gauze at certain distances within the tube; and if it
be found desirable to further protect the flame against strong currents of air,
a small valve may be placed at the inlet, as shown in the drawing. This valve
is made of sufficient weight to resist the force of a strong current, and is only
lifted from its seat by the pressure of the hand on the mouthpiece. It will be
apparent from the small size and elasticity of the detecter that the test can
easily be made with one hand, and when the ball is allowed to expand a
vacuum is formed within it, and a sample of the atmosphere drawn from the
breaks, cavities, or highest parts of the roof, or, of course, any portion of the
mine. When the sample is forced through the tube near the flame, gas if
present at once reveals itself by the elongation of the flame in the usual way,
at the same time giving an additional proof by burning with a blue flame on
the top of the test tube. If gas is not present, the distinction is easily seen by
the flame keeping the same size, but burning with somewhat greater
brightness, owing to the increased quality of oxygen forced upon it.

I venture to claim for this method of detecting fire-damp among other
advantages: 1. The detecter, on account of its size, can be placed in a break
in the roof where an ordinary lamp—even a small Davy—could not be put,
and a purer sample of the suspected atmosphere is obtained than would be

the case even a few inches below the level of the roof, 2. The obtaining and
testing of a sample in the manner above described takes away the possibility
of an explosion, which might be the result if a lamp with a defective gauze
were placed in an explosive atmosphere. No one knows how many
explosions have not been caused by the fire-trier himself. This will now be
avoided. (Although lamps fitted with a tin shield will be subjected to the
same strict examination as hitherto, still they do not admit of the same
frequent inspection as those without shields, for in the latter case each
workman can examine his own lamp as an extra precaution; whereas the
examination of the tin shield lamps will rest entirely with the lamp man.) 3.
The lamp can be kept in a pure atmosphere while the sample is obtained by
the detecter, and at a greater height than the flame in a safety-lamp could be
properly distinguished. The test can afterward be made in a safe place, at
some distance from the explosive atmosphere; and, owing to the vacuum
formed, the ball (without closing the mouthpiece) has been carried a mile or
more without the gas escaping. 4. The detecter supplies a better knowledge
of the condition of the working places, especially in breaks and cavities in
the roof; which latter, with the help of a nozzle and staff, may be reached to
a height of ten feet or more, by the detecter being pressed against the roof
and sides, or by the use of a special form of detecter. 5. Being able at will to
force the contents of the detecter on to the flame, the effects of an explosion
inside the lamp need not be feared. (This danger being removed, admits, I
think, of the glass cylinder being made of a larger diameter, whereby a better
light is obtained; it may also be considered quite as strong, when used with
the detecter, as a lamp with a small diameter, when the latter is placed in an
explosive atmosphere.) 6. The use of the detecter will permit the further
protection of the present tin shield lamp, by an extra thickness of gauze, if
such addition is found advantageous in resisting an increased velocity. 7. In
the Mueseler, Stephenson, and other lamps, where the flame is surrounded
by glass, there is no means of using the wire for shot firing. The detecter
tube, although protected by two thicknesses of gauze, admits of this being
done by the use of a special form of valve turned by the mouthpiece of the
detecter. The system of firing shots or using open lamps in the same pit
where safety lamps are used is exceedingly objectionable; still, under certain
conditions shots may be fired without danger. Whether safety lamps or
candles are used, it is thought the use of the detecter will afford such a ready
means of testing that more examinations will be made before firing a shot,
thereby insuring greater safety. 8. In testing for gas with a safety lamp there

is a fear of the light being extinguished, when the lamp is suddenly placed in
a quantity of gas, or in endeavoring to get a very small light; this is
especially the case with some kinds of lamps. With the detecter this is
avoided, as a large flame can be used, which is considered by some a
preferable means of testing for small quantities; and the test can be made
without risk. Where gas is present in large quantities, the blue flame at the
end of the test tube will be found a further proof. This latter result is
produced by the slightest compression of the ball. (I need not point out the
inconvenience and loss of time in having to travel a mile or more to relight.)
As regards the use of the detecter with open lights, several of the foregoing
advantages or modifications of them will apply. Instead of having to use the
safety lamp as at present, it is thought that the working place will be more
frequently examined, for a sample of the suspected atmosphere can be
carried to a safe place and forced on to the naked light, when, if gas be
present, it simply burns at the end of the mouthpiece like an ordinary gas jet.
There are other advantages, such as examining the return airways without
exposing the lamp, etc., which will be apparent, and become of more or less
importance according to the conditions under which the tests are made.

In conclusion, I wish to paint out that the practice adopted at some collieries,
of having all the men supplied with the most approved lamp (such as the
Mueseler or tin shield lamp) is not a safe one. If the strength of a chain is
only equal to the weakest link, it may be argued that the safety of a mine is
only equal to that of the most careless man or most unsafe lamp in it. If,
therefore, the deputies, whose duty it is to look for gas and travel the most
dangerous parts of the mine, are obliged to use the Davy on account of its
sensitiveness, may it not be said that, as their lamps are exposed equally with
the workmen's to the high velocities of air, they are the weak links in the
safety of the mine? For the reasons given, I venture to submit that the
difficulties and dangers I have mentioned will be largely reduced, if not
wholly overcome, by the use of the fire-damp detecter.

CAMERA ATTACHMENT FOR PAPER PHOTO
NEGATIVES.
In computing the weight of the various items for a photographic tour, the
glass almost invariably comes out at the head of the list, and the farther or
longer the journey, so much more does the weight of the plates stand out pre-
eminent; indeed, if one goes out on a trip with only three dozen half-plates,
the glass will probably weigh nearly as much as camera, backs, and tripod,
in spite of the stipulation with the maker to supply plates on "thin glass."

Next in importance to glass as a support comes paper, and it is quite easy to
understand that the tourist in out of the way parts might be able to take an
apparatus containing a roll of sensitive paper, when it would be altogether
impracticable for him to take an equivalent surface of coated glass, and in
such a case the roller slide becomes of especial value.

The roller slide of Melhuish is tolerably well known, and is, we believe, now
obtainable as an article of commerce. The slide is fitted up with two rollers,
a a, and the sensitive sheets, b b, are gummed together, making one long
band, the ends of which are gummed to pieces of paper always kept on the
rollers. The sensitive sheets are wound off the left or reserve roller on to the
right or exposed roller, until all are exposed.

The rollers are supported on springs, a¹ a¹, to render their motion equal; they
are turned by the milled heads, m m, and clamped when each fresh sheet is
brought into position by the nuts, a² a². c, is a board which is pressed
forward by springs, c¹ c¹, so as to hold the sheet to be exposed, and keep it
smooth against the plate of glass, d; when the sheet has been exposed, the
board is drawn back from the glass in order to release the exposed sheet, and
allow it to be rolled on the exposed roller; the board is kept back while this is
being done by turning the square rod, c², half round, so that the angles of the
square will not pass back through the square opening until again turned
opposite to it; e e are doors, by opening which the operator can see (through
the yellow glass, y y) to adjust the position of the sensitive sheets when
changing them.

The remarkable similarity of such a slide to the automatic printing-frame
described last week will strike the reader; and, like the printing-frame, it
possesses the advantage of speed in working—no small consideration to the
photographer in a distant, and possibly hostile, country.

Fine paper well sized with an insoluble size and coated with a sensitive
emulsion is, we believe, the very best material to use in the roller slide; and
such a paper might be made in long lengths at a very low price, a coating
machine similar to that constructed for use in making carbon tissue being
employed. We have used such paper with success, and hope that some
manufacturer will introduce it into commerce before long. But the question
suggests itself, how are the paper negatives to be rendered transparent, and
how is the grain of the paper to be obliterated? Simply by pressure, as
extremely heavy rolling will render such paper almost as transparent as
glass, a fact abundantly demonstrated by Mr. Woodbury in his experiments
on the Photo-Filigrane process, and confirmed by some trials which we have
made.

It must be confessed that roller slide experiments which we have made with
sensitive films supported on gelatine sheets, or on such composite sheets as
the alternate rubber and collodion pellicle of Mr. Warnerke, have been hardly
satisfactory—possibly, however, from our own want of skill; while no form
of the Calotype process which we have tried has proved so satisfactory as
gelatino-bromide paper.—Photo. News.

INSTANTANEOUS PHOTO SHUTTER.
M. Audra, in the name of M. Braun, of Angoulême, has presented to the
Photo Society of France a new instantaneous shutter. The shutter is formed
by a revolving metallic disk out of which a segment has been taken. This
disk is placed in the center of the diaphragms, in order to obtain the greatest
rapidity combined with the least possible distance to travel. On the axis to
which this circular disk is fixed is a small wheel, to which is attached a piece
of string, and when the disk is turned round for the exposure the string is
wound round the wheel. If the string be pulled, naturally the disk will
revolve back to its former position so much the more quickly the more
violently the string is pulled. M. Braun has replaced the hand by a steel
spring attached to the drum of the lens (Fig. 2) By shortening or lengthening
the string, more or less rapid exposures may be obtained.

AAA, lens; B, aperture of lens; C, metallic disk; D, wheel on the axis; E,
cord or string; E¹E¹E¹E¹, knots in string; G, steel spring; H, catch; K, socket
for catch.

SULPHUROUS ACID.—EASY METHOD OF
PREPARATION FOR PHOTOGRAPHIC
PURPOSES.
Within a short period sulphurous acid has become an important element in
the preparation of an excellent pyro developer for gelatine plates; and as it is
more or less unstable in its keeping qualities, some easy method of preparing
a small quantity which shall have a uniform strength is desirable. A method
recently described in the Photographic News will afford the amateur
photographer a ready way of preparing a small quantity of the acid.

In the illustration given above, A and B are two bottles, both of which can be
closed tightly with corks. A hole is made in the cork in the bottle, A, a little
smaller than the glass tube which connects A and B. It is filed out with a rat-
tail file until it is large enough to admit the tube very tightly. The tube may

be bent easily, by being heated over a common fish-tail gas burner or over
the top of the chimney of a kerosene lamp, so as to form two right angles,
one end extending close to the bottom of the bottle B as shown.

Having fitted up the apparatus, about two ounces of hyposulphite of soda are
placed in the bottle A, while the bottle B is about three-fourths filled with
water—distilled or melted ice water is to be preferred; some sulphuric acid
—about two ounces—is now diluted with about twice its bulk of water, by
first putting the water into a dish and pouring in the acid in a steady stream,
stirring meanwhile. It is well to set the dish in a sink, to avoid any damage
which might occur through the breaking of the dish by the heat produced;
when cool, the solution is ready for use and may be kept in a bottle.

The cork which serves to adapt the bent tube to the bottle A is now just
removed for an instant, the other end remaining in the water in bottle B, and
about two or three ounces of the dilute acid are poured in upon the
hyposulphite, after which the cork is immediately replaced.

Sulphurous acid is now evolved by the action of the acid on the hypo, and as
the gas is generated it is led as a series of bubbles through the water in the
bottle B as shown. The air space above the water in bottle B soon becomes
filled by displacement with sulphurous acid gas, which is a little over twice
as heavy as air; so in order to expedite the complete saturation of the water,
it is convenient to remove the bottle A with its tube from bottle B, and after
having closed the latter by its cork or stopper, to agitate it thoroughly by
turning the bottle upside down. As the sulphurous acid gas accumulated in
the air space over the water is absorbed by the water, a partial vacuum is
created, and when the stopper is eased an inrush of air may be noted. When,
after passing fresh gas through the liquid for some minutes, no further inrush
of air is noted on easing the stopper as before described after agitating the
bottle, it may be concluded that the water is thoroughly saturated with
sulphurous acid and is strong enough for immediate use. More gas can be
generated by adding more dilute sulphuric acid to the hypo until the latter is
decomposed; then it should be thrown aside, and a fresh charge put in the
bottle. On preparing the solution it is well to set the bottles on the outside
ledge of the window, or in some other open situation where no
inconvenience will result from the escape of the excess of sulphurous gas as
it bubbles through the water.

The solution of sulphurous acid, if preserved at all, ought to be kept in small
bottles, completely filled and perfectly closed; but as it is very easy to
saturate a considerable quantity of water with sulphurous acid gas in a short
time, there is but little inducement to use a solution which may possibly have
become weakened by keeping.

Care should be taken not to add too much dilute acid to the hypo at a time,
else excessive effervescence will occur, and the solution will froth over the
top of the bottle.

THE NATIONAL MONUMENT AT ROME.
About three years ago the Italian Government invited the architects and
artists of the world to furnish competitive designs for a national monument
to be erected to the memory of King Victor Emanuel II. at Rome. More than
$1,800,000 were appropriated for the monument exclusive of the foundation.
It is very seldom that an artist has occasion to carry out as grand and
interesting a work as this was to be: the representation of the creator of the
Italian union in the new capitol of the new state surrounded by the ruins and
mementos of a proud and mighty past. Prizes of $10,000, $6,000, and $4,000
were donated for the first, second, and third prize designs respectively.
Designs were entered, not only from Italy, but also from Germany, France,
Norway, Sweden, England, and America, and even from Caucasus and
Japan.

THE UNION OF ITALY. SACCONI'S PRIZE DESIGN FOR THE
NATIONAL MONUMENT, ROME, ITALY.

The height and size of the monument were not determined on, nor was the
exact location, and the competitors had full liberty in relation to the artistic
character of the monument, and it was left for them to decide whether it
should be a triumphal arch, a column, a temple, a mausoleum, or any other
elaborate design. This great liberty given to the competitors was of great
value and service to the monument commission, as it enabled them to decide
readily what the character of the monument should be but it was a dangerous
point for the artists, at which most of them foundered. The competition was
resultless. Two prizes were given, but new designs had to be called for,
which were governed more or less by a certain programme issued by the
committee.

In place of the Piazza de Termini, a square extending from the church of St.
Maria degli Angeli to the new Via Nazionale, to which preference was given
by the competitors, the heights of Aracoeli were chosen. The monument was
to be erected at this historic place in front of the side wall of the church, with
the center toward the Corso, high above the surrounding buildings. The
programme called for an equestrian statue of the King located in front of an
architectural background which was to cover the old church walls, and was
to be reached by a grand staircase.

Even the result of this second competition was not definite, but as the
designers were guided by the programme, the results obtained were much
more satisfactory. The commission decided not to award the first prize, but
honored the Italian architects Giuseppi Sacconi and Manfredo Manfredi, and
the German Bruno Schmitz, with a prize of $2,000 each; and requested them
to enter into another competition and deliver their models within four
months, so as to enable the commission to come to a final decision. On June
18, the commission decided to accept Sacconi's design for execution, and
awarded a second prize of $2,000 to Manfredi.

Sacconi's design, shown opposite page, cut taken from the Illustrirte
Zeitung, needs but little explanation. An elegant gallery of sixteen Corinthian
columns on a high, prominent base is crowned by a high attica and flanked
by pavilions. It forms the architectural background for the equestrian statue,
and is reached by an elaborately ornamented staircase.

Manfredi's design shows a handsomely decorated wall in place of the
gallery, and in front of the wall an amphitheater is arranged, in the center of
which the equestrian statue is placed. Bruno Schmitz' design shows a rich
mosaic base supporting an Ionic portico, from the middle of which a six
column Corinthian "pronaos" projects, which no doubt would have produced
a magnificent effect in the streets of Rome.

ON THE EVOLUTION OF FORMS OF
ORNAMENT. 1
The statement that modern culture can be understood only through a study of
all its stages of development is equally true of its several branches.

Let us assume that decorative art is one of these. It contains in itself, like
language and writing, elements of ancient and even of prehistoric forms, but
it must, like these other expressions of culture, which are forever undergoing
changes, adapt itself to the new demands which are made upon it, not
excepting the very arbitrary ones of fashion; and it is owing to this cause
that, sometimes even in the early stages of its development, little or nothing
of its original form is recognizable. Investigations the object of which is to
clear up this process of development as far as possible are likely to be of
some service; a person is more likely to recognize the beauties in the details
of ornamental works of art if he has an acquaintance with the leading styles,
and the artist who is freed from the bondage of absolute tradition will be put
into a better position to discriminate between accidental and arbitrary and
organic and legitimate forms, and will thus have his work in the creation of
new ones made more easy for him.

Hence I venture to claim some measure of indulgence in communicating the
results of the following somewhat theoretical investigations, as they are not
altogether without a practical importance. I must ask the reader to follow me
into a modern drawing-room, not into one that will dazzle us with its cold
elegance, but into one whose comfort invites us to remain in it.

The simple stucco ceiling presents a central rosette, which passes over by
light conventional floral forms into the general pattern of the ceiling. The
frieze also, which is made of the same material, presents a similar but
somewhat more compact floral pattern as its chief motive. Neither of these,
though they belong to an old and never extinct species, has as yet attained
the dignity of a special name.

The walls are covered with a paper the ornamentation of which is based
upon the designs of the splendid textile fabrics of the middle ages, and
represents a floral pattern of spirals and climbing plants, and bears evident
traces of the influence of Eastern culture. It is called a pomegranate or pine-
apple pattern, although in this case neither pomegranates nor pine-apples are
recognizable.

Similarly with respect to the pattern of the coverings of the chairs and sofas
and of the stove-tiles; these, however, show the influence of Eastern culture
more distinctly.

The carpet also, which is not a true Oriental one, fails to rivet the attention,
but gives a quiet satisfaction to the eye, which, as it were, casually glances
over it, by its simple pattern, which is derived from Persian-Indian
archetypes (Cashmere pattern, Indian palmettas), and which is ever
rhythmically repeating itself (see Fig. 1).

FIG. 1.

The floral pattern on the dressing-gown of the master of the house, as well as
on the light woolen shawl that is thrown round the shoulders of his wife, and
even the brightly colored glass knicknacks on the mantel-piece,
manufactured in Silesia after the Indian patterns of the Reuleaux collection,
again show the same motive; in the one case in the more geometrical linear
arrangement, in the other in the more freely entwined spirals.

Now you will perhaps permit me to denominate these three groups of
patterns that occur in our new home fabrics as modern patterns. Whether we
shall in the next season be able, in the widest sense of the word, to call these
patterns modern naturally depends on the ruling fashion of the day, which of
course cannot be calculated upon (Fig. 2).

FIG. 2.

I beg to be allowed to postpone the nearer definition of the forms that occur
in the three groups, which, however, on a closer examination all present a
good deal that they have in common. Taking them in a general way, they all
show a leaf-form inclosing an inflorescence in the form of an ear or thistle;

or at other times a fruit or a fruit-form. In the same way with the stucco
ornaments and the wall-paper pattern.

The Cashmere pattern also essentially consists of a leaf with its apex
laterally expanded; it closes an ear-shaped flower-stem, set with small
florets, which in exceptional cases protrude beyond the outline of the leaf;
the whole is treated rigorously as an absolute flat ornament, and hence its
recognition is rendered somewhat more difficult. The blank expansion of the
leaf is not quite unrelieved by ornament, but is set off with small points,
spots, and blossoms. This will be thought less strange if we reflect on the
Eastern representations of animals, in the portrayal of which the flat
expanses produced by the muscle-layers are often treated from a purely
decorative point of view, which strikes us as an exaggeration of convention.

FIG. 3.

One cannot go wrong in taking for granted that plant-forms were the
archetypes of all these patterns. Now we know that it holds good, as a
general principle in the history of civilization, that the tiller of the ground

supplants the shepherd, as the shepherd supplants the hunter; and the like
holds also in the history of the branch of art we are discussing—
representations of animals are the first to make their appearance, and they
are at this period remarkable for a wonderful sharpness of characterization.
At a later stage man first begins to exhibit a preference for plant-forms as
subjects for representation, and above all for such as can in any way be
useful or hurtful to him. We, however, meet such plant-forms used in
ornament in the oldest extant monuments of art in Egypt, side by side with
representations of animals; but the previous history of this very developed
culture is unknown. In such cases as afford us an opportunity of studying
more primitive though not equally ancient stages of culture, as for instance
among the Greeks, we find the above dictum confirmed, at any rate in cases
where we have to deal with the representation of the indigenous flora as
contradistinguished from such representations of plants as were imported
from foreign civilizations. In the case that is now to occupy us, we have not
to go back so very far in the history of the world.

FIG. 4.

The ornamental representations of plants are of two kinds. Where we have to
deal with a simple pictorial reproduction of plants as symbols (laurel
branches, boughs of olive and fir, and branches of ivy), i. e., with a mere
characteristic decoration of a technical structure, stress is laid upon the most
faithful reproduction of the object possible—the artist is again and again
referred to the study of Nature in order to imitate her. Hence, as a general
rule, there is less difficulty in the explanation of these forms, because even
the minute details of the natural object now and then offer points that one
can fasten upon. It is quite another thing when we have to deal with actual
decoration which does not aim at anything further than at employing the
structural laws of organisms in order to organize the unwieldy substance, to
endow the stone with a higher vitality. These latter forms depart, even at the
time when they originate, very considerably from the natural objects. The
successors of the originators soon still further modify them by adapting them
to particular purposes, combining and fusing them with other forms so as to
produce particular individual forms which have each their own history (e.g.,
the acanthus ornament, which, in its developed form, differs very greatly
from the acanthus plant itself); and in a wider sense we may here enumerate
all such forms as have been raised by art to the dignity of perfectly viable
beings, e.g., griffins, sphinxes, dragons, and angels.

Fig. 5.

The deciphering and derivation of such forms as these is naturally enough
more difficult; in the case of most of them we are not even in possession of
the most necessary preliminaries to the investigation, and in the case of
others there are very important links missing (e.g., for the well-known Greek
palmettas). In proportion as the representation of the plant was a secondary
object, the travesty has been more and more complete. As in the case of
language, where the root is hardly recognizable in the later word, so in
decorative art the original form is indistinguishable in the ornament. The
migration of races and the early commercial intercourse between distant
lands have done much to bring about the fusion of types; but again in
contrast to this we find, in the case of extensive tracts of country, notably in
the Asiatic continent, a fixity, throughout centuries, of forms that have once
been introduced, which occasions a confusion between ancient and modern
works of art, and renders investigations much more difficult. An old French
traveler writes: "J'ai vu dans le trésor d'Ispahan les vetements de Tamerlan;
ils ne different en rien de ceux d'aujourd'hui." Ethnology, the natural

sciences, and last, but not least, the history of technical art are here set face
to face with great problems.

FIG. 6.

In the case in point, the study of the first group of artistic forms that have
been elaborated by Western art leads to definite results, because the
execution of the forms in stone can be followed on monuments that are
relatively not very old, that are dated, and of which the remains are still
extant. In order to follow the development, I ask your permission to go back
at once to the very oldest of the known forms. They come down to us from
the golden era of Greek decorative art—from the fourth or fifth century B.C.
—when the older simple styles of architecture were supplanted by styles
characterized by a greater richness of structure and more developed
ornament. A number of flowers from capitals in Priene, Miletus, Eleusis,
Athens (monument of Lysicrates), and Pergamon; also flowers from the
calathos of a Greek caryatid in the Villa Albani near Rome, upon many
Greek sepulchral wreaths, upon the magnificent gold helmet of a Grecian
warrior (in the Museum of St. Petersburg)—these show us the simplest type

of the pattern in question, a folded leaf, that has been bulged out, inclosing a
knob or a little blossom (see Figs. 3 and 4). This is an example from the
Temple of Apollo at Miletus, one that was constructed about ten years ago,
for educational purposes. Here is the specimen of the flower of the
monument to Lysicrates at Athens, of which the central part consists of a
small flower or fruits (Figs. 5 and 6).

FIG. 7.

The form passes over into Roman art. The larger scale of the buildings, and
the pretensions to a greater richness in details, lead to a further splitting up
of the leaf into acanthus-like forms. Instead of a fruit-form a fir-cone
appears, or a pine-apple or other fruit in an almost naturalistic form.

In a still larger scale we have the club-shaped knob developing into a plant-
stem branching off something after the fashion of a candelabrum, and the
lower part of the leaf, where it is folded together in a somewhat bell-shaped
fashion, becomes in the true sense of the word a campanulum, out of which

an absolute vessel-shaped form, as e.g. is to be seen in the frieze of the
Basilica Ulpia in Rome, becomes developed.

FIG. 8.

Such remains of pictorial representation as are still extant present us with an
equally perfect series of developments. The splendid Græco-Italian vessels,
the richly ornamented Apulian vases, show flowers in the spirals of the
ornaments, and even in the foreground of the pictorial representations, which
correspond exactly to the above mentioned Greek relief representations.
[The lecturer sent round, among other illustrations, a small photograph of a
celebrated vase in Naples (representing the funeral rites of Patroclus), in
which the flower in question appears in the foreground, and is perhaps also
employed as ornament.] (Figs. 7 and 8.)

The Pompeian paintings and mosaics, and the Roman paintings, of which
unfortunately very few specimens have come down to us, show that the
further developments of this form were most manifold, and indeed they form
in conjunction with the Roman achievements in plastic art the highest point

that this form reached in its development, a point that the Renaissance,
which followed hard upon it, did not get beyond.

FIG. 9.

Thus the work of Raphael from the loggias follows in unbroken succession
upon the forms from the Thermæ of Titus. It is only afterward that a freer
handling of the traditional pattern arose, characterized by the substitution of,
for instance, maple or whitethorn for the acanthus-like forms. Often even the
central part falls away completely, or is replaced by overlapping leaves. In
the forms of this century we have the same process repeated. Schinkel and
Botticher began with the Greek form, and have put it to various uses; Stuler,
Strack, Gropius, and others followed in their wake until the more close
resemblance to the forms of the period of the Renaissance in regard to
Roman art which characterizes the present day was attained (Fig. 9).

Now, what plant suggested this almost indispensable form of ornament,
which ranks along with the acanthus and palmetta, and which has also
become so important by a certain fusion with the structural laws of both?

FIG. 10.

We meet with organism of the form in the family of the Araceæ, or aroid
plants. An enveloping leaf (bract), called the spathe, which is often
brilliantly colored, surrounds the florets, or fruits, that are disposed upon a
spadix. Even the older writers—Theophrastus, Dioscorides, Galen, and Pliny
—devote a considerable amount of attention to several species of this
interesting family, especially to the value of their swollen stems as a food-
stuff, to their uses in medicine, etc. Some species of Arum were eaten, and
even nowadays the value of the swollen stems of some species of the family
causes them to be cultivated, as, for instance, in Egypt and India, etc. (the
so-called Portland sago, Portland Island arrowroot, is prepared from the
swollen stems of Arum maculatum). In contrast with the smooth or softly
undulating outlines of the spathe of Mediterranean Araceæ, one species
stands out in relief, in which the sharply-marked fold of the spathe almost
corresponds to the forms of the ornaments which we are discussing. It is
Dracunculus vulgaris, and derives its name from its stem, which is spotted
like a snake. This plant, which is pretty widely distributed in olive woods
and in the river valleys of the countries bordering on the Mediterranean, was

employed to a considerable extent in medicine by the ancients (and is so still
nowadays, according to Von Heldreich, in Greece). It was, besides, the
object of particular regard, because it was said not only to heal snake-bite,
but the mere fact of having it about one was supposed to keep away snakes,
who were said altogether to avoid the places where it grew. But, apart from
this, the striking appearance of this plant, which often grows to an enormous
size, would be sufficient to suggest its employment in art. According to
measurements of Dr. Julius Schmidt, who is not long since dead, and was the
director of the Observatory at Athens, a number of these plants grow in the
Valley of Cephisus, and attain a height of as much as two meters, the spathe
alone measuring nearly one meter. [The lecturer here exhibited a drawing
(natural size) of this species, drawn to the measurements above referred to.]

FIG. 11.

Dr. Sintenis, the botanist, who last year traveled through Asia Minor and
Greece, tells me that he saw beautiful specimens of the plant in many places,
e.g., in Assos, in the neighborhood of the Dardanelles, under the cypresses of
the Turkish cemeteries.

The inflorescence corresponds almost exactly to the ornament, but the
multipartite leaf has also had a particular influence upon its development and
upon that of several collateral forms which I cannot now discuss. The shape
of the leaf accounts for several as yet unexplained extraordinary forms in the
ancient plane-ornament, and in the Renaissance forms that have been thence
developed. It first suggested the idea to me of studying the plant attentively
after having had the opportunity five years ago of seeing the leaves in the
Botanic Gardens at Pisa. It was only afterward that I succeeded in growing
some flowers which fully confirmed the expectations that I had of them
(Figs. 10 and 11).

FIG. 12.

The leaf in dracunculus has a very peculiar shape; it consists of a number of
lobes which are disposed upon a stalk which is more or less forked (tends
more or less to dichotomize). If you call to your minds some of the
Pompeian wall decorations, you will perceive that similar forms occur there
in all possible variations. Stems are regularly seen in decorations that run
perpendicularly, surrounded by leaves of this description. Before this, these

suggested the idea of a misunderstood (or very conventional) perspective
representation of a circular flower. Now the form also occurs in this fashion,
and thus negatives the idea of a perspective representation of a closed
flower. It is out of this form in combination with the flower-form that the
series of patterns was developed which we have become acquainted with in
Roman art, especially in the ornament of Titus' Thermæ and in the
Renaissance period in Raphael's work. [The lecturer here explained a series
of illustrations of the ornaments referred to (Figs. 12, 13, 14).]

The attempt to determine the course of the first group of forms has been to a
certain extent successful, but we meet greater difficulties in the study of the
second.

FIG. 13.

It is difficult to obtain a firm basis on which to conduct our investigations
from the historical or geographical point of view into this form of art, which
was introduced into the West by Arabico-Moorish culture, and which has
since been further developed here. There is only one method open to us in

the determination of the form, which is to pass gradually from the richly
developed and strongly differentiated forms to the smaller and simpler ones,
even if these latter should have appeared contemporaneously or even later
than the former. Here we have again to refer to the fact that has already been
mentioned, to wit, that Oriental art remained stationary throughout long
periods of time. In point of fact, the simpler forms are invariably
characterized by a nearer and nearer approach to the more ancient patterns
and also to the natural flower-forms of the Araceæ. We find the spathe,
again, sometimes drawn like an acanthus leaf, more often, however, bulged
out, coming to be more and more of a mere outline figure, and becoming
converted into a sort of background; then the spadix, generally conical in
shape, sometimes, however, altogether replaced by a perfect thistle, at other
times again by a pomegranate. Auberville, in his magnificent work
"L'Ornement des Tissus," is astonished to find the term pomegranate-pattern
almost confined to these forms, since their central part is generally formed of
a thistle-form. As far as I can discover in the literature that is at my disposal,
this question has not had any particular attention devoted to it except in the
large work upon Ottoman architecture published in Constantinople under the
patronage of Edhem Pasha. The pomegranate that has served as the original
of the pattern in question is in this work surrounded with leaves till it gives
some sort of an approach to the pattern. (There are important suggestions in
the book as to the employment of melon-forms.) Whoever has picked the
fruit from the tender twigs of the pomegranate tree, which are close set with
small altered leaves, will never dream of attributing the derivation of the
thorny leaves that appear in the pattern to pomegranate leaves at any stage of
their development.

FIG. 14

It does not require much penetration to see that the outline of the whole form
corresponds to the spathe of the Araceæ, even although in later times the
jagged contour is all that has remained of it, and it appears to have been
provided with ornamental forms quite independently of the rest of the
pattern. The inner thistle-form cannot be derived from the common thistle,
because the surrounding leaves negative any such idea. The artichoke theory
also has not enough in its favor, although the artichoke, as well as the thistle,
was probably at a later time directly pressed into service. Prof. Ascherson
first called my attention to the extremely anciently cultivated plant, the
safflor (Carthamus tinctoris, Fig. 15), a thistle plant whose flowers were
employed by the ancients as a dye. Some drawings and dried specimens, as
well as the literature of the subject, first gave me a hope to find that this
plant was the archetype of this ornament, a hope that was borne out by the
study of the actual plant, although I was unable to grow it to any great
perfection.

In the days of the Egyptian King Sargo (according to Ascherson and
Schweinfurth) this plant was already well known as a plant of cultivation; in
a wild state it is not known (De Candolle, "Originel des Plantes cultivées").
In Asia its cultivation stretches to Japan. Semper cites a passage from an
Indian drama to the effect that over the doorway there was stretched an arch
of ivory, and about it were bannerets on which wild safran (Saflor) was
painted.

FIG. 15

The importance of the plant as a dye began steadily to decrease, and it has
now ceased to have any value as such in the face of the introduction of
newer coloring matters (a question that was treated of in a paper read a short
time ago by Dr. Reimann before this Society). Perhaps its only use nowadays
is in the preparation of rouge (rouge végétale).

But at a time when dyeing, spinning, and weaving were, if not in the one
hand, yet at any rate intimately connected with one another in the narrow
circle of a home industry, the appearance of this beautiful gold-yellow plant,

heaped up in large masses, would be very likely to suggest its
immortalization in textile art, because the drawing is very faithful to nature
in regard to the thorny involucre. Drawings from nature of the plant in the
old botanical works of the sixteenth and seventeenth centuries look very like
ornamental patterns. Now after the general form had been introduced,
pomegranates or other fruits—for instance, pine-apples—were introduced
within the nest of leaves.

FIG. 16.

Into the detailed study of the intricacies of this subject I cannot here enter;
the East-Asian influences are not to be neglected, which had probably even
in early times an effect upon the form that was assumed, and have fused the
correct style of compound flowers for flat ornament with the above-
mentioned forms, so as to produce peculiar patterns; we meet them often in
the so-called Persian textures and flat ornaments (Fig. 16).

We now come to the third group of forms—the so-called Cashmere pattern,
or Indian palmetta. The developed forms, which, when they have attained

their highest development, often show us outlines that are merely fanciful,
and represent quite a bouquet of flowers leaning over to one side, and
springing from a vessel (the whole corresponding to the Roman form with
the vessel), must be thrown to one side, while we follow up the simpler
forms, because in this case also we have no information as to either the
where or the when the forms originated. (Figs. 17, 18, 19.)

FIG. 17.

Here again we are struck by resemblances to the forms that were the subjects
of our previous study, we even come across direct transitional forms, which
differ from the others only by the lateral curve of the apex of the leaf;
sometimes it is the central part, the spadix, that is bent outward, and the very
details show a striking agreement with the structure of the aroid
inflorescence, so much so that one might regard them as actually copied
from them.

FIG. 18.

This form of ornament has been introduced into Europe since the French
expedition to Egypt, owing to the importation of genuine Cashmere shawls.
(When it cropped up in isolated forms, as in Venice in the fifteenth century,
it appears not to have exerted any influence; its introduction is perhaps rather
to be attributed to calico-printing.) Soon afterward the European shawl-
manufacture, which is still in a flourishing state, was introduced. Falcot
informs us that designs of a celebrated French artist, Couder, for shawl-
patterns, a subject that he studied in India itself, were exported back to that
country and used there (Fig. 20).

In these shawl-patterns the original simple form meets us in a highly
developed, magnificent, and splendidly colored differentiation and
elaboration. This we can have no scruples in ranking along with the
mediæval plane-patterns, which we have referred to above, among the
highest achievements of decorative art.

FIG. 19.

It is evident that it, at any rate in this high stage of development, resisted
fusion with Western forms of art. It is all the more incumbent upon us to
investigate the laws of its existence, in order to make it less alien to us, or
perhaps to assimilate it to ourselves by attaining to an understanding of those
laws. A great step has been made when criticism has, by a more painstaking
study, put itself into a position to characterize as worthless ignorantly
imitated, or even original, miscreations such as are eternally cropping up. If
we look at our modern manufactures immediately after studying patterns
which enchant us with their classical repose, or after it such others as
captivate the eye by their beautiful coloring, or the elaborative working out
of their details, we recognize that the beautifully balanced form is often cut
up, choked over with others, or mangled (the flower springing up side down
from the leaves), the whole being traversed at random by spirals, which are
utterly foreign to the spirit of such a style, and all this at the caprice of
uncultured, boorish designers. Once we see that the original of the form was
a plant, we shall ever in the developed, artistic form cling, in a general way

at least, to the laws of its organization, and we shall at any rate be in a
position to avoid violent incongruities.

FIG. 20.

I had resort, a few years ago, to the young botanist Ruhmer, assistant at the
Botanical Museum at Schöneberg, who has unfortunately since died of some
chest-disease, in order to get some sort of a groundwork for direct
investigations. I asked him to look up the literature of the subject, with
respect to the employment of the Indian Araceæ for domestic uses or in
medicine. A detailed work on the subject was produced, and establishes that,
quite irrespective of species of Alocasia and Colocasia that have been
referred to, a large number of Araceæ were employed for all sorts of
domestic purposes. Scindapsus, which was used as a medicine, has actually
retained a Sanskrit name, "vustiva." I cannot here go further into the details
of this investigation, but must remark that even the incomplete and imperfect
drawings of these plants, which, owing to the difficulty of preserving them,
are so difficult to collect through travelers, exhibit such a wealth of shape,
that it is quite natural that Indian and Persian flower-loving artists should be

quite taken with them, and employ them enthusiastically in decorative art.
Let me also mention that Haeckel, in his '"Letters of an Indian Traveler,"
very often bears witness to the effect of the Araceæ upon the general
appearance of the vegetation, both in the full and enormous development of
species of Caladia and in the species of Pothos which form such
impenetrable mazes of interlooping stems.

In conclusion, allow me to remark that the results of my investigation, of
which but a succinct account has been given here, negative certain
derivations, which have been believed in, though they have never been
proved; such as that of the form I have last discussed from the Assyrian
palmetta, or from a cypress bent down by the wind. To say the least the laws
of formation here laid down have a more intimate connection with the forms
as they have come down to us, and give us a better handle for future use and
development. The object of the investigation was, in general words, to
prepare for an explanation of the questions raised; and even if the results had
turned out other than they have, it would have sufficed me to have given an
impulse to labors which will testify to the truth of the dead master's words:
"Was Du ererbt von deinen Vätern hast,
Erwirb es, um es zu besitzen."

[1]
From a paper by Prof. Jacobsthal in the Transactions of the
Archæological Society of Berlin.—Nature

STEPS TOWARD A KINETIC THEORY OF
MATTER.1
By Sir WILLIAM THOMSON.

The now well known kinetic theory of gases is a step so important in the
way of explaining seemingly static properties of matter by motion, that it is
scarcely possible to help anticipating in idea the arrival at a complete theory
of matter, in which all its properties will be seen to be merely attributes of
motion. If we are to look for the origin of this idea we must go back to
Democritus, Epicurus, and Lucretius. We may then, I believe, without
missing a single step, skip 1800 years. Early last century we find in
Malebranche's "Recherche de la Verite," the statement that "la durete de
corps" depends on "petits tourbillons."2 These words, embedded in a
hopeless mass of unintelligible statements of the physical, metaphysical, and
theological philosophies of the day, and unsupported by any explanation,
elucidation, or illustration throughout the rest of the three volumes, and only
marred by any other single sentence or word to be found in the great book,
still do express a distinct conception which forms a most remarkable step
toward the kinetic theory of matter. A little later we have Daniel Bernoulli's
promulgation of what we now accept as a surest article of scientific faith—
the kinetic theory of gases. He, so far as I know, thought only of Boyle's and
Mariotte's law of the "spring of air," as Boyle called it, without reference to
change of temperature or the augmentation of its pressure if not allowed to
expand for elevation of temperature, a phenomenon which perhaps he
scarcely knew, still less the elevation of temperature produced by
compression, and the lowering of temperature by dilatation, and the
consequent necessity of waiting for a fraction of a second or a few seconds
of time (with apparatus of ordinary experimental magnitude), to see a
subsidence from a larger change of pressure down to the amount of change
that verifies Boyle's law. The consideration of these phenomena forty years
ago by Joule, in connection with Bernoulli's original conception, formed the
foundation of the kinetic theory of gases as we now have it. But what a
splendid and useful building has been placed on this foundation by Clausius

and Maxwell, and what a beautiful ornament we see on the top of it in the
radiometer of Crookes, securely attached to it by the happy discovery of Tait
and Dewar,3 that the length of the free path of the residual molecules of air
in a good modern vacuum may amount to several inches! Clausius' and
Maxwell's explanations of the diffusion of gases, and of thermal conduction
in gases, their charmingly intelligible conclusion that in gases the diffusion
of heat is just a little more rapid than the diffusion of molecules, because of
the interchange of energy in collisions between molecules,4 while the chief
transference of heat is by actual transport of the molecules themselves, and
Maxwell's explanation of the viscosity of gases, with the absolute numerical
relations which the work of those two great discoverers found among the
three properties of diffusion, thermal conduction, and viscosity, have
annexed to the domain of science a vast and ever growing province.

Rich as it is in practical results, the kinetic theory of gases, as hitherto
developed, stops absolutely short at the atom or molecule, and gives not
even a suggestion toward explaining the properties in virtue of which the
atoms or molecules mutually influence one another. For some guidance
toward a deeper and more comprehensive theory of matter, we may look
back with advantage to the end of last century and beginning of this century,
and find Rumford's conclusion regarding the heat generated in boring a brass
gun: "It appears to me to be extremely difficult, if not quite impossible, to
form any distinct idea of anything capable of being excited and
communicated in the manner the heat was excited and communicated in
these experiments, except it be MOTION;" and Davy's still more suggestive
statements: "The phenomena of repulsion are not dependent on a peculiar
elastic fluid for their existence." ... "Heat may be defined as a peculiar
motion, probably a vibration, of the corpuscles of bodies, tending to separate
them." ... "To distinguish this motion from others, and to signify the causes
of our sensations of heat, etc., the name repulsive motion has been adopted."
Here we have a most important idea. It would be somewhat a bold figure of
speech to say the earth and moon are kept apart by a repulsive motion; and
yet, after all, what is centrifugal force but a repulsive motion, and may it not
be that there is no such thing as repulsion, and that it is solely by inertia that
what seems to be repulsion is produced? Two bodies fly together, and,
accelerated by mutual attraction, if they do not precisely hit one another,
they cannot but separate in virtue of the inertia of their masses. So, after

dashing past one another in sharply concave curves round their common
center of gravity, they fly asunder again. A careless onlooker might imagine
they had repelled one another, and might not notice the difference between
what he actually sees and what he would see if the two bodies had been
projected with great velocity toward one another, and either colliding and
rebounding, or repelling one another into sharply convex continuous curves,
fly asunder again.

Joule, Clausius, and Maxwell, and no doubt Daniel Bernoulli himself, and I
believe every one who has hitherto written or done anything very explicit in
the kinetic theory of gases, has taken the mutual action of molecules in
collision as repulsive. May it not after all be attractive? This idea has never
left my mind since I first read Davy's "Repulsive Motion," about thirty-five
years ago, and I never made anything of it, at all events have not done so
until to-day (June 16, 1884)—if this can be said to be making anything of it
—when, in endeavoring to prepare the present address, I notice that Joule's
and my own old experiments5 on the thermal effect of gases expanding from
a high-pressure vessel through a porous plug, proves the less dense gas to
have greater intrinsic potential energy than the denser gas, if we assume the
ordinary hypothesis regarding the temperature of a gas, according to which
two gases are of equal temperatures6 when the kinetic energies of their
constituent molecules are of equal average amounts per molecule.

Think of the thing thus. Imagine a great multitude of particles inclosed by a
boundary which may be pushed inward in any part all round at pleasure.
Now station an engineer corps of Maxwell's army of sorting demons all
round the inclosure, with orders to push in the boundary diligently
everywhere, when none of the besieged troops are near, and to do nothing
when any of them are seen approaching, and until after they have turned
again inward. The result will be that, with exactly the same sum of kinetic
and potential energies of the same inclosed multitude of particles, the throng
has been caused to be denser. Now Joule's and my own old experiments on
the efflux of air prove that if the crowd be common air, or oxygen, or
nitrogen, or carbonic acid, the temperature is a little higher in the denser than
in the rarer condition when the energies are the same. By the hypothesis,
equality of temperature between two different gases or two portions of the
same gas at different densities means equality of kinetic energies in the same
number of molecules of the two. From our observations proving the

temperature to be higher, it therefore follows that the potential energy is
smaller in the condensed crowd. This—always, however, under protest as to
the temperature hypothesis—proves some degree of attraction among the
molecules, but it does not prove ultimate attraction between two molecules
in collision, or at distances much less than the average mutual distance of
nearest neighbors in the multitude. The collisional force might be repulsive,
as generally supposed hitherto, and yet attraction might predominate in the
whole reckoning of difference between the intrinsic potential energies of the
more dense and less dense multitudes.

It is however remarkable that the explanation of the propagation of sound
through gases, and even of the positive fluid pressure of a gas against the
sides of the containing vessel, according to the kinetic theory of gases, is
quite independent of the question whether the ultimate collisional force is
attractive or repulsive. Of course it must be understood that, if it is attractive,
the particles must, be so small that they hardly ever meet—they would have
to be infinitely small to never meet—that, in fact, they meet so seldom, in
comparison with the number of times their courses—are turned through
large angles by attraction, that the influence of these surely attractive
collisions is preponderant over that of the comparatively very rare impacts
from actual contact. Thus, after all, the train of speculation suggested by
Davy's "Repulsive Motion" does not allow us to escape from the idea of true
repulsion, does not do more than let us say it is of no consequence, nor even
say this with truth, because, if there are impacts at all, the nature of the force
during the impact and the effects of the mutual impacts, however rare,
cannot be evaded in any attempt to realize a conception of the kinetic theory
of gases. And in fact, unless we are satisfied to imagine the atoms of a gas as
mathematical points endowed with inertia, and as, according to Boscovich,
endowed with forces of mutual, positive, and negative attraction, varying
according to some definite function of the distance, we cannot avoid the
question of impacts, and of vibrations and rotations of the molecules
resulting from impacts, and we must look distinctly on each molecule as
being either a little elastic solid or a configuration of motion in a continuous
all-pervading liquid. I do not myself see how we can ever permanently rest
anywhere short of this last view; but it would be a very pleasant temporary
resting-place on the way to it if we could, as it were, make a mechanical
model of a gas out of little pieces of round, perfectly elastic solid matter,

flying about through the space occupied by the gas, and colliding with one
another and against the sides of the containing vessel.

This is, in fact, all we have of the kinetic theory of gases up to the present
time, and this has done for us, in the hands of Clausius and Maxwell, the
great things which constitute our first step toward a molecular theory of
matter. Of course from it we should have to go on to find an explanation of
the elasticity and all the other properties of the molecules themselves, a
subject vastly more complex and difficult than the gaseous properties, for the
explanation of which we assume the elastic molecule; but without any
explanation of the properties of the molecule itself, with merely the
assumption that the molecule has the requisite properties, we might rest
happy for a while in the contemplation of the kinetic theory of gases, and its
explanation of the gaseous properties, which is not only stupendously
important as a step toward a more thoroughgoing theory of matter, but is
undoubtedly the expression of a perfectly intelligible and definite set of facts
in Nature.

But alas for our mechanical model consisting of the cloud of little elastic
solids flying about among one another. Though each particle have absolutely
perfect elasticity, the end must be pretty much the same as if it were but
imperfectly elastic. The average effect of repeated and repeated mutual
collisions must be to gradually convert all the translational energy into
energy of shriller and shriller vibrations of the molecule. It seems certain
that each collision must have something more of energy in vibrations of very
finely divided nodal parts than there was of energy in such vibrations before
the impact. The more minute this nodal subdivision, the less must be the
tendency to give up part of the vibrational energy into the shape of
translational energy in the course of a collision; and I think it is rigorously
demonstrable that the whole translational energy must ultimately become
transformed into vibrational energy of higher and higher nodal subdivisions
if each molecule is a continuous elastic solid. Let us, then, leave the kinetic
theory of gases for a time with this difficulty unsolved, in the hope that we
or others after us may return to it, armed with more knowledge of the
properties of matter, and with sharper mathematical weapons to cut through
the barrier which at present hides from us any view of the molecule itself,
and of the effects other than mere change of translational motion which it
experiences in collision.

To explain the elasticity of a gas was the primary object of the kinetic theory
of gases. This object is only attainable by the assumption of an elasticity
more complex in character, and more difficult of explanation, than the
elasticity of gases—the elasticity of a solid. Thus, even if the fatal fault in
the theory, to which I have alluded, did not exist, and if we could be
perfectly satisfied with the kinetic theory of gases founded on the collisions
of elastic solid molecules, there would still be beyond it a grander theory
which need not be considered a chimerical object of scientific ambition—to
explain the elasticity of solids. But we may be stopped when we commence
to look in the direction of such a theory with the cynical question, What do
you mean by explaining a property of matter? As to being stopped by any
such question, all I can say is that if engineering were to be all and to end all
physical science, we should perforce be content with merely finding
properties of matter by observation, and using them for practical purposes.
But I am sure very few, if any, engineers are practically satisfied with so
narrow a view of their noble profession. They must and do patiently observe,
and discover by observation, properties of matter and results of material
combinations. But deeper questions are always present, and always fraught
with interest to the true engineer, and he will be the last to give weight to any
other objection to any attempt to see below the surface of things than the
practical question, Is it likely to prove wholly futile? But now, instead of
imagining the question, What do you mean by explaining a property of
matter? to be put cynically, and letting ourselves be irritated by it, suppose
we give to the questioner credit for being sympathetic, and condescend to try
and answer his question. We find it not very easy to do so. All the properties
of matter are so connected that we can scarcely imagine one thoroughly
explained without our seeing its relation to all the others, without in fact
having the explanation of all; and till we have this we cannot tell what we
mean by "explaining a property" or "explaining the properties" of matter.
But though this consummation may never be reached by man, the progress
of science may be, I believe will be, step by step toward it, on many different
roads converging toward it from all sides. The kinetic theory of gases is, as I
have said, a true step on one of the roads. On the very distinct road of
chemical science, St. Claire Deville arrived at his grand theory of
dissociation without the slightest aid from the kinetic theory of gases. The
fact that he worked it out solely from chemical observation and experiment,
and expounded it to the world without any hypothesis whatever, and
seemingly even without consciousness of the beautiful explanation it has in

the kinetic theory of gases, secured for it immediately an independent
solidity and importance as a chemical theory when he first promulgated it, to
which it might even by this time scarcely have attained if it had first been
suggested as a probability indicated by the kinetic theory of gases, and been
only afterward confirmed by observation. Now, however, guided by the
views which Clausius and Williamson have given us of the continuous
interchange of partners between the compound molecules constituting
chemical compounds in the gaseous state, we see in Deville's theory of
dissociation a point of contact of the most transcendent interest between the
chemical and physical lines of scientific progress.

To return to elasticity: if we could make out of matter devoid of elasticity a
combined system of relatively moving parts which, in virtue of motion, has
the essential characteristics of an elastic body, this would surely be, if not
positively a step in the kinetic theory of matter, at least a fingerpost pointing
a way which we may hope will lead to a kinetic theory of matter. Now this,
as I have already shown,7 we can do in several ways. In the case of the last
of the communications referred to, of which only the title has hitherto been
published, I showed that, from the mathematical investigation of a
gyrostatically dominated combination contained in the passage of Thomson
and Tait's "Natural Philosophy" referred to, it follows that any ideal system
of material particles, acting on one another mutually through massless
connecting springs, may be perfectly imitated in a model consisting of rigid
links jointed together, and having rapidly rotating fly wheels pivoted on
some or on all of the links. The imitation is not confined to cases of
equilibrium. It holds also for vibration produced by disturbing the system
infinitesimally from a position of stable equilibrium and leaving it to itself.
Thus we may make a gyrostatic system such that it is in equilibrium under
the influence of certain positive forces applied to different points of this
system; all the forces being precisely the same as, and the points of
application similarly situated to, those of the stable system with springs.
Then, provided proper masses (that is to say, proper amounts and
distributions of inertia) be attributed to the links, we may remove the
external forces from each system, and the consequent vibration of the points
of application of the forces will be identical. Or we may act upon the
systems of material points and springs with any given forces for any given
time, and leave it to itself, and do the same thing for the gyrostatic system;
the consequent motion will be the same in the two cases. If in the one case

the springs are made more and more stiff, and in the other case the angular
velocities of the fly wheels are made greater and greater, the periods of the
vibrational constituents of the motion will become shorter and shorter, and
the amplitudes smaller and smaller, and the motions will approach more and
more nearly those of two perfectly rigid groups of material points moving
through space and rotating according to the well known mode of rotation of
a rigid body having unequal moments of inertia about its three principal
axes. In one case the ideal nearly rigid connection between the particles is
produced by massless, exceedingly stiff springs; in the other case it is
produced by the exceedingly rapid rotation of the fly wheels in a system
which, when the fly wheels are deprived of their rotation, is perfectly limp.

The drawings (Figs. 1 and 2) before you illustrate two such material
systems.8 The directions of rotation of the fly-wheels in the gyrostatic
system (Fig. 2) are indicated by directional ellipses, which show in
perspective the direction of rotation of the fly-wheel of each gyrostat. The
gyrostatic system (Fig. 2) might have been constituted of two gyrostatic
members, but four are shown for symmetry. The inclosing circle represents
in each case in section an inclosing spherical shell to prevent the interior
from being seen. In the inside of one there are fly-wheels, in the inside of the
other a massless spring. The projecting hooked rods seem as if they are
connected by a spring in each case. If we hang any one of the systems up by
the hook on one of its projecting rods, and hang a weight to the hook of the
other projecting rod, the weight, when first put on, will oscillate up and
down, and will go on doing so for ever if the system be absolutely
unfrictional. If we check the vibration by hand, the weight will hang down at
rest, the pin drawn out to a certain degree; and the distance drawn out will be
simply proportional to the weight hung on, as in an ordinary spring balance.

FIG. 1

FIG. 2

Here, then, out of matter possessing rigidity, but absolutely devoid of
elasticity, we have made a perfect model of a spring in the form of a spring
balance. Connect millions of millions of particles by pairs of rods such as
these of this spring balance, and we have a group of particles constituting an
elastic solid; exactly fulfilling the mathematical ideal worked out by Navier,
Poisson, and Cauchy, and many other mathematicians, who, following their
example, have endeavored to found a theory of the elasticity of solids on
mutual attraction and repulsion between a group of material particles. All
that can possibly be done by this theory, with its assumption of forces acting
according to any assumed law of relation to distance, is done by the
gyrostatic system. But the gyrostatic system does, besides, what the system
of naturally acting material particles cannot do—it constitutes an elastic
solid which can have the Faraday magneto-optic rotation of the plane of
polarization of light; supposing the application of our solid to be a model of
the luminiferous ether for illustrating the undulatory theory of light. The
gyrostatic model spring balance is arranged to have zero moment of
momentum as a whole, and therefore to contribute nothing to the Faraday
rotation; with this arrangement the model illustrates the luminiferous ether in
a field unaffected by magnetic force. But now let there be a different
rotational velocity imparted to the jointed square round the axis of the two
projecting hooked rods, such as to give a resultant moment of momentum
round any given line through the center of inertia of the system; and let pairs
of the hooked rods in the model thus altered, which is no longer a model of a
mere spring balance, be applied as connections between millions of pairs of
particles as before, with the lines of resultant moment of momentum all
similarly directed. We now have a model elastic solid which will have the
property that the direction of vibration in waves of rectilinear vibrations
propagated through it shall turn round the line of propagation of the waves,
just as Faraday's observation proves to be done by the line of vibration of
light in a dense medium between the poles of a powerful magnet. The case
of wave front perpendicular to the lines of resultant moment of momentum
(that is to say, the direction of propagation being parallel to these lines)
corresponds, in our mechanical model, to the case of light traveling in the
direction of the lines of force in a magnetic field.

In these illustrations and models we have different portions of ideal rigid
matter acting upon one another, by normal pressure at mathematical points
of contact—of course no forces of friction are supposed. It is exceedingly
interesting to see how thus, with no other postulates than inertia, rigidity, and
mutual impenetrability, we can thoroughly model not only an elastic solid,
and any combination of elastic solids, but so complex and recondite a
phenomenon as the passage of polarized light through a magnetic field. But
now, with the view of ultimately discarding the postulate of rigidity from all
our materials, let us suppose some to be absolutely destitute of rigidity, and
to possess merely inertia and incompressibility, and mutual impenetrability
with reference to the still remaining rigid matter. With these postulates we
can produce a perfect model of mutual action at a distance between solid
particles, fulfilling the condition, so keenly desired by Newton and Faraday,
of being explained by continuous action through an intervening medium.
The law of the mutual force in our model, however, is not the simple
Newtonian law, but the much more complex law of the mutual action
between electro magnets—with this difference, that in the hydro-kinetic
model in every case the force is opposite in direction to the corresponding
force in the electro-magnetic analogue. Imagine a solid bored through with a
hole, and placed in our ideal perfect liquid. For a moment let the hole be
stopped by a diaphragm, and let an impulsure pressure be applied for an
instant uniformly over the whole membrane, and then instantly let the
membrane be dissolved into liquid. This action originates a motion of the
liquid relatively to the solid, of a kind to which I have given the name of
"irrotational circulation," which remains absolutely constant however the
solid be moved through the liquid. Thus, at any time the actual motion of the
liquid at any point in the neighborhood of the solid will be the resultant of
the motion it would have in virtue of the circulation alone, were the solid at
rest, and the motion it would have in virtue of the motion of the solid itself,
had there been no circulation established through the aperture. It is
interesting and important to remark in passing that the whole kinetic energy
of the liquid is the sum of the kinetic energies which it would have in the
two cases separately. Now, imagine the whole liquid to be inclosed in an
infinitely large, rigid, containing vessel, and in the liquid, at an infinite
distance from any part of the containing vessel, let two perforated solids,
with irrotational circulation through each, be placed at rest near one another.
The resultant fluid motion due to the two circulations, will give rise to fluid
pressure on the two bodies, which, if unbalanced, will cause them to move.

The force systems—force-and-torques, or pairs of forces—required to
prevent them from moving will be mutual and opposite, and will be the same
as, but opposite in direction to, the mutual force systems required to hold at
rest two electromagnets fulfilling the following specification: The two
electro magnets are to be of the same shape and size as the two bodies, and
to be placed in the same relative positions, and to consist of infinitely thin
layers of electric currents in the surfaces of solids possessing extreme
diamagnetic quality—in other words, infinitely small permeability. The
distribution of electric current on each body may be any whatever which
fulfills the condition that the total current across any closed line drawn on
the surface once through the aperture is equal to ¼ π of the circulation9
through the aperture in the hydro-kinetic analogue.

It might be imagined that the action at a distance thus provided for by fluid
motion could serve as a foundation for a theory of the equilibrium, and the
vibrations, of elastic solids, and the transmission of waves like those of light
through an extended quasi-elastic solid medium. But unfortunately for this
idea the equilibrium is essentially unstable, both in the case of magnets and,
notwithstanding the fact that the forces are oppositely directed, in the hydro-
kinetic analogue also, when the several movable bodies (two or any greater
number) are so placed relatively as to be in equilibrium. If, however, we
connect the perforated bodies with circulation through them in the hydro-
kinetic system, by jointed rigid connecting links, we may arrange for
configurations of stable equilibrium. Thus, without fly-wheels, but with fluid
circulations through apertures, we may make a model spring balance or a
model luminiferous ether, either without or with the rotational quality
corresponding to that of the true luminiferous ether in the magnetic fluid—in
short, do all by the perforated solids with circulations through them that we
saw we could do by means of linked gyrostats. But something that we cannot
do by linked gyrostats we can do by the perforated bodies with fluid
circulation: we can make a model gas. The mutual action at a distance,
repulsive or attractive according to the mutual aspect of the two bodies when
passing within collisional distance10 of one another, suffices to produce the
change of direction of motion in collision, which essentially constitutes the
foundation of the kinetic theory of gases, and which, as we have seen before,
may as well be due to attraction as to repulsion, so far as we know from any
investigation hitherto made in this theory.

There remains, however, as we have seen before, the difficulty of providing
for the case of actual impacts between the solids, which must be done by
giving them massless spring buffers or, which amounts to the same thing,
attributing to them repulsive forces sufficiently powerful at very short
distances to absolutely prevent impacts between solid and solid; unless we
adopt the equally repugnant idea of infinitely small perforated solids, with
infinitely great fluid circulations through them. Were it not for this
fundamental difficulty, the hydro-kinetic model gas would be exceedingly
interesting; and, though we could scarcely adopt it as conceivably a true
representation of what gases really are, it might still have some importance
as a model configuration of solid and liquid matter, by which without
elasticity the elasticity of true gas might be represented.

But lastly, since the hydro-kinetic model gas with perforated solids and fluid
circulations through them fails because of the impacts between the solids, let
us annul the solids and leave the liquid performing irrotational circulation
round vacancy,11 in the place of the solid cores which we have hitherto
supposed; or let us annul the rigidity of the solid cores of the rings, and give
them molecular rotation according to Helmholtz's theory of vortex motion.
For stability the molecular rotation must be such as to give the same velocity
at the boundary of the rotational fluid core as that of the irrotationally
circulating liquid in contact with it, because, as I have proved, frictional slip
between two portions of liquid in contact is inconsistent with stability. There
is a further condition, upon which I cannot enter into detail just now, but
which may be understood in a general way when I say that it is a condition
of either uniform or of increasing molecular rotation from the surface
inward, analogous to the condition that the density of a liquid, resting for
example under the influence of gravity, must either be uniform or must be
greater below than above for stability of equilibrium. All that I have said in
favor of the model vortex gas composed of perforated solids with fluid
circulations through them holds without modification for the purely hydro-
kinetic model, composed of either Helmholtz cored vortex rings or of
coreless vortices, and we are now troubled with no such difficulty as that of
the impacts between solids. Whether, however, when the vortex theory of
gases is thoroughly worked out, it will or will not be found to fail in a
manner analogous to the failure which I have already pointed out in
connection with the kinetic theory of gases composed of little elastic solid
molecules, I cannot at present undertake to speak with certainty. It seems to

me most probable that the vortex theory cannot fail in any such way, because
all I have been able to find out hitherto regarding the vibration of vortices,12
whether cored or coreless, does not seem to imply the liability of
translational or impulsive energies of the individual vortices becoming lost
in energy of smaller and smaller vibrations.

As a step toward kinetic theory of matter, it is certainly most interesting to
remark that in the quasi-elasticity, elasticity looking like that of an India-
rubber band, which we see in a vibrating smoke-ring launched from an
elliptic aperture, or in two smoke-rings which were circular, but which have
become deformed from circularity by mutual collision, we have in reality a
virtual elasticity in matter devoid of elasticity, and even devoid of rigidity,
the virtual elasticity being due to motion, and generated by the generation of
motion.

[1]
Meeting of the British Association, Montreal. 1884. Section A.
Mathematical and Physical science. Opening Address by Prof. Sir
William Thomson, M.A., LL.D., D.C.L., F.R.SS.L. and E.,
F.R.A.S., President of the Section.

[2]
"Preuve de la supposition que j'ay faite: Que la matiere subtile ou
etheree est necessairement composee de PETITS
TOURBILLONS; et qu'ils sont les causes naturelles de tous les
changements qui arrivent a la matiere; ce que je confirme par
i'explication des effets les plus generaux de la Physique, tels que
sont la durete des corps, leur fluidite, leur pesanteur, legerete, la
lumiere et la refraction et reflexion de ses rayons."—
Malebranche, "Recherche de la Verite," 1712.

[3]
Proc. R.S.E., March 2, 1874, and July 5, 1875.

[4]
On the other hand, in liquids, on account of the crowdedness of
the molecules, the diffusion of heat must be chiefly by
interchange of energies between the molecules, and should be, as
experiment proves it is, enormously more rapid than the diffusion
of the molecules themselves, and this again ought to be much less
rapid than either the material or thermal diffusivities of gases.
Thus the diffusivity of common salt through water was found by
Fick to be as small as 0.0000112 square centimeter per second;
nearly 200 times as great as this is the diffusivity of heat through
water, which was found by J.T. Bottomley to be about 0.002
square centimeter per second. The material diffusivities of gases,
according to Loschmidt's experiments, range from 0.98 (the
interdiffusivity of carbonic acid and nitrous oxide) to 0.642 (the
interdiffusivity of carbonic oxide and hydrogen), while the
thermal diffusivities of gases, calculated according to Clausius'
and Maxwell's kinetic theory of gases, are 0.089 for carbonic
acid, 0.16 for common air of other gases of nearly the same

density, and 1.12 for hydrogen (all, both material and thermal,
being reckoned in square centimeters per second).

[5]
Republished in Sir W. Thomson's "Mathematical and Physical
Papers," vol. i., article xlix., p. 381.

[6]
That this is a mere hypothesis has been scarcely remarked by the
founders themselves, nor by almost any writer on the kinetic
theory of gases. No one has yet examined the question, What is
the condition as regards average distribution of kinetic energy,
which is ultimately fulfilled by two portions of gaseous matter,
separated by a thin elastic septum which absolutely prevents
interdiffusion of matter, while it allows interchange of kinetic
energy by collisions against itself? Indeed, I do not know but, that
the present is the very first statement which has ever been
published of this condition of the problem of equal temperatures
between two gaseous masses.

[7]
Paper on "Vortex Atoms," Proc. R.S.E. February. 1867: abstract
of a lecture before the Royal Institution of Great Britain, March 4,
1881, on "Elasticity Viewed as possibly a Mode of Motion";
Thomson and Tait's "Natural Philosophy," second edition, part 1,
§§ 345 viii. to 345 xxxvii.; "On Oscillation and Waves in an
Adynamic Gyrostatic System" (title only), Proc. R.S.E. March,
1883.

[8]
In Fig. 1 the two hooked rods seen projecting from the sphere are
connected by an elastic coach-spring. In Fig. 2 the hooked rods
are connected one to each of two opposite corners of a four-sided
jointed frame, each member of which carries a gyrostat so that the
axis of rotation of the fly-wheel is in the axis of the member of
the frame which bears it. Each of the hooked rods in Fig. 2 is
connected to the framework through a swivel joint, so that the
whole gyrostatic framework may be rotated about the axis of the

hooked rods in order to annul the moment of momentum of the
framework about this axis due to rotation of the fly-wheels in the
gyrostat.

[9]
The integral of tangential component velocity all round any
closed curve, passing once through the aperture, is defined as the
"cyclic-constant" or the "circulation" ("Vortex Motion," § 60 (a),
Trans. R.S.E., April 29, 1867). It has the same value for all closed
curves passing just once through the aperture, and it remains
constant through all time, whether the solid body be in motion or
at rest.

[10]
According to this view, there is no precise distance, or definite
condition respecting the distance, between two molecules, at
which apparently they come to be in collision, or when receding
from one another they cease to be in collision. It is convenient,
however, in the kinetic theory of gases, to adopt arbitrarily a
precise definition of collision, according to which two bodies or
particles mutually acting at a distance may be said to be in
collision when their mutual action exceeds some definite
arbitrarily assigned limit, as, for example, when the radius of
curvature of the path of either body is less than a stated fraction
(one one-hundredth, for instance) of the distance between them.

[11]
Investigations respecting coreless vortices will be found in a
paper by the author, "Vibrations of a Columnar Vortex," Proc.
R.S.E., March 1, 1880; and a paper by Hicks, recently read before
the Royal Society.

[12]
See papers by the author "On Vortex Motion." Trans. R.S.E.
April, 1867, and "Vortex Statics," Proc. R.S.E. December, 1875;
also a paper by J.J. Thomson, B.A., "On the Vibrations of a
Vortex Ring," Trans. R.S. December, 1881, and his valuable book
on "Vortex Motion."

APPLICATION OF ELECTRICITY TO
TRAMWAYS.
By M. HOLROYD SMITH.

Last year, when I had the pleasure of reading a paper before you on my new
system of electric tramways, I ventured to express the hope that before
twelve months had passed, "to be able to report progress," and I am happy
to say that notwithstanding the wearisome delay and time lost in fruitless
negotiations, and the hundred and one difficulties within and without that
have beset me, I am able to appear before you again and tell you of
advance.

FIG. 1

Practical men know well that there is a wide difference between a model
and a full sized machine; and when I decided to construct a full sized
tramcar and lay out a full sized track, I found it necessary to make many
alterations of detail, my chief difficulty being so to design my work as to
facilitate construction and allow of compensation for that inaccuracy of
workmanship which I have come to regard as inevitable.

In order to satisfy the directors of a tramway company of the practical
nature of my system before disturbing their lines, I have laid, in a field near
the works of Messrs. Smith, Baker & Co., Manchester, a track 110 yards
long, 4 ft. 8½ in. gauge, and I have constructed a full sized street tramcar to
run thereon. My negotiations being with a company in a town where there
are no steep gradients, and where the coefficient of friction of ordinary
wheels would be sufficient for all tractive purposes, I thought it better to
avoid the complication involved in employing a large central wheel with a
broad surface specially designed for hilly districts, and with which I had
mounted a gradient of one in sixteen.

FIG. 2

But as the line in question was laid with all the curves unnecessarily quick,
even those in the "pass-bies," I thought it expedient to employ differential
gear, as illustrated at D, Fig. 1, which is a sketch plan showing the
mechanism employed. M is a Siemens electric motor running at 650
revolutions per minute; E is a combination of box gearing, frictional clutch,
and chain pinion, and from this pinion a steel chain passes around the
chain-wheel, H, which is free to revolve upon the axle, and carries within it
the differential pinion, gearing with the bevel-wheel, B², keyed upon the
sleeve of the loose tram-wheel, T², and with the bevel-wheel, B¹, keyed
upon the axle, to which the other tram-wheel, T¹, is attached. To the other

tram-wheels no gear is connected; one of them is fast to the axle, and the
other runs loose, but to them the brake is applied in the usual manner.

The electric current from the collector passes, by means of a copper wire,
and a switch upon the dashboard of the car, and resistance coils placed
under the seats, to the motor, and from the motor by means of an adjustable
clip (illustrated in diagram, Fig. 2) to the axles, and by them through the
four wheels to the rails, which form the return circuit.

FIG. 3

I have designed many modifications of the track, but it is, perhaps, best at
present to describe only that which I have in actual use, and it is illustrated
in diagram, Fig. 3, which is a sectional and perspective view of the central
channel. L is the surface of the road, and SS are the sleepers, CC are the
chairs which hold the angle iron, AA forming the longitudinally slotted
center rail and the electric lead, which consists of two half-tubes of copper
insulated from the chairs by the blocks, I, I. A special brass clamp, free to
slide upon the tube, is employed for this purpose, and the same form of
clamp serves to join the two ends of the copper tubes together and to make

electric contact. Two half-tubes instead of one slotted tube have been
employed, in order to leave a free passage for dirt or wet to fall through the
slot in the center rail to the drain space, G. Between chair and chair hewn
granite or artificial stone is employed, formed, as shown in the drawing, to
complete the surface of the road and to form a continuous channel or drain.
In order that this drain may not become choked, at suitable intervals, in the
length of the track, sump holes are formed as illustrated in diagram, Fig. 4
These sump holes have a well for the accumulation of mud, and are also
connected with the main street drain, so that water can freely pass away.
The hand holes afford facility for easily removing the dirt.

In a complete track these hand holes would occasionally be wider than
shown here, for the purpose of removing or fixing the collector, Fig. 5,
which consists of two sets of spirally fluted rollers free to revolve upon
spindles, which are held by knuckle-joints drawn together by spiral springs;
by this means the pressure of the rollers against the inside of the tube is
constantly maintained, and should any obstruction occur in the tube the
spiral flute causes it to revolve, thus automatically cleansing the tubes.

FIG. 4

The collector is provided with two steel plates, which pass through the slit
in the center rail; the lower ends of these plates are clamped by the upper
frame of the collector, insulating material being interposed, and the upper
ends are held in two iron cheeks. Between these steel plates insulated

copper strips are held, electrically connected with the collector and with the
adjustable clip mounted upon the iron cheeks; this clip holds the terminal
on the end of the wire (leading to the motor) firmly enough for use, the
cheeks being also provided with studs for the attachment of leather straps
hooked on to the framework of the car, one for the forward and one for
backward movement of the collector. These straps are strong enough for the
ordinary haulage of the collector, and for the removal of pebbles and dirt
that may get into the slit; but should any absolute block occur then they
break and the terminal is withdrawn from the clip; the electric contact being
thereby broken the car stops, the obstruction can then be removed and the
collector reconnected without damage and with little delay.

FIG. 5

In order to secure continuity of the center rail throughout the length of the
track, and still provide for the removal of the collector at frequent intervals,
the framework of the collector is so made that, by slackening the side-bolts,
the steel plates can be drawn upward and the collector itself withdrawn
sideways through the hand holes, one of the half-tubes being removed for
the purpose.

Fig. 6 illustrates another arrangement that I have constructed, both of
collector and method of collecting.

FIG. 6

As before mentioned, the arrangement now described has been carried out
in a field near the works of Messrs. Smith, Baker & Co., Cornbrook
Telegraph Works, Manchester, and its working efficiency has been most
satisfactory. After a week of rain and during drenching showers the car ran
with the same speed and under the same control as when the ground was
dry.

This I account for by the theory that when the rails are wet and the tubes
moist the better contact made compensates for the slight leakage that may
occur.

At the commencement of my paper I promised to confine myself to work
done; I therefore abstain from describing various modifications of detail for
the same purpose. But one method of supporting and insulating the
conductor in the channel may be suggested by an illustration of the plan I
adopted for a little pleasure line in the Winter Gardens, Blackpool.

FIG. 7.

Fig. 7. There the track being exclusively for the electric railway, it was not
necessary to provide a center channel; the conductor has therefore been
placed in the center of the track, and consists of bar iron 1¼ in. by ½ in.,
and is held vertically by means of studs riveted into the side; these studs
pass through porcelain insulators, and by means of wooden clamps and
wedges are held in the iron chairs which rest upon the sleepers. The iron
conductors were placed vertically to facilitate bending round the sharp
curves which were unavoidable on this line.

The collector consists of two metal slippers held together by springs,
attached to the car by straps and electrically connected to the motor by clips
in the same manner as the one employed in Manchester.

I am glad to say that, notwithstanding the curves with a radius of 55 feet
and gradients of 1 in 57, this line is also a practical success.

FIRES IN LONDON AND NEW YORK.
When the chief of the London Fire Brigade visited the United States in
1882, he was, as is the general rule on the other side of the Atlantic,
"interviewed"—a custom, it may be remarked, which appears to be gaining
ground also in this country. The inferences drawn from these interviews
seem to be that the absence of large fires in London was chiefly due to the
superiority of our fire brigade, and that the greater frequency of
conflagrations in American cities, and particularly in New York, was due to
the inferiority of their fire departments. How unjust such a comparison
would be is shown in a paper presented by Mr. Edward B. Dorsey, a
member of the American Society of Civil Engineers, to that association, in
which the author discusses the comparative liability to and danger from
conflagrations in London and in American cities. He found from an
investigation which he conducted with much care during a visit to London
that it is undoubtedly true that large fires are much less frequent in the
metropolis than in American cities; but it is equally true that the
circumstances existing in London and New York are quite different. As it is
a well-known fact that the promptness, efficiency, and bravery of American
firemen cannot be surpassed, we gladly give prominence to the result of the
author's investigations into the true causes of the great liability of American
cities to large fires. In a highly interesting comparison the writer has
selected New York and London as typical cities, although his observations
will apply to most American and English towns, if, perhaps, with not quite
the same force. In the first place, the efforts of the London Fire Brigade
receive much aid from our peculiarly damp climate. From the average of
eleven years (1871-1881) of the meteorological observations made at the
Greenwich Observatory, it appears that in London it rains, on the average,
more than three days in the week, that the sun shines only one-fourth of the
time he is above the horizon, and that the atmosphere only lacks 18 per
cent. of complete saturation, and is cloudy seven-tenths of the time.
Moreover, the humidity of the atmosphere in London is very uniform,
varying but little in the different months. Under these circumstances, wood
will not be ignited very easily by sparks or by contact with a weak flame.

This is very different from the condition of wood in the long, hot, dry
seasons of the American continent. The average temperature for the three
winter months in London is 38.24 degrees Fahr.; in New York it is 31.56
degrees, or 6.68 degrees lower. This lower range of temperature must be the
cause of many conflagrations, for, to make up for the deficiency in the
natural temperature, there must be in New York many more and larger
domestic fires. The following statistics, taken from the records of the New
York Fire Department, show this. In the three winter months of 1881,
January, February, and December, there were 522 fire alarms in New York,
or an average per month of 174; in the remaining nine months 1,263, or an
average per month of 140. In the corresponding three winter months of
1882 there were 602 fire alarms, or an average per month of 201; in the
remaining nine months 1,401, or an average per month of 155. In round
numbers there were in 1881 one-fourth, and in 1882 one-third more fire
alarms in the three winter months than in the nine warmer months. We are
not aware that similar statistics have ever been compiled for London, and
are consequently unable to draw comparison; but, speaking from
recollection, fires appear to be more frequent also in London during the
winter months.

Another cause of the greater frequency of fires in New York and their more
destructive nature is the greater density of population in that city. The
London Metropolitan Police District covers 690 square miles, extending 12
to 15 miles in every direction from Charing Cross, and contained in 1881 a
population of 4,764,312; but what is generally known as London covers 122
square miles, containing, in 1881, 528,794 houses, and a population of
3,814,574, averaging 7.21 persons per house, 49 per acre, and 31,267 per
square mile. Now let us look at New York. South of Fortieth Street between
the Hudson and East Rivers, New York has an area of 3,905 acres, a
fraction over six square miles, exclusive of piers, and contained, according
to the census of 1880, a population of 813,076. This gives 208 persons per
acre. The census of 1880 reports the total number of dwellings in New York
at 73,684; total population, 1,206,299; average per dwelling, 16.37.
Selecting for comparison an area about equal from the fifteen most densely
populated districts or parishes of London, of an aggregate area of 3,896
acres, and with a total population of 746,305, we obtain 191.5 persons per
acre. Thus briefly New York averaged 208 persons per acre, and 16.37 per

dwelling; London, for the same area, 191.5 persons per acre, and 7.21 per
house. But this comparison is scarcely fair, as in London only the most
populous and poorest districts are included, corresponding to the entirely
tenement districts of New York, while in the latter city it includes the richest
and most fashionable sections, as well as the poorest. If tenement districts
were taken alone, the population would be found much more dense, and
New York proportionately much more densely populated. Taking four of the
most thickly populated of the London districts (East London, Strand, Old
Street, St. Luke's, St. Giles-in-the-Fields, and St. George, Bloomsbury), we
find on a total area of 792 acres a population of 197,285, or an average of
249 persons per acre. In four of the most densely populated wards of New
York (10th, 11th, 13th, and 17th), we have on an area of 735 acres a
population of 258,966, or 352 persons per acre. This is 40 per cent. higher
than in London, the districts being about the same size, each containing
about 1-1/5 square miles. Apart from the greater crowding which takes
place in New York, and the different style of buildings, another very fertile
cause of the spreading of fires is the freer use of wood in their construction.
It is asserted that in New York there is more than double the quantity of
wood used in buildings per acre than in London. From a house census
undertaken in 1882 by the New York Fire Department, moreover, it appears
that there were 106,885 buildings including sheds, of which 28,798 houses
were built of wood or other inflammable materials, besides 3,803 wooden
sheds, giving a total of 32,601 wooden buildings.

We are not aware that there are any wooden houses left in London. There
are other minor causes which act as checks upon the spreading of fires in
London. London houses are mostly small in size, and fires are thus confined
to a limited space between brick walls. Their walls are generally low and
well braced, which enable the firemen to approach them without danger.
About 60 per cent. of London houses are less than 22 feet high from the
pavement to the eaves; more than half of the remainder are less than 40 feet
high, very few being over 50 feet high. This, of course, excludes the newer
buildings in the City. St. James's Palace does not exceed 40 feet, the Bank
of England not over 30 feet in height; but these are exceptional structures.
Fireproof roofings and projecting party walls also retard the spreading of
conflagrations. The houses being comparatively low and small, the firemen
are enabled to throw water easily over them, and to reach their roofs with

short ladders. There is in London an almost universal absence of wooden
additions and outbuildings, and the New York ash barrel or box kept in the
house is also unknown. The local authorities in London keep a strict watch
over the manufacture or storage of combustible materials in populous parts
of the city. Although overhead telegraph wires are multiplying to an
alarming extent in London, their number is nothing to be compared to their
bewildering multitude in New York, where their presence is not only a
hinderance to the operations of the firemen, but a positive danger to their
lives. Finally—and this has already been partly dealt with in speaking of the
comparative density of population of the two cities—a look at the map of
London will show us how the River Thames and the numerous parks,
squares, private grounds, wide streets, as well as the railways running into
London, all act as effectual barriers to the extension of fires.

The recent great conflagrations in the city vividly illustrate to Londoners
what fire could do if their metropolis were built on the New York plan. The
City, however, as we have remarked, is an exceptional part of London, and,
taking the British metropolis as it is, with its hundreds of square miles of
suburbs, and contrasting its condition with that of New York, we are led to
adopt the opinion that London, with its excellent fire brigade, is safe from a
destructive conflagration. It was stated above, and it is repeated here, that
the fire brigade of New York is unsurpassed for promptness, skill, and
heroic intrepidity, but their task, by contrast, is a heavy one in a city like
New York, with its numerous wooden buildings, wooden or asphalt roofs,
buildings from four to ten stories high, with long unbraced walls, weakened
by many large windows, containing more than ten times the timber an
average London house does, and that very inflammable, owing to the dry
and hot American climate. But this is not all. In New York we find the five
and six story tenement houses with two or three families on each floor, each
with their private ash barrel or box kept handy in their rooms, all striving to
keep warm during the severe winters of North America. We also find
narrow streets and high buildings, with nothing to arrest the extension of a
fire except a few small parks, not even projecting or effectual fire-walls
between the several buildings. And to all this must be added the perfect
freedom with which the city authorities of New York allow in its most
populous portions large stables, timber yards, carpenters' shops, and the
manufacture and storage of inflammable materials. Personal liberty could

not be carried to a more dangerous extent. We ought to be thankful that in
such matters individual freedom is somewhat hampered in our old-
fashioned and quieter-going country.—London Morning Post.

THE LATEST KNOWLEDGE ABOUT GAPES.
The gape worm may be termed the bete noir of the poultry-keeper—his
greatest enemy—whether he be farmer or fancier. It is true there are some
who declare that it is unknown in their poultry-yards—that they have never
been troubled with it at all. These are apt to lay it down, as I saw a
correspondent did in a recent number of the Country Gentleman, that the
cause is want of cleanliness or neglect in some way. But I can vouch that
that is not so. I have been in yards where everything was first-rate, where
the cleanliness was almost painfully complete, where no fault in the way of
neglect could be found, and yet the gapes were there; and on the other hand,
I have known places where every condition seemed favorable to the
development of such a disease, and there it was absent—this not in isolated
cases, but in many. No, we must look elsewhere for the cause.

Observations lead me to the belief that gapes are more than usually
troublesome during a wet spring or summer following a mild winter. This
would tend to show that the egg from which the worm (that is in itself the
disease) emerges is communicated from the ground, from the food eaten, or
the water drunk, in the first instance, but it is more than possible that the
insects themselves may pass from one fowl to another. All this we can
accept as a settled fact, and also any description of the way in which the
parasitic worms attach themselves to the throats of the birds, and cause the
peculiar gaping of the mouth which gives the name to the disease.

Many remedies have been suggested, and my object now is to communicate
some of the later ones—thus to give a variety of methods, so that in case of
the failure of one, another will be at hand ready to be tried. It is a mistake
always to pin the faith to one remedy, for the varying conditions found in
fowls compel a different treatment. The old plan of dislodging the worms
with a feather is well known, and need not be described again. But I may
mention that in this country some have found the use of an ointment, first
suggested by Mr. Lewis Wright, I believe, most valuable. This is made of
mercurial ointment, two parts; pure lard, two parts; flour of sulphur, one
part; crude petroleum, one part—and when mixed together is applied to the

heads of the chicks as soon as they are dry after hatching. Many have
testified that they have never found this to fail as a preventive, and if the
success is to be attributed to the ointment, it would seem as if the insects are
driven off by its presence, for the application to the heads merely would not
kill the eggs.

Some time ago Lord Walsingham offered, through the Entomological
Society of London, a prize for the best life history of the gapes disease, and
this has been won by the eminent French scientist M. Pierre Mégnin, whose
essay has been published by the noble donor. His offer was in the interest of
pheasant breeders, but the benefit is not confined to that variety of game
alone, for it is equally applicable to all gallinaceous birds troubled with this
disease. The pamphlet in question is a very valuable work, and gives very
clearly the methods by which the parasite develops. But for our purpose it
will be sufficient to narrate what M. Mégnin recommends for the cure of it.
These are various, as will be seen, and comprise the experience of other
inquirers as well as himself.

He states that Montague obtained great success by a combination of the
following methods: Removal from infested runs; a thorough change of
food, hemp seed and green vegetables figuring largely in the diet; and for
drinking, instead of plain water, an infusion of rue and garlic. And Mégnin
himself mentions an instance of the value of garlic. In the years 1877 and
1878, the pheasant preserves of Fontainebleau were ravaged by gapes. The
disease was there arrested and totally cured, when a mixture, consisting of
yolks of eggs, boiled bullock's heart, stale bread crumbs, and leaves of
nettle, well mixed and pounded together with garlic, was given, in the
proportion of one clove to ten young pheasants. The birds were found to be
very fond of this mixture, but great care was taken to see that the drinking
vessels were properly cleaned out and refilled with clean, pure water twice
a day. This treatment has met with the same success in other places, and if
any of your readers are troubled with gapes and will try it, I shall be pleased
to see the results narrated in the columns of the Country Gentleman. Garlic
in this case is undoubtedly the active ingredient, and as it is volatile, when
taken into the stomach the breath is charged with it, and in this way (for
garlic is a powerful vermifuge) the worms are destroyed.

Another remedy recommended by M. Mégnin was the strong smelling
vermifuge assafoetida, known sometimes by the suggestive name of "devil's
dung." It has one of the most disgusting oders possible, and is not very
pleasant to be near. The assafoetida was mixed with an equal part of
powdered yellow gentian, and this was given to the extent of about 8 grains
a day in the food. As an assistance to the treatment, with the object of
killing any embryos in the drinking water, fifteen grains of salicylate of
soda was mixed with a pint and three-quarters of water. So successful was
this, that on M. De Rothschild's preserves at Rambouillet, where a few days
before gapes were so virulent that 1,200 pheasants were found dead every
morning, it succeeded in stopping the epidemic in a few days. But to
complete the matter, M. Mégnin adds that it is always advisable to disinfect
the soil of preserves. For this purpose, the best means of destroying any
eggs or embryos it may contain is to water the ground with a solution of
sulphuric acid, in the proportion of a pennyweight to three pints of water,
and also birds that die of the disease should be deeply buried in lime.

Fumigation with carbolic acid is an undoubted cure, but then it is a
dangerous one, and unless very great care is taken in killing the worms, the
bird is killed also. Thus many find this a risky method, and prefer some
other. Lime is found to be a valuable remedy. In some districts of England,
where lime-kilns abound, it is a common thing to take children troubled
with whooping-cough there. Standing in the smoke arising from the kilns,
they are compelled to breathe it. This dislodges the phlegm in the throat,
and they are enabled to get rid of it. Except near lime-kilns, this cannot be
done to chickens, but fine slaked lime can be used, either alone or mixed
with powdered sulphur, two parts of the former to one of the latter. The air
is charged with this fine powder, and the birds, breathing it, cough, and thus
get rid of the worms, which are stupefied by the lime, and do not retain so
firm a hold on the throat. An apparatus has recently been introduced to
spread this lime powder. It is in the form of an air-fan, with a pointed
nozzle, which is put just within the coop at night, when the birds are all
within. The powder is already in a compartment made for it, and by the
turning of a handle, it is driven through the nozzle, and the air within the
coop charged with it. There is no waste of powder, nor any fear that it will
not be properly distributed. Experienced pheasant and poultry breeders state

that by the use of this once a week, gapes are effectually prevented. In this
case, also, I shall be glad to learn the result if tried.

STEPHEN BEALE.

H——, Eng., Aug. 1.

—Country Gentleman.

WOLPERT'S METHOD OF ESTIMATING THE
AMOUNT OF CARBONIC ACID IN THE AIR
.

There is a large number of processes and apparatus for estimating the
amount of carbonic acid in the air. Some of them, such as those of Regnault,
Reiset, the Montsouris observers (Fig. 1), and Brand, are accurate analytical
instruments, and consequently quite delicate, and not easily manipulated by
hygienists of middling experience. Others are less complicated, and also
less exact, but still require quite a troublesome manipulation—such, for
example, as the process of Pettenkofer, as modified by Fodor, that of Hesse,
etc.

APPARATUS FOR ESTIMATING THE CARBONIC ACID OF THE AIR.
3.—Bertin-Sans Apparatus. FIG. 4.—Bubbling Glass. FIG. 5.—Pipette.

FIG. 6.—Arrangement of the U-shaped Tube. FIG. 7.—Wolpert's
Apparatus.

Hygienists have for some years striven to obtain some very simple
apparatus (rather as an indicator than an analytical instrument) that should
permit it to be quickly ascertained whether the degree of impurity of a place
was incompatible with health, and in what proportion it was so. It is from
such efforts that have resulted the processes of Messrs. Smith. Lunge,
Bertin-Sans, and the apparatus of Prof. Wolpert (Fig. 7).

It is of the highest interest to ascertain the proportion of carbonic acid in the
air, and especially in that of inhabited places, since up to the present this is
the best means of finding out how much the air that we are breathing is
polluted, and whether there is sufficient ventilation or not. Experiment has,
in fact, demonstrated that carbonic acid increases in the air of inhabited
rooms in the same way as do those organic matters which are difficult of
direct estimation. Although a few ten-thousandths more of carbonic acid in
our air cannot of themselves endanger us, yet they have on another hand a
baneful significance, and, indeed, the majority of hygienists will not tolerate
more than six ten-millionths of this element in the air of dwellings, and
some of them not more than five ten-millionths.

Carbonic acid readily betrays its presence through solutions of the alkaline
earths such as baryta and chalk, in which its passage produces an insoluble
carbonate, and consequently makes the liquid turbid. If, then, one has
prepared a solution of baryta or lime, of which a certain volume is made
turbid by the passage of a likewise known volume of CO2, it will be easy to
ascertain how much CO2 a certain air contains, from the volume of the
latter that it will be necessary to pass through the basic solution in order to
obtain the amount of turbidity that has been taken as a standard. The
problem consists in determining the minimum of air required to make the
known solution turbid. Hence the name "minimetric estimation," that has
been given to this process. Prof. Lescoeur has had the goodness to construct
for me a Smith's minimetric apparatus (Fig. 2) with the ingenious
improvements that have been made in it by Mr. Fischli, assistant to Prof.
Weil, of Zurich. I have employed it frequently, and I use it every year in my
lectures. I find it very practical, provided one has got accustomed to using

it. It is, at all events, of much simpler manipulation than that of Bertin-Sans,
although the accuracy of the latter may be greater (Figs. 3, 4, 5, and 6). But
it certainly has more than one defect, and some of the faults that have been
found with it are quite serious. The worst of these consists in the difficulty
of catching the exact moment at which the turbidity of the basic liquid is at
the proper point for arresting the operation. In addition to this capital defect,
it is regrettable that it is necessary to shake the flask that contains the
solution after every insufflation of air, and also that the play of the valves
soon becomes imperfect. Finally, Mr. Wolpert rightly sees one serious
drawback to the use of baryta in an apparatus that has to be employed in
schools, among children, and that is that this substance is poisonous. This
gentleman therefore replaces the solution of baryta by water saturated with
lime, which costs almost nothing, and the preparation of which is
exceedingly simple. Moreover, it is a harmless agent.

The apparatus consists of two parts. The first of these is a glass tube closed
at one end, and 12 cm. in length by 12 mm. in diameter. Its bottom is of
porcelain, and bears on its inner surface the date 1882 in black characters.
Above, and at the level that corresponds to a volume of three cubic
centimeters, there is a black line which serves as an invariable datum point.
A rubber bulb of twenty-eight cubic centimeters capacity is fixed to a tube
which reaches its bottom, and is flanged at the other extremity (Fig. 7).

The operation is as follows:

The saturated, but limpid, solution of lime is poured into the first tube up to
the black mark, the tube of the air bulb is introduced into the lime water in
such a way that its orifice shall be in perfect contact with the bottom of the
other tube, and then, while the bulb is held between the fore and middle
fingers of the upturned hand, one presses slowly with the thumb upon its
bottom so as to expel all the air that it contains. This air enters the lime-
water bubble by bubble. After this the tube is removed from the water, and
the bulb is allowed to fill with air, and the same maneuver is again gone
through with. This is repeated until the figures 1882, looked at from above,
cease to be clearly visible, and disappear entirely after the contents of the
tube have been vigorously shaken.

The measures are such that the turbidity supervenes at once if the air in the
bulb contains twenty thousandths of CO2. If it becomes necessary to inject
the contents of the bulb into the water twice, it is clear that the proportion is
only ten thousandths; and if it requires ten injections the air contains ten
times less CO2 than that having twenty thousandths, or only two per cent. A
table that accompanies the apparatus has been constructed upon this basis,
and does away with the necessity of making calculations.

An air that contained ten thousandths of CO2, or even five, would be almost
as deleterious, in my opinion, as one of two per cent. It is of no account,
then, to know the proportions intermediate to these round numbers. Yet it is
possible, if the case requires it, to obtain an indication between two
consecutive figures of the scale by means of another bulb whose capacity is
only half that of the preceding. Thus, two injections of the large bulb,
followed by one of the small, or two and a half injections, correspond to a
richness of 8 thousandths of CO2; and 5½ to 3.6 thousandths. This half-bulb
serves likewise for another purpose. From the moment that the large bulb
makes the lime-water turbid with an air containing two per cent. of CO2, it
is clear that the small one can cause the same turbidity only with air twice
richer in CO2, i.e., of four per cent.

This apparatus, although it makes no pretensions to extreme accuracy, is
capable of giving valuable information. The table that accompanies it is
arranged for a temperature of 17° and a pressure of 740 mm. But different
meteorological conditions do not materially alter the results. Thus, with 10°
less it would require thirty-one injections instead of thirty, and CO2 would
be 0.64 per 1,000 instead of 0.66; and with 10° more, thirty injections
instead of thirty one.

The apparatus is contained in a box that likewise holds a bottle of lime-
water sufficient for a dozen analyses, the table of proportions of CO2, and
the apparatus for cleaning the tubes. The entire affair is small enough to be
carried in the pocket.—J. Arnould, in Science et Nature.

[NATURE.]

THE VOYAGE OF THE VETTOR PISANI.
Knowing how much Nature is read by all the naturalists of the world, I send
these few lines, which I hope will be of some interest.

The Italian R.N. corvette Vettor Pisani left Italy in April, 1882, for a voyage
round the world with the ordinary commission of a man-of-war. The
Minister of Marine, wishing to obtain scientific results, gave orders to form,
when possible, a marine zoological collection, and to carry on surveying,
deep-sea soundings, and abyssal thermometrical measurements. The
officers of the ship received their different scientific charges, and Prof.
Dohrn, director of the Zoological Station at Naples, gave to the writer
necessary instructions for collecting and preserving sea animals.

At the end of 1882 the Vettor Pisani visited the Straits of Magellan, the
Patagonian Channels, and Chonos and Chiloe islands; we surveyed the
Darwin Channel, and following Dr. Cuningham's work (who visited these
places on board H.M.S. Nassau), we made a numerous collection of sea
animals by dredging and fishing along the coasts.

While fishing for a big shark in the Gulf of Panama during the stay of our
ship in Taboga Island, one day in February, with a dead clam, we saw
several great sharks some miles from our anchorage. In a short time several
boats with natives went to sea, accompanied by two of the Vettor Pisani's
boats.

Having wounded one of these animals in the lateral part of the belly, we
held him with lines fixed to the spears; he then began to describe a very
narrow curve, and irritated by the cries of the people that were in the boats,
ran off with a moderate velocity. To the first boat, which held the lines just
mentioned, the other boats were fastened, and it was a rather strange
emotion to feel ourselves towed by the monster for more than three hours
with a velocity that proved to be two miles per hour. One of the boats was
filled with water. At last the animal was tired by the great loss of blood, and
the boats assembled to haul in the lines and tow the shark on shore.

With much difficulty the nine boats towed the animal alongside the Vettor
Pisani to have him hoisted on board, but it was impossible on account of his
colossal dimensions. But as it was high water we went toward a sand beach
with the animal, and we had him safely stranded at night.

With much care were inspected the mouth, the nostrils, the ears, and all the
body, but no parasite was found. The eyes were taken out and prepared for
histological study. The set of teeth was all covered by a membrane that
surrounded internally the lips; the teeth are very little, and almost in a
rudimental state. The mouth, instead of opening in the inferior part of the
head, as in common sharks, was at the extremity of the head; the jaws
having the same bend.

Cutting the animal on one side of the backbone we met (1) a compact layer
of white fat 20 centimeters deep; (2) the cartilaginous ribs covered with
blood vessels; (3) a stratum of flabby, stringy, white muscle, 60 centimeters
high, apparently in adipose degeneracy; (4) the stomach.

By each side of the backbone he had three chamferings, or flutings, that
were distinguished by inflected interstices. The color of the back was brown
with yellow spots that became close and small toward the head, so as to be
like marble spots. The length of the shark was 8.90 m. from the mouth to
the pinna caudalis extremity, the greatest circumference 6.50 m., and 2.50
m. the main diameter (the outline of the two projections is made for giving
other dimensions).

The natives call the species Tintoreva, and the most aged of the village had
only once before fished such an animal, but smaller. While the animal was
on board we saw several Remora about a foot long drop from his mouth; it
was proved that these fish lived fixed to the palate, and one of them was
pulled off and kept in the zoological collection of the ship.

The Vettor Pisani has up the present visited Gibraltar, Cape Verde Islands,
Pernambuco, Rio Janeiro, Monte Video, Valparaiso, many ports of Peru,
Guayaquil, Panama, Galapagos Islands, and all the collections were up to
this sent to the Zoological Station at Naples to be studied by the naturalists.
By this time the ship left Callao for Honolulu, Manila, Hong Kong, and, as
the Challenger had not crossed the Pacific Ocean in these directions, we

made several soundings and deep-sea thermometrical measurements from
Callao to Honolulu. Soundings are made with a steel wire (Thompson
system) and a sounding-rod invented by J. Palumbo, captain of the ship.
The thermometer employed is a Negretti and Zambra deep-sea
thermometer, improved by Captain Maguaghi (director of the Italian R.N.
Hydrographic Office).

With the thermometer wire has always been sent down a tow-net which
opens and closes automatically, also invented by Captain Palumbo. This
tow-net has brought up some little animals that I think are unknown.

G. CHIERCHIA.

Honolulu July 1.

The shark captured by the Vettor Pisani in the Gulf of Panama is Rhinodon
typicus, probably the most gigantic fish in existence. Mr. Swinburne Ward,
formerly commissioner of the Seychelles, has informed me that it attains to
a length of 50 feet or more, which statement was afterward confirmed by
Prof. E.P. Wright. Originally described by Sir A. Smith from a single
specimen which was killed in the neighborhood of Cape Town, this species
proved to be of not uncommon occurrence in the Seychelles Archipelago,
where it is known by the name of "Chagrin." Quite recently Mr. Haly
reported the capture of a specimen on the coast of Ceylon. Like other large
sharks (Carcharodon rondeletii, Selache maxima, etc.), Rhinodon has a
wide geographical range, and the fact of its occurrence on the Pacific coast
of America, previously indicated by two sources, appears now to be fully
established. T. Gill in 1865 described a large shark known in the Gulf of
California by the name of "Tiburon ballenas" or whale-shark, as a distinct
genus—Micristodus punctatus—which, in my opinion, is the same fish.
And finally, Prof. W. Nation examined in 1878 a specimen captured at
Callao. Of this specimen we possess in the British Museum a portion of the
dental plate. The teeth differ in no respect from those of a Seychelles
Chagrin; they are conical, sharply pointed, recurved, with the base of
attachment swollen. Making no more than due allowance for such
variations in the descriptions by different observers as are unavoidable in
accounts of huge creatures examined by some in a fresh, by others in a
preserved, state, we find the principal characteristics identical in all these

accounts, viz.: the form of the body, head, and snout, relative
measurements, position of mouth, nostrils, and eyes, dentition, peculiar
ridges on the side of the trunk and tail, coloration, etc. I have only to add
that this shark is stated to be of mild disposition and quite harmless. Indeed,
the minute size of its teeth has led to the belief in the Seychelles that it is a
herbivorous fish, which, however, is not probable.

ALBERT GUNTHER.

Natural History Museum, July 30.

THE GREELY ARCTIC EXPEDITION.

THE GREELY ARCTIC EXPEDITION.—THE FARTHEST POINT
NORTH.

Some account has been given of the American Meteorological Expedition,
commanded by Lieutenant, now Major, Greely, of the United States Army,
in the farthest north channels, beyond Smith Sound, that part of the Arctic
regions where the British Polar expedition, in May, 1876, penetrated to
within four hundred geographical miles of the North Pole. The American
expedition, in 1883, succeeded in getting four miles beyond, this being
effected by a sledge party traveling over the snow from Fort Conger, the
name they had given to their huts erected on the western shore near
Discovery Cove, in Lady Franklin Sound. The farthest point reached, on
May 18, was in latitude 83 deg. 24 min. N.; longitude 40 deg. 46 min. W.,
on the Greenland coast. The sledge party was commanded by Lieutenant

Lockwood, and the following particulars are supplied by Sergeant Brainerd,
who accompanied Lieutenant Lockwood on the expedition. During their
sojourn in the Arctic regions the men were allowed to grow the full beard,
except under the mouth, where it was clipped short. They wore knitted
mittens, and over these heavy seal-skin mittens were drawn, connected by a
tanned seal-skin string that passed over the neck, to hold them when the
hands were slipped out. Large tanned leather pockets were fastened outside
the jackets, and in very severe weather jerseys were sometimes worn over
the jackets for greater protection against the intense cold. On the sledge
journeys the dogs were harnessed in a fan-shaped group to the traces, and
were never run tandem. In traveling, the men were accustomed to hold on to
the back of the sledge, never going in front of the team, and often took off
their heavy overcoats and threw them on the load. When taking
observations with the sextant, Lieutenant Lockwood generally reclined on
the snow, while Sergeant Brainerd called time and made notes, as shown in
our illustration. When further progress northward was barred by open water,
and the party almost miraculously escaped drifting into the Polar sea,
Lieutenant Lockwood erected, at the highest point of latitude reached by
civilized man, a pyramidal-shaped cache of stones, six feet square at the
base, and eight or nine feet high. In a little chamber about a foot square
half-way to the apex, and extending to the center of the pile, he placed a
self-recording spirit thermometer, a small tin cylinder containing records of
the expedition, and then sealed up the aperture with a closely fitting stone.
The cache was surmounted with a small American flag made by Mrs.
Greely, but there were only thirteen stars, the number of the old
revolutionary flag. From the summit of Lockwood Island, the scene
presented in our illustration, 2,000 feet above the sea, Lieutenant Lockwood
was unable to make out any land to the north or the northwest. "The awful
panorama of the Arctic which their elevation spread out before them made a
profound impression upon the explorers. The exultation which was natural
to the achievement which they found they had accomplished was tempered
by the reflections inspired by the sublime desolation of that stern and silent
coast and the menace of its unbroken solitude. Beyond to the eastward was
the interminable defiance of the unexplored coast—black, cold, and
repellent. Below them lay the Arctic Ocean, buried beneath frozen chaos.
No words can describe the confusion of this sea of ice—the hopeless
asperity of it, the weariness of its torn and tortured surface. Only at the

remote horizon did distance and the fallen snow mitigate its roughness and
soften its outlines; and beyond it, in the yet unattainable recesses of the
great circle, they looked toward the Pole itself. It was a wonderful sight,
never to be forgotten, and in some degree a realization of the picture that
astronomers conjure to themselves when the moon is nearly full, and they
look down into the great plain which is called the Ocean of Storms, and
watch the shadows of sterile and airless peaks follow a slow procession
across its silver surface."—Illustrated London News.

THE NILE EXPEDITION.

WHALER GIG FOR THE NILE.

As soon as the authorities had finally made up their minds to send a flotilla
of boats to Cairo for the relief of Khartoum, not a moment was lost in
issuing orders to the different shipbuilding contractors for the completion,
with the utmost dispatch, of the 400 "whaler-gigs" for service on the Nile.
They are light-looking boats, built of white pine, and weigh each about 920
lb., that is without the gear, and are supposed to carry four tons of
provisions, ammunition, and camp appliances, the food being sufficient for
100 days. The crew will number twelve men, soldiers and sailors, the
former rowing, while the latter (two) will attend the helm. Each boat will be
fitted with two lug sails, which can be worked reefed, so as to permit an
awning to be fitted underneath for protection to the men from the sun. As is
well known, the wind blows for two or three months alternately up and

down the Nile, and the authorities expect the flotilla will have the advantage
of a fair wind astern for four or five days at the least. On approaching the
Cataracts, the boats will be transported on wooden rollers over the sand to
the next level for relaunching.

THE PROPER TIME FOR CUTTING TIMBER.
To the Editor of the Oregonian:

Believing that any ideas relating to this matter will be of some interest to
your readers in this heavily-timbered region, I therefore propose giving you
my opinion and conclusions arrived at after having experimented upon the
cutting and use of timber for various purposes for a number of years here
upon the Pacific coast.

This, we are all well aware, is a very important question, and one very
difficult to answer, since it requires observation and experiment through a
course of many years to arrive at any definite conclusion; and it is a
question too upon which even at the present day there exists a great
difference of opinion among men who, being engaged in the lumber
business, are thereby the better qualified to form an opinion.

Many articles have been published in the various papers of the country
upon this question for the past thirty years, but in all cases an opinion only
has been given, which, at the present day, such is the advance and higher
development of the intellectual faculties of man, that a mere opinion upon
any question without sufficient and substantial reasons to back it is of little
value.

My object in writing this is not simply to give an opinion, but how and the
methods used by which I adopted such conclusions, as well also as the
reasons why timber is more durable and better when cut at a certain season
of the year than when cut at any other.

In the course of my investigations of this question for the past thirty years, I
have asked the opinion of a great many persons who have been engaged in
the lumber business in various States of the Union, from Maine to
Wisconsin, and they all agree upon one point, viz., that the winter time is
the proper time for cutting timber, although none has ever been able to give
a reason why, only the fact that such was the case, and therefore drawing

the inference that it was the proper time when timber should be cut; and so
it is, for one reason only, however, and that is the convenience for handling
or moving timber upon the snow and ice.

It was while engaged in the business of mining in the mountains of
California in early days, and having occasion to work often among timber,
in removing stumps, etc., it was while so engaged that I noticed one
peculiar fact, which was this—that the stumps of some trees which had
been cut but two or three years had decayed, while others of the same size
and variety of pine which had been cut the same year were as sound and
firm as when first cut. This seemed strange to me, and I found upon inquiry
of old lumbermen who had worked among timber all their lives, that it was
strange to them also, and they could offer no explanation; and it was the
investigation of this singular fact that led me to experiment further upon the
problem of cutting timber.

It was not, however, until many years after, and when engaged in clearing
land for farming purposes, that I made the discovery why some stumps
should decay sooner than others of the same size and variety, even when cut
a few months afterward.

I had occasion to clear several acres of land which was covered with a very
dense growth of young pines from two to six inches in diameter (this work
for certain reasons is usually done in the winter). The young trees, not being
suitable for fuel, are thrown into piles and burned upon the ground. Such
land, therefore, on account of the stumps is very difficult to plow, as the
stumps do not decay for three or four years, while most of the larger ones
remain sound even longer.

But, for the purpose of experimenting, I cleaned a few acres of ground in
the spring, cutting them in May and June. I trimmed the poles, leaving them
upon the ground, and when seasoned hauled them to the house for fuel, and
found that for cooking or heating purposes they were almost equal to oak;
and it was my practice for many years afterward to cut these young pines in
May or June for winter fuel.

I found also that the stumps, instead of remaining sound for any length of
time, decayed so quickly that they could all be plowed up the following

spring.

From which facts I draw these conclusions: that if in the cutting of timber
the main object is to preserve the stumps, cut your trees in the fall or winter;
but if the value of the timber is any consideration, cut your trees in the
spring after the sap has ascended the tree, but before any growth has taken
place or new wood has been formed.

I experimented for many years also in the cutting of timber for fencing,
fence posts, etc., and with the same results. Those which were cut in the
spring and set after being seasoned were the most durable, such timber
being much lighter, tougher, and in all respects better for all variety of
purposes.

Having given some little idea of the manner in which I experimented, and
the conclusions arrived at as to the proper time when timber should be cut, I
now propose to give what are, in my opinion, the reasons why timber cut in
early summer is much better, being lighter, tougher and more durable than if
cut at any other time. Therefore, in order to do this it is necessary first to
explain the nature and value of the sap and the growth of a tree.

We find it to be the general opinion at present, as it perhaps has always been
among lumbermen and those who work among timber, that the sap of a tree
is an evil which must be avoided if possible, for it is this which causes
decay and destroys the life and good qualities of all wood when allowed to
remain in it for an unusual length of time, but that this is a mistaken idea I
will endeavor to show, not that the decay is due to the sap, but to the time
when the tree was felled.

We find by experiment in evaporating a quantity of sap of the pine, that it is
water holding in solution a substance of a gummy nature, being composed
of albumen and other elementary matters, which is deposited within the
pores of the wood from the new growth of the tree; that these substances in
solution, which constitute the sap, and which promote the growth of the
tree, should have a tendency to cause decay of the wood is an impossibility.
The injury results from the water only, and the improper time of felling the
tree.

Of the process in which the sap promotes the growth of the tree, the
scientist informs us that it is extracted from the soil, and flows up through
the pores of the wood of the tree, where it is deposited upon the fiber, and
by a peculiar process of nature the albumen forms new cells, which in
process of formation crowd and push out from the center, thus constituting
the growth of the tree in all directions from center to circumference.
Consequently this new growth of wood, being composed principally of
albumen, is of a soft, spongy nature, and under the proper conditions will
decay very rapidly, which can be easily demonstrated by experiment.

Hence, we must infer that the proper time for felling the tree is when the
conditions are such that the rapid decay of a new growth of wood is
impossible; and this I have found by experiment to be in early summer,
after the sap has ascended the tree, but before any new growth of wood has
been formed. The new growth of the previous season is now well matured,
has become hard and firm, and will not decay. On the contrary, the tree
being cut when such new growth has not well matured, decay soon takes
place, and the value of the timber is destroyed. The effect of this cutting and
use of timber under the wrong conditions can be seen all around us. In the
timbers of the bridges, in the trestlework and ties of railroads and in the
piling of the wharves will be found portions showing rapid decay, while
other portions are yet firm and in sound condition.

Much more might be said in the explanation of this subject, but not wishing
to extend the subject to an improper length, I will close. I would, however,
say in conclusion that persons who have the opportunities and the
inclination can verify the truth of a portion, at least, of what I have stated, in
a simple manner and in a short time; for instance, by cutting two or three
young fir or spruce saplings, say about six inches in diameter, mark them
when cut, and also mark the stumps by driving pegs marked to correspond
with the trees. Continue this monthly for the space of about one year, and
note the difference in the wood, which should be left out and exposed to the
weather until seasoned.

C.W. HASKINS.

RAISING FERNS FROM SPORES.

1, PAN; 2, BELL GLASS; 3, SMALL POTS AND LABELS.

This plan, of which I give a sketch, has been in use by myself for many
years, and most successfully. I have at various times given it to growers, but
still I hear of difficulties. Procure a good sized bell-glass and an
earthenware pan without any holes for drainage. Prepare a number of small
pots, all filled for sowing, place them inside the pan, and fit the glass over
them, so that it takes all in easily. Take these filled small pots out of the pan,
place them on the ground, and well water them with boiling water to
destroy all animal and vegetable life, and allow them to get perfectly cold;
use a fine rose. Then taking each small pot separately, sow the spores on the
surface and label them; do this with the whole number, and then place them
in the pan under the bell-glass. This had better be done in a room, so that
nothing foreign can grow inside. Having arranged the pots and placed the

glass over them, and which should fit down upon the pan with ease, take a
clean sponge, and tearing it up pack the pieces round the outside of the
glass, and touching the inner side of the pan all round. Water this with cold
water, so that the sponge is saturated. Do this whenever required, and
always use water that has been boiled. At the end of six weeks or so the
prothallus will perhaps appear, certainly in a week or two more; perhaps
from unforeseen circumstances not for three months. Slowly these will
begin to show themselves as young ferns, and most interesting it is to watch
the results. As the ferns are gradually increasing in size pass a small piece
of slate under the edge of the bell-glass to admit air, and do this by very
careful degrees, allowing more and more air to reach them. Never water
overhead until the seedlings are acclimated and have perfect form as ferns,
and even then water at the edges of the pots. In due time carefully prick out,
and the task so interesting to watch is performed.—The Garden.

THE LIFE HISTORY OF VAUCHERIA.1
By A.H. BRECKENFELD.

Nearly a century ago, Vaucher, the celebrated Genevan botanist, described a
fresh water filamentous alga which he named Ectosperma geminata, with a
correctness that appears truly remarkable when the imperfect means of
observation at his command are taken into consideration. His pupil, De
Candolle, who afterward became so eminent a worker in the same field,
when preparing his "Flora of France," in 1805, proposed the name of
Vaucheria for the genus, in commemoration of the meritorious work of its
first investigator. On March 12, 1826, Unger made the first recorded
observation of the formation and liberation of the terminal or non-sexual
spores of this plant. Hassall, the able English botanist, made it the subject of
extended study while preparing his fine work entitled "A History of the
British Fresh Water Algæ," published in 1845. He has given us a very
graphic description of the phenomenon first observed by Unger. In 1856
Pringsheim described the true sexual propagation by oospores, with such
minuteness and accuracy that our knowledge of the plant can scarcely be
said to have essentially increased since that time.

GROWTH OF THE ALGA, VAUCHERIA, UNDER THE MICROSCOPE.

Vaucheria has two or three rather doubtful marine species assigned to it by
Harvey, but the fresh water forms are by far the more numerous, and it is to
some of these I would call your attention for a few moments this evening.
The plant grows in densely interwoven tufts, these being of a vivid green
color, while the plant is in the actively vegetative condition, changing to a
duller tint as it advances to maturity. Its habitat (with the exceptions above
noted) is in freshwater—usually in ditches or slowly running streams. I
have found it at pretty much all seasons of the year, in the stretch of boggy
ground in the Presidio, bordering the road to Fort Point. The filaments attain
a length of several inches when fully developed, and are of an average
diameter of 1/250 (0.004) inch. They branch but sparingly, or not at all, and
are characterized by consisting of a single long tube or cell, not divided by
septa, as in the case of the great majority of the filamentous algæ. These
tubular filaments are composed of a nearly transparent cellulose wall,
including an inner layer thickly studded with bright green granules of
chlorophyl. This inner layer is ordinarily not noticeable, but it retracts from
the outer envelope when subjected to the action of certain reagents, or when

immersed in a fluid differing in density from water, and it then becomes
distinctly visible, as may be seen in the engraving (Fig. 1). The plant grows
rapidly and is endowed with much vitality, for it resists changes of
temperature to a remarkable degree. Vaucheria affords a choice hunting
ground to the microscopist, for its tangled masses are the home of
numberless infusoria, rotifers, and the minuter crustacea, while the
filaments more advanced in age are usually thickly incrusted with diatoms.
Here, too, is a favorite haunt of the beautiful zoophytes, Hydra vividis and
H. vulgaris, whose delicate tentacles may be seen gracefully waving in
nearly every gathering.

REPRODUCTION IN VAUCHERIA.

After the plant has attained a certain stage in its growth, if it be attentively
watched, a marked change will be observed near the ends of the filaments.
The chlorophyl appears to assume a darker hue, and the granules become
more densely crowded. This appearance increases until the extremity of the
tube appears almost swollen. Soon the densely congregated granules at the
extreme end will be seen to separate from the endochrome of the filament, a
clear space sometimes, but not always, marking the point of division. Here
a septum or membrane appears, thus forming a cell whose length is about
three or four times its width, and whose walls completely inclose the dark
green mass of crowded granules (Fig. 1, b). These contents are now
gradually forming themselves into the spore or "gonidium," as Carpenter
calls it, in distinction from the true sexual spores, which he terms
"oospores." At the extreme end of the filament (which is obtusely conical in
shape) the chlorophyl grains retract from the old cellulose wall, leaving a
very evident clear space. In a less noticeable degree, this is also the case in
the other parts of the circumference of the cell, and, apparently, the granular
contents have secreted a separate envelope entirely distinct from the parent
filament. The grand climax is now rapidly approaching. The contents of the
cell near its base are now so densely clustered as to appear nearly black
(Fig. 1, c), while the upper half is of a much lighter hue and the separate
granules are there easily distinguished, and, if very closely watched, show
an almost imperceptible motion. The old cellulose wall shows signs of great
tension, its conical extremity rounding out under the slowly increasing
pressure from within. Suddenly it gives way at the apex. At the same

instant, the inclosed gonidium (for it is now seen to be fully formed)
acquires a rotary motion, at first slow, but gradually increasing until it has
gained considerable velocity. Its upper portion is slowly twisted through the
opening in the apex of the parent wall, the granular contents of the lower
end flowing into the extruded portion in a manner reminding one of the
flow of protoplasm in a living amoeba. The old cell wall seems to offer
considerable resistance to the escape of the gonidium, for the latter, which
displays remarkable elasticity, is pinched nearly in two while forcing its
way through, assuming an hour glass shape when about half out. The rapid
rotation of the spore continues during the process of emerging, and after
about a minute it has fully freed itself (Fig 1, a). It immediately assumes the
form of an ellipse or oval, and darts off with great speed, revolving on its
major axis as it does so. Its contents are nearly all massed in the posterior
half, the comparatively clear portion invariably pointing in advance. When
it meets an obstacle, it partially flattens itself against it, then turns aside and
spins off in a new direction. This erratic motion is continued for usually
seven or eight minutes. The longest duration I have yet observed was a little
over nine and one-half minutes. Hassall records a case where it continued
for nineteen minutes. The time, however, varies greatly, as in some cases
the motion ceases almost as soon as the spore is liberated, while in open
water, unretarded by the cover glass or other obstacles, its movements have
been seen to continue for over two hours.

The motile force is imparted to the gonidium by dense rows of waving cilia
with which it is completely surrounded. Owing to their rapid vibration, it is
almost impossible to distinguish them while the spore is in active motion,
but their effect is very plainly seen on adding colored pigment particles to
the water. By subjecting the cilia to the action of iodine, their motion is
arrested, they are stained brown, and become very plainly visible.

After the gonidium comes gradually to a rest its cilia soon disappear, it
becomes perfectly globular in shape, the inclosed granules distribute
themselves evenly throughout its interior, and after a few hours it
germinates by throwing out one, two, or sometimes three tubular
prolongations, which become precisely like the parent filament (Fig 2).

Eminent English authorities have advanced the theory that the ciliated
gonidium of Vaucheria is in reality a densely crowded aggregation of
biciliated zoospores, similar to those found in many other confervoid algæ.
Although this has by no means been proved, yet I cannot help calling the
attention of the members of this society to a fact which I think strongly
bears out the said theory: While watching a gathering of Vaucheria one
morning when the plant was in the gonidia-forming condition (which is
usually assumed a few hours after daybreak), I observed one filament, near
the end of which a septum had formed precisely as in the case of ordinary
filaments about to develop a spore. But, instead of the terminal cell being
filled with the usual densely crowded cluster of dark green granules
constituting the rapidly forming spore, it contained hundreds of actively
moving, nearly transparent zoospores, and nothing else. Not a single
chlorophyl granule was to be seen. It is also to be noted as a significant fact,
that the cellulose wall was intact at the apex, instead of showing the
opening through which in ordinary cases the gonidium escapes. It would
seem to be a reasonable inference, I think, based upon the theory above
stated, that in this case the newly formed gonidium, unable to escape from
its prison by reason of the abnormal strength of the cell wall, became after a
while resolved into its component zoospores.

WONDERS OF REPRODUCTION.

I very much regret that my descriptive powers are not equal to conveying a
sufficient idea of the intensely absorbing interest possessed by this
wonderful process of spore formation. I shall never forget the bright sunny
morning when for the first time I witnessed the entire process under the
microscope, and for over four hours scarcely moved my eyes from the tube.
To a thoughtful observer I doubt if there is anything in the whole range of
microscopy to exceed this phenomenon in point of startling interest. No
wonder that its first observer published his researches under the caption of
"The Plant at the Moment of becoming an Animal."

FORMATION OF OTHER SPORES.

The process of spore formation just described, it will be seen, is entirely
non-sexual, being simply a vegetative process, analogous to the budding of

higher plants, and the fission of some of the lower plants and animals.
Vaucheria has, however, a second and far higher mode of reproduction, viz.,
by means of fertilized cells, the true oospores, which, lying dormant as
resting spores during the winter, are endowed with new life by the
rejuvenating influences of spring. Their formation may be briefly described
as follows:

When Vaucheria has reached the proper stage in its life cycle, slight
swellings appear here and there on the sides of the filament. Each of these
slowly develops into a shape resembling a strongly curved horn. This
becomes the organ termed the antheridium, from its analogy in function to
the anther of flowering plants. While this is in process of growth, peculiar
oval capsules or sporangia (usually 2 to 5 in number) are formed in close
proximity to the antheridium. In some species both these organs are sessile
on the main filament, in others they appear on a short pedicel (Figs. 3 and
4). The upper part of the antheridium becomes separated from the parent
stem by a septum, and its contents are converted into ciliated motile
antherozoids. The adjacent sporangia also become cut off by septa, and the
investing membrane, when mature, opens: it a beak-like prolongation, thus
permitting the inclosed densely congregated green granules to be penetrated
by the antherozoids which swarm from the antheridium at the same time.
After being thus fertilized the contents of the sporangium acquire a peculiar
oily appearance, of a beautiful emerald color, an exceedingly tough but
transparent envelope is secreted, and thus is constituted the fully developed
oospore, the beginner of a new generation of the plant. After the production
of this oospore the parent filament gradually loses its vitality and slowly
decays.

The spore being thus liberated, sinks to the bottom. Its brilliant hue has
faded and changed to a reddish brown, but after a rest of about three months
(according to Pringsheim, who seems to be the only one who has ever
followed the process of oospore formation entirely through), the spore
suddenly assumes its original vivid hue and germinates into a young
Vaucheria.

CHARM OF MICROSCOPICAL STUDY.

This concludes the account of my very imperfect attempt to trace the life
history of a lowly plant. Its study has been to me a source of ever increasing
pleasure, and has again demonstrated how our favorite instrument reveals
phenomena of most absorbing interest in directions where the unaided eye
finds but little promise. In walking along the banks of the little stream,
where, half concealed by more pretentious plants, our humble Vaucheria
grows, the average passer by, if he notices it at all, sees but a tangled tuft of
dark green "scum." Yet, when this is examined under the magic tube, a
crystal cylinder, closely set with sparkling emeralds, is revealed. And
although so transparent, so apparently simple in structure that it does not
seem possible for even the finest details to escape our search, yet almost as
we watch it mystic changes appear. We see the bright green granules,
impelled by an unseen force, separate and rearrange themselves in new
formations. Strange outgrowths from the parent filament appear. The
strange power we call "life," doubly mysterious when manifested in an
organism so simple as this, so open to our search, seems to challenge us to
discover its secret, and, armed with our glittering lenses and our flashing
stands of exquisite workmanship, we search intently, but in vain. And yet
not in vain, for we are more than recompensed by the wondrous revelations
beheld and the unalloyed pleasures enjoyed, through the study of even the
unpretentious Vaucheria.

The amplification of the objects in the engravings is about 80 diameters.

[1]
Read before the San Francisco Microscopical Society, August 13,
and furnished for publication in the Press.

JAPANESE CAMPHOR—ITS PREPARATION,
EXPERIMENTS, AND ANALYSIS OF THE
CAMPHOR OIL.1
By H. OISHI. (Communicated by Kakamatsa.)

LAURUS CAMPHORA, or "kusunoki," as it is called in Japan, grows
mainly in those provinces in the islands Shikobu and Kinshin, which have
the southern sea coast. It also grows abundantly in the province of Kishu.

The amount of camphor varies according to the age of the tree. That of a
hundred years old is tolerably rich in camphor. In order to extract the
camphor, such a tree is selected; the trunk and large stems are cut into small
pieces, and subjected to distillation with steam.

An iron boiler of 3 feet in diameter is placed over a small furnace, the boiler
being provided with an iron flange at the top. Over this flange a wooden tub
is placed, which is somewhat narrowed at the top, being 1 foot 6 inches in
the upper, and 2 feet 10 inches in the lower diameter, and 4 feet in height.
The tub has a false bottom for the passage of steam from the boiler beneath.
The upper part of the tub is connected with a condensing apparatus by
means of a wooden or bamboo pipe. The condenser is a flat rectangular
wooden vessel, which is surrounded with another one containing cold
water. Over the first is placed still another trough of the same dimensions,
into which water is supplied to cool the vessel at the top. After the first
trough has been filled with water, the latter flows into the next by means of
a small pipe attached to it. In order to expose a large surface to the vapors,
the condensing trough is fitted internally with a number of vertical
partitions, which are open at alternate ends, so that the vapors may travel
along the partitions in the trough from one end to the other. The boiler is
filled with water, and 120 kilogrammes of chopped pieces of wood are
introduced into the tub, which is then closed with a cover, cemented with
clay, so as to make it air-tight. Firing is then begun; the steam passes into

the tub, and thus carries the vapors of camphor and oil into the condenser,
in which the camphor solidifies, and is mixed with the oil and condensed
water. After twenty-four hours the charge is taken out from the tub, and new
pieces of the wood are introduced, and distillation is conducted as before.
The water in the boiler must be supplied from time to time. The exhausted
wood is dried and used as fuel. The camphor and oil accumulated in the
trough are taken out in five or ten days, and they are separated from each
other by filtration. The yield of the camphor and oil varies greatly in
different seasons. Thus much more solid camphor is obtained in winter than
in summer, while the reverse is the case with the oil. In summer, from 120
kilogrammes of the wood 2.4 kilogrammes, or 2 per cent. of the solid
camphor are obtained in one day, while in winter, from the same amount of
the wood, 3 kilogrammes, or 2.5 per cent., of camphor are obtainable at the
same time.

The amount of the oil obtained in ten days, i.e., from 10 charges or 1,200
kilogrammes of the wood, in summer is about 18 liters, while in winter it
amounts only to 5-7 liters. The price of the solid camphor is at present
about 1s. 1d. per kilo.

The oil contains a considerable amount of camphor in solution, which is
separated by a simple distillation and cooling. By this means about 20 per
cent. of the camphor can be obtained from the oil. The author subjected the
original oil to fractioned distillation, and examined different fractions
separately. That part of the oil which distilled between 180°-185° O. was
analyzed after repeated distillations. The following is the result:

Calculated as
Found. C10H16O.
C = 78.87 78.95
H = 10.73 10.52
O = 10.40 (by difference) 10.52

The composition thus nearly agrees with that of the ordinary camphor.

The fraction between 178°-180° C., after three distillations, gave the
following analytical result:

C = 86.95
H = 12.28
—————
99.23

It appears from this result that the body is a hydrocarbon. The vapor density
was then determined by V. Meyer's apparatus, and was found to be 5.7
(air=1). The molecular weight of the compound is therefore 5.7 × 14.42 × 2
= 164.4, which gives

H = (164.4 × 12.28)/100 = 20.18
or C12H20
C = (164.4 × 86.95)/100 = 11.81

Hence it is a hydrocarbon of the terpene series, having the general formula
CnH2n-4. From the above experiments it seems to be probable that the
camphor oil is a complicated mixture, consisting of hydrocarbons of terpene
series, oxy-hydrocarbons isomeric with camphor, and other oxidized
hydrocarbons.

Application of the Camphor Oil.

The distinguishing property of the camphor oil, that it dissolves many
resins, and mixes with drying oils, finds its application for the preparation
of varnish. The author has succeeded in preparing various varnishes with
the camphor oil, mixed with different resins and oils. Lampblack was also
prepared by the author, by subjecting the camphor oil to incomplete
combustion. In this way from 100 c.c. of the oil, about 13 grammes of soot
of a very good quality were obtained. Soot or lampblack is a very important
material in Japan for making inks, paints, etc. If the manufacture of
lampblack from the cheap camphor oil is conducted on a large scale, it
would no doubt be profitable. The following is the report on the amount of
the annual production of camphor in the province of Tosa up to 1880:
Amount of Camphor produced. Total Cost.

1877.......... 504,000 kins.... 65,520 yen.
1878.......... 519,000 " .... 72,660 "
1879.......... 292,890 " .... 74,481 "

1880.......... 192,837 " .... 58,302 "

(1 yen = 2s. 9d.)
(1 kin = 1-1/3lb.)

[1]
From the Journal of the Society of Chemical Industry.

THE SUNSHINE RECORDER.
McLeod's sunshine recorder consists of a camera fixed with its axis parallel
to that of the earth, and with the lens northward. Opposite to the lens there
is placed a round-bottomed flask, silvered inside. The solar rays reflected
from this sphere pass through the lens, and act on the sensitive surface.

The construction of the instrument is illustrated by the subjoined cut, A
being a camera supported at an inclination of 56 degrees with the horizon,
and B the spherical flask silvered inside, while at D is placed the ferro-
prussiate paper destined to receive the solar impression. The dotted line, C,
may represent the direction of the central solar ray at one particular time,
and it is easy to see how the sunlight reflected from the flask always passes
through the lens. As the sun moves (apparently) in a circle round the flask,
the image formed by the lens moves round on the sensitive paper, forming
an arc of a circle.

Although it is obvious that any sensitive surface might be used in the
McLeod sunshine recorder, the inventor prefers at present to use the
ordinary ferro-prussiate paper as employed by engineers for copying
tracings, as this paper can be kept for a considerable length of time without
change, and the blue image is fixed by mere washing in water; another
advantage is the circumstance that a scale or set of datum lines can be
readily printed on the paper from an engraved block, and if the printed
papers be made to register properly in the camera, the records obtained will
show at a glance the time at which sunshine commenced and ceased.

Instead of specially silvering a flask inside, it will be found convenient to
make use of one of the silvered globes which are sold as Christmas tree
ornaments.

The sensitive fluid for preparing the ferro-prussiate paper is made as
follows: One part by weight of ferricyanide of potassium (red prussiate) is
dissolved in eight parts of water, and one part of ammonia-citrate of iron is
added. This last addition must be made in the dark-room. A smooth-faced
paper is now floated on the liquid and allowed to dry.—Photo. News.

BREAKING OF A WATER MAIN.
In Boston, Mass., recently, at a point where two iron bridges, with stone
abutments, are being built over the Boston and Albany Railroad tracks at
Brookline Avenue, the main water pipe, which partially supplies the city
with water, had to be raised, and while in that position a large stone which
was being raised slipped upon the pipe and broke it. Immediately a stream
of water fifteen feet high spurted out. Before the water could be shut off it
had made a breach thirty feet long in the main line of track, so that the
entire four tracks, sleepers, and roadbed at that point were washed
completely away.

A catalogue, containing brief notices of many important scientific papers
heretofore published in the SUPPLEMENT, may be had gratis at this office.

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