largest scale, on an apparently hopeless field, is without appeal. The
Commissioners propose a medical officer of health for the army,[32] second
in rank to the principal medical officer, and attached to the
quartermaster-general in the field. This officer, says the Report, should
be the head of the sanitary police of the army, should be answerable for
all the measures to be adopted for the prevention of disease, and should
report to the quartermaster-general, and to the principal medical officer.
In order to prevent any evasion of responsibility, they further recommend
that the sanitary officer shall give his advice in writing, and that the
disregard of it on strategical grounds shall be equally recorded by the
officer in command. Having thus provided for the army in the field, the
Commissioners propose that there shall be associated with the Medical
Director-General of the Army a sanitary, statistical, and medical
colleague. Each of these officers would be at the head of a distinct
department--the sanitary officer taking cognizance of all questions of
food, dress, diet, exercise, and lodging for the soldier; the statistical
department gathering together those invaluable details relative to the
health of the army, for the want of which the British troops have so long
suffered a mortality out of all proportion to the civil community; while
the medical department would serve as a connecting link between civil and
military medicine, keeping the latter up to the last word of science, as
spoken by the great medical authorities in all countries. Some of these
suggestions will require deep consideration before they are adopted.
Nothing, at any rate, must be permitted to fetter the absolute power of
the commander in the field, who must have a real as well as a nominal
freedom. But every precaution which can guard the health of the soldier
without cramping the discretion of the general is demanded alike by
humanity and policy. What was so powerfully said in the last century has
remained in a great degree true in our own. "The life of a modern soldier
is ill-represented by heroic fiction. War has means of destruction more
formidable than the cannon and the sword. Of the thousands and ten
thousands that perished in our late contests with France and Spain, a very
small part ever felt the stroke of an enemy; the rest languished in tents
and ships, amidst damps and putrefaction; pale, torpid, spiritless and
helpless; gasping and groaning unpitied among men, made obdurate by long
continuance of hopeless misery; and were at last whelmed in pits or heaved
into the ocean, without notice or remembrance. By incommodious encampments
and unwholesome stations, where courage is useless and enterprise
impracticable, fleets are silently dispeopled, and armies sluggishly
melted away."
THE ELECTRIC TELEGRAPH.
If a needle turning upon a pivot were fixed at York, and if, by a wire
placed in close proximity to it, the needle could be made to move to the
right or to the left through the agency of a power applied at the other
end of the wire in London, and if it were agreed that one motion of the
needle to the left should signify _a_, and one to the right _b_, &c.,[33]
we should have just such a contrivance as the common needle telegraph now
in use.
Such is the dry statement of a problem the more detailed working of which
we are about to explain to the reader.
When a schoolboy places a sixpence and a piece of zinc in juxta-position
with each other in his mouth, he immediately perceives a singular taste,
which as instantly disappears upon their separation; it is an experiment
which most of us have performed, wondered at for a moment, and then
forgotten. How little did we ever dream that in so doing we were calling
into life one of the most subtle, active, and universal agents in
nature--a spirit like Ariel to carry our thoughts with the speed of
thought to the uttermost ends of the earth--a workman more delicate of
hand than the Florentine Cellini, and more resistless in force than the
Titans of old!
[Illustration: Fig. 1.]
[Illustration: Fig. 2.]
If now we place a piece of zinc, Z, and of copper, C, in a glass of
acidulated water, instead of in the saliva of the mouth, and if we then
attach to the piece of zinc the wire D K, and to the piece of copper the
wire B A, and approximate the two ends, A K, until they touch, we shall
have the philosophic expression of the contrivance of the boy--a
decomposition of the water will immediately take place, and either as its
cause or consequence--for scientific men have not yet decided which--an
electric current will flow in a continued stream from the zinc plate or
positive pole to the copper plate or negative pole of the battery, and
this action, provided the plates are kept clean and the acidulated water
is supplied, will go on as long as the materials last. If this little
instrument, which generates a very small amount of electric force, is
combined with others, as in figure 2,--the zinc plate of one cell being
connected with the copper plate of the next by a piece of wire--we shall
have the celebrated battery invented by Volta in 1800, in which the
accumulated current, after flowing from one cell into another, by means of
the little hoops of wire, is transmitted along the large hoop, D K A B,
from the one pole of the battery to the other. Within the narrow chambers
of some such battery (which may be made of any number of cells, according
to the force required), the motive power is generated by which the
electric telegraph is worked, and the large hoop by which its two poles
are connected represents the telegraphic wire we see running beside the
railroad, whose office is to form a conducting pipe for the conveyance of
the electricity. Different substances possess this property in various
degrees; some, such as dry paper, not permitting the passage of the
electric fluid to any sensible extent; and others transmitting it with
great freedom. Of all known bodies, the metals are the most perfect
conductors, and copper is in this respect superior to iron; but the
latter, being cheaper and more durable, is commonly employed in the
construction of the telegraph. Thus we have two of the indispensable
requisites--a constant force and a channel which conveys it from place to
place.
[Illustration: Fig. 3.]
There was yet a third thing necessary--some contrivance by which the force
could be made instrumental in forming signs or characters at its destined
goal; and this final condition was supplied by Oersted's discovery in
1819, that a _magnetic_ needle is deflected by the passage of a circuit of
electricity through a wire parallel and in close neighbourhood to it. The
following cut will explain our meaning:--When the fluid passes from the U
pole of the battery in the direction of B A K L M Z, and enters V, its
opposite pole, "a current," as it is called, is completed, running from
left to right, the effect of which upon the needle, N, is to deflect it in
the direction of the dotted line (seen in perspective) 2, 3, or to an
angle of 90 degrees, with the wire, if the current is sufficiently strong.
If, however, the current be reversed, and the electric fluid made to
traverse the wire from right to left, in the direction of the letters V Z
M L K A B to the U end of the battery, the needle will immediately reverse
its position and place itself at 90 degrees in the opposite direction.
This then is the whole principle and mystery of the needle telegraph, the
one still most extensively used in this country. The break that occurs
between the letters B U and Z V is intended to show the method in which
the needle is made to work. "Whilst the wires are thus apart the circuit
is broken," or the fluid no longer passes along the wire, but immediately
they are approximated the circulation again commences, and the needle
"answers the helm." By the opening and closing, then, of this small space,
which is effected by a lever, the needle is made to oscillate at will.
[Illustration: Fig. 4.]
The mere fact, however, of an electric current passing along a wire in
proximity to a magnetic needle was not sufficient to enable any person to
construct a telegraph. Would the needle be deflected by a wire, the
battery of which was placed at any considerable distance? it would not;
therefore, for all telegraphic purposes Oersted's discovery was worthless.
Schweigger, however, soon after ascertained that by passing a great number
of times round the needle a wire, thoroughly insulated by a "serving" of
silk thread, as shown in figure 4, the deflecting powers of the currant
were _multiplied_, and the sensibility of the instrument marvellously
increased.
[Illustration: Fig. 5.]
In the same year that Oersted made his brilliant discovery, M. Arago
detected another law, which furnished a second method by which the
electric current could be made to tell its tale. He announced to the
French Academy the fact so pregnant in its consequences, that the fluid
possessed the power of imparting magnetism to steel or iron; and shortly
afterwards our own countryman, Sturgeon, invented the first
electro-magnet, by coiling around a piece of soft iron a great length of
fine insulated copper wire, the ends of which communicated with a battery.
Figure 5 will give a rough idea of this instrument. The wire U B A, when
it reaches the cylinder K L, is wound many times round it, and returns to
the battery at V. As long as the current is passing, the soft iron becomes
a magnet and attracts the iron armature P; but directly the circuit is
broken its magnetic power ceases, and P, by the action of a spring, flies
back. It will at once be seen that by alternately making and breaking the
circuit, which can be done as fast as the hand can move the handle of a
lever, an up and down movement of the armature P will take place, and this
is the principle of action in Wheatstone's electro-magnetic dial
instrument and Morse's recording telegraph, so extensively used in
America. The general _modus operandi_ of the latter, which is a
contrivance of singular merit and efficiency, can be easily understood. At
the station at which the message is received, a poised iron lever has a
metal pin on its upper surface at one end, and an armature on its under
surface at the other end. When the magnet, which is placed beneath the
armature, attracts and draws it down, the pin at the opposite extremity is
raised, and presses against a strip of paper, which is moved between the
metal point, and a roller supported above it, at a uniform rate by means
of clock-work. The pin or style will then make a simple dot, or trace
lines of variable length upon the paper, according as the electric current
is kept up only for a single instant, or for a longer period. "The
impressions on the paper," says Dr. Turnbull, "resemble the raised
printing for the blind." Out of these dots and lines an alphabet is formed
similar to that which we have given in a subsequent page, when speaking of
the chemical telegraph at Bain. The instrument of Morse requires only a
single wire to work it, and is, says the Abbé Moigno, "an excellent
telegraph, very simple, very efficacious, and very rapid in its
transmissions. A practised clerk can indent on an average seventeen words
a minute, which is consequently as many as a skilful writer could
transcribe with a pen. It is, moreover, a great advantage to have fixed on
a band of paper the messages which the needle telegraphs merely figure in
the air."
Since the year 1821 the principles of action of two of the working
telegraphs of the present day were known to scientific men, and the
question naturally arises, how was it that it still took so many years to
make the telegraph a working fact? The answer is, that the combination of
circumstances necessary to bring it to perfection had not arisen. What
interest had practical men in carrying out the dreams of philosophers? No
one imagined that it would ever become a necessary social engine, or that
it would pay "seven per cent." to a public Company. The patronage of the
Government could alone have been looked to by any of the proposers of the
new method of telegraphy, and the sort of encouragement received from this
quarter may be judged from the fact that when Mr. Ronalds attempted to
draw the attention of some of the officials to the working of his
instrument, they did not even deign to pay it a visit, but returned for
answer, "That the telegraph was of no use in time of peace, and that the
semaphore in time of war answered all the required purposes." The occasion
that suddenly ripened the invention and brought it into practical
operation was the introduction of railroads. Were it not for the universal
spread of this new means of locomotion, the telegraph might still have
remained in that limbo from which so many discoveries have never emerged.
The vast advantage to a railroad of a method of conveying signals
instantaneously throughout its entire length was at once seen, and the
continuity of its property, together with the protection afforded by its
servants, presented facilities for its introduction and maintenance which
had never before occurred.
A problem of great scientific interest as well as of practical importance
in connection with the electric telegraph had still to be solved. The
experiments of Dr. Watson on Shooter's Hill, in the middle of the last
century, proved, it is true, that _a shock of electricity_ passed along a
four mile circuit without any appreciable loss of time, but nothing was
definitely known about the speed at which it really travelled. This
difficult question was answered by Professor Wheatstone. His beautiful
investigations on the subject were made by means of a very rapidly
revolving mirror, upon which the passage of the electric fluid, at
different and distant parts of a severed wire, was indicated by sparks,
which appeared as lines of light on the rapidly turning glass, on the same
principle that a bit of lighted charcoal whirled round and round in the
air appears as a circle of fire. By this instrument, which we cannot
render intelligible to the general reader, but for a fuller account of
which we refer him to the Philosophical Transactions of 1834, he made it
evident to the eye that one spark or leap of the electric fluid did occur
before the other--thus proving that its transit along the wire _was_ a
matter of time. The manner in which he took measure of this infinitesimal
period was extremely ingenious. By attaching a hollow piece of metal--a
metallic humming-top as it were--to the spindle of his revolving mirror,
and at the same time directing a current of air against it, he was enabled
to test its speed by the pitch of the sound produced: this once known, the
measuring of time that elapsed between the different sparks was easy. Thus
he forced the lightning to tell how fast it was going. His
admirably-contrived apparatus has since proved of considerable use to
philosophers in measuring very minute parts of time, and scientific men
can now with the greatest ease ascertain the period a flash of light takes
to traverse a distance of 50 feet--and light, be it remembered, travels at
the speed of 200,000 miles a second!
By this experiment it appeared that electricity travels through a
copper-wire with at least the velocity of light through the celestial
space, though the recent experiments made for Professor Bache, director of
the national survey of America, have proved that the velocity of the
current through suspended _iron_ wires is not more than 15,400 miles per
second. The philosophic proof of the marvellous rate at which the electric
current moved, doubtless turned many minds once more in the direction of
the long sought for telegraph, and it is not surprising that the eminent
elucidator of the fact was among the number. A short time after this he
insulated four miles of wire in the vaults of King's College, on which he
performed most of his subsequent experiments.[34] Thus in the silence of
these gloomy vaults, as early as 1836, the lightning that was to flash
with intelligence round the world--the nervous system so shortly destined
to spread itself through two hemispheres, string together continents and
islands, and carry human thought under the wide-spreading seas, was slowly
being trained to the service of man by one of the most distinguished of
the many philosophers who have contributed to the development of this
branch of science.
Following up his experiment, Professor Wheatstone worked out the
arrangements of his telegraph, and having associated himself in 1837 with
Mr. Cooke, who had previously devoted much time to the same subject, a
patent was taken out in the June of that year in their joint names. Their
telegraph had five wires and five needles; the latter being worked upon
the face of a lozenge-shaped dial inscribed with the letters of the
alphabet, any one of which could be indicated by the convergence of two of
the needles. This very ingenious instrument could be manipulated by any
person who knew how to read, and did not labour under the disadvantage of
working by a code which required time to be understood. Immediately upon
the taking out of the patent, the directors of the North Western Railway
sanctioned the laying down of wires between the Euston Square and Camden
Town stations, and towards the end of July the telegraph was ready to
work.
Late in the evening of the 25th of that month, in a dingy little room near
the booking-office at Euston square, by the light of a flaring dip-candle,
which only illuminated the surrounding darkness, sat the inventor, with a
beating pulse and a heart full of hope. In an equally small room at the
Camden Town station, where the wires terminated, sat Mr. Cooke, his
co-patentee, and among others, two witnesses well known to fame, Mr.
Charles Fox and Mr. Stephenson. These gentlemen listened to the first word
spelt by that trembling tongue of steel which will only cease to discourse
with the extinction of man himself. Mr. Cooke in his turn touched the keys
and returned the answer. "Never did I feel such a tumultuous sensation
before," said the Professor, "as when all alone in the still room I heard
the needles click, and as I spelled the words I felt all the magnitude of
the invention, now proved to be practical beyond cavil or dispute." The
telegraph thenceforward, as far as its mechanism was concerned, went on
without a check, and the modifications of this instrument, which is still
in use, have been made for the purpose of rendering it more economical in
its construction and working, two wires at present being employed, and in
some cases only one.
A frequently renewed and still unsettled controversy has arisen upon the
point of who is to be considered the first contriver of the telegraph in
the form which made it available for popular use. Two names alone are now
put forward to dispute the claim with Wheatstone--Steinheil of Munich and
Morse of New York.
From a communication of M. Arago to the French Academy of Sciences, it
appears that the telegraph of Steinheil was in operation, for a distance
of seven miles, on the 19th of July, 1837, the same month in which
Wheatstone put his own contrivance to the test upon the North Western
Railway. But besides that the patent of Wheatstone was taken out in the
preceding June, and was itself founded upon previous and thoroughly
successful experiments, there is another material circumstance which gives
him a claim to priority over Steinheil, viz., that the latter published no
description of his instrument until August, 1838, that he altered and
improved it in the interval, and that the only accounts we have of his
contrivance describe its amended and not its original form. It was,
however, a very meritorious performance, and, in addition to its other
excellences, Steinheil was the first who employed the earth to complete
the circuit--a most important fact, which we shall explain hereafter.
Still his telegraph was inferior in its mechanical arrangements to that of
Wheatstone, and the inventor himself soon abandoned it in favour of a
modification of the instrument of Morse.
Morse dates his claim to _the invention of the telegraph_ from the year
1832, when the first idea of such an instrument, he tells us, struck him
as he was returning home from Havre in the ship Sully. A fellow-passenger,
Professor Jackson, it appears, was in the habit of amusing himself, in
common with the rest of the passengers, with some accounts of the wonders
of electricity; and when Morse later developed his contrivance, Professor
Jackson not only claimed it as a plagiarism from his own conversation, but
added that Morse was so ignorant as to ask, upon hearing the term
Electro-Magnetism, "In what does that differ from ordinary Magnetism?" The
telegraph was at best, on the part of both of them, a crude idea; and it
was not till September, 1837, that Professor Morse was able to exhibit his
still imperfect machinery in action. He ultimately succeeded, as we have
before stated, in producing a telegraph of first-rate excellence; and, out
of 15,000 miles of wire which had been erected by 1852 in the United
States, 12,124 were worked on the system of Morse.
The question of priority is, in our opinion, after all, of no sort of
importance, at least as regards the rival claims of Wheatstone and
Steinheil. When the progress of science has prepared the way for a great
discovery, two geniuses will occasionally take the step together, because
each is able to take the step of a giant. It was thus that the Calculus
was found out by both Newton and Leibnitz, and the place of Neptune in the
heavens by both Adams and Leverrier. It was the same with the telegraph.
The investigations of Wheatstone and Steinheil were entirely independent
of each other, and it cannot lessen the merit of either that there was a
second man in Europe who was equal to the task.
There are some who dispute Professor Wheatstone's claim, by urging that,
inasmuch as all the main features of the telegraph existed before he took
out his patent, there was nothing left to invent. It is true that much had
been done, but it is equally certain that there was much to do. When
Wheatstone first directed his attention to electricity as a means of
communicating thoughts to a distance, the telegraph was a useless and
inoperative machine. He and his partner established as a working, paying
fact, what had hitherto been little better than a philosophic toy. To
those who now disparage the Professor's labours we think it sufficient to
reply by the admirable saying of the French _savant_, M. Biot, "Nothing is
so easy as the discovery of yesterday; nothing so difficult as the
discovery of to-day."
Let us return, however, to the history of the telegraph in England, from
which we have digressed. After the successful working of the
mile-and-a-quarter line, the Directors of the London and Birmingham
Railway proposed to lay it down to the latter town if the Birmingham and
Liverpool Directors would continue it on their line; but they objected,
and the telegraph received notice to quit the ground it already occupied.
Of course, its sudden disappearance would have branded it as a failure in
most men's minds, and, in all probability, the telegraph would have been
put back many years, had not Mr. Brunel, to his honour, in 1839,
determined to adopt it on the Great Western line. It was accordingly
carried at first as far as West Drayton, thirteen miles, and afterwards to
Slough, a distance of eighteen miles. The wires were not at this early
date suspended upon posts, but insulated and encased in an iron tube,
which was placed beneath the ground.
The telegraph hitherto had been strictly confined to railway business, and
in furtherance of this object Brunel proposed to continue it to Bristol as
soon as the line was opened. Here, again, the folly and blindness of
railway proprietors threw obstacles in the way, which led, however, to an
unlooked-for application of its powers to public purposes. At a general
meeting of the proprietors of the Great Western Railway in Bristol, a Mr.
Hayward, of Manchester, got up and denounced the invention as a
"new-fangled scheme," and managed to pass a resolution repudiating the
agreement entered into with the patentees. Thus within a few years we find
the telegraph rejected by two of the most powerful railway companies, the
persons above all others who ought to have welcomed it with acclamation.