Scientific American Supplement No. 275

V >> Various >> Scientific American Supplement No. 275

Pages:
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11

GENERAL RESULTS.

Casting a retrospective glance at the four methods of transmission of power
which have been examined, it would appear that transmission by ropes forms
a class by itself, while the three other methods combine into a natural
group, because they possess a character in common of the greatest
importance. It may be said that all three involve a temporary
transformation of the mechanical power to be utilized into potential
energy. Also in each of these methods the efficiency of transmission is
the product of three factors or partial efficiencies, which correspond
exactly--namely, first, the efficiency of the instrument which converts
the actual energy of the prime mover into potential energy; second, the
efficiency of the instrument which reconverts this potential energy into
actual energy, that is, into motion, and delivers it up in this shape
for the actual operations which accomplish industrial work; third, the
efficiency of the intermediate agency which serves for the conveyance of
potential energy from the first instrument to the second.

This last factor has just been given for transmission by electricity. It
is the exact correlative of the efficiency of the pipe in the case of
compressed air or of pressure water. It is as useful in the case of
electric transmission, as of any other method, to be able, in studying the
system, to estimate beforehand what results it is able to furnish, and for
this purpose it is necessary to calculate exactly the factors which compose
the efficiency.

In order to obtain this desirable knowledge, the author considers that the
three following points should form the aim of experimentalists: First,
the determination of the efficiency, K, of the principal kinds of
magneto-electric, or dynamo-electric machines working as generators;
second, the determination of the efficiency, K1, of the same machines
working as motors; third, the determination of the law according to which
the magnetism of the cores of these machines varies with the intensity of
the current. The author is of opinion that experiments made with these
objects in view would be more useful than those conducted for determining
the general efficiency of transmission, for the latter give results only
available under precisely similar conditions. However, it is clear that
they have their value and must not be neglected.

There are, moreover, many other questions requiring to be elucidated by
experiment, especially as regards the arrangement of the conducting wires:
but it is needless to dwell further upon this subject, which has been ably
treated by many English men of science--for instance, Dr. Siemens and
Professor Ayrton. Nevertheless, for further information the author would
refer to the able articles published at Paris, by M. Mascart, in the
_Journal de Physique_, in 1877 and 1878. The author would gladly have
concluded this paper with a comparison of the efficiencies of the four
systems which have been examined, or what amounts to the same thing--with a
comparison of the losses of power which they occasion. Unfortunately, such
a comparison has never been made experimentally, because hitherto the
opportunity of doing it in a demonstrative manner has been wanting, for the
transmission of power to a distance belongs rather to the future than to
the present time. Transmission by electricity is still in its infancy; it
has only been applied on a small scale and experimentally.

Of the three other systems, transmission by means of ropes is the only one
that has been employed for general industrial purposes, while compressed
air and water under pressure have been applied only to special purposes,
and their use has been due much more to their special suitableness for
these purposes than from any considerations relative to loss of power.
Thus the effective work of the compressed air used in driving the
tunnels through the Alps, assuming its determination to be possible, was
undoubtedly very low; nevertheless, in the present state of our appliances
it is the only process by which such operations can be accomplished. The
author believes that transmission by ropes furnishes the highest proportion
of useful work, but that as regards a wide distribution of the transmitted
power the other two methods, by air and water, might merit a preference.

* * * * *

THE HOTCHKISS REVOLVING GUN.

The Hotchkiss revolving gun, already adopted in the French navy and by
other leading European nations, has been ordered for use in the German navy
by the following decree of the German Emperor, dated January 11 last: "On
the report made to me, I approve the adoption of the Hotchkiss revolving
cannon as a part of the artillery of my navy; and each of my ships,
according to their classification, shall in general be armed with this
weapon in such a manner that every point surrounding the vessel may be
protected by the fire of at least two guns at a minimum range of 200
meters."

* * * * *

THALLIUM PAPERS AS OZONOMETERS.

Schoene has given the results of an extended series of experiments on the
use of thallium paper for estimating approximately the oxidizing material
in the atmosphere, whether it be hydrogen peroxide alone, or mixed with
ozone, or perhaps also with other constituents hitherto unknown. The
objection to Schoenbein's ozonometer (potassium iodide on starch paper) and
to Houzeau's ozonometer (potassium iodide on red litmus paper) lies in
the fact that their materials are hygroscopic, and their indications vary
widely with the moisture of the air. Since dry ozone does not act on these
papers, they must be moistened; and then the amount of moisture varies the
result quite as much as the amount of ozone. Indeed, attention has been
called to the larger amount of ozone near salt works and waterfalls, and
the erroneous opinion advanced that ozone is formed when water is finely
divided. And Boettger has stated that ozone is formed when ether is
atomized; the fact being that the reaction he observed was due to the
H_2O_2 always present in ether. Direct experiments with the Schoenbein
ozonometer and the psychrometer gave parallel curves; whence the author
regards the former as only a crude hygrometer. These objections do not lie
against the thallium paper, the oxidation to brown oxide by either ozone or
hydrogen peroxide not requiring the presence of moisture, and the color,
therefore, being independent of the hygrometric state of the air. Moreover,
when well cared for, the papers undergo no farther change of color and may
be preserved indefinitely. The author prepares the thallium paper a few
days before use, by dipping strips of Swedish filtering paper in a solution
of thallous hydrate, and drying. The solution is prepared by pouring a
solution of thallous sulphate into a boiling solution of barium hydrate,
equivalent quantities being taken, the resulting solution of thallous
hydrate being concentrated in vacuo until 100 c.c. contains 10 grammes
Tl(OH). For use the strips are hung in the free air in a close vessel,
preferably over caustic lime, for twelve hours. Other papers are used, made
with a two per cent. solution. These are exposed for thirty-six hours. The
coloration is determined by comparison with a scale having eleven degrees
of intensity upon it. Compared with Schoenbein's ozonometer, the results are
in general directly opposite. The thallium papers show that the greatest
effect is in the daytime, the iodide papers that it is at night. Yearly
curves show that the former generally indicate a rise when the latter give
a fall. The iodide curve follows closely that of relative humidity, clouds,
and rain; the thallium curve stands in no relation to it. A table of
results for the year 1879 is given in monthly means, of the two thallium
papers, the ozonometer, the relative humidity, cloudiness, rain, and
velocity of wind.--_G. F. B., in Ber. Berl. Chem. Ces._

* * * * *

THE AUDIPHONE IN ENGLAND.

The audiphone has been recently tried in the Board School for Deaf and
Dumb at Turin street, Bethnal Green, with very satisfactory results--so
satisfactory that the report will recommend its adoption in the four
schools which the London Board have erected for the education of the deaf
and dumb. Some 20 per cent. of the pupils in deaf and dumb schools have
sufficient power of hearing when assisted by the audiphone to enable them
to take their places in the classes of the ordinary schools.

* * * * *

CONDUCTIVITY OF MOIST AIR.

Many physical treatises still assert that moist air conducts electricity,
though Silberman and others have proved the contrary. An interesting
experiment bearing on this has been described lately by Prof. Marangoni.
Over a flame is heated some water in a glass jar, through the stopper of
which passes a bent tube to bell-jar (held obliquely), which thus gets
filled with aqueous vapor. The upper half of a thin Leyden jar charged is
brought into the bell-jar, and held there four or five seconds; it is
then found entirely discharged. That the real cause of this, however, is
condensation of the vapor on the part of the glass that is not coated with
tin foil (the liquid layer acting by conduction) can be proved; for if that
part of the jar be passed several times rapidly through the flame, so as
to heat it to near 100 deg. C., before inserting in the bell-jar, a different
effect will be had; the Leyden jar will give out long sparks after
withdrawal. This is because the glass being heated no longer condenses the
vapor on its surface, and there is no superficial conduction, as in the
previous case.

* * * * *

FLOATING PONTOON DOCK.

Considerable attention has been given for some years past to the subject of
floating pontoon docks by Mr. Robert Turnbull, naval architect, of South
Shields, Eng., who has devised the ingenious arrangement which forms the
subject of the annexed illustration. The end aimed at and now achieved by
Mr. Turnbull was so to construct floating docks or pontoons that they may
rise and fall in a berth, and be swung round at one end upon a center post
or cylinder--nautically known as a dolphin--projecting from the ground at
a slight distance from the berth. The cylinder is in deep water, and,
when the pontoon is swung and sunk to the desired depth by letting in the
necessary amount of water, a vessel can be floated in and then secured. The
pontoon, with the vessel on it, is then raised by pumping out the contained
water until she is a little above the level of the berth. The whole is then
swung round over the berth, the vessel then being high and dry to enable
repairs or other operations to be conducted. For this purpose, one end of
the pontoon is so formed as to enable it to fit around the cylinder, and
to be held to it as to a center or fulcrum, about which the pontoon can be
swung. The pontoon is of special construction, and has air-chambers at the
sides placed near the center, so as to balance it. It also has chambers at
the ends, which are divided horizontally in order that the operation of
submerging within a berth or in shallow water may be conducted without
risk, the upper chambers being afterwards supplied with water to sink the
pontoon to the full depth before a vessel is hauled in. When the ship is in
place, the pontoon with her is then lifted above the level of the berth in
which it has to be placed, and then swung round into the berth. In some
cases, the pontoon is provided with a cradle, so that, when in berth, the
vessel on the cradle can be hauled up a slip with rails arranged as
a continuation of the cradle-rails of the pontoon, which can be then
furnished with another cradle, and another vessel lifted.

It is this latter arrangement which forms the subject of our illustration,
the vessel represented being of the following dimensions: Length between
perpendiculars, 350 feet; breadth, moulded, 40 feet; depth, moulded, 32
feet; tons, B. M., 2,600; tons net, 2,000. At A, in fig. 1, is shown in
dotted lines a portion of the vessel and pontoon, the ship having just been
hauled in and centered over the keel blocks. At B, is shown the pontoon
with the ship raised and swung round on to a low level quay. Going a step
further in the operation, we see at C, the vessel hauled on to the slipways
on the high-level quay. In this case the cylinder is arranged so that
the vessel may be delivered on to the rails or slips, which are arranged
radially, taking the cylinder as the center. There may be any number of
slips so arranged, and one pontoon may be made available for several
cylinders at the deep water parts of neighboring repairing or building
yards, in which case the recessed portion of the pontoon, when arranged
around the cylinder, has stays or retaining bars fitted to prevent it
leaving the cylinder when the swinging is taking place, such as might
happen in a tideway.

[Illustration: Fig. 1. IMPROVED FLOATING PONTOON DRY DOCK.]

The arrangements for delivering vessels on radial slips is seen in plan at
fig. 2, where A represents the river or deep water; B is the pontoon with
the vessel; C being the cylinder or turning center; D is the low-level
quay on to which the pontoon carrying the ship is first swung; E is the
high-level quay with the slip-ways; F is an engine running on rails around
the radial slips for drawing the vessels with the cradle off the pontoon,
and hauling them up on to the high-level quay; and G shows the repairing
shops, stores, and sheds. A pontoon attached to a cylinder may be fitted
with an ordinary wet dock; and then the pontoon, before or after the vessel
is upon it, can be slewed round to suit the slips up which the vessel has
to be moved, supposing the slips are arranged radially. In this case, the
pivot end of the pontoon would be a fixture, so to speak, to the cylinder.

The pontoon may also be made available for lifting heavy weights, by
fitting a pair of compound levers or other apparatus at one end, the
lifting power being in the pontoon itself. In some cases, in order to
lengthen the pontoon, twenty-five or fifty foot lengths are added at
the after end. When not thus engaged, those lengths form short pontoons
suitable for small vessels.--_Iron_.

* * * * *

WEIRLEIGH, BRENCHLEY, KENT.

Some few years since, Mr. Harrison Weir (whose drawings of natural history
are known probably to a wider circle of the general public than the works
of most artists), wishing to pursue his favorite study of animals and
horticulture, erected on the steep hillside of the road leading from
Paddock Wood to Brenchley, a small "cottage ornee" with detached studio.
Afterward desiring more accommodation, he carried out the buildings shown
in our illustrations. Advantage has been taken of the slope of the hill on
one side, and the rising ground in the rear on the other, to increase the
effect of the buildings and meet the difficulty of the levels. The two
portions--old, etched, and new, shown as black--are connected together by a
handsome staircase, which is carried up in the tower, and affords access to
the various levels. The materials are red brick, with Bathstone dressings,
and weather-tiling on the upper floors. Black walnut, pitch pine, and
sequoias have been used in the staircase, and joiner's work to the
principal rooms. The principal stoves are of Godstone stone only, no iron
or metal work being used. The architects are Messrs. Wadmore & Baker, of 35
Great St. Helens, E.C.; the builders, Messrs. Penn Brothers, of Pembury,
Kent.--_Building News_.

[Illustration: ARTISTS HOMES NO 11 "WEIRLEIGH" BRENCHLEY, KENT. THE
RESIDENCE OF HARRISON WEIR ESQ'RE WADMORE & BAKER ARCHITECTS]

* * * * *

RAPID BREATHING AS A PAIN OBTUNDER IN MINOR SURGERY, OBSTETRICS, THE
GENERAL PRACTICE OF MEDICINE AND OF DENTISTRY.

[Footnote: Read before the Philadelphia County Medical Society, May 12,
1880, by W. G. A. Bonwill, M.D., D.D.S., Philadelphia.]

Through the kind invitation of your directors, I am present to give you
the history of "rapid breathing" as an analgesic agent, as well as my
experience therein since I first discovered it. It is with no little
feeling of modesty that I appear before such a learned and honorable
body of physicians and surgeons, and I accept the privilege as a high
compliment. I trust the same liberal spirit which prompted you to call this
subject to the light of investigation will not forsake you when you have
heard all I have to say and you sit in judgment thereon. Sufficient time
has now elapsed since the first promulgation of the subject for the shafts
of ridicule to be well nigh spent (which is the common logic used to crush
out all new ideas), and it is to be expected that gentlemen will look upon
it with all the charity of a learned body, and not be too hasty to condemn
what they have had but little chance to investigate; and, of course, have
not practiced with that success which can only come from an intelligent
understanding of its application and _modus operandi_.

Knowing the history of past discoveries, I was well prepared for the
crucible. I could not hope to be an exception. But, so far, the medical
profession have extended me more favor than I have received at the hands of
the dental profession.

My first conception of the analgesic property of a pain obtunder in
contradistinction to its anaesthetic effect, which finally led to the
discovery of the inhalation of common air by "rapid breathing," was in 1855
or 1856, while performing upon my own teeth certain operations which gave
me intense pain (and I could not afford to hurt myself) without a resort to
ether and chloroform. These agents had been known so short a time that no
one was specially familiar with their action. Without knowing whether I
could take chloroform administered by myself, and at the same time perform
with skill the excavation of extremely sensitive dentine or tooth-bone, as
if no anaesthetic had been taken, and not be conscious of pain, was more
than the experience of medical men at that time could assure me. But,
having a love for investigation of the unknown, I prepared myself for the
ordeal. By degrees I took the chloroform until I began to feel very plainly
its primary effects, and knowing that I must soon be unconscious, I applied
the excavator to the carious tooth, and, to my surprise, found no pain
whatever, but the sense of touch and hearing were marvelously intensified.
The small cavity seemed as large as a half bushel; the excavator more the
size of an ax; and the sound was equally magnified. That I might not be
mistaken, I repeated the operation until I was confident that anaesthetics
possessed a power not hitherto known--that of analgesia. To be doubly
certain, I gave it in my practice, in many cases with the same happy
results, which saved me from the risks incident to the secondary effects of
anaesthetics, and which answered for all the purposes of extracting from
one to four teeth. Not satisfied with any advance longer than I could find
a better plan, I experimented with the galvanic current (to and fro) by so
applying the poles that I substituted a stronger impression by electricity
from the nerve centers or ganglia to the peripheries than was made from the
periphery to the brain. This was so much of a success that I threw
aside chloroform and ether in removing the living nerve of a tooth with
instruments instead of using arsenic; and for excavating sensitive caries
in teeth, preparatory to filling, as well as many teeth extracted by it.
But this was short-lived, for it led to another step. Sometimes I would
inflict severe pain in cases of congested pulps or from its hasty
application, or pushing it to do too much, when my patient invariably would
draw or inhale the breath _very forcibly and rapidly_. I was struck with
the repeated coincidence, and was led to exclaim: "Nature's anaesthetic."
This then reminded me of boyhood's bruises. The involuntary action of every
one who has a finger hurt is to place it to the mouth and draw violently in
the air and hold it for an instant, and again repeat it until the pain is
subdued. The same action of the lungs occurs, except more powerfully,
in young children who take to crying when hurt. It will be noticed they
breathe very rapidly while furiously crying, which soon allays the
irritation, and sleep comes as the sequel. Witness also when one is
suddenly startled, how violently the breath is taken, which gives relief.
The same thing occurs in the lower animals when pain is being inflicted at
the hand of man.

This was advance No. 3, and so sure was I of this new discovery, that I at
once made an application while removing decay from an extremely sensitive
tooth. To be successful, I found I must make the patient take the start,
and I would follow with a thrust from the excavator, which move would be
accomplished before the lungs could be inflated. This was repeated for
at least a minute, until the operation was completed, I always following
immediately or synchronously with the inhalation.

This led to step No. 4, which resulted in its application to the extracting
of teeth and other operations in minor surgery.

Up to this time I had believed the sole effect of the rapid inhalation was
due to mere diversion of the will, and this was the only way nature could
so violently exert herself--that of controlling the involuntary action of
the lungs to her uses by the _safety valve_, or the voluntary movement.

The constant breathing of the patient for thirty seconds to a minute left
him in a condition of body and mind resembling the effects of ether and
chloroform in their primary stages. I could but argue that the prolonged
breathing each time had done it; and, if so, then there must be some
specific effect over and above the mere diversion by the will. To what
could it be due? To the air alone, which went in excess into the lungs in
the course of a minute! Why did I not then immediately grasp the idea of
its broader application as now claimed for it? It was too much, gentlemen,
for that hour. Enough had been done in this fourth step of conception to
rest in the womb of time, until by evolution a higher step could be made at
the maturity of the child. Being self-satisfied with my own baby, I watched
and caressed it until it could take care of itself, and my mind was again
free for another conception.

The births at first seemed to come at very short intervals; but see how
long it was between the fourth and the fifth birth. It was soon after that
my mind became involved in inventions--a hereditary outgrowth--and the
electric mallet and then the dental engine, the parent of your surgical
engine, to be found in the principal hospitals of this city, took such
possession of my whole soul, that my air analgesic was left slumbering. It
was not until August, 1875--nineteen years after--that it again came up in
full force, without any previous warning.

This time it was no law of association that revived it; but it seemed
the whispering of some one in the air--some ethereal spirit, if you
please--which instituted it, and advanced the following problem: "Nitrous
oxide gas is composed of the same elements as ordinary air, with a larger
equivalent of oxygen, except it is a chemical compound, not a mechanical
mixture, and its anaesthetic effects are said to be due to the excess of
oxygen. If this be a fact, then why can you not produce a similar effect by
rapid breathing for a minute, more or less, by which a larger quantity of
oxygen is presented in the lungs for absorption by the blood?"

This query was soon answered by asking myself another: "If the rapid
inhalation of air into the lungs does not increase the heart's action and
cause it to drive the blood in exact ratio to the inhalations, then _I can_
produce partial anaesthesia from this excess of oxygen brought about by the
voluntary movements over their ordinary involuntary action of the lungs."
The next question was: Will my heart be affected by this excess of air in
the lungs to such an extent that there will be a full reciprocity between
them? Without making any trial of it, I argued that, while there is no
other muscular movement than that of the chest as under the control of the
will, and as nature has given to the will the perfect control over the
lungs to supply more or less air, as is demanded by the pneumogastric nerve
for the immediate wants of the economy, when the _involuntary action_ is
not sufficient; and the heart not being under the control of the will, and
its action never accelerated or diminished except by a specific poison, or
from the general activity of the person in violent running or working, the
blood is forced into the heart faster and must get rid of it, when a larger
supply of oxygen is demanded and rapid breathing must occur, or asphyxia
result. I was not long in deciding that the heart _would not be
accelerated_ but a trifle--say a tenth--and, under the circumstances, I
said: "The air _is_ an anaesthetic."

Pages:
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11