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Title: Torpedoes and Torpedo Warfare

Author: Charles William Sleeman

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Griffin & Co. Portsmouth. W.F. Mitchell del.

TORPEDOES

AND

TORPEDO WARFARE:
CONTAINING A

COMPLETE AND CONCISE ACCOUNT OF THE

RISE AND PROGRESS OF SUBMARINE WARFARE;

ALSO A

DETAILED DESCRIPTION OF ALL MATTERS APPERTAINING
THERETO,
INCLUDING THE LATEST IMPROVEMENTS.

BY

C. W. SLEEMAN, Esq.,
LATE LIEUT. R.N., AND LATE COMMANDER IMPERIAL OTTOMAN NAVY.

WITH FIFTY-SEVEN FULL-PAGE ILLUSTRATIONS, DIAGRAMS,
WOODCUTS, &c.

PORTSMOUTH:
GRIFFIN & CO., 2, THE HARD,
(Publishers by Appointment to H.R.H. The Duke of Edinburgh.)
London Agents: SIMPKIN, MARSHALL, & CO.

————
1880.
All Rights reserved.]

PREFACE.

In the following pages the Author has endeavoured to supply a want, viz. a
comprehensive work on Torpedo Warfare, brought down to the latest date.
The information has been obtained while practically engaged in torpedo
work at home and abroad, and from the study of the principal books which
have already appeared on the subject, and to the authors of which he would
now beg to express his acknowledgments, viz.: "Submarine Warfare," by
Lieut.-Commander Barnes, U.S.N.; "Notes on Torpedoes," by Major
Stotherd, R.E.; "Art of War in Europe," by General Delafield, U.S.A.; "Life
of Fulton," by C. D. Colden; "Torpedo War," by R. Fulton; "Armsmear," by
H. Barnard; "Treatise on Coast Defence," by Colonel Von Scheliha;
Professional Papers of the Royal Engineers; "The Engineering"; "The
Engineer"; "Scientific American"; "Iron"; &c., &c.
The Author is also desirous of thanking the following gentlemen, to
whom he is indebted for much of the valuable information contained herein:
—
Messrs. Siemens Brothers, Messrs. Thornycroft and Co., Messrs. Yarrow
and Co., Captain C. A. McEvoy, 18 Adam Street, W.C., Mr. L. Lay, Messrs.
J. Vavaseur and Co.
London, 1879.

CONTENTS.

PAGE
Preface iii

CHAPTER I.
The early History of the Torpedo—Remarks on the existing State of
1
Torpedo Warfare

CHAPTER II.
Defensive Torpedo Warfare—Mechanical Submarine Mines—
13
Mechanical Fuzes—Mooring Mechanical Mines

CHAPTER III.
Defensive Torpedo Warfare (continued)—Electrical Submarine Mines
—Electrical Fuzes—Insulated Electric Cables—Electric Cable Joints 27
—Junction Boxes—Mooring Electrical Submarine Mines

CHAPTER IV.
Defensive Torpedo Warfare (continued)—Circuit Closers—Firing by
Observation—Voltaic Batteries—Electrical Machines—Firing Keys
60
and Shutter Apparatus—Testing Submarine Mines—Clearing a
Passage through Torpedo Defences

CHAPTER V.
Offensive Torpedo Warfare—Drifting Torpedoes—Towing Torpedoes
—Locomotive Torpedoes—Spar Torpedoes—General Remarks on 115
Offensive Torpedoes

CHAPTER VI.
Torpedo Vessels and Boats—The Uhlan—The Alarm—The Destroyer 158
—Thornycroft's Torpedo Boats—Yarrow's Torpedo Boats—Schibau's

Torpedo Boats—Herreshoff's Torpedo Boats—Torpedo Boat Attacks
—Submarine Boats

CHAPTER VII.
Torpedo Operations—The Crimean War (1854-56)—The Austro-
Italian War (1859)—The American Civil War (1861-65)—The
187
Paraguayan War (1864-68)—The Austrian War (1866)—The Franco-
German War (1870-71)—The Russo-Turkish War (1877-78)

CHAPTER VIII.
On Explosives—Definitions—Experiments—Gunpowder—Picric
Powder—Nitro-Glycerine—Dynamite—Gun-cotton—Fulminate of
204
Mercury—Dualin—Lithofracteur—Horsley's Powder—Torpedo
Explosive Agents—Torpedo Explosions

CHAPTER IX.
Torpedo Experiments—Chatham, England, 1865—Austria—
Carlscrona, Sweden, 1868—Kiel, Prussia—England, 1874—
Copenhagen, Denmark, 1874—Carlscrona, Sweden, 1874-75—
Portsmouth, England, 1874-75—Pola, Austria, 1875—Portsmouth, 220
England, 1876—Experiments with Countermines—The Medway,
England, 1870—Stokes Bay, England, 1873—Carlscrona, Sweden,
1874

CHAPTER X.
The Electric Light—The Nordenfelt and Hotchkiss Torpedo Guns—
239
Diving

CHAPTER XI.
Electricity 265

APPENDIX.
McEvoy's Single Main Systems 283
Siemens' Universal Galvanometer Tables 287
Synopsis of the Principal Events that have occurred in connection with
290
the History of the Torpedo

Index 297

LIST OF PLATES.

Destruction of Turkish Gunboat "Suna" (Frontispiece).
I. Fulton's Torpedoes.
II. Frame Torpedoes, Buoyant Mechanical Mines.
III. Singer's and McEvoy's Mechanical Mines.
IV. Extempore Mechanical Mine, Mechanical Primers.
V. Mechanical Fuzes.
VI. Form of Case of Submarine Mines.
VII. Electric Fuzes.
VIII. Electric Cables, Extempore Cable Joints.
IX. Permanent Joints for Electric Cables.
X. Junction Boxes, Mechanical Turk's Head.
XI. Moorings for Submarine Mines.
XII. Steam Launch for Mooring Submarine Mines.
XIII. Mathieson's Circuit Closer.
XIV.Austrian Circuit Closer, Mercury Circuit Closer.
XV. McEvoy's Magneto Electro Circuit Closer.
XVI. Russian Submarine Mine, Firing by Observation.
XVII. Apparatus for Firing by Observation.
XVIII. Systems of Defence by Submarine Mines.
XIX.Firing Batteries, Testing Batteries.
XX. Firing Keys, Shutter Apparatus.
XXI. Shutter Apparatus.
XXII. Galvanometers for Testing.
XXIII. Siemens' Universal Galvanometer.
XXIIIa. Ditto Ditto.
XXIV. Ditto Ditto.
XXIVa. Ditto Ditto.
XXV. Shunt, Commutator, Rheostat.
XXVI. Wheatstone's Bridge.

XXVII. Test Table, Differential Galvanometer.
XXVIII. Methods of Testing—Armstrong—Austrian.
XXIX. Drifting Torpedoes.
XXX. Harvey's Towing Torpedo.
XXXI. Ditto Ditto.
XXXII. Systems of Attack with Harvey's Sea Torpedo.
XXXIII. Ditto Ditto.
XXXIV. Ditto Ditto.
XXXV. German and French Towing Torpedoes.
XXXVI. Whitehead's Fish Torpedoes.
XXXVII.Thornycroft's Boat Apparatus for Fish Torpedoes.
XXXVIII. Lay's Locomotive Torpedo.
XXXIX. Ditto Ditto.
XL. Ditto Ditto.
XLI. Ditto Ditto.
XLII. Ditto Ditto.
XLIII. Ditto Ditto.
XLIV. McEvoy's Duplex Spar Torpedoes.
XLV. The "Alarm" Torpedo Ship.
XLVI. The "Destroyer" Torpedo Ship.
XLVII. Thornycroft's Torpedo Boats.
XLVIII. Ditto Ditto.
XLIX. Yarrow's Torpedo Boats.
L. Ditto Ditto.
LI. Russian Torpedo Boat, Herreshoff's Torpedo Boat.
LII. Submarine Mine Explosion.
LIII. Ditto Ditto.
LIV. McEvoy's Single Main System.

Torpedoes and Torpedo Warfare.

CHAPTER I.
THE EARLY HISTORY OF THE TORPEDO.—
REMARKS ON THE EXISTING STATE OF
TORPEDO WARFARE.
THE earliest record we have of the employment of an infernal machine
at all resembling the torpedo of the present day, was in 1585 at
the siege of Antwerp. Here by means of certain small vessels,
drifted down the stream, in each of which was placed a
magazine of gunpowder, to be fired either by a trigger, or a
combination of levers and clockwork, an Italian engineer,
Lambelli, succeeded in demolishing a bridge that the enemy
had formed over the Scheldt.
So successful was this first attempt, and so tremendous was the effect
produced on the spectators, by the explosion of one of these torpedoes, that
further investigation of this new mode of Naval warfare was at once
instituted.
But it was not until some two hundred years after that any real progress
was effected, though numerous attempts were made during this period, to
destroy vessels by means of sub-marine infernal machines.
It was owing to the fact, that the condition which is now considered as
essential in torpedo warfare, viz., that the charge must be submerged, was
then entirely ignored, that so long a standstill occurred in this new art of
making war.
Captain Bushnell, the Inventor of Torpedoes.—To Captain David
Bushnell, of Connecticut, in 1775, is most certainly due the credit of
inventing torpedoes, or as he termed them submarine magazines. For he
first proved practically that a charge of gunpowder could be fired under
water, which is incontestably the essence of submarine warfare.

Submarine Boat.—To Captain Bushnell is also due the credit of first
devizing a submarine boat for the purpose of conveying his magazines to
the bottom of hostile ships and there exploding them.
Drifting Torpedoes.—Another plan of his for destroying vessels, was
that of connecting two of his infernal machines together by means of a line,
and throwing them into the water, allowing the current to carry them across
the bows of the attacked ship.
Mode of Ignition.—The ignition of his magazines was generally effected
by means of clockwork, which, when set in motion, would run for some
time before exploding the machines, thus enabling the operators to get clear
of the explosion.
Captain Bushnell's few attempts to destroy our ships off the American
coast in 1776 and 1777, with his submarine boat, and his drifting torpedoes
were all attended with failure, a result generally experienced, where new
inventions are for the first time subjected to the test of actual service.
Robert Fulton.—Robert Fulton, an American, following in his footsteps,
some twenty years after, revived the subject of submarine warfare, which
during that interval seems to have been entirely forgotten.
A resident in France, in 1797, he is found during that year making
various experiments on the Seine with a machine which he had constructed,
and by which he designed "to impart to carcasses of gunpowder a
progressive motion under water, to a certain point, and there explode them."
[A]

Fulton's Failures.—Though these first essays of his resulted in failure,
Fulton thoroughly believed in the efficacy of his schemes, and we find him,
during that and succeeding years, vainly importunating the French and
Dutch Governments, to grant him aid and support in carrying out
experiments with his new inventions, whereby he might perfect them, and
thus ensure to whichever government acceded to his views, the total
destruction of their enemy's fleets.
Bonaparte aids Fulton.—Though holding out such favourable terms, it
was not until 1800, when Bonaparte became First Consul, that Fulton's

solicitations were successful, and that money was granted him to carry out a
series of experiments.
In the following year (1801), under Bonaparte's immediate patronage,
Fulton carried out various and numerous experiments in the harbour of
Brest, principally with a submarine boat devised by him (named the
Nautilus), subsequently to his invention of submarine carcasses as a means
of approaching a ship and fixing one of his infernal machines beneath her,
unbeknown to the crew of the attacked ship.
First Vessel destroyed by Torpedoes.—In August, 1801, Fulton
completely destroyed a small vessel in Brest harbour by means of one of his
submarine bombs, then called by him for the first time, torpedoes,
containing some twenty pounds of gunpowder. This is the first vessel
known to have been sunk by a submarine mine.
Bonaparte's patronage withdrawn.—Notwithstanding the apparent
success, and enormous power of Fulton's projects, on account of a failure
on his part to destroy one of the English Channel fleet, at the end of 1801,
Bonaparte at once withdrew his support and aid.
Disgusted with this treatment, and having been previously pressed by
some of England's most influential men, to bring his projects to that
country, so that the English might reap the benefit of his wonderful
schemes, Fulton left France, and arrived in London, in May, 1804.
Pitt supports Fulton.—Mr. Pitt, then Prime Minister, was much struck
with Fulton's various schemes of submarine warfare, and after examining
one of his infernal machines, or torpedoes, exclaimed, "that if introduced
into practice, it could not fail to annihilate all military marines."[B]
Though having secured the approval of Mr. Pitt, and a few other
members of the Government, he was quite unable to induce the English to
accept his schemes in toto, and at once employ them in the Naval service.
Twice Fulton attempted to destroy French men-of-war, lying in the
harbour of Boulogne, by means of his drifting torpedoes, but each time he
failed, owing as he then explained, and which afterwards proved to be the
case, to the simple mistake of having made his machines specifically

heavier than water, thus preventing the current from carrying them under a
vessel's bottom.
Destruction of the "Dorothea."—Though in each of the above-
mentioned attempts Fulton succeeded in exploding his machines, and
though on the 15th October, 1805, in the presence of a numerous company
of Naval and other scientific men, he completely demolished a stout brig,
the Dorothea, off Walmer Castle, by means of his drifting torpedoes, similar
to those employed by him at Boulogne, but considerably improved, still the
English Government refused to have anything further to do with him or his
schemes.
England, at that time, being mistress of the seas, it was clearly her
interest to make the world believe that Fulton's schemes were impracticable
and absurd.
Earl St. Vincent, in a conversation with Fulton, told him in very strong
language, "that Pitt was a fool for encouraging a mode of warfare, which, if
successful, would wrest the trident from those who then claimed to bear it,
as the sceptre of supremacy on the ocean."[C]
Wearied with incessant applications and neglect, and with failures, not
with his inventions, but in inducing governments to accept them, he left
England in 1806, and returned to his native country.
Application to Congress for Help.—Arrived there, he lost no time in
solicitating aid from Congress to enable him to carry out experiments with
his torpedoes and submarine boats, practice alone in his opinion being
necessary to develop the extraordinary powers of his invention, as an
auxiliary to harbour defence.
By incessant applications to his government, and by circulating his
torpedo book[D] among the members, in which he had given detailed
accounts of all his previous experiments in France and England, and
elaborate plans for rendering American harbours, etc., invulnerable to
British attack, a Commission was appointed to inquire into and practically
test the value of these schemes.
They were as follows:—

1.—Drifting Torpedoes.—Two torpedoes connected by a line floated
in the tide at a certain depth, and suffered to drift across the
bows of the vessel to be attacked; the coupling line being
arrested by the ship's cable would cause the torpedoes to be
forced under her bottom; this plan is represented and will be
readily understood by Fig. 3.
2.—Harpoon Torpedo.—A torpedo attached to one end of a line, the
other part to a harpoon, which was to be fired into the bows of
the doomed vessel from a piece of ordnance mounted in the
bows of a boat, specially constructed for the purpose; the line
being fixed to the vessel by the harpoon, the current, if the
vessel were at anchor, or her progress if underweigh, would
carry the torpedo under her bottom. Fig. 2 represents this type
of Fulton's submarine infernal machine.
3.—Spar Torpedo.—A torpedo attached to a spar suspended by a
swivel from the bowsprit of a torpedo boat, so nearly balanced,
that a man could easily depress, or elevate the torpedo with one
hand, whilst with the other he pulled a trigger and exploded it.
4.—Block Ship.—Block ships, that is vessels from 50 to 100 tons,
constructed with sides impervious to cannon shot, and decks
made impenetrable to musket shot. A spar torpedo a, a, a, to be
carried on each bow and quarter Fig. 4 represents this curious
craft.
Stationary Mines.—Stationary buoyant torpedoes for harbour defence,
to be fired by means of levers attached to triggers. This kind of
mine is shown at Fig. 1.
5.—Cable Cutters.—Cable cutters, that is submarine guns discharging
a sharp piece of iron in the shape of a crescent, with sufficient
force to cut through ship's cables, or other obstructions.[E]
Practical Experiments.—Various and exhaustive experiments were
carried out in the presence of the Commissioners, tending generally to
impress them with a favourable view of Fulton's many projects.
As a final test, the sloop Argus was ordered, under the superintendence
of Commodore Rodgers, to whom Fulton had previously explained his
mode of attack, to be prepared to repel all attempts made against her by
Fulton, with his torpedoes.

Defence of the "Argus."—Though repeated attempts were made, none
were successful, owing to the energetic, though somewhat exaggerated
manner in which the defence of the sloop had been carried out. She was
surrounded by numerous spars lashed together, nets down to the ground,
grappling irons, heavy pieces of metal suspended from the yard arms ready
to be dropped into any boat that came beneath them, scythes fitted to long
spars for the purpose of mowing off the heads of any who might be rash
enough to get within range of them.
As Robert Fulton very justly remarked, "a system, then only in its
infancy, which compelled a hostile vessel to guard herself by such
extraordinary means could not fail of becoming a most important mode of
warfare."
Three of the Commissioners reported as favourably as could be
expected, considering its infancy, on the practical value of Fulton's scheme
of torpedo warfare.
Congress refuse aid.—But on the strength of Commodore Rodgers's
report, which was as unfair and prejudiced, as the others were fair and
unprejudiced, Congress refused Fulton any further aid, or to countenance
any further experiments that he might still feel inclined to prosecute.
Though undeterred by this fresh instance of neglect, and still having a
firm belief in the efficacy of his various torpedo projects, yet other
important matters connected with the improvement of the steam engine
occupied his whole time and prevented him from making any further
experiments with his submarine inventions.
Mode of Firing, 1829.—Up to 1829, that is to say for nearly sixty years
after the invention of torpedoes, mechanical means only were employed to
effect the ignition of the torpedo charges, such as levers, clockwork, and
triggers pulled by hand; with such crude means of exploding them, it is not
extraordinary to find, that all the attempts made to destroy hostile ships,
resulted in failure.
FULTON'S TORPEDOES.

Briefly reviewing the history of the torpedo during its first period of
existence, viz., from Captain Bushnell's invention of submarine magazines
in 1775, down to the introduction of electricity, as a means of exploding

submarine mines, by Colonel Colt, in 1829, we find that due to the
unwearied exertions, and numerous experiments carried out by Captain
Bushnell, Mr. R. Fulton and others, the following very important principles
in the art of torpedo warfare were fully proved:—
1.—That a charge of gunpowder could be exploded under water.
2.—That any vessel could be sunk by a torpedo, provided only the
charge were large enough.
3.—That it was possible to construct a boat which could be navigated,
and remain for several hours under water, without detriment to
her crew.
4.—That a ship at anchor could be destroyed, by means of drifting
torpedoes, or by a submarine or ordinary boat, armed with a
spar torpedo.
5.—That a vessel underweigh could be destroyed by means of
stationary submarine mines, and by the harpoon torpedo.
These principles, which at the time were fully admitted, laid the
foundations of the systems of torpedo warfare, that are at the present day in
vogue, all over the world.
Second Epoch.—The second epoch in the life of the torpedo dates from
1829, when Colonel Colt, then a mere lad, commenced experiments with
his submarine battery.
Colt's Experiments.—His first public essay, was on the 4th June, 1842,
when he exploded a case of powder in New York harbour, while himself
standing at a great distance off.
Having by numerous successful experiments satisfactorily proved that
vessels at anchor could be sunk by means of his electrical mines, Colonel
Colt engaged to destroy a vessel underweigh by similar means, which feat
he successfully accomplished on 13th April, 1844.
Colt's Electric Cable.—The electric cable as used by Colonel Colt, was
insulated by cotton yarn, soaked in a solution of asphaltum and beeswax,
and the whole enclosed in a metal case.
Colt's Reflector.—On examining Colt's papers after his death, one was
found illustrating one of his many devices for effecting the explosion of a

submarine mine at the proper instant.
Description of Reflector.—One set of conducting wires from all the
mines is permanently attached to a single pole of a very powerful firing
battery, the other wires lead to metal points which are attached to marks on
a chart of the channel in front of the operator and which marks correspond
with the actual positions of the mines in the channel. A reflector, is arranged
to throw the image of a hostile vessel on the chart, and as this image passes
over either of the wire terminations on it, the operator with the other battery
wire, completes the circuit, and explodes the torpedo, over which by her
image thrown on the chart, the vessel is supposed to be at that precise
moment.[F] In his experiment with a vessel under weigh, Colt had probably
taken the precaution of laying down several circles of mines, and thus aided
by cross staffs, ensured the experiment being a success.
With regard to the invention of the word torpedo, for submarine infernal
machines, Dr. Barnard in his life of Colt says, "that Fulton used the word
torpedo, probably on account of its power of stunning or making torpid, and
that a long way through the water,—in so naming it, he buildeth better than
he knew, for Colt's torpedoes being fired by electricity may with special
fitness take its name from the electric eel."[G]
Theoretical Knowledge.—Though many opportunities have occurred
during the last thirty-five years for practically testing the effectiveness of
torpedoes when employed on actual service, especially during the American
Civil War (1861-65) and the late Turco-Russian War (1877-78), yet in so far
as the offensive and electrical portion of submarine warfare is concerned,
our knowledge of them is still principally theoretically.
Failure of Offensive Torpedoes.—The manipulation of the ordinary spar
or outrigger torpedo boats, and of the various automatic torpedoes, appears
simple enough, when practice is made with those submarine weapons
during peace time, also the results of such practice is without doubt
uniformly successful, yet when the crucial test of actual service is applied,
as was the case during the war of 1877, with the Whitehead and spar
torpedoes, then a succession of failures had to be recorded.[H]
The cause of this want of success in war-time with offensive torpedoes,
lies in the fact, that during peace time the experiments and practice carried

out with them, are done so, under the most favourable circumstances, that is
to say in daylight, and the nerves of the operators not in that high state of
tension, which would be the case, were they attacking a man-of-war on a
pitch dark night, whose exact position cannot be known, and from whose
guns at any moment a sheet of fire may be belched forth, and a storm of
shot and bullets be poured on them, whilst on actual service, this would in
nine out of ten instances be the case.
Some uncertainty must and will always exist in offensive torpedo
operations when carried out in actual war, where, as in this case, the success
of the enterprise depends almost wholly on the state of a man's nerves, yet
this defect, a want of certainty, may to a considerable extent be eradicated
were means to be found of carrying out in time of peace, a systematic
practice of this branch of torpedo warfare, under circumstances similar to
those experienced in war time, and this is not only possible, but practicable.
Moral Effect of Torpedoes.—We now come to the moral effect of
torpedoes, which is undoubtedly the very essence of the vast power of these
terrible engines of war. Each successive war that has occurred, in which the
torpedo has taken a part, since Captain Bushnell's futile attempt in 1775 to
destroy our fleet by drifting numerous kegs charged with gunpowder down
the Delawarre, teem with proofs of the great worth of torpedoes in this
respect alone.
That such a dread of them should and always will be met with in future
Naval wars, at times creating a regular torpedo scare or funk, is not
extraordinary, when it is remembered that these submarine weapons of the
present day, are capable of sinking the finest ironclad afloat, and of
launching into eternity without a moment's warning or preparation, whole
ships' crews.
The torpedoes existing at the present day have, without doubt, reached a
very high degree of excellence, in so far as their construction, fuzes, cables,
&c., both electrically and mechanically, is concerned, but much has yet to
be done to develop their actual effectiveness.
The result of the numerous and exhaustive experiments that have of late
years been carried out by England, America, and Europe prove that the

necessary distances between stationary submarine mines are by far greater
than those within which the explosions are effective.
Therefore it will be found necessary to supplement those submarine
harbour defences, by automatic torpedoes that can be controlled and
directed from the shore, as well as by specially constructed torpedo boats.
Automatic Arrangements.—And to ensure certainty, which is the
desideratum in torpedo warfare, circuit closers, or other automatic
arrangements for exploding the submarine mines, must be employed, as the
system of firing them by judgment is not at all a sure one.
Ship Defence.—The problem, which occupies the attention of Naval and
other scientific men, at the present day, is how best to enable a ship to guard
herself against attacks from the fish and other automatic torpedoes, and this
without in any way impairing her efficiency as a man-of-war.
The means of such defence, should most certainly be inherent in the
vessel herself, outward methods, such as nets, booms, etc., are to great
extent impracticable, besides one of the above mentioned torpedoes, being
caught by such obstructions would, on exploding, most probably destroy
them, thus leaving the vessel undefended against further attacks.
Mechanical Mines.—Several ingenious methods have of late been
devised for the purpose of obviating one of the principal defects common to
all kinds of mechanical submarine mines, the most efficient and practical of
which will be found fully described in the following pages, viz., the great
danger attendant on the mooring of such mines; but as yet, no really
practical mode of rendering mechanical mines safe, after they have once
been moored and put in action, has been discovered, were such to be
devised, a very difficult and extremely important problem of defensive
torpedo warfare would be solved.
Electrical Mines.—In regard to electrical submarine mines, much has
been done by torpedoists in general to simplify this otherwise somewhat
complicated branch of defensive torpedo warfare, by adopting the platinum
wire fuze, in the place of the high tension one, by the employment of
Leclanché firing batteries, by the simplification of the circuit closer, and
discarding the use of a circuit breaker, by altering the form of torpedo case,

and whenever possible by enclosing the circuit closer in the submarine
mine.
The necessity of a very elaborate system of testing should, if possible, be
overcome, for a system of submarine mines that requires the numerous and
various tests that are at the present day employed, to enable those in charge
of them to know for certain that when wanted the mines will explode,
cannot be considered as adaptable to actual service. It must be remembered
that the safety of many ports, etc., will in future wars depend almost
entirely on the practical efficiency of electrical and mechanical mines. As
yet, in actual war, little or no experience has been gained of the real value of
a mode of coast defence by electrical mines, excepting from a moral point
of view, though in this particular they have most undoubtedly been proved
to be exceedingly effective.
A submarine mine much wanted on active service, is one that can be
carried on board ships, capable of being fitted for use at a moment's notice,
and of being easily and rapidly placed in position by the ordinary boats of a
man-of-war. It should be a self-acting electrical mine, with the circuit
closing apparatus enclosed in the torpedo case, and capable of carrying
about 100 lbs. of guncotton. This form of mine would be found extremely
useful to secure the entrance to a harbour, etc., where ships might happen to
be anchored for the night, or which might have been wrested from the
enemy, etc.
They should be capable of being placed in position and picked up again,
in the shortest possible space of time.
Offensive Torpedoes.—Coming to the question of offensive torpedoes
there still seems to be a great difference of opinion as to the real value of
the Whitehead fish torpedo, and this point will never be finally settled until
that weapon has been more thoroughly tested on actual service; from a
specially built torpedo boat, by which is meant a Thornycroft or Yarrow
craft, the spar torpedo would seem to be the most effective weapon.
Torpedo vessels for the special purpose of experimenting with the
Whitehead torpedo have been built by England, America, and several
continental governments, so that we may soon hope to get some more
decided opinion as to the utility of that weapon. When manipulated from

the shore, or large ships, the Lay torpedo boat, if only its speed be increased
will prove an exceedingly effective submarine weapon, for the purposes of
offence, active defence, or clearing harbours, etc., of mines, in fact, it may
be more truly said of this weapon, than of the Whitehead, "that it can do
everything but speak." Captain Harvey has greatly improved his towing
torpedo, but it is still a somewhat complicated and difficult weapon to
manipulate by ordinary persons, that is, those not specially trained for the
work.
Drifting torpedoes under certain circumstances should prove invaluable,
but little or no improvement has been effected in this direction. Submarine
boats have also remained in statu quo, though for the purpose of clearing an
enemy's harbour of mines, it seems impossible to devise any better method.
Electric lights are now universally adopted for use on board ship, and
will play a very important part in the defence of ships against torpedo
attacks in future wars. Glancing back on what has been effected in the
matter of improving the system of torpedo warfare in all its branches during
the last few years, with the exception of the vast improvements in the form
and construction of steam torpedo boats, their engines, etc., very little has
been done, owing principally to the want of that practical knowledge which
unfortunately can only be gained from their employment in actual war.
The late Turco-Russian war afforded a splendid opportunity for applying
the crucial test of actual service to both the offensive and defensive
branches of torpedo warfare, yet little or no light was thrown on the
somewhat shadowy subject of submarine warfare. The present struggle
between Peru and Chili may furnish some experience, but it will not be very
satisfactory, as hardly any knowledge of manipulating torpedoes is
possessed by either side.

FOOTNOTES:
[A] C. D. Colden's "Life of Fulton."
[B] C. D. Colden's "Life of Fulton."
[C] C. D. Colden's "Life of Fulton."
[D] "Torpedo Warfare," by R. Fulton, 1810.

[E] C. D. Colden's "Life of Fulton."
[F] Johnston's Cyclopædia.
[G] Armsmear.
[H] See Chapter VII.

CHAPTER II.
DEFENSIVE TORPEDO WARFARE.—
MECHANICAL MINES.—MECHANICAL
FUZES.—MOORING MECHANICAL MINES.

B Y defensive torpedo warfare is meant the protection of harbours,
rivers, etc., by means of various descriptions of torpedoes moored
beneath the surface of the water.
Submarine, or sea mine, is the term that has been generally adopted to
designate this particular species of torpedo.
Submarine Mines.—Defence in Future Wars.—The very conspicuous
part played by submarine mines, in the many wars that have taken place
since the introduction of the torpedo as a legitimate mode of Naval warfare,
when their manipulation was comparatively little understood, and
construction very imperfect, proves that, with the experience so gained, and
the vast improvements that have been, and are daily being effected, in all
that appertains to the art of torpedo warfare, the protection of harbours, etc.,
will in future wars depend in a great measure on the adoption of a
systematic and extensive employment of submarine mines.
The utility and power of this mode of coast defence has been fully
exemplified in actual war, more especially during the Franco-German war
(1870-1) and the late Turco-Russian war (1877-8).
Torpedoes in the Franco-German War.—In the former instance, the
superiority of the French over the Germans, in the matter of ships, was
more than neutralised, by the use on the part of the latter of electrical,
mechanical, and dummy mines for the protection of their harbours, etc. In
regard to the utility of the latter, it is on record that a certain German port
was entirely defended by dummy mines, the Burgomaster of that place
having been unable to obtain men to place the active mechanical ones in
position, owing to the numerous and serious accidents that had previously

occurred in other German ports at the commencement of the war, in
mooring the latter kind of submarine mine.
The effect, so far as keeping the French fleet at a distance was
concerned, was precisely the same, as though active instead of dummy
mines had been employed, thus still further proving the vast moral power
possessed by torpedoes.
Torpedoes in the Russo-Turkish War.—In the war of 1877, the Turks,
though possessing a powerful fleet in the Black Sea and flotilla on the
Danube, made little or no use of their superiority over the Russians in this
respect. They failed to even attempt to destroy the bridges formed by the
Russians over the Danube, nor did they make any attempt to capture Poti,
re-take Kustendje, or to create diversions on the Russian coast in the Black
Sea. Had the latter service alone been effectually carried out, by which
means, a large force of the enemy would have been held in check, immense
help would have been afforded to the Ottoman armies in Europe and Asia.
Again, during the whole of the war, the Russian port of Odessa was never
sighted, and Sebastopol only once by the Ottoman fleet.
Cause of Failure of the Ottoman Fleet.—The cause of this repeated
neglect on the part of the Turkish fleet may be traced almost entirely to the
assumption (which in nine out of ten cases was an erroneous one) on the
part of the Naval Pashas and Beys that every Russian harbour, etc., was a
mass of submarine mines, and this in several instances extending many
miles to seaward.
So also, some of the many failures experienced by the Russians in their
numerous torpedo boat attacks, were due in a great measure to an erroneous
supposition on the part of the captain of the Russian steamer, Constantine
(employed to convoy the torpedo boats), that the Turks had defended the
entrance, to a distance of some miles to seaward, of their harbours, etc., and
thus the torpedo boats were dispatched to the attack some miles off the
entrance, causing them, owing to the darkness, to enter the harbour in which
the Turkish vessels were lying, in a very straggling manner. And to a similar
reason the failure of the Russians to capture Sulina, in the attack made on
that place in October, 1877, was principally owing to their not daring to
send their Popoffkas to attack from the sea.

One of the chief points of usefulness of an extensive and systematic
employment of submarine mines, will be to minimise the number of vessels
necessary for the protection of harbours, etc., thus enabling a far larger
number of ships to operate at sea against those of an enemy, this especially
applies to countries like England and America possessing a large extent of
seacoast, numerous harbours, rivers, etc., which it would be necessary to
defend in the event of war.
Science of Torpedo Warfare.—The science of defensive torpedo warfare
may be considered to consist of:—
1.—The arrangement of the mines in positions, such that it would not
be possible for a hostile vessel attempting to force a passage
into a harbour, etc., defended by such means, to pass more than
one line of them, without coming within the destructive radius
of some one or other of the remaining mines.
Note.—The difficulty of attaining the above effect, lies in the fact that
the destructive radius of a submarine mine, is considerably less than the
distance that must be maintained between them, to prevent injury by
concussion to the cases, circuit closers, electric cables, etc., of such mines
on the explosion of an adjacent one.
As an illustration of the above, take the case of a 500 lb. guncotton
submarine mine. Now the destructive radius of a sea-mine is found by the
formula R = [3rt](32 × C), where R is the destructive radius in feet of a
mine moored at its most effective depth, and C is the charge (guncotton) in
lbs.
In the above case R would be about 24 feet, which in so far as the actual
destruction of a ship is concerned, may be taken as correct, but if injury to a
vessel's engines, boilers, etc., be also taken into consideration, and as the
vessel would most probably be underweigh on such an occasion, this would
be a very vital and important consideration, R would under those
circumstances be more than doubled. Now the necessary interval for safety
between such mines, according to torpedo authorities, is equal to 10 R, and
should certainly be not less than 8 R, which in this case would give about
200 feet, therefore assuming the radius of destruction to be 50 feet, it is

seen that there would be under those conditions a clear undefended space of
about 100 feet between each couple of 500 lb. mines in the same line.
2.—The combined arrangement of submarine mines with forts and
batteries, in such a manner, that every one of the former shall
be well covered by the guns of the latter, and also that it would
be impossible for an enemy's ships to get within effective range
of the forts, or batteries, without moving over ground where
mines were laid.
Note.—This applies to the defence of the more important harbours, etc.,
in which case the submarine mines (which would be chiefly electrical ones)
would only act as auxiliaries to the land defences. To effectually carry out
the above, there can be no question but that they who plan the forts, etc.,
should also plan the systems of submarine defence.
A harbour, river, etc., which it is necessary to protect by electrical
submarine mines, etc., and where no land defences exist, should have its
mines supported by a powerful ship or ships, as maybe thought desirable.
Success in Torpedo Warfare.—The two most important conditions
essentially necessary to the successful employment of torpedoes, both
offensive and defensive, are:—

1. Certainty of Action.
2. Simplicity of Manipulation.

Without the former this mode of Naval warfare is comparatively useless,
while without the latter the former condition is rarely obtained, more
especially in the case of offensive torpedoes.
Submarine mines are divided into separate classes, viz.:—

1. Mechanical Mines.
2. Electrical Mines.

Mechanical Mines.—By this description of submarine mines, is meant
those whose charges are fired by mechanical means alone.

Mechanical Mines in the American Civil War.—During the civil war of
America (1861-5), the Confederates depended almost entirely on
mechanical submarine mines for the protection of their harbours, rivers,
etc., and to this extensive use of such mines may be traced nearly the whole
of the Federal disasters afloat.
In the principal wars that have subsequently occurred, though this form
of submarine mine has been to a certain extent used, it has generally been
only as an auxiliary to the more effective electrical torpedo, and owing to
the deterrent effect produced by the numerous torpedo successes that
characterised the American Civil War, on Naval Commanders, etc., few
vessels have been destroyed by their means, the effect of the employment of
defensive torpedoes having been almost wholly a moral one.
Mechanical Mines for Coast Defence.—The experience hitherto gained,
with regard to the employment of mechanical mines for coast defence in
actual war, proves that they will be found exceedingly valuable in the
following positions:—
1.—In combination with booms or other obstructions placed in
defence of narrow channels, etc., which are intended to be
completely blocked up.
2.—In shallow water on the flanks of electrical mines.
3.—In protecting unfrequented bays, channels, etc., and a long line of
seacoast, which may otherwise be entirely undefended.
Note.—In this latter instance, though the mines may not be covered by
any guns, still they will be of great use, in so far, that being mechanical
ones, they cannot be rendered useless by the process of cutting cables, etc.,
but must be destroyed, which in time of peace is a work of considerable
labour and danger, and, therefore, would in the time of war, cause at the
very least, serious delay to an enemy desirous of effecting a landing, etc., at
a point so protected.
There are numerous objections against their employment, the principal
ones being:—
1.—That they are all, more or less dangerous to place in position.
2.—That they cannot be tested when moored.

3.—That they are as dangerous to friend as to foe, when once placed in
action.
4.—That an exploded, or known damaged mine cannot be replaced.
Note.—The above objections, especially 2 and 3, constitute without
doubt very serious defects in a system of defence by mechanical mines, and
in the case of purely mechanical ones, it seems almost impossible to
eradicate any of them, though, notwithstanding, under the particular
circumstance before-mentioned, these species of defensive torpedo will be
found extremely useful.
The Advantages of Mechanical Mines.—They possess a few advantages,
which are as follows:—
1.—They are comparatively cheap.
2.—They can be kept in store and ready for use at a moment's notice.
3.—They do not require specially trained men to manipulate them.
4.—Extempore ones can be easily and readily made.
Best Kinds of Mechanical Mines.—Among the very numerous and
various kinds of mechanical submarine mines that have been devised the
following may be considered as the most effective, and practicable of them
all:—

1.—Frame Torpedoes.
2.—Buoyant Mines.

This includes:—

a.—Barrel Mine.
b.—Brook's Mine.
3.—Singer's Mine.
4.—McEvoy's Improved Mine.
5.—Extempore Mine.

Frame Torpedoes.—This form of defensive mine is shown at Fig. 6. It
consists of a frame work which is formed of four strong timbers a, a, a, a,
these being kept parallel and only a few feet apart by means of cross
timbers b, b. A cast-iron torpedo c, c, c, in the shape of a shell, is bolted to

the head of each of the timbers a, a, a, containing about thirty pounds of
fine grained gunpowder, and fitted with a percussion fuse, which is so
placed that it would come into contact with a vessel striking against the
framework, directly or not. One end of the frame is securely anchored, the
other, that on which the torpedoes are fixed, is kept at its proper distance
below the surface of the water by means of chains, d, d, and anchors. To
prevent the frame from sinking when sodden with water, the uprights e, e,
are provided.
This form of mechanical mine, which performs the double function of
torpedo and obstruction, was much used by the Confederates, and found
extremely useful, no passage was attempted to be forced by the Federals
where these torpedoes were known to be placed.
Stake Torpedo.—Fig. 7 represents another form of the frame torpedo.
It consists of a piece of timber, a, its heels secured by a heavy metal shoe
b, working in a universal joint in the mooring, c. At the head of the piece of
timber is secured a torpedo d, containing about fifty pounds of gunpowder,
and fitted with four or five sensitive fuzes. The proper angle of inclination
is obtained by securing the upper end of the timber to an anchor as shown at
e. As a proof of the efficiency of this species of mechanical mine, even
though having been in position for a great length of time, the U.S. gunboat,
Jonquil, was nearly destroyed whilst attempting to remove some similar
torpedoes which had been in position for two years.
FRAME TORPEDOES, BUOYANT MECHANICAL MINES.

The Barrel Torpedo.—One description of this form of mechanical
submarine mine is shown at Fig. 8. It consists of a barrel a, to the ends of

which are attached two cones of pine b, b, for the purpose of preventing the
current from turning the mine over.
To ensure its being watertight, pitch is poured into the interior through
the bunghole, and the barrel rolled about, so that the inside may be evenly
covered. The outside was also thoroughly coated with pitch. These mines
usually contain about 100 lbs. of gunpowder, and are exploded by means of
percussion or chemical fuzes (c, c, c,) generally five in number, screwed
into sockets on each side and on the top of the bilge of the barrels. To keep
them upright a weight d is hung below the mine.
This kind of mechanical mine was much used by the Confederates, and
to some extent by the Turks in their late war with Russia.
They are cheap, convenient, and under certain circumstances very
effective. One of the objections to their use is the difficulty of mooring
them securely in strong currents, as otherwise they are very liable to shift
their positions. Three Confederate vessels were "hoisted by their own
petards," from this cause.[I]
Brook's Torpedo.—Another form of buoyant mechanical mine is
represented at Fig. 9. It was designed for the express purpose of preventing
its discovery by dragging, etc., by the enemy. It consists of the torpedo case
a, formed of copper, which is attached to a spar b, the lower end of which is
secured to an universal joint in its anchor c. Five percussion or chemical
fuzes d, d, d, are screwed into the head of the copper case.
Turtle Torpedo.—To increase the danger and uncertainty of any attempt
to remove this form of buoyant mine, a turtle torpedo A, is attached to it by
a wire e. This torpedo contains about 100 lbs. of gunpowder, and is
exploded by means of a friction primer which passes through a watertight
joint f, and is attached to the wire e.
Whether this combination would prove effective, has yet to be seen, but
the buoyant mine alone was considered one of the most dangerous used by
the Confederates.
Singer's Mechanical Mine.—An elevation and section of this form of
mechanical mine is shown at Fig. 10. It consists of an air chamber a, and a
powder chamber b; in the latter is fixed a rod of iron c, one end of which

rests in a cup formed in a lug d, where there is a screw by means of which
the rod c may be screwed against the bottom of the torpedo case, on the
interior. In the cup is placed the fulminating substance. A heavy cast iron
cap A B rests upon the top of the case and is prevented from falling off by a
low rim of tin, which enters an aperture in the cap as at e: a wire f connects
this cap with a pin g, which keeps a plunger h at rest. The head of this
plunger h is directly beneath the bottom of the rod c, within the case; by
means of a spring i, directly the pin g is drawn out, which is done by a
hostile vessel striking against the mine and knocking off the cap A B, the
plunger h is forced against the bottom of the case and drives the rod c into
the cup containing the fulminate, and so explodes the torpedo. The case of
these mines, as used by the Confederates, was formed of tin, and they
contained from 50 to 100 lbs. of powder. A safety pin k is provided to
prevent a premature explosion due to the pin g being accidentally
withdrawn.
This form of submarine mine was one of the most successful and most
extensively employed of all, on the part of the Confederates.
Though no accidents are stated to have occurred in placing this mine in
position, yet the fact of the iron rod c having to be fixed for action, and that
close against the interior of the bottom of the case, before the charge of
powder has been put in, is an element of great danger, for a comparatively
slight blow beneath it, which might easily occur in transport, etc., would
explode the torpedo prematurely.
McEvoy's Improved Singer's Mine.—To obviate this defect Captain
McEvoy has designed an improved mode of ignition for Singer's mine. This
is shown at Fig. 11. The form of case, and arrangement of heavy cap are
similar to those in Singer's mine. The mode of ignition is as follows:—In
the powder chamber b is fixed a friction fuze f, which by means of a piece
of wire secured to a length of chain k, k, is connected with the heavy cast
iron cap A B. The piece of wire passes through a diaphragm of thin metal h,
which is soldered all around, thus forming a complete watertight joint.
Premature explosion is prevented by passing a link of the chain, through a
slot in the bolt c, securing it there by a pin of bent wire l. The dotted line of
chain k, k, shows its position during the process of mooring this form of
Singer's torpedo. The manner of lowering this and also Singer's mine is

shown at Fig. 12. A buoy x, is attached by means of a line, in the former
case to the pin l, Fig. 12, in the latter case to the pin k, Fig. 10, the pulling
out of either, sets their respective mines in action.
SINGER'S AND McEVOY'S MECHANICAL MINES.

Mathieson's Cement Safety Plug.—In the place of the safety pin l, Fig.
11, employed by Captain McEvoy in his improved form of Singer's mine,

Quartermaster-Sergeant Mathieson, late Royal Engineers, employs a plug or
disc of soluble cement, so arranged that the action of the sea-water after the
mine has been placed in position destroys the plug or disc, and so frees the
chain which is connected with the fuze and the heavy cap of the torpedo.
This plan does away with the necessity of using a buoy and line as shown in
Fig. 12, and also affords ample time for the men engaged in mooring the
mine to get far away before it is ready for action.
Mechanical Mine.—The extempore mechanical submarine mine, shown
at Fig. 13, will be found to possess all the qualities which are necessary to a
perfect mine of that description.
It is extremely simple, it can be readily and quickly made, all the
materials of which it is constructed are at hand on board every man-of-war,
and it is certain in its action.
It consists of a barrel a, which is thoroughly coated inside and out with
hot pitch, etc., to make it watertight, a block of wood b, secured to the top
of the cask a, and having a recess cut in it to receive a round shot c, also a
hole through which a strop d, is passed, and another hole to receive a toggle
e. At the bottom of the cask on the inside, is fixed a wooden frame work f, f,
to the top of which two ordinary gun friction tubes are fixed g, g. A piece of
wood h, is secured to the bottom of the cask on the outside, bored with two
holes, one to receive a thin iron rod i, the other for the safety pin k. Wires x,
x, secure the gun tubes g, g, to one end of the iron rod i, the other end of
which is connected by means of a rope lanyard to the shot c. Weights are
slung beneath the barrel to keep the mine upright. The principle of action of
this form of mechanical mine is precisely similar to that of Captain
McEvoy's improved Singer's mine, and need not, therefore, be described.
McEvoy's Mechanical Primer.—A sectional view of this apparatus is
represented by Fig. 14. It consists of two brass tubes fitting accurately one
within the other, of which a, a, is the inner one. To this inner tube are
affixed two brass diaphragms b, b. A brass spindle c, carries a weight d,
which is regulated by a spring, e. A locking rod, f, moves in a ball and
socket joint at g. A hammer h, which is shown in Fig. 14, at full cock, is
kept in that position by the rod f. A vessel, striking the mine, in which this
apparatus is placed causes the weight, d, to cant over, allowing the rod, f, to

be forced upwards by means of the spring e, and so frees the hammer h,
which falls on a nipple i, on which is placed the percussion substance, and
so explodes the mine.
McEvoy's Papier Maché Safety Plug.—To prevent a premature
explosion during transport, etc., of a mine in which this apparatus is placed,
a plug of papier maché, which is soluble in water, is inserted in the two
spaces p, p, by which the spindle c, is prevented from moving to one side or
the other. The use of a papier maché, instead of a cement plug for the
purposes of safety, is a great improvement, as by the simple process of
pressure, any period of time that it is necessary should elapse before the
complete destruction of the plug, can be readily and certainly obtained,
which when a cement plug, formed of different ingredients is used, is not
always the case.
McEvoy's Mechanical Mines.—Captain McEvoy has also devised a plan,
whereby a mechanical mine of the foregoing form may be placed in a state
of safety, even after it has been rendered active. In the place of the aforesaid
papier maché wad at p, Fig. 14, he uses a plunger which fits into the cavity
p, of the heavy weight d. This plunger is always kept in a position clear of
the weight by means of a spiral spring, unless it is desired to render the
mine inactive when the plunger is forced into the aforesaid cavity and kept
there by means of a pin inserted above it. Above this there is another
plunger, acted on by a spiral spring sufficiently powerful to enable it to
force the previous mentioned plunger into the safety position; this upper
plunger is rendered inactive by means of a pin. The mine being placed in
position, that pin which is keeping the lower plunger inserted in the cavity
p, of the weight d, is withdrawn and the mine rendered active. To the pin of
the upper plunger is attached a line which is anchored some distance from
the mine in a known position. Then to render the mine inactive for the
purpose of picking it up, etc., it is only necessary to raise the aforesaid line,
and draw out the pin of the upper plunger, which by means of the strong
spiral spring will force the lower plunger into the safety position, and render
the mine inactive.
Whether this invention is a practicable one or not, remains to be proved,
but anyhow it is a step in the right direction.
EXTEMPORE MECHANICAL MINE, MECHANICAL PRIMERS.

Abel's Mechanical Primer.—This is shown in section and elevation at
Fig. 15 (A and B). a, a, is the powder chamber in which the priming charge
is placed; b is a screw plug to close the chamber; c is a flexible india rubber
tube; d, d, are screw bands; e is a glass tube containing oil of vitriol
enclosed in a lead tube; f which contains the explosive mixture; g, an eye at
the head of the primer to receive the firing line; h, h are segmental guards; i
is the guard ring; and j the safety screw pin. This apparatus is screwed into a
socket in the upper part of the torpedo case, as shown at Fig. 15 (C).
Mode of Action.—When placed in position, to render the primer ready
for action, the guard ring, i, is pulled off, first having removed the safety pin
j, when the segmental guards h, h, will fall away, leaving the india rubber
tube c, c, exposed.
A sufficient strain being brought on the rope secured to the ring g, the
lead tube f bends, causing the fracture of the glass tube e, thus igniting the
priming charge and exploding the mine.
A submarine mine so fitted may be fired at will, by bringing a line, from
the ring g, to the shore, or it may be made self-acting by connecting two of
them together, etc.
Percussion and Chemical Fuzes.—Many forms of this mode of
mechanical ignition have been from time to time devised, of which the
following are the most important ones:—
Sensitive Fuze.—It consists of an inner cylinder a, a, Fig. 15, of
composition metal, 1-1/2" diameter, and 2-1/2" long, having a thread cut on
its outside, and a bouching b, 2-1/4" diameter and 2" long with a sexagonal
projection c, for applying a wrench, also with an external and internal
thread. The upper end of the inner cylinder a, is solid for 1", and is
perforated by three holes d, d, d, in each of which a percussion primer is
placed e, e. A piece of thin, soft and well annealed copper f is soldered to
the upper end of the bouching b, to keep moisture from the primers, and is
so thin that a slight blow will crush without breaking it. A safety cap can be
screwed on to the external thread above the projection c.
Rain's Detonating Composition.—The detonating composition employed
in this and many other forms of percussion fuzes by the Confederates, etc.,

consisted of a combination of fulminate of mercury and ground glass, and
was invented by, and is named after, General Rains, Chief of the Torpedo
Bureau, at Richmond, during the Civil War (1861-5). So sensitive was this
composition that seven pounds pressure, applied to the head of one of the
primers, would explode it.
When required for use the internal cylinder a, containing the primers e,
e, is screwed up until contact between them and the copper cap f is secured.
McEvoy's Percussion Fuze.—Fig. 16 represents a longitudinal section,
full size, of the mechanical percussion fuze, used by Captain McEvoy in
connection with his drifting torpedo, which latter will be hereafter
described. a is a piece of metal, having an external and internal thread, and
a projection b, to which is applied the spanner for screwing it into the
torpedo case. This piece a is hollow at its upper end, and is closed by means
of a thin copper dome c, which is soldered to it. Screwed into the piece a is
the plug, or nipple d, with a hole through it from end to end, it is rammed
full of mealed powder, and then a fine hole is drilled through the
composition. A cavity e at the head of the plug, or nipple d, is filled with a
fulminating substance. A spiral spring f, encircles the plug d, on which a cap
g rests; h is a needle in this cap. The action of this fuze will be readily
understood from the plan of the fuze at Fig. 16. A safety cap is provided,
which fits into the slots i, i, and is fixed there by means of a set screw.
Improved Form of Jacobi's fuze.—The section shown in Fig. 17 is an
improved form of the chemical fuze, invented by Professor Jacobi, and used
by the Russians in their land and sea mines during the Crimean war (1854-
5). It consisted of a small glass tube a, containing sulphuric acid, enclosed
in a lead cylinder b. A mixture of chlorate of potash and white sugar
surrounds the tube and holds it in position; c is a primer filled with mealed
powder in connection with the charge of the mine. The action of this fuze is
as follows:—On a vessel striking against the lead cylinder b, it is crushed
in, breaking the glass tube containing the sulphuric acid, and thus causes it
(acid) to flow into the mixture of chlorate of potash and white sugar,
producing fire, which by means of the primer c, passes into the charge, and
explodes the mine.
MECHANICAL FUZES.

Defect of Chemical Fuze.—The defect of the chemical fuze just
described is its slow rate of ignition when compared to gunpowder. This

may be remedied by adding a small quantity of sulphuret of antimony or
perro cyanide of potassium.
Both the Turks and the Germans employed, as a mode of ignition for
their mechanical submarine mines, the chemical fuze described above, with
but slight modifications in the shape of the lead cylinder and manner of
fixing the fuze into the torpedo case.
Mechanical fuzes, both percussion and chemical, which require a blow
to effect their ignition, are to a certain extent defective when applied to
submarine mechanical mines (which are always buoyant ones) in so far that
a hostile vessel passing over ground supposed to be defended by torpedoes
of any description, would do so at as slow a rate of speed as it would be
possible to proceed at, and would, under those circumstances, push away
rather than strike a buoyant mine, with which she might come in contact.
During the American civil war and the Russo-Turkish war, especially in the
former, there are several instances on record of vessels passing over
buoyant mechanical mines unharmed, whilst similar vessels have
afterwards been destroyed by those self-same mines; and the only cause for
such apparent inconsistency being the above-mentioned one, viz., the
pushing rather than striking effect produced on a buoyant mine by a vessel
under weigh proceeding at a very slow speed, or merely drifting with the
current.
Steward's Safety-Cock Arrangements.—To obtain security to a certain
extent in placing mechanical submarine mines in position, which, as has
been previously stated, is one of the defects common to all forms of such
torpedoes, many ingenious methods have been devised, such as safety caps
to their fuzes, safety pins, soluble plugs, &c. Another method, suggested by
Captain Harding Steward, R.E., which it is intended should be used in
connection with the other safety arrangements, is shown at Fig. 18. It
consists of a stop-cock A, which, in connection with a tube, is introduced
between the fuze and the charge. It is so arranged that when the cock is
turned in the direction of the tube, as shown in section B at e, the gas on
formation can pass easily through and explode the charge; but when the
cock is shut off, the gas on formation escapes through the side d, as shown
in section C. To prevent destruction of the charge through leakage under the
pressure of the water, the cone in connection with the stop-cock should fit

very accurately, and, as an additional preventive, the escape hole should be
covered with a waterproof plaster, which at a moderate depth would keep
the water out and yet offer no material resistance to the escape of the gas if
the stop-cock were shut off, as at C. The efficiency of this arrangement, as
far as relates to its cutting off the gas from the charge, has been
satisfactorily proved by practical experiments.
Mooring Mechanical Mines.—This description of defensive torpedo will
rarely be used in deep-water channels, &c., and on account of the
impossibility of ascertaining whether such a mine has drifted or otherwise,
it should not be moored in a very rapid current. Such being the case, an
ordinary mushroom anchor, heavy stone, &c., and single steel wire
mooring-rope, will be generally found quite sufficient to keep such mines in
position.
When only a few mechanical submarine mines are moored in position,
and at some distance apart, it would be found a useful plan to moor them
each with three anchors, one anchor being up-stream. By this method, at
low water, on the up-stream anchor being raised, the mine would show
itself, and might in that position be approached and rendered inactive. Were
this plan to be adopted when several such mines are in position, there would
be the danger of the up-stream anchor on being raised, bringing up to the
surface, and probably in contact with the boat at work, a mine to which that
particular anchor does not belong, an explosion being the result.

FOOTNOTE:
[I] "Submarine Warfare," by Commander S. Barnes, U.S.N.

CHAPTER III.
DEFENSIVE TORPEDO WARFARE—continued.

B Y electrical submarine mines is meant those whose charges are ignited
by the agency of electricity.
Submarine Mines during the Crimean and American Wars.—It was
during the Crimean war (1854-6) that this description of defensive
torpedoes was for the first time employed on actual service. Several of the
principal Russian harbours were protected by this form of submarine mine,
but owing to the smallness of their charges, and to the want of electrical
knowledge on the part of the Russian officers and men in charge of them,
none of the ships of the Allies were sunk, or even rendered hors de combat
by this mode of harbour defence, though in several instances ground known
to be covered with submarine mines was passed over by both English and
French vessels of war.
Subsequently the Confederates, during the American civil war, employed
electrical submarine mines in considerable numbers for the defence of their
numerous harbours, rivers, &c.; but though in so far as the size of the
torpedo charges was concerned, they did not make the same mistake as the
Russians, yet, owing to the absence of proper electrical apparatus, and the
want of any practical knowledge of the manipulation of electrical sea
mines, on the part of the Confederate torpedoists, they were almost entirely
unsuccessful in destroying the Federal warships; the Commodore Jones
being the sole instance, out of the large number of vessels belonging to the
Northerners which were sunk and severely injured by torpedoes, of a war
steamer being sunk by means of electrical submarine mines.
In the Franco-German and Russo-Turkish wars which have lately
occurred, electrical sea mines were very extensively used in coast defence,
but with the exception of the loss of the gunboat Suna to the Turks, during
the latter struggle, by this form of defensive torpedo, no other damage to
vessels resulted from their use, yet owing to the vast moral power possessed

by these submarine weapons, they were enabled to most effectually carry
out the work of defence entrusted to their care.
Of late years many important discoveries have been made in the science
of electricity, and vast improvements have been effected in electrical
apparatus, to which causes may be traced the vastly improved system of
electrical submarine mines as adopted by the English, American, and
principal European governments at the present day, as compared with those
that have hitherto been employed.
The certainty of action when required of electrical submarine mines,
which is of course the desideratum of all torpedoists, has, by the improved
mode and manner of ascertaining the exact electrical condition of each
particular mine, and of the system as a whole, which is at present in vogue,
been made almost absolute.
Advantages of Electrical Submarine Mines.—This form of defensive
torpedo possesses numerous important advantages, the principal of which
are as follows:—
1.—They are always absolutely under control.
Note.—By detaching or connecting the firing battery, which is effected
by means of a plug, key, &c., they may be respectively rendered harmless,
or dangerous. Thus friendly ships may pass over them in safety, whilst those
of the enemy are debarred from so doing. On this account harbours, &c.,
protected by such mines are termed "Harbours of refuge."
2.—Fresh mines may be added to a system of such defensive
torpedoes, thereby allowing an exploded mine to be replaced.
Note.—This is a very important point in connection with a system of
defence by submarine mines, as in the case of a deep water channel, a
hostile vessel being sunk by one of them, would not become an obstruction,
as, were the channel a comparatively shallow one would most probably be
the result, and therefore it would be necessary to put a fresh mine in the
place of the exploded one; this would also apply were a mine to be
prematurely ignited, or if any portion of its firing apparatus were injured.

3.—At night, or in a fog, no vessel can pass through a channel, &c., so
protected without affording a means of ascertaining her
presence.
Note.—This is also a very important advantage of a system of defence
by electrical sea mines, affording as it does a complete
safeguard against surprise.
4.—The power of obtaining proof, without going near it, by a system
of testing that the electrical condition of the mine, &c., is
perfect.
Note.—This again is an extremely important point. For were a charge to
become wet, one of the electric cables of the mine broken, or damaged, &c.,
it would instantly be made apparent at the firing station, and could be at
once remedied.
5.—They can be raised for examination, or removed when no longer
required, with ease and safety.
Such are some of the chief advantages of employing the agency of
electricity to effect the ignition of the charge in a system of defence by
submarine mines.
Defects of Electrical Submarine Mines.—The following are the chief
defects connected with the use of electrical mines:—
1.—The number of wires that are required to be used with them.
2.—The necessity of employing specially trained men in their
manipulation.
In time there seems little doubt but that the former obstacle will be to a
considerable extent overcome, but the latter must always be a flaw in an
otherwise perfect system of coast defence by submarine mines.
Rules to be observed in using Electrical Submarine Mines.—In
connection with a system of electrical submarine mines the following rules
should be carefully observed:—
1.—They should be moored in deep channels, that is to say, where the
larger class of vessels would in attempting to force a passage
be obliged to go.

Note.—Mechanical submarine mines should never be used under these
circumstances, as the difficulties of mooring them and keeping them in
position would be very considerable, also a vessel being sunk in a very deep
channel would not necessarily block it, and as a mechanical mine cannot be
replaced, a gap would be left in the defence.
2.—They should be placed in the narrowest parts of the channel.
Note.—The object of this rule is evident, fewer mines being required,
and consequently in the case of electrical ones, a far less number of wires
are needed, which gives an increase of simplicity, and consequently more
effectiveness. This point should be observed in connection with mechanical,
as well as electrical submarine mines.
3.—They should where practicable be moored on the ground.
Note.—The advantages attendant on an observance of this rule are:—
a.—Increased vertical effect.
b.—Avoidance of mooring difficulties.
c.—Less liability of shifting from its original position.
d.—Less chance of its being discovered and rendered useless by an
enemy.
e.—By far heavier charges may be conveniently employed.
4.—Where possible, no indication whatever should be given of the
position of the mines by their circuit closers, or in the case of
small buoyant ones, by the mines themselves.
Note.—In some instances this will be almost impracticable, as for
example, where there is a very great rise and fall of tide. For instance, at
Noel Bay in the Bay of Fundy, the rise is over fifty feet. Here, when circuit
closers, or small buoyant mines are used, both of which ought never to be
more than twenty feet below the surface, long before low water they would
be found floating on the surface in full view. Many attempts have been
made to overcome this difficulty, but as yet no really practicable means
have been devised.
5.—The stations where the firing batteries, &c., are placed, should be
in the defensive work likely to be held the longest, thus
enabling the mines to be commanded up to the last moment.

6.—The electric cables should be laid in positions such that their
discovery by the enemy would be extremely difficult, and
almost impossible.
Note.—This may be to a certain extent effected by leading them from
the mines to the firing and observing stations by circuitous routes, and by
burying them in trenches.
7.—They should not be thrown away on boats.
Notes.—As they can in all cases be fired by will, even when circuit
closers are used, this rule is easily observed. But to prevent an enemy's
boats from rendering the mines useless, a line of small torpedoes might be
placed in advance of the large ones, or the circuit closers themselves might
be charged.
At night, or in foggy weather it will be necessary to employ guard-boats,
electric lights, &c., to protect them against damage by an enemy's boats,
&c.
In the foregoing pages of this chapter will be found the requirements and
conditions essential to a perfect system of electrical submarine mines for
the defence of a harbour, river, &c.; in the following pages a general
description of the component parts of such defensive torpedoes, under the
following heads—Form and Construction of Case; Electrical Fuzes;
Electric Cables; Watertight Joints; Junction Boxes; and Mode of Mooring,
will be considered.
Form and Construction of Torpedo Case.—The case of a submarine
mine should be capable of fulfilling the following conditions:—
1. It must be able at great depths to withstand a great pressure of water,
and remain perfectly watertight.
Note.—This in the case of a charge of gunpowder being an imperative
necessity.
2. As a buoyant mine, it must be capable of affording a considerable
excess of buoyancy, by which it may be rendered stationary
when moored.

Note.—This is generally obtained by having an air space within the
torpedo, thus requiring a much larger case in which the charge is enclosed
than would otherwise be necessary, causing increased difficulties in
transportation, mooring, and raising them for examination, &c.
3. When explosive agents which require a certain time for thorough
combustion are used as the charge, such as gunpowder, picric
powder, gun-cotton (not fired by detonation), &c., a much
stronger case is necessary to obtain the full explosive effect
than would be the case were detonated charges, under the same
conditions, employed.
Note.—This is an extremely important point, for if a weak case is
employed with a charge of gunpowder, &c., fired by a fuze primed with
powder only, a portion of it on being fired would generate a sufficient
quantity of gas to burst the case, thus blowing out the remainder of the
charge before its ignition had been effected.
4. It should be of such a form that the complete ignition of the charge
is obtained by the employment of the least number of fuzes
possible to effect this result.
Note.—This point is especially to be observed when gunpowder is the
explosive agent.
The various forms of defensive torpedo cases may be classed under the
following heads:—

1.—Spherical shape.
2.—Cylindrical shape.
3.—Conical shape.

Spherical Shape.—This form of case is theoretically the very best one
possible to devise, but on account of the difficulty of constructing it, and its
comparative costliness, such a form may be put aside as being
impracticable.
Cylindrical Shape.—Torpedoists in general have hitherto adopted the
cylindrical form of case as being the best adaptable for both ground and

buoyant mines containing a heavy charge.
The Confederates employed exclusively this shape for their electrical
submarine mines, which were ground ones, and the Austrians in the war of
"66" approved of this form of case for their electrical submarine mines,
which were buoyant ones. Fig. 19 and 20 represent respectively the
American and Austrian mines.
In England the cylindrical shape has up to quite lately found most favour
with her torpedoists for both buoyant and ground mines. At Fig. 21 is
represented a 100-lb. buoyant electrical mine, surrounded by a wooden
jacket, e, and having its circuit closer, C, enclosed within it; and at Fig. 22
is shown a 250-lb. electrical mine, which may be used either as a buoyant
or ground one.
For large ground mines, the best form of torpedo case seems to be that of
the turtle mine, which is shown at Fig. 9. A heavy charge may be contained
in it; it forms its own anchor; and it would withstand an explosion of an
adjacent mine without sustaining any injury. At present the cylindrical
shape is the form generally used, though as far as retaining its position on
the ground in a strong tide, it cannot be compared to the turtle form.
FORM OF CASE OF SUBMARINE MINES.

The Conical Shape.—Hitherto this shape of submarine mine case was
only used in connection with mechanical mines, but now it is the form

considered most suitable for all buoyant mines, electrical or mechanical. At
Fig. 23 is shown the conical shaped mechanical mine, employed by the
Confederates for use with sensitive fuzes. The conical form of torpedo case
lately approved of by the English torpedo authorities is somewhat similar to
that one, the charge being contained in a kind of box hung from the top of
the case, and the circuit closer is screwed into the bottom of the case;
surrounding the upper part of the case is a thick buffer of wood, by which
damage to the mine is prevented by the passage of friendly ships. This is
altogether a very neat and serviceable form of torpedo case. This form of
case is also more difficult to discover by dragging, and easier to retain in
position.
Electrical Fuzes.—The fuzes employed in connection with electrical
submarine mines may be divided into two classes:—
1. Platinum wire bridge fuzes.
Note.—That is where the evolution of heat is caused by a large quantity
of the electric force flowing through a good conductor of large section, such
as the copper core of electric cables, being suddenly checked by a very thin
wire composed of a metal which compared with the conductor offers a very
great resistance, such as platinum.
2. High tension fuzes.
Note.—That is where the evolution of heat is caused by the electric
spark, or by the electric discharge taking place through a substance which
offers very great resistance to the passage of the electric force.
Platinum Wire Fuze.—This is the form of electrical fuze most commonly
used, and which will most certainly supersede altogether the high tension
fuze.
There are numerous advantages accruing from the use of platinum wire
fuzes, the chief of which are here enumerated:—
a.—Great facilities for, and entire safety whilst testing the circuit.
b.—Extreme simplicity of manufacture.
c.—Non-liability to deteriorate.

d.—Perfect insulation of the electric cables used in connection with
submarine mines not necessary.
English Service Platinum Wire Fuze.—The following is a description of
the platinum wire fuze of the form adopted in the English service, a section
of which is shown at Fig. 24. It consists of a head of ebonite a, hollowed
out, in which a metal mould is fixed, the wires which have been previously
bared are inserted into holes in this mould, and firmly fixed thereto by
means of a composition poured into the mould, whilst hot; this is shown at
b. The two bared ends of the wires which project beyond the metal mould,
as c, c, are connected by a bridge of platinum-silver wire ·0014" in diameter
and weighing ·21 grs. per yard. This is effected as follows:—
A very fine shallow groove is made in the flat ends of the bare wires c, c,
and the platinum-silver wire is laid across in the incisions, and fixed there
by means of solder. The length of the bridge d is ·25."
A tube e, made of tin, and soldered to a brass socket f, is fixed by means
of cement to the ebonite head a; in this tube is placed the fulminate of
mercury, the open end of the tube g being closed with a pellet of red lead
and shellac varnish; around the bridge of the fuze is placed some loose gun-
cotton.
McEvoy's Platinum Wire Fuze.—Another form of platinum wire fuze,
which has been devised by Captain McEvoy, formerly of the Confederate
Service, is shown at Fig. 25. It consists of the head a, formed of a mixture
of ground glass, or Portland cement, worked up with sulphur as a base: this
mixture when hot is poured into a mould, in which the two insulated copper
wires, b, b, have been previously placed; when cold, the mixture with the
wires affixed is removed from the mould, and the platinum wire bridge c
being secured to the bare ends of the copper wires, the whole is firmly fixed
in a brass socket d, by means of cement; the space e is filled with loose dry
gun-cotton, so as to surround the bridge c; a copper tube f, closed at one
end, is partly filled with fulminate of mercury, and when the fuze is
required for service, this tube is secured to the brass socket d by means of
cement.
In this form of low tension fuze there is no liability whatever of any
injury being caused to the bridge by the working of the wires in the head, or

by damp even after lying in the water for a month or more. One peculiarity
of this fuze is that the composition is run over the insulated wires without
materially softening the dielectric, or affecting in the slightest degree the
insulation of the wires.
High Tension Fuzes.—The high tension fuze was devised for use with
electrical submarine mines, in the place of the platinum wire fuze, on
account of the little knowledge possessed, in the early days of submarine
warfare, in regard to the manipulation of Voltaic batteries.
Platinum wire requires a temperature of some 500° F. to heat it to
incandescence, and therefore necessitates the use of a powerful Voltaic
battery, both in intensity and power, to effect the ignition of gunpowder by
this means at considerable distances.
The Grove and Bunsen pile were the only suitable form of Voltaic
battery known at the period of the introduction of high tension fuzes, both
of which possessed the defects of uncertainty and inconstancy, and also
were by far too cumbersome and too difficult to keep in effective working
order to be of any real practicable value.
High tension fuzes may be ignited by means of either an electro-
magneto machine, an electro-dynamo machine, a frictional machine, or by a
Voltaic battery, generating an electric current of high intensity. Various
kinds of this form of electrical fuze have been designed, the principal of
which are as follows:—

1.—Statham's fuze.
2.—Beardslee's fuze.
3.—Von Ebner's fuze.
4.—Abel's fuze.
5.—Extempore fuze.

Statham's Fuze.—A section and elevation of this electric fuze are shown
at Fig. 26; a, b is a gutta percha tube, with an opening cut in it, as shown in
figure. The interior of this vulcanised gutta percha tube is coated with a thin
layer of sulphide of copper, which coating is obtained by leaving a bare
copper wire for some time in connection with the above-mentioned tube.
The extremities of two insulated copper wires c, c, considerably smaller

than the conducting wires, are uncovered, scraped, and then inserted into
the tube a, b, with an interval of ·15 inch between them. The wires are then
bent as shown in the figure, and the priming placed between the terminals.
The whole is covered with a gutta percha bag, which is filled with fine
grained gunpowder. The priming substance is composed of fulminate of
mercury worked up with gum water. The objection to this fuze, which was
used by the Allies in their destruction of the Russian fortifications at
Sebastopol, is the want of sensitiveness of sulphide of copper, and the
consequent necessity of a very powerful firing battery.
Beardslee's Fuze.—This high tension fuze is shown at Fig. 27. It
consists of a cylindrical piece of soft wood a, which is about three-quarters
of an inch in length and in diameter; two copper nails, b, b, are driven
through this piece of wood a, in such a way that while the two heads come
together as close as possible without absolutely touching, the pointed ends
are some distance apart from each other, and project through the wood a;
two insulated copper wires, c, c, are firmly soldered to these projecting
ends, and a piece of soft wax, d, is pressed around the junction points. In a
groove, across the heads of the copper nails, is placed a little black lead, to
which is added a minute quantity of some substance, the nature of which is
known only to Mr. Beardslee. Several folds of paper are wrapped round the
wooden cylinder, forming a cylinder about 2-1/2 inches long, one end of
which is tightly fastened round the insulated wires as at e. The other end of
the cylinder is then filled with powder, f, and closed by a piece of twine.
The whole fuze is then coated with black varnish. Though not highly
sensitive, Beardslee's fuze is exceedingly efficient, and extremely simple.
Von Ebner's Fuze.—This form of fuze was devised by Colonel Von
Ebner of the Austrian Engineers. A section and elevation of it is shown at
Fig. 28. It consists of an outer cylinder, a, of gutta percha, and an inner one
of copper, b, which latter encloses a core formed of ground glass and
sulphur, c, which core is cast round the two conducting wires d, d in such a
way that they are completely insulated from one another. In the first
instance the wire is in one continuous length, the opening e being
subsequently made, and carefully gauged, so as to ensure a uniform break,
or interval in the conductor of each fuze. The priming composition, which
consists of equal parts of sulphide of antimony and chlorate of potash, is
placed in the hollow f, to which is added some powdered plumbago, for the

purpose of increasing the conducting power of the composition. This
mixture is put into the hollow, f, of the fuze under considerable pressure, the
terminals being connected with a sensitive galvanometer, in circuit with a
test battery, and the pressure applied so as to obtain, as far as possible,
uniformity in the electrical resistance of each fuze.
The Austrians employed this form of high tension fuze in connection
with a frictional machine for the electrical mines used in their defence of
Venice, &c. during the war of 1866.
Abel's Fuze.—Mr. Abel devised a high tension fuze, which in 1858 was
extensively experimented with; the Beardslee and Von Ebner fuze being
based upon the principles applied for the first time in Abel's fuze.
ELECTRICAL FUZES.

Many modifications of it have been from time to time devised by Mr.
Abel; a section and elevation of the more recent form of his fuze is shown

at Fig. 29. It consists of b, b, a body of beech wood, hollowed for half its
length, in which space the priming charge is placed; it is also perforated by
three holes, one vertical for the reception of the capsule of sensitive
mixture, the other two horizontal, in which the conducting wires are placed;
a, a are two insulated copper wires, passing into the vertical hole, and
resting on the sensitive mixture; in a cavity, d, of the body of the fuze is
placed some mealed powder, which is fired by the ignition of the sensitive
mixture on the passage of the electrical current.
The insulated wires used in connection with this fuze consist of two
copper wires, about 2 inches long, and ·022 inch in diameter, enclosed in a
covering of gutta percha ·13 inch in diameter, and separated about ·06 inch
from each other.
At one end the wires are bared to 1·25 inch, at the other they are merely
cut across by a very sharp pair of scissors. This end of the double covered
wire is inserted into a paper cylinder c, c, which holds a small quantity of
the priming mixture. This capped end of the wires is inserted into the
wooden body of the fuze through the vertical hole i, and projects ·15 inch
into the cavity d. The bare ends of the double covered wires are pressed into
small grooves in the head of the cylinder e e, and each extremity is bent into
one of the small channels d' d', which are at right angles to the vertical
perforation. d' d' are two small copper tubes driven into these channels over
the wire ends, to keep the wires in position, and to form the opening into
which the conducting wires f are inserted and bent round, as at e'.
The priming mixture of Abel's original fuze, which was the one used by
the Confederates, was composed of 10 parts of subphosphide of copper, 45
parts of subsulphide of copper, and 15 parts of chlorate of potash. These
ingredients reduced to a very fine state of division, and intimately mixed, in
a mortar, with the addition of a little alcohol, are dried at a low temperature
and preserved in bottles until required for use. The sensitive mixture used
by Mr. Abel more recently for his submarine electrical high tension fuzes, is
composed of an intimate mixture of graphite and fulminate of mercury. By
the process of ramming, the electrical resistance of the fuze is regulated.
Extempore Fuzes.—It may be necessary in some cases, when a specially
manufactured fuze is not attainable, to make a fuze on the spot. The

following is a neat and simple method of constructing an extempore high
tension fuze.
Fisher's Extempore Fuze.—This form of fuze was devised by Lieutenant
now Captain Fisher, R.N. It consists of a small disc of gutta percha, through
which the ends of two wires are inserted about 1/4 inch apart, their ends
terminating in small copper plates formed by hammering down the wire.
These flat ends should be fixed parallel, and in the first place in contact
with one another, also should be level with the surface of the gutta percha.
The other two extremities of the wires are then placed in circuit with a
sensitive galvanometer and a test battery; the needle of the former deflects
violently, there being a complete metallic circuit; the flat ends of the wires
or poles of the fuze are then separated very carefully, until the needle just
ceases to deflect. In the space thus formed, a little scraped charcoal is
placed, and rammed in by a piece of wood. By the application of pressure,
any degree of sensitiveness may be attained, merely observing the
deflection of the galvanometer needle. Over the charcoal a little powdered
resin is shaken, and pressed down, by which means the charcoal is fixed in
position, and owing to the inflammability of the resin, the ignition of the
gunpowder priming is ensured. The disc of gutta percha is then placed in an
empty Snider ball cartridge, &c., and by the application of a little warm
gutta percha applied externally, the holes where the projecting ends of the
wires pass are closed, and the disc is fixed and insulated. The case is then
filled with some mealed powder and fine grained powder, on the top of
which is placed a little cotton wool, and the whole pressed down tightly
with the finger, the open end of the case being then choked, as in
Beardslee's fuze and Abel's extempore one. The apex is then covered with
some warm gutta percha, and the whole of the fuze coated over with red
sealing-wax dissolved in methylated spirits.
Insulated Electric Cables.—For the work of defence by electrical
submarine mines, the wires along which the electric current flows have, on
account of their being led underground and through the water, to be covered
with some substance which shall prevent the current during its passage from
escaping to earth, or in other words, they (the wires) must be insulated.
The substances in general use for such purposes are as follows:—

1.—Gutta percha.
2.—Ordinary india rubber.
3.—Hooper's material.

Gutta Percha.—This substance was used by Messrs. Siemens in the
cables manufactured by them for the Austrian government in 1866, and is to
some extent still employed, though Hooper's material or vulcanised india
rubber, has been found to be more suitable. The dielectric, gutta percha,
possesses the following advantages:—
a.—It can be put on the conducting wire, as an unbroken tube.
b.—It only absorbs 1 per cent. of water.
c.—It has the property of clinging to the metallic conductor, by which
is meant, that should it (conductor) be cut through, and any
strain be brought on the cable, there is a tendency on the part of
the gutta percha to cling to the conducting wire, thereby not
increasing the fault.
The defects of such an insulator are:—
a.—Its liability to become hard and brittle when exposed to dry heat,
and consequently it requires to be stored under water.
b.—It becomes comparatively a bad dielectric at 100° F.
c.—It becomes plastic at high temperatures, which causes the
conducting wire to alter its position.
In some particulars ordinary india rubber is a better insulator than gutta
percha, but this substance is equally inferior to Hooper's material, &c. The
advantages possessed by this substance are:—
a.—It is not easily affected by a dry heat.
b.—It is a very excellent dielectric.
The defects of this mode of insulation are:—
a.—It must be put on the conducting wires in a series of jointed pieces.
b.—It does not cling to the conducting wire, so that if the electric cable
be cut, and any strain be brought on it (cable), the previous
fault is increased.
c.—It absorbs 25 per cent. of water.

Hooper's Material.—This insulating material consists of an inside
coating of pure india rubber, then another similar coating in conjunction
with oxide of zinc, which is termed the separator, and an outside coating of
india rubber combined with sulphur. The use of the separator is to prevent
any damage to the conducting wires by the action of the sulphur. The three
coatings are then baked for some hours at a very high temperature, which
fuses the whole into a solid mass, and vulcanises the outer coating. The
properties of the pure india rubber which is in contact with the metallic
conductor are thus preserved, while any decay of the outer covering is
prevented by the vulcanising process.
The advantages claimed by Mr. Hooper for this mode of insulating
electric submarine cables, are:—
a.—High insulation.
b.—Flexibility.
c.—Capability of withstanding the bad effects of dry heat.
The qualifications essential to a perfect insulated electrical cable for use
with submarine mines are as follows:—
1.—Capacity to bear a certain amount of strain without breaking.
2.—Perfect insulation, or at least as nearly so as it is possible to obtain,
and composed of a substance capable of being readily stored,
and kept for a considerable length of time without being
injured.
3.—Pliability so that it may be wound on, or paid out from, a
moderately sized drum without injury.
4.—Provided with an external covering capable of protecting the
dielectric from injury when used in situations where there is a
rocky or shingly bottom, &c.
The insulated wire of a submarine cable is technically spoken of as its
core.
By a cable is meant to be understood any piece of covered wire.
Several forms of submarine electrical cables have been devised, all of
which more or less possess the qualifications enumerated above. The
following are some of the most effective:—

1.—Siemens's cable.
2.—Hooper's cable.
3.—Gray's cable.
4.—Service cable.

Siemens's Cable.—This form of cable is represented at Fig. 30. It
consists of a strand a, which is composed of three or more copper wires
formed by laying up the several single copper wires spirally, several layers
of gutta percha, or india rubber, b, two coverings of hemp, saturated with
Stockholm tar, c and d, and several plies of copper tape e, wound on, so that
each strip overlaps the preceding one, as shown at Fig. 30. The conductivity
of the copper employed for the strand is equal to at least 90 per cent. of that
of pure copper.
This exterior covering of copper tape is a patent of Messrs. Siemens
Brothers, and when once laid down, the cable so covered is very efficiently
protected, and of course it is little affected by the action of the sea water.
This mode of protection has one great defect, viz., that in the event of a
kink occurring in paying out the line, and at the same time a sharp strain
being applied, the copper tape at that point is extremely likely to destroy the
insulation by being drawn in such a way as to cut through the dielectric. On
this account great care must be observed in handling this form of cable.
In practice precautions must be taken to prevent the copper tape
covering from being brought into contact with any iron, for were such to
happen, electrical action would at once ensue, causing the iron to corrode
with enormous rapidity.
In some of Siemens's cables, vulcanised india rubber replaces the gutta
percha insulation. Iron covered cables, either galvanised or plain, are
manufactured as well as the copper tape covered ones by that firm.
Hooper's Cable.—This form of cable is represented at Fig. 31. It
consists of a metal conducting wire, generally copper, a, covered with an
alloy to protect it from chemical action, the insulating substance b, known
as Hooper's material, previously described at page 39, a covering of tarred
hemp c, and an outer covering of iron wires (No. 11 B. W. G.), each of
which is separately covered with tarred hemp and wound on spirally, d.

Gray's cable is very similar to the one just described, the chief difference
in it as compared with Hooper's being the absence of the separator.
Silvertown Cables.—The following is a description of the core of an
electrical submarine cable, which is used by the English government, and is
supposed to contain all the advantages of the foregoing, and none of their
defects. It consists of a strand conductor of four copper wires (No. 20 B. W.
G.) of quality not less than 92 per cent. of pure copper, and possessing an
electrical resistance of not more than 14 ohms per nautical mile. This strand
is tinned and insulated with vulcanised india rubber to a diameter of ·24
inch, and then covered with a layer of felt, and the whole subjected to a
temperature of 300° F. under steam pressure. This forms the core of the
various kinds of cables employed in connection with a system of defence by
electrical submarine mines, which are enumerated as follows:—

1.—Single core armoured cable.
2.—Multiple cable.
3.—Circuit closer cable.
4.—Single core unarmoured cable.
5.—Special cables for firing by cross bearings.
Single Core Armoured Cable.—This form of cable is used in connection
with each mine of a group or system, and also to connect forts, &c. across
an arm of the sea. Over the core, which has been fully described, is laid a
spiral covering of tanned, picked Russian hemp, over this are laid ten
galvanised iron wires (No. 13 B. W. G.), each one of which is covered with
a similar hemp, which is laid in an opposite spiral to the former similar
covering, with a twist of one revolution in about thirteen inches; in order to
prevent these wires from gaping when the cable is kinked, a further
covering of two servings of hemp passed spirally in opposite directions is
laid, and the whole passed through a hot composition of a tar and pitch
mixture. Exterior diameter of this cable is 7/8 inch. Its weight in air is 27-
50/112 cwt., and in water 14-40/112 cwt. per nautical mile. The breaking
strain of a cable thus manufactured is 62-1/2 cwt., and its cost about £47 per
nautical mile. A diagram of this cable is shown at Fig. 32.
Multiple Cable.—This form of cable is employed in cases where it is
necessary to carry a large number of cables into the firing station, &c. It
consists of seven single cores formed into a strand, over which a padding of
hemp fibres is laid longitudinally, and over this again is laid an armouring
of sixteen (No. 9 B. W. G.) galvanised iron wires, each one of which is
covered with a layer of tarred tape put on spirally with a twist of one
revolution in 15 inches. The exterior covering consists of two layers of
hemp and composition, which is laid on with a short twist, and in opposite
directions. The external diameter of this cable is 1-1/4 inch. Its weight in air
and water is 78-25/112 cwt., and 45-32/112 cwt. respectively per nautical
mile. Its breaking strain is 135 cwt., and cost about £357 per nautical mile.
This form of cable is used in connection with a junction box, from which
the single armoured cables leading to the different mines radiate, and is
shown at Fig. 33.
Circuit Closer Cable.—This cable, which connects the mine and circuit
closer, has been found to be subjected to exceptional wear and tear, and

therefore requires a special form of exterior protection. The core of this
cable is the same as the one described at page 41, also it is covered with a
similar padding of hemp, but instead of the iron wires as in the case of the
multiple cable, &c., nine strands, each of which is composed of fourteen
No. 22 Bessemer Steel Wires, are wound on, each such strand being
covered with hemp, which is put on with a twist of one revolution in every
7-1/2 inches, the external covering being the same as in other cables.
This form of armouring for an electric cable possesses the qualifications
of pliability, lightness, and great tensile strength. Its weight in air is 52-
106/112 cwt., and in water 28-4/112 cwt. per nautical mile. Its breaking
strain 65 cwt., and cost about £127 per nautical mile.
Single Core Unarmoured Cable.—This form of cable is used in a system
of defence by submarine mines to connect the detached works of a maritime
fortress, &c., for the purpose of telegraphing.
It consists of the ordinary service core, over which are laid two servings
of tarred hemp, put on spirally. The weight of this cable in air is 4-13/112
cwt., and in water 1-36/112 cwt. per nautical mile; its breaking strain is 7-
1/2 cwt., and its cost per nautical mile is about £35.
Special Cables.—In firing electrical submarine mines by means of cross
bearings, a special cable is employed. As a general rule there would be three
lines of mines placed to converge on one of the stations.
Each of these lines would be provided with a conducting wire in
connection with the firing arrangements, while one line of wire in
connection with the firing station would be required for telegraphing. For
the purpose in question a four cored cable is used.
Land Service Cable.—The cable employed for this service consists of a
core formed similar to that of the multiple cable, described at page 41; over
which is laid a padding of hemp, and finally two servings of tarred hemp
laid spirally in opposite directions are wound on. Its weight in air is 16 cwt.,
and in water 4-50/112 cwt. per nautical mile. Its breaking strain 17-1/2 cwt.,
and cost per nautical mile about £137.
Sea Service Cable.—This consists of a similar core to the land service
cable, and padding of hemp, over which is laid an armouring of fifteen No.

13 galvanised iron wires, each one being covered with tarred tape, and
finally the ordinary servings of tarred hemp. Its weight in air is 49-101/112
cwt., and in water 25-109/112 cwt. per nautical mile. Its breaking strain 65-
100/112 cwt., and cost per nautical mile about £202.
When frictional electricity is used to fire high tension fuzes, it has been
found by experiment that if several lines of insulated cables are laid in the
same trench for a few hundred yards, the inductive effect of the electrical
charge generated by a frictional machine is so great that its discharge
through one cable is sufficient not only to fire the fuze in immediate
connection with it, but by induction every other fuze in connection with the
remaining wires laid in the trench. And this effect equally occurs when the
electric cables are some feet apart, provided they run parallel for a few
hundred yards, and whether the shore ends of the cables, the fuzes in
connection with which are not intended to be fired, are insulated, or put
directly to earth, the connections beyond the fuzes being to earth, or even
insulated, provided a very few yards of conductor exist beyond the fuze.
The length of wire which it is necessary to use between the mine and its
circuit closer would be quite sufficient for the purpose of effecting ignition
by induction. With platinum wire fuses there is no danger whatever of the
above happening, nor in the case of high tension fuzes is there so much
danger of ignition by induction, when a constant instead of a frictional
electric battery is used to generate the current.
Another mode of protecting an insulated cable is to place it, as it were, in
the core of a hempen cable. In forming the rope on the cable, great care is
necessary to prevent any serious amount of torsion, or tension coming on
the insulated wire, either of which would most assuredly result in injury to
the cable. This form of cable might in connection with obstructions, &c., be
of great use, as on account of its closely resembling an ordinary rope, it
would be very unlikely to excite suspicion, and so would most probably be
cut, the result of which, by previous arrangement, would be an explosion of
a mine, or by means of a galvanometer, &c., an indication that the
obstructions, &c., were being interfered with.
Jointing Electrical Cables.—This is a very important point in connection
with a system of defence or offence by electrical torpedoes. In many

instances it will be found necessary to join either two lengths of cable, or an
insulated wire and a cable, together, in both of which cases, great care must
be used in making the joints, so that the insulation and the continuity of the
circuit may be perfect.
ELECTRIC CABLES, EXTEMPORE CABLE JOINTS.

Many species of junctions have been from time to time devised, the most
practical and generally employed of which are:—

1.—India rubber tube joint.
2.—Mathieson's joint.
3.—Beardslee's joint.
4.—McEvoy's joint.
5.—Permanent junction.

India rubber Tube Joint.—This form of joint is a very useful one for
extempore purposes, being easily and quickly made, and being very
effective. At Fig. 34 is shown a sketch of such a junction. About 1·5 inches
of the copper conductor of the two insulated cables are laid bare and
connected together by means of Nicoll's metallic joint, as shown at Fig. 36,
or by turning one of the conductors round the other, their ends being
carefully pressed down by means of pliers, to prevent any chance of the
india rubber tube being pierced; over the splice thus formed serve some
twine, and over the whole put a coating of india rubber cement, grease, &c.,
then draw the vulcanised india rubber tube, which has been previously
placed on one of the insulated cables, over the splice a, as shown at b, and
secure it firmly by means of twine, c, c, and then to prevent any strain being
brought on the joint, form a half-crown as shown in Fig. 35 at A.
In forming the splice, it is very important that the metallic ends should
be perfectly clean. The danger to this mode of jointing of the piercing of the
tube by the ends of the conductors is entirely removed by employing the
Nicoll metallic joint, which is formed as follows:—
Nicoll Metallic Joint.—One of the conducting wires, as a, Fig. 36, is
formed into a spiral twist by means of a very simple instrument, and the
other wire b, which is left straight, is inserted into the spiral, the whole
being placed on an anvil, and pressed closely and securely together by a
single blow of a hammer.
Mathieson's Joint.—This somewhat complicated, though very effective
mode of jointing, which is adopted in the English torpedo service, is shown
at Fig. 37, in elevation and section. It consists of two ebonite cylinders a, a,
through which the cables to be connected are passed. Within these cylinders
an ebonite tube b, b is placed, the ends of which are wedge-shaped, and
which press against two vulcanite rings c, c; in the interior of this tube b, b
is the metallic joint d of the two cables. The centre of the tube b, b is of

square section, and fits into a hollow of similar form in the cylinders a, a,
the object of this being to prevent any twisting of the wires during the
process of screwing up, which would be liable to injure the metallic joint d.
The manner of making this joint will be easily understood from the
figure. With this, as with all other temporary joints, it is advisable to form a
half-crown in the cable, including the joint.
Beardslee's Joint.—This form of temporary joint when used with strand
conductors, which are composed of a number of small wires, has been
found to be exceedingly useful and effective, the only defect of such a joint
being the liability of straightening the wires of the conductors should a
direct strain be brought upon the wire extremities. Fig. 38 represents a
section of this joint; it consists of an ebonite cylinder a, one end of which is
solid, and the other open and fitted with a screw thread, into which is
screwed a plug b; through both the plug b, and the solid end of the cylinder
a, perforations are made just large enough to admit the insulated wires c, c;
about half an inch of the extremities of these wires are bared and cleaned,
and then passed, the one through the plug b, a disc of vulcanised india
rubber d, and a metal disc e, and the end of the strand conductor turned
back on the face of this metal disc, the other through the perforation in the
solid end of the cylinder a, then through similar discs d and e, and the end
of the strand conductor treated in the same manner as the former one; then
by means of the screw plug b, the two metallic discs b, b, and consequently
the bare extremities of the strand conductors are brought into close metallic
contact.
McEvoy's Joint for Iron Wire covered Cable.—This form of joint is
shown in section at Fig. 39. Two brass caps a, a are slipped over the ends of
the cables required to be joined, then the iron wire and other coverings of
the cables down to the insulating substance are removed, the former being
bent back close against the bottom of the caps a, a, as shown in Fig. 39 at b,
b; the cores of the cables are then joined by an india rubber temporary joint
c, which has been described at page 45: the whole is then placed in the body
of the joint, and the brass caps a, a screwed up, jamming the bent back iron
wires against a solid piece of brass d, d, by which means a firm and perfect
joint is made in the cables.
PERMANENT JOINTS FOR ELECTRIC CABLES.

Fig. 40 represents a section of a McEvoy temporary joint for single
cored unarmoured cables, which seems to fulfil all the conditions necessary

to a perfect joint of that description. This joint is, with the exception of
there being two screw plugs instead of one, very similar to Beardslee's joint
described at page 46; this alteration is a great improvement, remedying as it
does the one defect of Beardslee's joint, viz., the liability of the cables to be
drawn apart due to any great tension being brought on them.
A permanent joint in electrical submarine cables, which from its nature
requires to be an exceptionally good one, is a somewhat difficult and
troublesome operation, and also requires a considerable time to form a
thoroughly reliable one.
Siemens's Methods of Jointing.—The following methods, and
instructions for forming such joints, are those adopted by Messrs. Siemens
Brothers in connection with their telegraph cables, and which will be found
generally applicable to all insulated cables.
The Formation of a Joint in the Conductor of an Insulated Cable.—The
conductor is either covered with a gutta percha or an india rubber dielectric.
In both cases cut off the dielectric so as to bare the conductor-wire for a
length of about three inches, taking care never to cut at right angles to the
conductor-wire, for fear of injuring it with the cutting-knife or scissors.
Then clean the wires forming the strand with file-card and emery-paper,
and solder them into a solid bar for a length of about one inch.
Having soldered the wires, forming the ends of the two lengths of
conductors to be joined, into two solid rods, file each of them off in a
slanting manner, so that they will form a scarf-joint when put together.
Place the two ends of strand in the two small vices on a stand which is
supplied for the purpose, so that the two scarfed ends overlap each other,
and bind them round with a piece of fine black iron wire, in the shape of a
spiral, so as to keep the ends close together, then solder the two ends
together by applying a hot soldering iron.
Then remove the iron binding wire and clean up the joint, filing off all
unnecessary solder.
And make a band of four fine tinned copper wires, and bind them tightly
side by side round the joint, covering the whole length of the scarf, and then

solder the band and joint solidly together.
Then make another band of four fine tinned copper wires and bind them
round the joint in the same manner as before, but extending about a quarter
of an inch beyond each end of the other binding wire, the parts only of this
second binding which project beyond the end of the first binding are to be
soldered, so that the centre part remains loose and may keep up a
connection between the two ends by forming a spiral between them in the
event of the scarf giving way and the two ends of the conductor separating
slightly.
This form of joint is called the "spring" joint.
The finished joint should be washed with spirit of wine and brushed, so
as to take away all particles of soldering flux, and to avoid oxidation of the
wire. The washed joint should then be dried with a piece of cloth and
exposed to the flame of a spirit lamp to dry it thoroughly. A cable conductor
ought never to be jointed with the help of soldering acid, but with that of
resin, sal ammoniac, or borax only, so that any chance oxidation, and
consequently destruction, of the conducting wire may be avoided.
There are other modes of jointing conductors, such as the twisting and
scale joint, but the foregoing method will sufficiently explain this part of
electric cable work.
The Formation of a Joint in an India rubber Insulated Cable.—In
making a joint in any insulated cable, the very greatest care must be taken
to keep the hands, tools, and materials clean and dry.
Remove the felt for about twelve inches from each end of the core by
soaking it with mineral naphtha and then rubbing it off clean with the file-
card. The cleaned surface sear with a red-hot iron, to burn off all remaining
fibres of the felt. Wash these seared ends clean with naphtha.
Then cut off about four inches of the insulating material (taking care
never to cut at right angles to the conducting wire for fear of injuring it) so
as to leave enough of the conductor bare to join and solder in the manner
described at page 47.

After the conductor is jointed and soldered, clean again the seared parts
of the insulator with the glazed side of the squares of cloth moistened with
mineral naphtha, so as to leave a clean adhesiveness only; taper again the
insulating material down to the conductor for about two inches on each side
of the conductor-joint with a pair of curved and very clean scissors.
The tapering must be completed in such slanting way that the different
layers of the dielectric are so far exposed as to enable a secure laying on of
the new jointing material.
India rubber core consists chiefly of three layers of insulating material:
the first layer next to the strand is called the pure or brown; the second layer
is the white or separating; the third layer is the light red or jacket rubber.
Coat the conductor with a pure (brown) rubber tape tightly laid on in a
spiral form, commencing at the spot where the separator (white) ends,
across the corresponding place on the opposite side of the joint and back
again in a contrary direction. The ends are fastened down by pressing a
clean, heated searing-iron or a heated knife on them. By doing so the band
will stick; the remaining portions of the band to be cut off with the scissors.
Lay on tightly the separating india rubber tape in the same manner, but
beginning where the jacket or outer layer of rubber ends. One lap will be
sufficient.
Complete the insulation by lapping on tightly two layers of red india
rubber tape: the last lap must cover each end of the core to four inches on
each side of the conductor-joint, or extend to the searing or tackiness, but
not beyond it.
Lay on three tight bindings of the cloth tapes, all in the same direction,
care being taken to avoid wrinkles. The ends of the cloth tapes are cemented
down with a thin coating of india rubber cement.
Immerse the joint in the jointing-bath at 150° to 200° F. and gradually
raise the heat so that in half an hour the temperature will be 320° F., at
which temperature keep the joint for twenty minutes: then take it out and let
it cool in the open air.

The Formation of a Joint in a Gutta percha Insulated Cable.—Having
jointed the conducting wires in the manner described at page 47, clean and
dry the joint well and cover the bare conductor with a thin layer of
compound. This is best done by heating a small stick of compound to nearly
its melting point, and rubbing it over the bare conductor, which has been
previously heated with the flame of a spirit-lamp.
Heat the gutta percha covering of both ends gently until it is quite soft,
without, however, causing it to bubble or burn. Draw, then, with the fingers,
the gutta percha coverings of both ends down, tapering them off until they
meet in the middle of the joint; heat them sufficiently to make them adhere
together.
Apply a layer of compound on the tapered-off gutta percha in the same
manner as described for coating the bare conductor, and cover it with a first
coating of gutta percha sheet to about half the thickness necessary to finish
the joint. This is done by heating a small sheet of gutta percha, of about
one-eighth of an inch in thickness, until it is quite soft, and by pressing it in
that state round the joint to the required size; the greatest care to be taken to
expel all the air.
The projecting lips are then cut off with a pair of curved scissors. The
seam thus produced is to be rubbed with a hot iron until it is completely
closed and the joint well rounded off.
Apply another layer of compound and a second layer of gutta percha in
exactly the same manner as described for the first layer; care, however, is to
be taken to get the seam in this second layer of gutta percha not over, but as
nearly as possible right opposite to, the seam in the layer underneath.
The whole to be worked as cylindrical as possible, and to a size not
exceeding the original core. The joint, so far finished, is then to be cooled
with water until the gutta percha is quite consolidated.
Another, the overlapping gutta percha joint, is made in the following
manner:—
Cut off the two ends of the core, so that the gutta percha and the
conductor-wire are flush. Warm the gutta percha for a distance of about
three inches from each of the ends with the flame of a spirit lamp, and,

when sufficiently soft, push it back until it forms an enlargement. The two
ends of the conductor are then to be soldered according to instructions for
making joint in conductors.
To have a perfectly clean surface of the two gutta percha enlargements,
remove all impurities by the way of peeling them with a sharp knife. Warm
gently both knobs and the copper joint, and cover the whole length of the
bare wire with compound, planing it with a warm smoothing-iron.
Draw then with the fingers one of the warmed and softened knobs
carefully up to the other knob or enlargement, leaving on its way a perfect
tube of gutta percha upon the wire, decreasing gradually to the thickness of
the copper strand towards the other knob. Any superfluous gutta percha is
removed. This scarf is finished with a warm smoothing-iron, so as to unite
it to the compound on the wire strand, and a thin layer of compound is also
put over the scarf in the same manner as before.
The other knob is then warmed and drawn in the same way over the tube
already formed, which is at the same time heated sufficiently to make the
two adhere.
Apply a layer of compound on the second scarf of gutta percha, covering
it in the same manner as described for coating the bare conductor, and cover
it with a small sheet of gutta percha in the same manner as described above,
so as to make the finished joint to the size of the core as manufactured.
Rules to be observed in forming Joints.—The following rules must be
carefully observed in forming either a temporary or permanent joint:—
1.—In laying bare the conductor, the dielectric should be warmed and
then pulled off, so preventing any chance of it being damaged,
which might be the case were the dielectric to be cut off.
2.—For a perfect junction, soldering is necessary.
3.—The wires before connection should be carefully cleaned, and the
hands of those performing the work must be dry.
4.—Gutta percha should not be given too much heat, for it then
becomes oily and will not, in that state, properly adhere.
5.—Grease and dirt must be scrupulously avoided.

Great care is absolutely necessary in making junctions, as they are the
principal sources of defect in the insulation of electrical submarine cables.
Junction Boxes.—When it is necessary to employ a multiple cable, a
junction box is used to facilitate the connection of the several separate wires
diverging from the extremities of such a cable. In one angle of such a box
the multiple cable is introduced, while the separate cables make their exit
on the opposite sides and pass to the different mines. Different views of a
junction box are shown at Fig. 41, where A is a plan of the top or lid, B a
plan of the bottom, with the lid off, C an elevation, and D a section of the
box.
The manner of using the junction box is as follows:—
The multiple cable is put in at a, and secured there by means of a
nipping hook, shown at Fig. 42, which hook passes through the bottom of
the junction and is made secure by means of a nut. The single core cables
radiating from the junction box pass through the openings b, b, b on the
sides, and angle opposite to where the multiple cable a enters. Each
multiple cable is composed of seven cores, and each of these is connected
by means of joints with the mine cables within the junction box, and each of
these seven cables is secured by means of a nipper similar to, but smaller
than, the one shown at Fig. 42, which are also secured by means of nuts, as
in the case of the multiple cable nipping hook. When all the connections are
made, the lid A is placed so as to rest on the studs c, c, c, and firmly secured
by a bolt d, which is made water-tight by means of a washer and nut.
By means of the nipping hooks, which take any strain that may be
brought on the cables, the connections within the box are ensured against
injury by such a cause.
To enable the whole to be lifted together for the purposes of examination
of the cables, &c., a buoyed rope is connected to the eye-bolt e. For this
service a dummy circuit closer is the best form of buoy, it having great
buoyancy and resembling in appearance an active circuit closer.
A junction box should be placed in such a position as to be easily
attained, even in the presence of an enemy, and its buoy should, if possible,
not be seen. It is also very essential that it should be in a safe and guarded

position, for any injury to the junction box or multiple cable would be fatal
to the group of mines in connection.
In the following cases, special junction boxes are used:—
1.—A seven cored armoured cable to be connected direct to another
length of the same.
2.—A single armoured cable to be connected as in foregoing instance.
3.—A T junction box for the branch system of electrical contact mines.
Junction Box for Multiple Cables.—At Fig. 43 is represented a plan of
lower half of this form of junction box. It consists of a pair of cast iron
plates of precisely similar form to the one shown at Fig. 43, and so made as
to be capable of being fastened tightly together by means of four bolts and
nuts passing through the holes a, a. The grooves b, b at the two extremities
are just large enough to grip the armoured cable firmly, when the upper and
lower parts are screwed together. A larger space is provided in the hollow
for the joint.
Junction Box for Single Cored Cables.—For this purpose a junction box
similar to, but smaller than the one above described is employed.
T Junction Box.—This form of junction box is employed when the
system of electrical contact mines on branches from a single cable is used.
This system is dependent on the use of a platinum wire fuze in connection
with a platinum wire bridge in each branch close to its junction with the
main cable.
This form of junction box, which is shown at Fig. 44 is very similar to
the one used for the connection of two multiple cables, only differing in its
shape, which is that of a T. a is a disconnector, which will be described
further on; b, b, b' are the armoured electric cables, b, b being the main, and
b' the branch cable in connection with the forked joint formed within the T
junction box; c, c, c are Turk's heads formed to prevent any strain being
brought on the forked joint. This form of Turk's head is made by turning
back the wires of the cable armouring, and frapping them round with spun
yarn until the necessary size and shape is attained.
McEvoy's Turk's Head.—Another form of Turk's head, devised by
Captain McEvoy, is shown at Fig. 45. It consists of two separate pieces of

brass, a and b, the former screwing over the latter. The mode of using it is
as follows:—
Slip the piece of brass b over the cable c, and turn back the wires of the
cable d, d, &c., so that they lie against the shoulder of the brass piece b,
then slip the other piece of brass a over the cable and screw it on the piece
b, firmly jamming the turned back wires d, d, &c. This is a very neat and
quick method of forming a Turk's head, and it should be invariably used in
preference to the foregoing method, which is clumsy, and which takes some
time to form.
The section of a disconnector is shown at Fig. 46. It consists of an iron
cover, or dome a, which is provided with a screw fitting on to another screw
on the ebonite body b of the apparatus. When the dome a is screwed tightly
down on the washer i, the whole is made perfectly watertight. c, c are
insulated terminals for connecting the cores of the branch and main cables
after their armouring has been removed, as shown at Fig. 44. d, d are two
copper conducting wires (No. 16 B. W. G.) passing through the centre of the
ebonite body b, and projecting into the interior of the apparatus. These
wires are held in position and insulated by means of a composition formed
of a mixture of pitch, tallow, beeswax and gutta percha. This composition is
put on whilst hot and allowed to cool gradually, when it becomes hard and
durable. Great care is necessary to ensure the cavity within the ebonite body
b being completely filled, as otherwise a leakage might occur, owing to the
great pressure of water at depths where the disconnection would be
generally used. f is a boxwood cover which is slipped on, and fits fairly
tight to the ebonite body b; g is a piece of thin platinum wire, weighing 1·6
grains to the yard, and being 4/10 inch in length; h is an ebonite pin, which
passes through two small holes in the boxwood cover f, into which it fits
tightly, and in such a position as to be directly beneath the platinum wire
bridge g, when the boxwood cover f is fixed on. The pin h is pushed
through the holes in the cover f from the outside, so as to pass beneath the
bridge g after the priming has been inserted, and the cover has been placed
on.
When prepared for use, the platinum wire bridge g is surrounded by
some loose gun-cotton priming, sufficient in quantity to blow off the
boxwood cover f, without destroying the dome a; the cover f being blown

off, carries the ebonite pin h with it, and through the platinum wire bridge g,
thereby rupturing it, and breaking the continuity of the circuit. The object of
so doing is to cut off the connection of an exploded mine, so that the full
amount of the firing current is available for the other mines, and not
suffered to be wasted by passing through the exposed wire of the broken
circuit, which, were the disconnector not employed, would be the case.
When any particular mine of a system is struck, the current passes
through the main cable b, the disconnector a (which is in connection with
that mine), and branch cable b' to the fuze, and so explodes the mine, and
destroys the platinum wire bridge g of the disconnector at practically the
same instant. The effect of the latter operation would be to cut off and
insulate the branch cable of the exploded mine, and so prevent any loss of
the electrical current, when another mine of that system is required to be
fired.
The platinum wire bridge g is 4/10 inch long, while that of the fuze is
3/10 inch, the object of this difference in length of the bridges being to
ensure the former one g being fired, and thus the insulation made doubly
sure. Many other forms of disconnectors have been devised, but none have
proved in practice so effective as the one just described.
JUNCTION BOXES. MECHANICAL TURK'S HEAD.

Mooring Electrical Submarine Mines.—This is one of the most difficult
problems to be solved in connection with a system of submarine mines. The

objects to be attained in mooring are as follows:—
1.—The mines should preserve the exact positions in which they are
laid down.
Note.—From the comparatively small radius of destructive effect, of
even heavily charged submarine mines, it will be understood how
absolutely essential, in the case of mines fired by judgment, it is that this
object should be attained.
2.—The mooring chains, or ropes, must be so arranged that no twisting
whatever should occur, as otherwise fracture of the insulated
wire would be likely to happen.
3.—In the case of buoyant mines, their distance from the bottom must
be so adjusted, that at no time shall a vessel passing over them
be out of their vertical range of destruction, nor shall they be
visible.
The difficulties attendant upon the efficient mooring of submarine mines
are immense, as will be understood when the action of gales of wind, and
strong tides, which latter vary continually in their direction and in their rise
and fall, are taken into consideration.
The foregoing remarks apply more particularly to a system of buoyant
submarine mines, as those placed on the ground are comparatively easy to
moor.
Several modes of mooring buoyant submarine mines have been
suggested, the most practicable of which are as follows:—

1.—Ladder moorings.
2.—Fore and aft moorings.
3.—Austrian method of mooring.
4.—Single rope mooring.

Ladder Mooring.—This is a method of mooring, which in places where
it may be necessary to place the anchors far apart will be found useful.
The circuit closer is connected to the mine by two ropes which lead
thence to two anchors, the ropes being separated by wooden rounds, or

spreaders, 1 to 3 feet long, by which the tendency to twisting is prevented.
The anchors are placed some 12 feet apart.
The only defect of the ladder mooring is the quantity of sea-weed, &c.,
that is liable to be lodged on the rounds, thus causing the circuit closer to be
drawn out of its proper position.
Fore and aft Mooring.—This mode may be advantageously employed in
a tideway where the current runs very strong, that is to say, five knots per
hour, or more. It consists simply of two anchors, one of which is moored
up, and the other down the stream.
Austrian Method of Mooring.—This method of mooring, adopted by the
Austrians during the war of 1866, is shown at Fig. 47. It consists of a
wooden triangular platform on which several heavy weights a, a, a are
placed; the mine is attached to this platform by means of three wire ropes b,
b, b, connected to the angles of the latter, and fastened to three chains,
which by means of a catch holds the mine at the position required.
This catch consists of a pulley attached to the extremity of the wire rope
of the platform, through which the mooring chain of the mine is passed, and
fastened by a key at the required depth by means of a self-acting
arrangement.
This key, which is of considerable weight, slips down as the mine is
being hauled into position, but the moment the chain is slacked, two arms
catch into a link of the chain, and so hold the mine in position. The weight
of such a key is about 60 lbs. It is fitted with nuts, &c., to enable it to be
taken to pieces.
This plan of mooring proved very effective in the harbours of the
Adriatic, where there is hardly any tide or current to twist the mooring
ropes, or otherwise disturb the mines. The Austrians have lately adopted the
mushroom sinker in place of the wooden platform and weights, for their
anchor.
Single Rope Mooring.—This simple method of mooring has after
numerous exhaustive experiments been adopted as the most practicable and
effective of all others. Whenever possible, a wire instead of hempen cable

should be used to connect the mine and its circuit closer to the mooring
anchor, as the former is less liable to twist, kink, or wear from friction than
the latter.
A ground mine with circuit closer attached is represented at Fig. 48,
where a is the wire mooring rope, b the electric cable leading from the mine
to the circuit closer, C, and c the cable leading from the firing station to the
mine; d is the oblong sinker attached to the mine, and e the tripping chain
leading to the shore, to which the cable c is attached at intervals, so that by
underrunning the electric cable, the tripping chain may be easily picked up,
and the mine raised.
MOORINGS FOR SUBMARINE MINES.

At Fig. 49 is shown a buoyant mine. The only difference in the mooring
of this and the one before described, is that instead of resting on its anchor

on the ground, it is moored at a certain distance above its anchor d, to which
it is secured by a chain e.
Fig. 50 represents an electro contact mine. M is the mine with circuit
closer enclosed, a the wire mooring rope, d the mushroom anchor, and b the
electric cable leading from the mine to the disconnector D.
The mushroom sinker or anchor, which is undoubtedly the most
effective of all other forms of mooring anchors used for the purposes of
anchoring submarine mines, is shown at e, Fig. 49; the legs are added for
use on rocky or hard bottoms, under which circumstances the weight of the
anchor should also be increased.
For ground mines the form of sinker shown at d, Fig. 48 is employed; it
is of an oblong shape, and hollowed out in the centre to allow of its being
lashed close up to the mine.
Large blocks of stones with their bases slightly hollowed are useful as
extempore moorings, so also is the one shown at Fig. 51, which consists of
a strong heavy wooden shaft a, with a number of wooden arms b, b attached
to its base; this form of extempore sinker was considered very efficient by
the American authorities.
The wooden weighted platform, which was described at page 56, is also
a very useful form of extempore sinker.
For dead weight moorings, pigs of ballast, heavy stones, &c., may be
used.
The weight of the anchor or sinker for mooring submarine mines is a
very important consideration. It will depend on the amount of buoyancy of
the mine, on the strength of current, and on the nature of the bottom, also
whether the mines are to be hauled down to, or moored with the anchor.
Stotherd uses the following formula:

W = 2√B2 + P2
where B is the excess of the flotation over the weight of the charge of a
given submarine mine;

P is the pressure exerted by any given current on the same buoyant mine;
W the weight of sinker necessary to overcome the tendency of the mine
to move. In still water P becomes nothing, and therefore W equal to 2 B,
that is, in still water double the buoyancy of a mine is a sufficient weight for
its anchor.

The value of P may be found from the formula P = 4·085 × V2, where V
is the velocity of the current in miles per hour.
From this equation P will be found in terms of pressure in pounds per
square foot of flat surface, which is nearly double that on the curved surface
of a cylinder.
In regard to the amount of buoyancy of a submarine mine, it has been
found by actual practice that in the case of a mine moored in still water it
should certainly be not less than the weight of the charge, whilst if
subjected to the lateral pressure due to a current, it should be not less than
three times the pressure exerted by the current.
It is always necessary to allow an excess of buoyancy over the calculated
amount to counteract any leakage, or other disturbing cause which might
otherwise materially affect the efficiency of the mine.
There are two modes of placing a mine in position; either by attaching
the anchor, with the cable necessary for the depth of water, to the mine, and
lowering both together, or by placing the anchor first, and then hauling the
mine down to it, and by means of a catch, fastening it at the required depth.
The first mode is exceedingly simple, but except under very favourable
circumstances cannot be relied on when firing by observation is the means
adopted to explode a system of submarine mines. The second plan is
practically easy to carry out, and by it a mine may be placed more
accurately. To enable either of the above methods to be properly carried out,
specially fitted steamboats, &c., are requisite.
At Fig. 52 is represented a 42 feet launch fitted for laying down a
submarine mine by the first of the two modes enumerated above.
STEAM LAUNCH FOR MOORING SUBMARINE MINES.

a is the mine; b is the electric cable carried from the drum c to the
charge, and connected for use; d is the circuit closer, which is attached to
the mine by its electric cable and mooring rope; f is the mushroom sinker
attached by means of its mooring chain to the mine, it is suspended by a slip
rope g, which passes over a small crutch fitted with a sheave h; i is a hollow
iron derrick, and k the tackle and fall for lifting mine into boat; this derrick
is formed of an iron tube about 3 inches diameter, 3/8 inch thick, and 10
feet 6 inches long; it is attached to an iron tube mast of similar diameter and
thickness to the derrick, but 12 feet 3 inches long, an iron chain 6 feet 6
inches long and 5/8 inch diameter, connects the derrick to the mast; m is a
leading sheave to keep the cable clear whilst it is being paid out; l is a crab,
for working the tackle k, &c., and c is the drum on which the electric cable
is wound.
In connection with the defence of a harbour by a system of electrical
submarine mines of large size, it will be necessary to employ a service of
steamtugs, steamboats, mooring-barges, &c., specially fitted for such work.
One of the great advantages of the hauling down method of placing mines
in position, is, that the anchors, with the cables connected thereto, may be
carefully and accurately got into position during the time of peace, and the

mines themselves, which should be kept in store ready fitted for immediate
use, need not be placed in position until they are actually required. The
drums used for reeling a multiple cable on, are capable of holding half a
nautical mile in length. That used for a single core armoured cable is similar
to but smaller than the aforesaid drum, and is capable of stowing one
nautical mile of such a cable. For transportation wooden drums are
ordinarily used.

CHAPTER IV.
DEFENSIVE TORPEDO WARFARE—continued.

C LOSING the Electric Circuit.—In connection with the system of coast
defence by means of electrical submarine mines, there are two distinct
methods of effecting the closing of the electric circuit, and consequently,
the firing battery being connected, the explosion of the mine or mines,
which methods may be used separately, or in combination, and are as
follows:—

1.—The self-acting method.
2.—The firing by judgment, or observation method.

During the early days of submarine defensive warfare, the latter method
alone was used, owing to the absence of anything like a practicable form of
self-acting apparatus; but within the last few years, the former has almost
entirely superseded the latter method, except in very exceptional cases; this
revolution being due to the vast improvements that have been, and still are
being effected in the system of firing electrical submarine mines
automatically.
Use of Circuit Closers.—Electrical submarine mines may by means of
an apparatus, termed a circuit closer, be rendered self-acting; that is to say,
by the action of a vessel coming in contact with such an apparatus, which
may be either within the mine itself, or within a buoy attached to the mine,
the electric circuit is closed, and the mine in connection with the circuit
closer so struck, exploded. The essential feature of such a mode of closing
the electric circuit is, that electrical submarine mines may be rendered
either active or harmless, at the will of the operator, which is effected by the
putting in, or taking out of a plug, by which means the firing current is
either thrown in, or out of the circuit.
Circuit closers.—Many different forms of circuit closers have been
devised, among which the following seem the most suitable and are those
generally used:—

1.—Mathieson's inertia circuit closer.
2.—Mathieson's spiral spring circuit closer.
3.—Austrian self-acting circuit closer.
4.—McEvoy's mercury circuit closer.
5.—McEvoy's weight magneto circuit closer.

Mathieson's Circuit Closer.—This form of circuit closer has been
adopted by the English government in connection with their system of
defence by electrical submarine mines.
The details of this apparatus are shown at Pl. xiii.
Fig. 53, a is a gun-metal dome screwed on to a metal base b, its foot
resting on a gutta percha washer c, so as to exclude any water; d is a cap
screwed on to the top of the dome, and made watertight by the leather
washer e; f is a guard cap screwed into the cap d, this is to keep the spindle
of the circuit closer steady during transport, and would be removed when
the apparatus is prepared for service; g is the ebonite base plug through
which pass the insulated wires E and L; h is an hexagonal collar, working in
the metal base plate b, by means of which, and the brass collar i, and the
leather washer k, the base plug is secured, and water is excluded from the
interior of the circuit closer; l, l, l are brass columns supporting a circular
ebonite piece m; n is a metal bridge screwed on to the base plate b, into
which is screwed the spindle p, both of which are prevented from moving
after being screwed up by the set screws r and s.
The spindle p carries a leaden ball t, which is supported upon the rest v,
and is secured in position by the screw nut w; x is an india rubber ring, the
object of which is to prevent any damage being done to the spindle should
the ball when set in action by a heavy blow from a passing vessel be
brought into contact with the dome; 2 is a brass disc attached to the spindle
carrying an ebonite disc 4, connected to it by screws; 6 is a brass contact
ring also fixed to the ebonite disc 4, provided with a screw 8, for the
attachment of one of the base plug wires, and with platinised projections 3,
3, 3, Fig. 56. The contact ring 6 is completely insulated from the spindle
and brass disc 2. Three contact springs 5, are attached to the circular ebonite
piece m, and the faces opposite to the platinised projections of the disc 2 are
also platinised. 7 shows the contact screws of the connecting pieces, which

serve also as adjusting screws to regulate the sensitiveness of the apparatus,
the points of which as well as their bearings on the springs are platinised.
The springs are connected together by means of the wires 9, Fig. 55, one
end of which is secured to the connecting piece by the screw 10, and the
other passes through to the top of the ebonite piece, and is attached to the
top of the spring next in succession to that to which it is fixed below.
One terminal of a coil of 1000 ohms resistance (which is used for testing
purposes) is attached to the line L, terminal of the ebonite base plug, which
latter is also connected to the screw 8, on the circumference of the contact
ring 6; the other terminal of the resistance coil is connected to the earth, E
terminal of the base plug.
A bare copper wire of No. 16 B. W. G. connects the top of the last
contact spring with the set screw s; a piece of similar wire jointed to it is
passed round one of the brass collars and connected to the screw r. As a
precaution against bad contact, the contact springs are connected together
by bare wires A, B, C. This completes the connections for the signalling
circuit, the earth being formed by the body of the instrument; D is a hole
left in the metal base for the passage of the insulating wire which connects
the earth plate to the earth E terminal of the base plug.
Testing Current.—For testing purposes the current from the test battery
arrives by the line wire L, and passes thence through the resistance coil to
earth by means of the wire E, which is attached to a zinc earth plate placed
in a recess in the jacket of the circuit closer.
Action of the Circuit.—The action of the apparatus is as follows:—
Closer.—On the circuit closer being struck, the weight of the lead ball t
causes the steel rod p to be deflected and brings the brass ring 6 in contact
with one of the springs 5; the signalling current which up to this moment
has been passing through the 1000 ohms coil to earth, then passes to the
contact ring 6 (avoiding the resistance coil) thence to the spring which is in
contact with it, and from there by means of the wire connections to the set
screws s and r, and so to earth through the metal body of the apparatus; the
effect of the resistance coil being thus eliminated, is to strengthen the

signalling current, and thus enable it to work the shutter apparatus, by
which means the firing current is thrown into circuit and the mine exploded.
MATHIESON'S CIRCUIT CLOSER.

Circuit Breaker.—By altering the mode of connecting the wires, the
above apparatus may be used as a circuit breaker, that is to say, the signal

may be given, and the mine exploded by the cessation of a passing current,
instead of by the closing of the electric circuit. This system was specially
designed for use with platinum wire fuzes, but is rarely used.
Circuit Closer of Electro Contact Mines.—When the inertia circuit
closer is employed in connection with electro contact mines, the circular
ebonite piece m is replaced by a similar shaped piece of brass, and which is
in metallic connection through the brass pillars l, l, l with the mass of the
metal of the apparatus which forms the earth plate.
The insulated wire of the base plug is connected to one pole of a
platinum wire fuze, the other pole of which is connected by another wire to
the outer metal rim of the disc of the spindle. As long as the circuit closer
remains undisturbed, a break will remain in the circuit, which is due to the
ebonite insulation between the spindle and the outer metal rim of the disc;
but the moment the apparatus is struck, which causes the spindle to vibrate,
the outer metal rim will come in contact with one of the springs completing
the circuit, through the circular metal portion and the pillars of the circuit
closer to earth.
Adjustment of Circuit Closer.—The sensitiveness of Mathieson's inertia
circuit closer is determined by the distance between the disc 4 and the
springs 5, 5, 5, which is regulated by means of the adjusting screws 7, 7, 7,
which press against the inner faces of the springs. Owing to the great
weight of the leaden ball, when by any cause the circuit closer is inclined
for a length of time, a permanent set is given to the spindle, thereby
destroying the adjustment of the instrument.
Improvements in the Inertia Circuit Closer.—To remedy this very
serious defect, a cylinder of india rubber is substituted for the leaden ball; a
circuit closer so fitted is also less affected by the action of counter mines,
which is a very important advantage.
Mathieson's Spiral Spring Circuit Closer.—A sectional elevation of this
form of circuit closer is shown at Fig. 57. It consists of a brass base a,
provided with a grooved flange for carrying a gutta percha washer, and it
has also an hexagonal projection for the purpose of screwing the circuit
closer into the gun-metal mouth of its air-tight cylinder, or buoy; b is a brass
dome enclosing the apparatus for the purpose of protecting it from injury,

and also by means of india rubber washers to prevent an ingress of water,
should the circuit closer case become injured, and leak; c is a brass collar to
which the brass contact springs i, i are attached, and which are regulated by
the set screws j, j; a brass spiral spring d carries a metal rod e, which
supports a brass ball f, surrounded by an india rubber band h. A contact disc
g is secured to the base of the spindle e, but insulated from it by an ebonite
boss; k is an ebonite base plug with two channels in it, through which the
wires m, m1 pass.
An Improvement on the Inertia Circuit Closer.—This instrument is a vast
improvement on the inertia apparatus previously described, being more
simple and more certain in its action, a desideratum in all circuit closers;
but notwithstanding, up to the present time Mathieson's inertia apparatus
has been used by our government, to the exclusion of all other instruments
of a similar nature, some of which were proved to be far superior when
subjected to the crucial test of actual practice.
Austrian Self-acting Circuit Closer.—This form of circuit closing
apparatus, which is purely a self-acting one, that is to say, a mine so fitted
cannot be fired at will, is shown at Fig. 58.
It consists of several buffers a, a, a, which by means of strong springs
are held in position, their heads projecting outside the torpedo case b; on
being pressed in by the contact of a passing vessel, the ends of these buffers
would be forced against a ratchet wheel c, which is also kept in position by
means of a spring. Several strong pieces of wood d, d within the case keep
the buffers and their attached arms in the proper direction, and also afford
rigidity to the torpedo case. The brass ratchet wheel c being put in motion
carries round with it a central arrangement e, the lower part of which is
shown at Fig. 58, A.
This portion consists of a cylinder of brass f divided into two parts
insulated one from the other by a piece of ebonite g; on one side of this
cylinder there are three arms of brass, h, i, and k, and on the other there are
two arms, l and m, all of which are insulated from each other.
AUSTRIAN CIRCUIT CLOSER, MERCURY CIRCUIT CLOSER.

The arm h is close to, but insulated from a metal plate n, which latter is
permanently connected with the conducting wire leading from the firing

battery, and thus while in a state of rest is electrically charged; beyond the
arm i is a spring o, which is connected with the earth, and in such a position
that when the central portion is moved round, this spring o comes in contact
with the arm i, and the plate n with the arm h simultaneously, and the circuit
is thus completed through earth to the battery, but the current of electricity
does not pass through the fuze. The arms k, l on the opposite sides of the
cylinder, and consequently insulated one from the other, are connected with
the fuze, and the arm m is connected with the earth.
On a further pressure of the vessel on the buffer, the arm i is pushed
beyond the spring, and in contact therewith, and consequently the circuit by
earth to the battery is broken, while the contact of the arm h and plate n is
still retained, and the current is passed by the arm k through the fuze to the
arm l, and then to earth through the arm m, thus completing the electric
circuit of the firing battery through the fuze, and to exploding the mine.
The spring acts as a circuit breaker, and by means of an intensity coil in
connection with the firing battery, the current is only passed through the
fuze when at the point of greatest intensity.
By detaching the firing battery, the channel defended by such submarine
mines may be rendered safe.
Fuze only in Circuit at Moment of Firing it.—One of the principal
objects to be gained by the employment of such an arrangement for the
closing of the electric circuit in connection with submarine mines, is the
prevention of premature explosion from induction which might be caused
by the proximity of any atmospheric electricity, the fuze in this system
being entirely cut out of circuit until the moment when it is necessary to fire
it.
The Austrians employed this form of circuit closing instrument during
the war of 1866, and still continue to use it in connection with their coast
defence by submarine mines.
McEvoy's Mercury Circuit Closer.—At Fig. 59 is represented a
longitudinal section of a circuit closer of this construction.
It is placed in the mine in such a manner that when undisturbed it
maintains an approximately upright position.

It consists of a metal tube a into which the cup b of vulcanite, or other
insulating material is fixed. The cup is contracted at some distance from the
top by the perforated plug c, which is also of insulating material; d is a
metal pin fixed into the bottom of the cup b, it is connected with the wire e,
which is insulated and passes to the battery; f is a metal plug closing the
tube a and the cup b at the top; g is a wire attached to the plug f, and
passing from it to an earth connection. The cup b is filled with mercury up
to the level of the plug c. By the contact of a passing vessel the instrument
would be tilted sufficiently to cause the mercury to flow into contact with
the metal plug f, thus completing the electric circuit and exploding the
mine.
This form of circuit closer, though not generally adopted, would, on
account of its being less liable to derangement by the motion of the waves,
or by the explosion of an adjacent or counter mine, seem to fulfil the many
requirements of a circuit closer for general service.
McEvoy's Weight Magneto Circuit Closer.—This form of circuit closer,
which is shown in section and plan at Fig. 60 and 61, is one of the most
important improvements that has ever been effected in such apparatus, and
bids fair to become universally adopted.
A heavy metal conical shaped weight a (Fig. 60), hollowed out in its
base and working in a ball and socket joint b, rests on a solid brass base c,
and is so arranged that on the apparatus being struck, the weight a will fall
over, pivoting on one of its supports d, d; e is a band of india rubber,
encircling the weight a, for the purpose of preventing a jar on its falling
against the sides of the brass cylinder f, which contains the weight a and
joint b. A brass rod g, connected to the ball and socket joint, passes through
the base c, through a strong spiral spring h (which latter rests on an
adjusting screw k), through a piece of ebonite l, which supports the bobbins
and core m, m1; then between these bobbins m, m1 through an armature n,
which is pivoted at p; and lastly through a slight spiral spring o, which is
kept in position by the adjusting screw i.
The armature n is fitted with a small piece of brass r, so arranged that
when it (the armature) is in the position shown in Fig. 60, this piece of brass
r does not make contact with the two strips of metal, s, s, between which it,

r, works; but when the armature n is in contact with the cores of the bobbins
m, m1, then the piece of brass r makes contact with the metal strips s s, and
so makes a short circuit for the electric current. An ordinary telephone t,
Fig. 61, in which some small shot, bells, &c., are placed, is fixed to the top
of the brass cylinder f.
Action of Circuit Closer.—The action of this apparatus is as follows:—
On the mine carrying this form of circuit closer being struck by a
passing vessel, the weight a is caused to fall over towards the side of the
brass cylinder f, thus allowing the strong spiral spring h to act on the brass
rod g in an upward direction, by which means the armature n is brought into
contact with the soft iron cores of the bobbins m, m1.
Mc.EVOY'S MAGNETO ELECTRO CIRCUIT CLOSER.

The connections of the wires are made as follows:—

The line wire w is led through the base of the apparatus and connected to
a piece of brass under the ebonite support l, in connection with one of the
wires of the bobbin m, the other wire of which is attached to the metal strip
s; the wires of the bobbin m1 are connected, the one to the metal strip s1, the
other to a piece of brass under the ebonite support l; from this latter piece of
brass a wire w1 is led to the brass screw x. The wires w2, w3, from the fuzes
are led, the one to the brass screw x, the other to a screw y, which forms
through the metal of the apparatus the earth plate. One of the wires of the
telephone t is connected to the brass screw x, the other w4 is connected to
the piece of brass to which the line wire w is also attached. While the circuit
closer remains in a state of rest, the current from the signalling battery
flows along the line wire w, up the telephone wire w4, through the telephone
which has a high resistance, then by the wire w2 through the fuzes, and to
earth by the wire w3.

On the circuit closer being struck, by which cause the armature n is
brought up to the cores of the bobbins m, m1, and the piece of brass r in
contact with the metal strips s, s1, the signalling current, instead of
circulating through the high resistance of the telephone t, passes round the
bobbin m, down the metal strip s, across the brass piece r, up the metal strip
s1, round the bobbin m1 (thus forming an electro magnet of m, m1), and by
the wire w, direct through the fuzes to earth, and so explodes the torpedo.
The effect of the telephone resistance being cut out, is to strengthen the
signalling current, and enable it to work the shutter apparatus and so throw
the firing battery in circuit and explode the mine.
The advantages of this circuit closing apparatus are:—
1.—Simplicity.
2.—Compactness.
3.—Increased certainty of action, due to the sustained contact of the
armature n, on the apparatus being struck.
4.—Additional means of testing a system of electrical submarine
mines, which is afforded by the telephone:—
When this form of circuit closer is put in action by a friendly vessel
coming in contact with it, or when experiments are being made, the

signalling current must be reversed, so that no doubt may exist as to the
armature n having dropped, on the apparatus coming to rest.
The telephone test indicates whether the circuit closer is in position or
not, the shot, &c., within the telephone being shaken about by the
movement of the buoyant circuit closer, the noise so created is readily
distinguished by the receiving telephone at the station.
Another form of submarine mine is that known as the "Electro
Mechanical" mine. The difference between this form and an ordinary
mechanical mine is, that the exploding agent is electricity, and that it may
be converted into an electro contact mine if desirable.
Description of a Russian Electro.—The electro mechanical mine, used
by the Russians during the late Turco-Russian war, is shown in elevation
and section at Fig. 62 and 63.
Mechanical Submarine Mine, used by them during the late Turco-
Russian War.—A is the conical shaped case; B the loading hole; C the base
plug; D, D, &c., are five horns, screwed into the head of the case A; these
are composed of a glass tube A, containing a chlorate of potash mixture,
enclosed in a lead tube B, over which is screwed a brass safety cylinder C;
when ready for action this latter tube C is removed; directly beneath each of
the horns A, on the inside of the case, as at E, is a thin brass cylinder, closed
at one end by a piece of wood d, and containing several pieces of zinc and
carbon, arranged in the form of a battery, the zinc and carbon wires z and x
being led through the piece of wood d; F is a copper cylinder containing the
priming charge of gun-cotton g, and detonating fuse f; the terminals of the
fuze are connected to two insulated wires, w and w1, the former of which is
led direct to the loading hole B, and attached on the inside to the five zinc
connecting wires z, &c.; the latter is attached to one end of a safety
arrangement S, the other end of which is connected to the wire w2, which is
attached on the inside to the carbon wires x, &c.; the safety arrangement S
consists of an ebonite cylinder, containing a brass spiral spring fixed to one
end of it, and pressing against a brass plate at the other, thus preserving a
metallic connection between the wires w1, and w2; the mine is rendered
inactive by pressing the spring down, and inserting a piece of ebonite
between it and the plate.

Its Action.—The action of this form of electro mechanical submarine
mine is very simple; the brass safety cylinders c, c, &c., being removed on a
vessel striking either of the horns, D, D, &c., the lead tube b is bent, causing
the glass tube a to be broken, and the mixture contained therein to flow into
the cylinder E, instantly generating a current of electricity in the zinc carbon
battery, and exploding the mine.
Mode of Converting into an Electro Contact or Observation Mine.—To
convert this mine into an electro contact one, it is only necessary to connect
the wires w1 and w2 to other wires leading from the shore; also by replacing
the horns D, D by solid brass screw plugs, the mine may be converted into
an ordinary observation one. In this case the two wires w and w1 attached to
the fuze f, terminals would have to be connected to the observation
instruments on shore.
Turkish Vessel sunk.—It was by means of one of these electro
mechanical mines, that the Turkish gunboat Suna was sunk at Soulina.
Firing by observation, that is to say, effecting the ignition of an electrical
submarine mine at the precise moment of a hostile vessel being vertically
over it, through the agency of one or two observers stationed at a very
considerable distance from the mine, should, with the very perfect self-
acting circuit closers that exist at the present time, be resorted to only in
very exceptional cases, or in connection with the self-acting system.
There are two defects, which are common to all methods of firing
submarine mines by observation, and these are:—
1.—At night time, or in foggy weather, it cannot be employed.
2.—It is necessary to employ at least two observers, at a considerable
distance apart, who to effect a proper action at the right
moment, must work in perfect unison. These defects alone are
sufficient to explain the preference given to a self-acting
method of closing the electric circuit at the precise moment of a
vessel being in position over a mine by those governments who
have adopted electrical submarine mines as a means of coast
defence.

Methods of Firing by Observation.—There are several methods of firing
by observation, of which the following are the ones principally used:—

1.—By pickets or range stakes.
2.—By cross bearings.
3.—By intersectional arcs fitted with telescopes.
4.—The Prussian system.

Intersection by Pickets or Range Stakes.—In narrow channels and at
short distances, this system of ascertaining the relative position of a hostile
vessel and a submarine mine may be used, provided that skilled and careful
men are employed to work it. Two or more pickets or stakes are arranged in
front of the firing station in such a manner that a vessel passing up the
channel on the prolongation of these stakes will be over a mine. This
arrangement should of course always be considered as an extempore one; it
was used on several occasions by the Confederates during the American
civil war.
Firing by Cross Bearings.—The simplest method of so determining the
relative position of a vessel and a submarine mine, and exploding it at the
right moment, is that in which observers are placed on the prolongation of
the mines. This mode is shown at Fig. 64, where m1, m2, m3, &c., and n1,
n2, n3, &c., are the mines; A and B, the points in prolongation of the mines
where the observers are stationed; D the firing battery, and s, and s1 two
hostile vessels.
At the stations A and B firing keys are placed, at the former one for each
separate mine, perfectly distinct and insulated from each other, at the latter
a single key. The pivot points of the series of keys at A are connected by
separate wires to one pole of the firing battery D, the other pole of which is
connected by a single cored insulated cable to the pivot point of the key at
B; the contact points of the series of keys at A are connected by separate
line wires as A m1, A m2, A m3, &c., to the different mines, while the contact
point of the key at B is put to earth. Thus it will be seen that, in the case of
the row of mines, m1, m2, &c., unless the key at B, and the key at A, of
either of those mines are both pressed down at the same instant, no current
can pass, and therefore none of those mines can be exploded.

RUSSIAN SUBMARINE MINE, FIRING BY OBSERVATION.

In the case of the vessel S, though at C, she is on the prolongation of the
line A m5, C, and therefore the key of the mine m5, is pressed down at A, yet
not being on the prolongation of the line B, E, the key at B is not pressed
down, therefore the firing battery is not thrown in circuit, or the mine m5
exploded, but when the vessel s reaches the position N, that is over the mine
m3, she being on the prolongation of the lines A m3, and B E, the key (m3) at
A, and the key at B would both be pressed down, and therefore the mine m3
exploded, and the ship destroyed. In the case of a vessel passing through an
interval between any two mines at such a distance as to be out of the radius
of destructive effect of either of the mines belonging to the first row (which
is shown at s1,) only the key at B would be pressed down, and thus the
vessel enabled to pass safely through, but only to come to grief at the
second or third row of mines, provided they have been properly placed, and
separate though similar arrangements as in the case of the line of mines, m1,
m2, &c. have been made.

Firing by a Preconcerted Signal.—At Fig. 65 is represented a somewhat
similar, though a much simpler plan of the foregoing system, by employing
a preconcerted signal at the station B in the place of the firing key and
insulated cable, as in the former case. The only material difference in the
arrangement of these two methods, is that in the latter case the pole of the
firing battery at A, which in the former case was connected to the firing key
at B, is put direct to earth. As will be readily understood, this latter system
requires great coolness and nerve on the part of the operator at A, who has
not only to watch the vessel passing across his intersections, but also to be
on the alert to receive the signal from the observer at B. Should it ever be
necessary to adopt this latter system, it will be found advisable to employ
two men at station A, one to watch station B, the other to attend to the firing
key and intersections. A separate signal-flag for each line of mines, and also
a separate firing arrangement, would be required. As in many cases it would
not be practicable to have a station in such an advanced position as at B, in
Fig. 64 and 65, on account of the danger of its being cut off by an enemy,
another combination becomes necessary. In this instance the station B is
placed on the opposite side of the river, &c., to that on which the station A
is placed, and a series of firing keys, instead of a single one, is here used,
necessitating a multiple cable between the stations A and B, in the place of

single cored cable; the manner of manipulating this method is very similar
to that previously described.
Firing by Intersectional Arcs fitted with Telescopes.—The foregoing
methods of firing by cross bearings are replete with many serious defects, to
remedy which, to a considerable extent, special arrangements have been
devised, that is, the employment of intersectional arcs fitted with telescopes
at the stations A and B.
Fig. 66 and 67 show the arrangements of these arcs, the former being the
one used at the firing station A, the latter at the converging station B. At
each station one arc is provided for each row of mines placed in position.
The firing arc Fig. 66 consists of a cast iron frame a, with three feet b, b, b,
these being provided with levelling screws.
To ascertain when this frame is level, a circular spirit level is attached
thereto, a telescope d provided with one horizontal and three vertical cross
wires, supported on Y's, admitting of vertical motion and attached to an
upright e. A mill-headed screw f enables the telescope d to be raised or
lowered; the telescope, which is rigidly connected to a vernier g, traversing
over a graduated arc h, can be moved rapidly in a lateral direction by means
of a rack and pinion arrangement i, and it can be clamped in any position by
means of the screw h. Sights are fixed on the telescope in a vertical plane
passing through its axis. To the outer rim of the frame of the arc, which is
smooth, are secured the sights l l (shown on a large scale at Fig. 68), to give
the direction of the mines. These sights are provided each with a brass point
of V form, m, and a binding screw, n, in metallic connection with each
other, but insulated by means of an ebonite plate from the rest of the metal
of the sight. One end of a short piece of insulated wire is attached to the
binding screw n, and the other passes through a hole in the base of the sight
and projects below it; o is a brass tube rigidly connected to and moving
with the upright carrying the telescope d, and projecting in front of this
latter. A brass spring p (see Fig. 69) is attached to, but insulated from the
outer extremity of this tube, and is so arranged as to make contact with the
V point m on the sight, by means of a corresponding projection fitted to its
under side. An insulated wire passing the tube o, the outer end of which is
connected to a screw on the spring p, forms a metallic connection between
this projection and the firing key.

At Fig. 68 is shown an enlarged view of the front of the sight; in addition
to the V projection m, and binding screw n, it is fitted with a capstan-headed
screw to bear against the inner rim of the frame, and a thin wire upright t for
giving the alignment of the mine, to which a disc is attached, on which the
number of the mine is affixed.
When the distance between the station and the mine is only about one
mile, an ordinary eyepiece is used in the place of the telescope d.
At Fig. 67 is represented the arc employed at the converging station,
which with the exception of there being no tube o, and only one sight, is
precisely similar in construction to the one used at the firing station, and
which has been described.
APPARATUS FOR FIRING BY OBSERVATION.

Application of the Intersectional Arc Method.—The application of the
method of firing by observation, by means of intersectional arcs fitted with
telescopes, is shown at Fig. 70. C, D, and E are three of the larger kind of
arcs, one being used for each row of mines at the firing station A. At the
converging station B, one of the smaller arcs is used for each row of mines,
as shown at F, G, and H. S, S1, S2, are the signalling apparatus, the F
terminals of which are connected to the sights l, l, l, Fig. 69, of arcs C, D, E.
Firing keys a, a, a at station A are connected to each arc, and to three of the
cores of the cable connecting the two stations A and B, respectively. At the
converging station B, three firing keys b, b, b are connected to earth and to
three cores of the connecting cable respectively. The remaining core of this
cable is connected to the recording instruments d, e. The action of the arcs,
&c., will be readily understood from the diagram at Fig. 70.
This arrangement does not interfere with the action of the circuit closer,
as all that is effected by the observing arc circuit is to put the signalling
battery current at the converging station B to earth instead of at the circuit
closer.
Prussian System of Firing by Observation.—The principle on which this
system is based, depends upon the proposition that if c d, in the triangle
shown in Fig. 71, be always kept parallel to H B, then A c, c d, d A bear
exactly the same proportion to each other as A B, B H, H A do to one
another; so that by means of the small triangle A d c, the lengths of the sides
of the large triangle A B H can be obtained, and hence the position of the
point H, the base A B being of course known. In Fig. 71 at A there is a slate
table representing the roadstead, and upon it the exact position of every
torpedo is laid down, corresponding to their position in the roadstead. At A
and B, 500 yards apart, telescopes having cross wires are placed; at A a long
narrow straight-edged strip of glass A d is arranged to move in unison with
the telescope at A; and by the application of dynamo electricity, a similarly
constructed piece of glass c d moves in exact unison with the telescope at B,
and having its pivot at C; that is to say, C d keeps parallel with B H, the line
of sight of the observer at B.
Then if the observers at A and B have got a ship in their telescopes, the
point of intersection d of the two pieces of glass A d and C d gives the
position of the ship on the slate table at A, and when this point d comes over

the position of any one mine on the slate, it is known that the ship is over
that particular mine in the harbour, and she may be destroyed accordingly,
by throwing the firing battery into circuit.
By the employment of electricity and a mirror, the great defect of this
method, viz., the necessity of employing four people to manipulate it,
would be remedied. The foregoing is a modification of Siemens's method of
ascertaining distances at sea, &c.
Rules observed in Planting Mines.—In placing a system of submarine
mines in position, the following are some of the chief points to be attended
to, this work depending in a great measure on local circumstances, and on
the method that is to be adopted in exploding and mooring them:—
1.—The plan of defence must be carefully laid down on a chart, on a
scale of not less than six inches to the mile, and on this plan are
to be marked the sites of the observing stations, the positions of
each mine, circuit closer, and junction box, with their
corresponding numbers, and also of the electric cables.
2.—The position of each mine having been determined, should be
marked off by buoys.
3.—The utmost care should be taken to lay the electric cables, so that
they shall be as far as possible away from the mines in the
vicinity of which it may be necessary to take them, so as to
lessen the liability of injury to them, by the explosion of the
latter.
4.—The electric cables should be laid parallel, and never be allowed to
cross directly over each other, otherwise the operation of
underrunning them will be much complicated, also a certain
amount of slack should be allowed to facilitate in picking the
cables up for repair, &c.
5.—Every manner of device is to be used to conceal the electric
cables, such as laying dummies, making detours inland, &c.
6.—All marks indicating position of the mines to be removed, after the
mines have been placed in position.
7.—The identity of each cable and mine to be very carefully preserved
throughout, by means of a number.

8.—A number of electro contact mines should be placed in advance of
the leading line of mines, at irregular intervals, to prevent the
enemy, having once ascertained the position of one mine of a
line, from knowing within limits the position of the others of
that line.
SYSTEMS OF DEFENCE BY SUBMARINE MINES.

In connection with a system of defence by electrical submarine mines,
the following batteries are required:—

1.—Firing battery.
2.—Signalling, or shutter battery.
3.—Testing battery.
4.—Telegraph battery.

Firing Battery.—The firing battery should be suited to the nature of the
fuze employed, and should possess considerable excess of power to enable
it to overcome accidental defects, such as increased resistance in the various
connections, or defective insulation in the line wire, &c.
As platinum wire or low tension fuzes are now universally adopted as
the mode of ignition for submarine mines, it will be only necessary to
describe those electrical batteries which are most suitable as an exploding
agent in connection with such fuzes; these are as follows:—

1.—Siemens's dynamo low tension machine.
2.—Von Ebner's Voltaic battery.
3.—Chromic acid or Bichromate Voltaic battery.
4.—Leclanché's Voltaic battery.

Siemens's Low Tension Dynamo Electrical Machine.—This instrument
consists of an electro magnet and an ordinary Siemens armature, which, by
the turning of a handle, is caused to revolve between the poles of the electro
magnet. The coils of the electro magnet are in circuit with the wire of the
revolving armature, and during rotation the residual magnetism of the soft
iron electro magnet cores at first excites weak currents which pass into the
electro magnet coils, increasing the magnetism of the core, thus inducing
still stronger currents in the armature wire. This accumulation by mutual
action goes on until the limit of magnetic saturation of the iron cores of the
electro magnets is reached.
By the automatic action of the machine, the powerful current so
produced is sent into the leading wire or cable to the fuze to be exploded.
In this apparatus the electric current passes continuously through the line
wire until a sufficiently powerful current is generated to heat or fuze the

bridge of the fuze, and so ignite the gun-cotton priming. The coils of the
armature and electro magnets are wound with wire of large diameter, to a
total resistance of 8 to 10 Siemens units, or 7·6 to 9·5 ohms, in about 2,000
windings.
With a platinum wire weighing 1·65 grains per yard, 6-1/2 inches can be
fuzed on short circuit, and 14 inches can be heated to redness.
The total weight of this machine, which is manufactured by Messrs.
Siemens Brothers, is about 60 lbs.
Advantages of Siemens's Dynamo Electrical Machine.—The advantages
of such a machine over Voltaic apparatus are:—
1.—The absence of chemical agents.
2.—There is less liability to get out of order.
3.—No special knowledge is required to work them, or to keep them in
order.
4.—Greater durability.
The great defect of this and all similar machines is that the electric force
has to be developed by turning a handle for a certain time before it is
possible to generate a current sufficiently powerful to ignite a fuze, which
defect, in connection with a system of defence by self-acting submarine
mines, particularly at night, renders them inferior to Voltaic batteries, as
under such circumstances, an apparatus is required that will cause an
electric current to flow at any moment when the circuit is completed.
The application of steam power would to a certain extent remedy the
above-mentioned defect, but the cost of such a method, compared to that of
a Voltaic arrangement, would be far too great to allow of its superseding the
latter arrangement.
Von Ebner's Voltaic Battery.—This form of Voltaic battery, which may
be considered as a modification of that known as Smee's, was designed by
Baron von Ebner, colonel of the Austrian imperial corps of engineers, for
use in connection with the Austrian system of submarine defence, by self-
acting electrical mines.

A section of one of these cells is shown at Fig. 72. It consists of a glass
vessel a, to contain the diluted sulphuric acid, within which is suspended a
plate b of platinised lead, which is bent round into a cylindrical form to fit
close around the inner surface of the glass vessel. In the centre of this latter
is hung a porcelain perforated cup c, containing some cut-up zinc and
mercury to keep it (the zinc) amalgamated. The top of each cell is furnished
with a porcelain cover, through which the wires attached to the positive and
negative poles of the cell project.
Due to the large quantity of liquid contained in the cell, the tendency to
alter its internal resistance is retarded; also by the arrangement of the
porcelain cup, above detailed, the consumption of zinc and mercury, which
in an ordinary Voltaic battery is very considerable, is materially diminished.
Chromic Acid or Bichromate Battery.—This form of battery is very
similar to Grove's, the difference being that, in the place of the nitric acid as
the exciting liquid, either chromic acid, or a solution of bichromate of
potash, sulphuric acid and water is substituted.
A form of this battery, as designed by Dr. Hertz, is used in connection
with the German system of torpedo defence.
Leclanché Voltaic Battery.—This form of Voltaic battery was invented
by M. Leclanché, some twelve years ago. At Fig. 73 is shown a cell of this
battery in its original form. The positive pole a consists of a plate of
graphite in a porous pot b, and surrounded by a mixture of peroxide of
manganese and graphite. The negative pole c is a rod or pencil of
amalgamated zinc. The whole is enclosed in an outer vessel of glass d
containing a solution of sal ammoniac.
A modified form of the Leclanché cell as used in a firing battery is
shown at Fig. 74. It consists of an ebonite trough or outer vessel a about 16"
long, 9" deep, and 2-3/4" wide. The negative pole or zinc plate b is of
similar shape to the trough a, but with its base removed, and does not fit the
trough exactly, the space between it and the trough being left to ensure the
former being completely surrounded by the sal ammoniac solution; the
positive pole, or carbon element, consists of four gas carbon plates c
attached together at their head by means of lead, and enclosed in a flannel
bag, in which they are firmly embedded in the peroxide of manganese

mixture; the positive element is of such a shape that it fits loosely between
the sides, and is nearly of the same height as the zinc plate.
The object of such a form of cell was to obtain an electric current of
large quantity, with as few cells as possible, by which means the loss of
power which might occur from the employment of a great number of small
cells is avoided.
Advantages of a Leclanché Firing Battery.—The advantages of the
Leclanché firing battery are:—
1.—The absence of chemical action when the battery circuit is not
complete, and consequently there is no waste of material.
2.—Requires little or no looking after.
3.—It may be kept ready for action in store without in any way
deteriorating.
4.—It is comparatively very cheap.
These advantages combine to make a Leclanché battery the most
suitable of any other form of electrical battery for use as the exploding
agent for electrical submarine mines, and it is now universally used for such
purposes.
Signalling Battery.—The signalling battery should be so constituted as to
be capable of working the electro magnet of the shutter apparatus
effectually when the circuit is closed direct to earth, and yet not so powerful
as by the continuous passage of the current generated by it to fire the fuze in
the mine. In the case of a platinum wire fuze being in the circuit, plenty of
power may be given to the battery without fear of a premature explosion
from this cause, but in the case of a high tension fuze it is necessary to be
very careful in order to guard against such a contingency.
As in the case of a signalling or shutter battery, the electric current will
be continually flowing, it is necessary to employ a constant battery, or one
that requires least trouble and expense to maintain it in working order, and
it is for this reason that a modified form of Daniell battery has been adopted
to work the shutter apparatus.
Daniell Signalling Battery.—At Fig. 75 is shown the manner of
arranging a Daniell cell. A glass or porcelain vessel a contains a saturated

solution of sulphate of copper, in which is immersed a copper cylinder b
open at both ends and perforated by holes; at the upper part of this cylinder
there is an annular shelf d, also perforated by holes, and below the level of
the liquid; this is for the purpose of supporting crystals of sulphate of
copper for the replacing of that decomposed as the electrical action
proceeds. Inside the cylinder b is a thin porous vessel c of unglazed
earthenware; this contains either water, or a solution of common salt, or
dilute sulphuric acid, in which is placed the cylinder of amalgamated zinc e.
Two strips of copper p and n, fixed by binding screws to the copper and to
the zinc, serve for connecting the elements in series, or otherwise.
For the purposes of testing, either the Leclanché or Daniell battery
specially arranged, or the Menotti battery, which is really a modification of
the Daniell, may be used.
FIRING BATTERIES, TESTING BATTERIES.

Description of a Menotti Cell.—A Menotti cell, shown at Fig. 76,
consists of a copper cup containing some crystals of sulphate of copper and
covered with a fearnought diaphragm a, placed at the bottom of an ebonite
cell b; over this cup is put some sawdust, and resting on top of this is a disc
of zinc c on another piece of fearnought. The upper portion of the zinc and
its connection with the insulated wire are carefully insulated. Fresh water
poured on the sawdust renders the battery active.
Description of a Menotti Test Battery.—Fig. 77 represents a plan of the
top of such a test battery with a 20-ohm galvanometer attached thereto. The
connections are made as follows:—
One of the wires w of the object to be tested is attached to the terminal f,
which is also connected by an insulated wire to the copper cup a; the other
main wire w1 is attached to the terminal g of the galvanometer; h, the other
terminal of the galvanometer, is connected by a short piece of wire k to the
terminal l of the contact key m; and the contact point n is in connection with
the zinc plate c; thus the current from the battery flows along the wire w
through the object to be tested, back along the wire w1, through the coils of
the galvanometer, along the wire k to the contact key m, and if this is
pressed down to the zinc plate c, so completing the circuit.
To steady the needle of the galvanometer a bar magnet is used, which is
inserted in the space r. The whole of the apparatus is enclosed in a leathern
case fitted with a cover and strap.
This is a very compact and simple form of test battery, and will be found
extremely useful in boats, &c., when placing mines in position.
Telegraph Battery.—For the purposes of telegraphing between torpedo
stations, &c., a form of Leclanché battery, known as No. 3 commercial
pattern, is generally used.
Voltaic Batteries.—The following points in connection with the use of
voltaic batteries, which are taken from Beechey's 'Electro Telegraphy,'
should be carefully observed:—
1.—Each cell of a battery should be carefully insulated.

2.—The floors and tables in the battery room should be kept
scrupulously clean and dry, so as to prevent the least leakage or
escape of the current.
3.—The plates of a battery should be clean.
4.—Porous cells should be examined, and cracked ones replaced.
5.—No sulphate of zinc or dirt should be allowed to collect at the lips
of the cells.
In the case of a Daniell battery—
1.—The solutions should be inspected daily, and crystals of sulphate of
copper added as required.
2.—The zinc plate must not touch the porous cell, or copper will be
deposited on it (the zinc).
3.—The battery should be charged with sulphate of zinc from the first.
4.—The copper solution must be watched and prevented from rising
over the edge of the porous jar, the tendency of such solutions being to mix
with each other by an action termed osmosis.
These being in addition to foregoing general directions for Voltaic
batteries.
Defects in a Voltaic Battery on its Current becoming Deficient.—On the
electric current of a Voltaic battery becoming deficient, the following
defects should be looked for:—
1.—Solutions exhausted; for instance, sulphate of copper in a Daniell's
entirely or nearly gone, leaving a colourless solution.
2.—Terminals or connections between the cells corroded, so that
instead of metallic contact there are oxides of almost insulating
resistance intervening in the circuit.
3.—Cells empty, or nearly so.
4.—Filaments of deposited metals stretching from electrode (pole) to
electrode (pole).
Also intermittent currents are sometimes produced by loose wires or a
broken electrode, which alternately makes and breaks contact when shaken.
Inconstant currents are also sometimes produced when batteries are shaken.

The motion shakes the gases off the electrodes, thus increasing temporarily
the electro-motive force of the battery.
Firing Keys and Shutter Apparatus.—The following is a description of
the various firing keys and shutter signalling apparatus, which is used in
connection with a system of electrical submarine mines. By means of the
former the firing or other batteries may be thrown into circuit at will, whilst
by means of the latter the firing battery is thrown in circuit without the aid
of an operator, and a signal at the same instant given, indicating that a
certain mine of the system has been struck.
Description of a Series of Firing Keys.—At Fig. 78 is shown a plan and
section of a series of firing keys as arranged for firing several mines by
observation.
It consists of a strong wooden frame a, of a convenient form for the
purpose of attaching it to the firing table by screws through the holes b, b.
On this frame a series of keys c, c, c are fixed at convenient intervals. These
consist of a strong brass spring firmly screwed to a series of brass plates d,
d, d on the front of the wooden box a. From these latter short copper wires
pass through the woodwork, and of such a length that, when required, the
mine wires may be easily attached by means of binding screws, as shown at
f. The inner end of each key is fitted with an ebonite knob (which is shown
at c in the section) to insulate the hand of the operator when using the key.
On the frame, and directly under each of the ebonite knobs, are arranged a
series of metallic points g, g, g, so placed that on either of the keys c being
pressed down, a perfect contact is made between it and its respective
metallic point; h, h, h are copper wires leading from the metallic points g, g,
g through the box, and of such a length that binding screws f, f, f can be
easily attached to them when necessary.
A single firing key of an improved form is shown at Fig. 79. It consists
of a strong wooden box a a, weighted at the bottom with lead in order to
steady the key on the table, &c., on which it may be placed; on the inside of
the bottom of the box is fixed a piece of ebonite, by which means the
metallic point b, and the terminal of the firing key c, are insulated from
each other; d d' are two terminals at the end of the box, to which the circuit
wires are attached, one of these terminals is connected in metallic circuit to

the firing key at c, the other one to the metallic point b; a wooden cover h,
fitted with a catch k, protects the connections of the wires; by means of a
plate, and catch e e, the key can be rendered inactive, thus preventing the
danger of a premature closing of the electric circuit; by means of a spring s
a break is always established between the key and the metallic point. It is
immaterial to which of the two terminals d d' either wire is connected.
The Morse Firing Key.—This form of key is so well known in
connection with the Morse telegraph, that it is not necessary to describe it.
It is usually employed in torpedo work in connection with a testing and
firing table.
The Shutter Apparatus.—The shutter signalling and firing apparatus was
devised to enable the firing battery current to be thrown in circuit without
the aid of a personal operator, the signalling current (which is always kept
in circuit) at the same instant ringing a bell, by which is known the
particular mine that has been struck.
At Fig. 80 is represented a diagram of such an apparatus. a is an
armature working on a pivot between the two horns of an electro magnet b
b, and held in position by a spiral spring c; the latter is in connection with a
regulating screw, by which more or less pressure may be brought to bear in
an opposite direction to that of the attractive action of the electro magnet. A
stud i regulates the distance to which the armature may be drawn back; d is
a shutter on which a reference number for each mine should be indicated,
attached to a lever pivoted at the point e, the inner arm of which is just long
enough to catch under the point of the armature a; when a current of
sufficient strength is passed through the coils b b of the electro magnet, the
armature a is attracted, releasing the lever attached to the shutter d, which
by its own weight falls into the position shown by the dotted lines. f and g
are two mercury cups, the former being in connection with the signalling
current, and the latter with the firing current. When the lever is horizontal
and the shutter drawn up and ready for action, the circuit of the signalling
battery s is completed through the mercury cup f, along an arm h of the
lever to the pivot e, and thence to the mine by the line wire w. When the
circuit closer is struck by a passing vessel, and consequently the shutter
thrown into the position shown by the dotted lines, another arm k, a

prolongation of the lever, falls into the mercury cup g, which latter is in
connection with the firing battery F. The armature a is prevented from
coming into actual contact with the horns of the electro magnet by two
small studs. The object of this is to prevent any effect of residual magnetism
which might otherwise interfere with the rapidity of action of the armature
when released and drawn back by the spring c.
FIRING KEYS, SHUTTER APPARATUS.

The object of employing Mercury Cups.—Mercury cups were devised in
the place of the springs used in connection with the original design of a
shutter apparatus, for the reason that electrical circuits dependent on the
pressure of springs are always liable to interruption from dirt or oxide
intervening between the points of contact.
Shutter Apparatus used with a Circuit Breaker.—When the circuit
breaking system is used with the shutter signalling apparatus, the action of
the armature in releasing the lever must be reversed; that is to say, that
when the current is passing and the armature a attracted to the electro
magnet b b, the shutter d must be held up, and when the current ceases, and
the armature a drawn back by the spring c, the lever must be released, and
the shutter allowed to fall. This is effected by altering the end of the lever,
so that it hooks into, instead of abutting against the armature a.
To each shutter apparatus an electric bell is fitted, by which notice is
given when a circuit closer has been struck. For general service, a box
containing seven such shutter signalling and firing apparatus has been
adopted, a plan of which is represented at Figs. 81, 82 and 83. The
connections of the different circuits are as follows:—
The insulated wire of the upper bobbin of the electro magnet is
connected to the spring of the armature; the pivot of the lever is connected
with the right-hand terminal B, or main line connection on the top of the
box; the insulated wire from the lower bobbin is connected to the middle
brass plate k in the front ledge of the apparatus, the circuit from B to k being
thus completed. The front adjoining brass plate A, provided with a terminal,
is connected with the negative pole of the signalling battery, the positive
pole being put to earth.
On a brass plug being put in the hole l, the signalling current will flow to
the plate k, thence through the lower and upper bobbin to the spring of the
armature, along the latter to the shutter lever, and from the pivot through the
main line wire to the mine. The innermost brass plates H H are all
connected in the same metallic circuit, and to them are attached by means
of the binding screw D the test battery and galvanometer. Thus on the brass
plug being removed from l, and placed in m, the signalling battery is cut out
of circuit, and the test battery thrown in. In this way the condition of each

individual mine may be ascertained while the connections of the remaining
mines are left undisturbed. The positive pole of the firing battery (the
negative being to earth) is connected to the terminal S at the right-hand
corner of the lower ledge of the box; the plate to which the terminal S is
fixed is divided at G, the left-hand portion being connected to a bar which
runs horizontally the whole length of the box, and in metallic connection
with each mercury cup g, Fig. 80. A brass plug is placed in the hole G, and
when from any cause the lever drops, the firing battery will be thrown into
circuit, and the mine to which the lever that has fallen is attached will be
exploded.
Shutter Instrument and Observing Telescope.—Each mine is given a
number, which is put on the disc of the shutter instrument connected to it,
and also on the corresponding tablet C. From the brass plate in connection
with the spring c, Fig. 80, a wire is taken to the terminal f, Fig. 81, on top of
the box. From this terminal a wire is led to the connections of the observing
telescope, and thus the mines can be fired by judgment if required, without
the aid of the circuit closer.
The signal battery current is always circulating, even when the system is
in a state of rest, but in consequence of the resistance placed in this circuit,
which may be either a resistance coil in the circuit, added to the resistance
of the fuzes, when high tension fuzes are used, or only the former resistance
in the case of low tension fuzes, this current is too feeble to form an electro
magnet; directly, however, a circuit closer is struck, this resistance is cut
out, and thus the signal battery current becomes sufficiently powerful to
work the electro magnet of that particular mine.
The circuit of the signal battery, and that to the observing telescope, are
broken the instant the lever commences to fall.
To enable the apparatus to be used on the circuit breaking system, a
spare lever E is provided for that purpose with each box.
The object to be gained by a system of testing is to ascertain the
condition of the electrical submarine mines placed in the defence of a
harbour, &c., and should there exist any fault, not only to detect its exact
position and cause, but also its magnitude, so that it may be at once

determined whether it is necessary to remedy the fault, or whether the
electrical apparatus is sufficiently powerful to overcome the defect.
Tests.—There are two distinct kinds of tests, viz.:—

1.—Mechanical tests.
2.—Electrical tests.
SHUTTER APPARATUS.

Mechanical tests are applied to ascertain that the mechanical
arrangements of the shutter apparatus, circuit closers, and all similar
appliances work efficiently and easily; that the several parts of the mine
case when put together for service are thoroughly watertight; that the
chains, wire cables, and ropes in connection with the mooring apparatus are
of sufficient strength to perform the work required of them; that the weights
of the anchors, or sinkers, are such as to keep the mines in position after
submersion; and that the case of the mine be sufficiently strong to enable it
to bear the external pressure due to the depth at which it may be submerged
for a considerable time without any leakage.

The foregoing tests of the mine case and moorings would of course be
performed during the process of manufacture, but to prevent any chance of
failure they should be repeated before being employed on actual service.
Electrical Tests.—Electrical tests are those which are applied to the
several component parts of the system, to ascertain that the electrical
conditions necessary to a successful result exist.
The importance of being able to carry out the above in its entirety is
understood when it is remembered that a submarine mine becomes
practically valueless unless it acts efficiently at the single instant of time
that it would be required so to do.
List of Instruments used in Testing.—The following are some of the
instruments that are employed in connection with a system of electrical
tests:—

1.—Thomson's electrometer.
2.—Thomson's reflecting galvanometer.
3.—Astatic galvanometer.
4.—Differential galvanometer.
5.—Detector galvanometer.
6.—Three coil galvanometer.
7.—Thermo galvanometer.
8.—Siemens's universal galvanometer.
9.—A shunt.
10.—Commutator.
11.—Rheostat.
12.—Resistance coils.
13.—Wheatstone's balance.

Electrometers indicate the presence of a statical charge of electricity, by
showing the force of attraction or repulsion between two conducting bodies
placed near together. This force depending in the first place on the quantity
of electricity with which the conducting bodies are charged, ultimately
depends on the difference of potential between them; an electrometer is
therefore strictly an instrument for measuring difference of potential.[J]

Sir William Thomson's quadrant electrometer is the most perfect form of
electrometer yet constructed, and the one usually employed in cable testing.
It consists of a very thin flat aluminium needle spread out into two wings,
and hung by a wire from an insulated stem inside a Leyden jar, which
contains a cupful of strong sulphuric acid, the outer surface of which forms
the inner coating of the Leyden jar. A wire stretched by a weight connects
the aforesaid needle with this inner coating. A mirror, rigidly attached to
this needle by a rod, serves to indicate the deflection of the needle by
reflecting the image of a flame on to a scale. The needle hangs inside four
quadrants, which are insulated by glass stems: each pair of opposite
quadrants are in electrical connection. Above and below the quadrants two
tubes, at the same potential as the needle, serve to screen it and the wires in
connection with it from all induction except that produced by the four
quadrants. Suppose the needle charged to a high negative potential (-), then
if the quadrants are symmetrically placed, it will deflect neither to the right
nor to the left, so long as the near quadrants are at the same potential. If one
of these be positive relatively to the other, the end of the needle under them
will be repelled from the negative quadrant to the positive one, and at the
same time the other end of the needle will be repelled from in the opposite
direction. This motion will be indicated by the motion of the spot of light
reflected by the mirror, and the number of divisions which the spot of light
traverses on the scale measures in an arbitrary unit the difference of
potential between the + and - quadrants.
The reflecting electrometer being a very delicate instrument, requires
careful handling, and should only be used by a practised electrician. Its use
would therefore be restricted to important stations, and special tests of a
delicate nature.
Thomson's Reflecting Galvanometer.—A galvanometer is an instrument
intended to detect the presence of a current and measure its magnitude.
The most sensitive galvanometer as yet constructed is the reflecting
galvanometer of Sir William Thomson, a diagram of which is shown at Fig.
84.
A small piece of magnetised steel watch spring, 3/8ths of an inch long, is
fastened with shellac on the back of a little round concave mirror, and of

about the size of a fourpenny piece. This is suspended by a piece of unspun
silk thread in the centre of a coil of many hundred turns of fine copper wire
insulated with silk, and well protected between the turns with varnish. The
two ends of the coils are soldered to terminal screws a, b, so that any
conducting wire can be joined up to it as required. The little mirror hangs in
the middle of its coil, with the magnet lying horizontally. By means of a
lamp L placed behind the screen, the light of which passes through a slit M,
and is thrown on the face of the mirror, a spot of light is reflected on the
scale N.
When a current passes through the coil, the little magnet is deflected,
and since the magnet is attached to the mirror, which is very light, both are
deflected as forming one body, and the spot of light moves accordingly
along the scale N.
A powerful steel magnet S is placed above the coil, and can be moved up
or down, whereby the directive force of the earth may be increased or
weakened. This magnet S is used to steady the spot of light, which
otherwise would shake about, and there would be no certainty about the
measurement. A second magnet T is placed perpendicular to the magnetic
meridian, to adjust the zero of the instrument, i.e., to bring back the spot of
light to a fiducial mark at the centre of the scale when no current is passing.
This instrument should only be used at important stations, and when
special tests of a delicate nature are required to be applied.
Astatic Galvanometer.—An astatic galvanometer is that in connection
with which an astatic needle is employed, by the use of which the
sensitiveness of a galvanometer is greatly increased.
An astatic needle is a combination of magnetised needles with their
poles turned opposite ways.
At Fig. 85 a diagram of such an instrument is shown. Two magnets D
and C are joined, with the north pole of one over the south pole of the other,
forming one suspended system. In the ordinary form of astatic
galvanometer the needles D and C are about two inches long, and are each
covered by a coil, these latter being so joined that the current must circulate
in opposite directions round the two so as to deflect both magnets similarly.

The deflection of the needles D and C is observed by means of a pointer or
glass needle A, B, rigidly connected with the astatic system by a
prolongation of the brass rod connecting the needles D and C. The coils are
flat and of the shape indicated in Fig. 85, and are also made in two halves,
placed side by side with just sufficient space between them to allow the rod
to hang freely.
This form of galvanometer, though less delicate than the preceding one,
is still a very sensitive one, and should only be applied in the case of fine
and delicate tests.
Differential Galvanometer.—A differential galvanometer consists of a
magnetic needle surrounded by two separate coils of equal length and
material carefully insulated from each other and wound in opposite
directions. In using it one circuit acts against the other. If a current of equal
strength were passing through each there would be no deflection of the
needle, because the influence in both directions is equal. If one current were
stronger than the other, the needle would be deflected by the stronger.
This form of galvanometer will be found extremely useful in connection
with a system of electrical tests.
Latimer Clark's double shunt differential galvanometer is the instrument
best adapted for submarine mine tests.
Detector Galvanometer.—A detector galvanometer is usually made with
a vertical needle, and is employed to detect and roughly estimate the
strength of a current where no particular accuracy is required.
It consists of a magnetic needle pivoted in the centre of a coil of
insulated wire, and having an index needle attached to move with it, the
latter appearing on a dial, divided into 360 equal arcs or portions: a diagram
of such an instrument is shown at Fig. 86.
This instrument should be of small size and portable form, and as
sensitive as it is possible to make it, under such conditions.
Three Coil Galvanometer.—The three coil galvanometer is provided
with a vertical needle, and is in other respects very similar in appearance to
the detector galvanometer before described. It is formed with three coils of

2, 10, and 1000 ohms resistance; each coil is connected with a brass plate
on the top of the box which encloses the whole, and may be switched into
circuit by means of a plug at will. The object of the three resistances is to
suit the different resistances that may occur, with a perfect, or imperfect
state of the electrical combination in connection with each mine. A diagram
of this instrument is shown at Fig. 87, the dotted portions are inside the
case.
Thermo Galvanometer.—A thermo galvanometer is an instrument used
to ascertain the power of a firing battery which is employed to ignite
platinum wire or low tension fuzes.
The form of thermo galvanometer generally used in connection with a
test table, is arranged as follows:—
Two ebonite studs, fitted with brass connecting screws, are fixed to the
lid of a box containing some resistance coils, and placed in circuit with
them; these studs, placed about ·3 of an inch apart, are arranged to receive a
piece of platinum wire which is stretched from one stud to the other; the
firing battery being placed in circuit with the platinum wire, and the
resistance coils, its working power would then be tested by the fusion of the
wire through a given electrical resistance, as indicated by the resistance
coils put in circuit.
Another form of thermo galvanometer, which is very compact and
portable, is shown at Fig. 88. It consists of a wooden box a, with a cover of
ebonite b, within the box is placed a resistance coil c; d and e are two
ebonite standards ·3" apart, the former of which is connected by a copper
wire with the terminal f, the latter to the terminal g; the terminal h is
similarly connected to the contact piece k, and the terminal l to the firing
key m, at n; the resistance coil c is connected to the terminal g and to the
copper wire n; the platinum wire (of which several lengths are used,
according to the resistance of the coil c) is placed between the standards d
and e. To test a battery, it is only necessary to connect it to the terminals f
and h, when by pressing down the key m the power of the battery, according
as to its fusing or not the platinum wires, will be ascertained; the use of the
terminals g and l is to cut out the resistance, which is effected by connecting
them by means of a copper wire.

Siemens's Universal Galvanometer.—Siemens's universal galvanometer
is an instrument combining in itself all the arrangements necessary for the
following operations:—

1.—For measuring electrical resistances.
2.—For comparing electromotive forces.
3.—For measuring the intensity of a current.

The instrument which is shown in elevation and plan at Pl. xxiii., Fig. 1
and 2 respectively, consists of a sensitive galvanometer which can be turned
in a horizontal plane, combined with a resistance bridge (the wire of which
bridge instead of being straight is stretched round part of a circle). The
galvanometer has an astatic needle, suspended by a cocoon fibre, and a flat
bobbin frame wound with fine wire. The needle swings above a cardboard
dial divided in degrees; as however, when using the instrument the
deflection of the needle is never read off, but the needle instead always
brought to zero, two ivory limiting pins are placed at about 20 degrees on
each side of zero.
The galvanometer is fixed on a graduated slate disc, round which the
platinum wire is stretched. Underneath the slate disc three resistance coils
of the value of 10, 100, and 1000 Siemens' units are wound on a hollow
wooden block, which protrudes at one side, and on the projection carries the
terminals for the reception of the leading wires from the battery and
unknown resistance. The adoption of three different resistance coils enables
the measuring of large as well as small resistances with sufficient accuracy.

GALVANOMETERS FOR TESTING.

The whole instrument is mounted on a wooden disc, which is supported
by three levelling screws, so that it may be turned round its axle. On the
same axle a lever is placed which bears at its end an upright arm, carrying a
contact roller. This roller is pressed against the platinum wire round the
edge of the slate disc by means of a spring acting on the upright arm, and
forms the junction between the A and B resistances of a Wheatstone's
bridge, which resistances are formed by the platinum wire on either side of
the contact roller, one of the three resistance coils forming the third
resistance of the bridge. G is the galvanometer, k a milled head from which
the needles are suspended, and by turning k they can be raised or lowered,
m is the head of a screw which arrests or frees the needle when in motion.
h1, h2, h3, h4, are the terminals of the respective ends of the three resistance
coils, viz., 10, 100, and 1000 units, which are wound on the wooden block
C; these terminals may be connected to each other by means of stoppers,
and therefore one or more of the resistances may be brought into circuit as
desired, and to the ends of these terminals the wires of the artificial
resistances are connected as shown on diagrams Pl. xxiv., Figs. 1, 2, 3a and
3b; f is the graduated slate disc, round which the platinum wire is stretched
in a slight groove at the edge of the disc, and is inserted in such manner that
about half its diameter protrudes beyond the slate. The ends of the platinum
wire are soldered to two brass terminals l and l1, which are placed at the
angles formed by the sides of the gap in the slate disc, and which form the
junctures, as in the ordinary resistance bridge, between A, n, and the
galvanometer on one side, and B, X, and the galvanometer on the other side,
of the parallelogram. The terminal l is permanently connected by a thick
copper wire or metal strip to terminal h_{1}, and the other terminal l1 is
connected in a similar manner to terminal III.
Slate is adopted for the material of which to make the disc f, because it is
found by experience to be the material which is the least sensitive to
variations in the weather or temperature.
The slate disc is graduated on its upper edge through an arc of 300
degrees, zero being in the centre, and the graduations figured up to 150 on
each side at the terminals l and l1 of the bridge wire.
In the centre of the circular plate E of polished wood, supported upon
three levelling screws b, b, b, a metal boss is inserted, in which turns the

vertical pin a which carries the instrument. This pin, being well fitted to the
boss, supports the instrument firmly, but at the same time allows it to be
turned freely round its vertical axis without losing its horizontal position
when once obtained.
On the arm D D, which turns on the pin a, and somewhat behind the
handle g, there is a small upright brass arm d turning between two screw
points r, and carrying in a gap at its upper end a small platinum jockey
pulley e turning on a vertical axis. This pulley forms the movable contact
point along the bridge wire, against which it is kept firmly pressed by
means of a spring acting on the arm d. The arm D D, which is insulated
from the other parts of the apparatus, is permanently connected with the
terminal I. On the top of d a pointer Z or a vernier is fixed, which laps over
the upper edge of the slate disc and points to the graduations.
To the pin a is attached a circular disc of polished wood C, about one
inch thick, and having a groove turned in its edge for the reception of the
insulated wires composing the resistances. The disc C has a projection c,
which carries the five insulated terminals marked I., II., III., IV., V., as
shown on Fig. 1 and 2, Pl. xxiii. Terminals III. and IV. can be connected by
a plug, II. and V. by the contact key K. Terminal I. is in connection with the
lever D D.
Fig. 3 and 4, Pl. xxiii. show the shunt box supplied with the
galvanometer if specially desired; the copper connecting arms a, a are
screwed to the terminals II. and IV. By inserting a plug at c (Fig. 4, Pl.
xxiii.), the galvanometer is put out of circuit altogether, whilst by plugging
either of the other holes shunts of the value of 1/9, 1/99, or 1/999, are
introduced into the circuit, and the effect upon the galvanometer is reduced
to 1/10, 1/100, 1/1000, respectively of what it would have been without the
insertion of the shunt.
Fig. 5 and 6, Pl. xxiii., show a battery commutator allowing to bring into
the circuit four different amounts of battery power. It is placed in the battery
circuit whenever consecutive tests with different batteries are desired to be
made, it being only necessary to change the place of the stopper in the
battery commutator, the terminal screw a of the battery commutator being

connected to terminal V. of the galvanometer, and the screws b, b, b, b to
various sections of the battery: see diagram of connections, Fig. 4, Pl. xxiv.
The application of the universal galvanometer will be clear from the
diagrams on Pl ii.; instructions, however, for its practical use are added
further on, and also tables for use when measuring conducting resistances.
As will be seen from diagram, Fig. 1, Pl. xxiv., the proportion between
the unknown resistance X, and the artificial resistance n is, when the
deflection is read off on the side of the slate disc marked A:
X : n = 150 + a : 150 - a
= 150 + a
or, X · n.
150 - a
but if read off on the B side of the disc—

150 - a
X= · n.
150 + a

The values of these two fractions, for every half degree, will be found in
the columns headed A and B of the table in the Appendix.
SIEMEN'S UNIVERSAL GALVANOMETER.

SIEMEN'S UNIVERSAL GALVANOMETER.

SIEMEN'S UNIVERSAL GALVANOMETER.

SIEMEN'S UNIVERSAL GALVANOMETER

Measuring Electrical Resistances.—For this purpose the instrument is
arranged as a Wheatstone's balance. The connections are made as shown at

Pl. xxiv., Fig. 1 and 5, where X is the unknown resistance.
a.—The needle i is to be brought to the zero point of the small
cardboard scale by turning the galvanometer G round its
vertical axis, taking care that the needle moves with perfect
freedom.
b.—The pointer or vernier Z is to be brought, by means of the handle
g, to the zero point of the large scale on the slate disc.
c.—A plug is to be inserted between the terminals marked III. and IV.
d.—The holes 10, 100, and 1000 are, two of them, to be plugged, and
one left open, according to the extent of the unknown
resistance to be measured; either 10 or 100 must be left open if
the resistance is small, and 1000 if it is large.
e.—The two ends of the unknown resistance are to be connected to
terminals II. and IV.
f.—The two poles of some galvanic battery are to be connected to
terminals I. and V.
When the above-mentioned connections have been made, and on
depressing the key K, the battery current is sent into the combination and
deflects the needle, say, to the right-hand or B side of the instrument, the
pointer or vernier Z must then be pushed, by means of the handle g, to the B
side of the instrument. If this is found to increase the deflection of the
needle i, the pointer Z should be pushed to the other or A side of the
instrument beyond the zero point of the large scale until the needle remains
stationary when the key K is depressed.
The number indicated by the vernier Z should be read off carefully, and
notice taken whether it is on the A or B side of the large scale. This number
must then be referred to the galvanometer table,[K] when the figure opposite
to the number, multiplied by the resistance unplugged, is the resistance of
X. The value of the resistance to be determined will be thus found by a
single operation.
Supposing the reading to be 50 on the A side of the large scale, the
resistance n unplugged having been 100 units, we get according to the
before-mentioned law of resistance bridge the following proportion (see
Fig. 5, Pl. xxiiiA.):—

X : 100 = 150 + 50 : 150 - 50
150 + 50
X × 100
150 - 50
X = 200 units.
For measuring very small resistances a single cell will be found
sufficient; but for large resistances more should be used, say, 15 to 20. If
very accurate measurements of small resistances are to be taken, the screw
at the end of the moving arm D D should receive one battery wire, terminal
V. receiving the other.
Comparing Electromotive Forces.—For this purpose Professor E. du
Bois-Reymond's modification of Poggendorff's compensation method is
used.
The connections are made as shown at Pl. xxiiiA., Fig. 2 and 6.
For comparing two electromotive forces E1 and E2, a third electromotor
of higher electromotive force E0 is used, and two separate tests taken.

The manipulations a and b are to be the same as before.
c.—The hole between III. and IV. to be left unplugged.
d.—Plugs to be inserted in 10, 100 and 1000.
e.—The two poles of the electromotor of an electromotive force E0 are
to be connected to the terminals III. and V.
f.—The poles of the battery whose electromotive force E1 is to be
compared are connected to terminals I. and IV. in such a
manner that the similar poles of the two electromotors are
joined to terminals I. and III., and to IV. and V. respectively.
When depressing the key K the galvanometer needle will be deflected
and can be brought back to zero by turning the pointer Z either to the right
or to the left. Should for instance the pointer have to be brought to 30° on
the A side we have the following equation—
150 - 30
E1 = E 0 . . . . . . . . (1),
300 + n

where n is the resistance of the battery E0.

The electromotor E2 is now to be inserted in the place of E1, and the
galvanometer needle, when it deflects, again brought back to zero by
moving the pointer Z. If for instance the pointer has to be pushed to 40° on
the B side to obtain equilibrium we have—
150 - 40
E2 = E 0 . . . . . . . . (2).
300 + n
By eliminating n from equations 1 and 2 we have
E1 : E2 = (150 - 30) : (150 + 40) = 12 : 19 . . . . . . . . (3).

The two electromotive forces are in the same proportion as the two
observed distances of the pointer Z from 150° on the A side of the
instrument.
For measuring the Intensity of a Current.—For this purpose the
instrument is simply used as a sine galvanometer. The connectionsare made
as shown at Pl. xxiv., Figs. 3a and 7.
The manipulations a, b, c, and d same as in the second case.
e.—Connect one pole of a battery to terminal II. and put the other pole
to earth.
f.—Connect the line to terminal IV.
The galvanometer is then to be turned in the same direction as the needle
is deflected until the needle coincides with the zero point. Whilst this is
being done the large scale on the slate disc will move under the pointer Z,
which must be left stationary; the sine of the angle indicated by Z will thus
give the value proportionate to the strength of the current. Should the shunt
box be required, it has to be connected with terminals II. and IV.
Fig. 4 shows the same connections as Fig. 7, but without the shunt box,
and with the battery commutator. Fig. 3a shows diagram of the same
connections but with the key K, and Fig. 3b the same without the key.

A Shunt.—A "Shunt" is a second path offered to a current traversing a
given circuit, or portion of a circuit, so as to diminish the amount of the
current flowing through that portion of the circuit. In the diagram shown at
Fig. 89 the shunt diminishes the amount of the current flowing along the
circuit between A and B.
If only 1/Nth of the current is to pass along the circuit between A and B
(of resistance R) then the resistance of the shunt must equal R/(N - 1).
By the aid of shunts it is quite possible to make use of very sensitive
instruments to measure powerful currents.
Commutators or Switch Plates.—A commutator or switch plate is an
apparatus by which the direction of currents may be changed at will, or by
which they may be opened or closed. Bertin's commutator, which is
represented at Fig. 90, consists of a small base of hard wood on which is an
ebonite plate, this by means of the handle m is turned about a central axis
between two stops c and c'. On the disc are fixed two copper plates, one of
which o is always positive, being connected by the axis and by a plate (+)
with the binding screw P, which receives the positive electrode of the
battery; the other copper plate i, e, bent in the form of a horse-shoe, is
connected by friction below the disc with a plate (-), which plate is
connected with the negative electrode N. On the opposite side of the board
are two binding screws b, and b', to which are attached two elastic metal
plates r, and r'.
On the disc being turned as shown in the figure, the current coming by
the binding screw P passes into the piece o, the plate r, and finally the
binding screw b, which by means of a copper wire leads the current to the
apparatus in connection with b; then returning to the binding screw b', the
current reaches the plate r', the piece i, e, and so to the battery by the
binding screw N.
If the disc is turned so that the handle m is half way between c and c', the
pieces o and i, e, being no longer in contact with the plates r and r', the
current will not pass. If m is turned as far as c, the plate o will then touch r',
and the current pass to b', and return by b, thus reversing its direction.

"Peg" switches are also often used; they are arranged so that the removal
or insertion of a brass peg or plug cuts out, or completes a circuit.
Rheostat.—A rheostat is an instrument used for the comparison of
resistances.
SHUNT, COMMUTATOR, RHEOSTAT.

Wheatstone's rheostat, which is shown in elevation at Fig. 91, consists of
two cylinders A and B, one of brass and the other of non-conducting
material, so arranged that a copper wire can be wound off the one on to the
other by turning a handle C. The surface of the non-conducting cylinder B
has a screw thread cut in it for its whole length, in which the turns of the
copper wire lie, so that its successive convolutions are well insulated from
each other. Two binding screws D, D' connected with the ends of the copper
wire are provided, to which the circuit wires are connected. A scale is
attached at E, by means of which the number of convolutions on B can be
read off; and parts of a revolution are indicated on a circle at one end. The
handle C can be shifted from one cylinder to the other.
Supposing the rheostat introduced into a circuit, and the whole of the
copper wire wrapped on the metal cylinder A, then, on account of the large
section of this metal cylinder, its resistance may be entirely neglected, but
for every convolution of the wire on the non-conducting cylinder B, a
specific resistance is introduced into the circuit. The amount of resistance
can thus be varied as gradually as desired by winding on and off the
cylinder B. This instrument is often used in connection with the thermo
galvanometer.
Resistance Box.—The general arrangement of a resistance box is shown
in the diagram Fig. 92.
Between two terminal binding screws T and T1 secured on a vulcanite
slab are fixed a series of brass junction pieces a, b, c, d; each of these is
connected by a resistance coil to its neighbour, as shown at 1, 2, 3, and 4. A
number of brass conical plugs with insulating handles of vulcanite are
provided, which can be inserted between any two successive junction
pieces, as between T and a, or a and b.
With all the plugs inserted, the electrical current will flow direct from T
to T1, the large metallic junction pieces directly connected by the plugs
would offer no sensible resistance; but if all the plugs were removed, then
the current would flow through each of the coils 1, 2, 3, and 4, and the
resistance in the circuit would be the sum of the resistances of those four
coils. With the plugs arranged as in the figure, the current would flow

through coil 4 only, and the resistance in the circuit would be equal to the
resistance of that coil.
Wheatstone's Balance.—The electrical conductivity of a body is
determined by ascertaining the ratio between the resistance of a certain
length of the conductor in question, having a given section, to that of a
known length of a known section of some substance taken as a standard.
For this purpose Wheatstone's bridge in connection with a box of
resistance coils is the most convenient method.
At Fig. 94 is shown Wheatstone's balance (Post-office pattern), and at
Fig. 93 the apparatus is reduced into the form of a parallelogram, which is
the usual diagram of Wheatstone's bridge. The theory of the bridge is as
follows:
Four conductors A B, B C, A D, and D C are joined at A and C to the
poles of a battery Z; the resistance between A and B is R; that between A
and D is r; that between D and C is R1; and that between B and C is x, the
unknown resistance to be measured. A convenient constant ratio is chosen
for R1 and r, such as equality 1 to 10, 1 to 100, or 1 to 1000; and then R1 is
adjusted until no current flows through the galvanometer G; when this is the
case we have R : r=R1 : x, or x = (r/R) × R1; so that if r = R/100, x will be
equal to R1/100.

Two keys a and b are inserted; the current is wholly cut off the four
conductors until contact is made at a; and then after the currents in the four
conductors have come to their permanent condition, contact is made at b to
test whether any current flows through the galvanometer. The three
resistances R, R1 and r and the resistance of the galvanometer should be
small if x is small, and great if x is great.
The conductors A B and A D of the bridge are each formed of three
resistance coils having a resistance of 10, 100, and 1000 ohms respectively,
inserted between the terminals B and D of the balance, Fig. 94.
The conductor D C is formed of a set of resistance coils from 1 up to
4000 ohms, amounting altogether to 11,110 ohms, inserted between the
terminals D and C of the balance; in the balance, a brass plug being inserted

between the terminals D and D1, they may be considered as one terminal D.
The conductor B C is the wire to be tested, and is connected to the terminals
B and C of the balance.
Measurement of Resistances.—When a resistance is to be measured that
is within the range of the coils in R1, R and r are made equal. The needle of
the galvanometer will move in a different direction, either to the right or to
the left, according as the resistance in R1 is greater or less than the line wire
x. The needle remains at zero only when the resistance in R1 is equal to that
in x. For r : R :: R1 : x.
WHEATSTONE'S BRIDGE.

When the resistance of x is greater than that of R1, as in an insulation
test, the resistance in r is made less than that in R, in order that r and R may

have such a proportion one to the other as will enable the coils in R1 to
balance a resistance in x, greater than their own, that is to say, greater than
11,100 ohms; thus r : R :: R1 : x, or 10 : 1000 :: 10,000 : 1,000,000, the
resistance in the line to be tested would be 1,000,000 ohms, supposing the
values of r, R and R1 to be respectively 10, 1000, and 10,000 ohms.

When the resistance to be tested is less than that of the least coil in R1 (1
ohm), then the resistance in r is made greater than in R. Thus r : R :: R1 : x,
or 100 : 10 :: 2 : 0·2; the resistance of the line to be tested would in this case
be 1/20 of an ohm.
Manipulation.—In all cases the key in connection with the battery
should first be depressed, then the galvanometer key, making very short
contacts by the latter, just sufficient to show the direction of the deflection,
until the coils in R1 are nearly adjusted, otherwise considerable time will be
lost in making a series of tests, owing to the swing given to the needle,
which will take some little time before it again remains steady at zero.
When once the coils in R1 are adjusted, and a balance obtained, it should be
ascertained whether the needle will remain steady when contact is made and
broken.
Test Tables.—In connection with a system of testing electrical submarine
mines, for the sake of convenience and simplicity it is necessary to use a
table (termed a "Test Table"), on which all the apparatus used for the
purpose of testing are fixed. Several forms of tables have been designed for
such a purpose. At Fig. 95 is shown the method of arranging such a table.[L]
A is an astatic galvanometer placed between two switch plates, B and C;
ten other similar switch plates, 1, 2, 3, 4, D, 5, 6, 7, E, and 8, are arranged in
front of the galvanometer A; F, G, and H are three terminal plates; K is a
box of resistance coils used in connection with the thermo galvanometer M;
L is a firing key, and N a battery commutator; O is a three-coil
galvanometer; R is a Wheatstone balance (Post-office pattern).
The ten switch plates, 1, 2, 3, 4, D, &c., are used for the connection of
any particular line to be tested, as well as for the earth connections and
instruments employed in that operation.

"Sea Cell" Tests.—The arrangement shown in the figure is that required
in connection with the sea cell test, and Mr. Brown's method of keeping
certain earth plates in a bucket instead of in the sea.
If two plates of suitable metal to form a Voltaic battery are placed in salt
water and connected by a metallic conductor, a battery is at once formed
capable of producing considerable deflection on a moderately delicate
galvanometer. Testing by this arrangement has been termed the "sea cell"
test.
Arranging Earth Plates.—Mr. Brown's, Assistant-Chemist to the War
Department, method of arranging the earth plates is as follows:—
A series of earth plates, such as copper, carbon, tin, zinc, &c., are placed
in a bucket filled with sea water, and which is placed in the testing room.
The water in the bucket is put in connection with the water of the sea by
means of a conducting wire, terminating at one end with a zinc plate in the
bucket, and at the other with a zinc plate in the sea. By this means the tests
made with the different earth plates in the bucket are identical with those
made with corresponding earths placed absolutely in the sea, and therefore
these latter may be done away with, the sea cell tests being entirely carried
out by means of the bucket earth plates.
In addition to the bucket earth plates there will be several other earth
plates in connection with the testing room, these being placed in the sea,
such as the zinc earth for the firing battery, the zinc earth for the signalling
battery, &c.
Connections of Switch Plates.—The switch plate D is used for the
connection of any particular mine cable which it may be required to test.
The switch plate E is connected with a zinc earth plate used for testing the
firing battery. This must always be in the sea. The switch plate 1 is in
connection with a zinc earth in the bucket; 2 is attached to a copper earth
plate in the bucket; 3 is attached to a carbon earth plate in the bucket; 4 to a
tin earth plate in the bucket; 5 is used for connection with the zinc
signalling earth connection in the sea; 6 is attached to a copper earth plate
used for the sea cell test, or any other purpose required, in the sea; 7 is
attached to a zinc earth plate in the sea; and 8 is a common zinc earth in the
sea.

The terminal plates G and H are used for the connection, for testing
purposes of the negative and positive poles, of the firing battery, and F is
connected with a zinc earth in the sea, for a similar purpose. These plates
are in connection with the resistance coils K and the thermo galvanometer
M, employed for testing the firing battery, the circuit being closed by the
firing key L. Other ways of using these plates may of course be adopted if
desired. The resistance coils K range from 0·5 to 100 ohms, and are
composed of wire adapted for the passage of a quantity current. A reversing
key is generally used in connection with a testing battery and the three-coil
galvanometer O. This reversing key would consist of two bridges
completely insulated from each other, the upper one attached to the
negative, the lower one to the positive pole of the test battery. In their
normal position both keys press against the upper bridge, and until one or
other of the keys is pressed down no current will pass, the direction of the
current being altered by pressing down a different key. The point of each
key is provided with a terminal and connected, the one to a zinc earth
through the switch plate 8, the other to one terminal of the three-coil
galvanometer when the tests are to be applied.
The Wheatstone balance R is used in finding the resistances of electrical
cables, balancing fuzes, &c. By means of a commutator, N, the necessary
number of cells for any particular test may be thrown in circuit when
required.
Test of Platinum Wire Fuze for Conductivity.—The platinum wire fuze
may be tested electrically as follows:—
If placed in circuit with a few cells of a Daniell or Leclanché battery and
a detector galvanometer, before the platinum wire bridge of the fuze is
fixed, there should be no deflection of the needle, for no metallic circuit
exists; if it did, such would be fatal to the efficiency of the fuze. If similarly
placed in circuit after the bridge has been fixed, a considerable deflection of
the needle should result, such deflection being due to the current passing
through the metallic bridge, which to be efficient ought to be the sole
medium through which the circuit is completed.
Test of Resistance of Platinum Wire Fuze.—The electrical resistance of a
platinum wire fuze is ascertained by means of the Wheatstone's balance R

and galvanometer A, Fig. 95. The terminals of the fuze are connected to the
binding screws of the balance, the commutator N and galvanometer A being
connected up in circuit. The resistance of the coils is then adjusted by taking
out plugs until the needle of the galvanometer A is brought to zero, when
the sum of the resistances indicated by the unplugged coils will be equal to
that of the fuze. The resistance of a platinum wire fuze might also be
ascertained by means of a differential galvanometer instead of a Wheatstone
balance.
The electrical resistance of 3/10" of fine platinum wire, weighing 1·9
grains to the yard, is 3/10 of an ohm nearly (Schaw).
Testing High Tension Fuzes.—High tension fuzes require very delicate
and careful management in testing them, due to the high electrical
resistance of such fuzes, which ranges from 1500 to 2000 ohms, combined
with the danger of premature explosion when testing even with a small
number of battery cells. Very sensitive galvanometers, such as the reflecting
galvanometer, should if possible be used, otherwise the mode of making the
tests for conductivity and resistance of a high-tension fuze is similar to that
already given for a platinum wire fuze.
Detonating fuzes should always be placed in an iron case during the
process of testing.
Insulation Test for Electrical Cables.—To test an electrical cable for
insulation, it should first be put in a tank of water, or in the sea, and allowed
to soak for at least forty-eight hours. The object of this is to allow the water
to penetrate the outer protection of hemp and iron wires, &c., and to search
out and get into any weak places there may be in the insulation under the
armouring. At Fig. 96 is shown the method of performing this test. A is a
tank holding the electrical cable, which has been in soak for forty-eight
hours; B is an astatic galvanometer; C, Z a Leclanché or Daniell battery of
great power; and C is an ordinary firing key. One end of the electric cable D
is connected to the galvanometer B through the firing key C; the other end
of the cable is very carefully insulated; one pole of the battery is connected
to the galvanometer B, the other is put to earth in the tank at F; should the
insulation be perfect, no deflection of the needle should follow on the key
being pressed down. A very slight deflection might be observed on a

moderately sensitive galvanometer, due to the current passing through the
insulation; its whole length being immersed, the surface through which such
a current would pass would be large, and the sum of the infinitesimally
small quantities escaping over the whole length, would in the aggregate be
sufficient to deflect the needle to a small extent in completing the circuit of
the battery. Should any considerable deflection occur, it would indicate a
defect or leak in the insulation of the cable, the extent of which would be
roughly measured by the amount of such deflection.
By using a reflecting galvanometer a very much more delicate test
would be obtained, but for the comparatively short lengths of electric cables
used in connection with submarine mines, such accuracy is hardly
necessary.
To test an electric cable for conductivity, it would be only necessary to
expose the metallic conductor G, and put it in the water of the tank. If the
conductivity were good, then the whole of the current would pass through
the cable and the needle of the galvanometer would be violently deflected.
If the continuity were broken, no deflection would be observed.
Defects observed in the Conductivity of the Cable.—To ascertain the
position of a defect in the insulation of a cable, as indicated by the tests
above described, it would be only necessary to keep a continuous current
flowing through the cable, and gradually take it out of the tank. If the fault
existed at a single point, the deflection of the needle would be suddenly
reduced at the moment of that point of the cable being lifted out of the
water, and therefore its position would be determined with considerable
accuracy. Should several defects exist as each was lifted out, a sudden
reduction of the deflection would occur.
Discharge Test.—The conductor of an electrical cable may be broken
without destroying the insulation, and on applying the foregoing tests, good
insulation would be indicated, but no conductivity, and no information
would be given as to the position of the fault. Under such circumstances the
following test must be applied:—
Put one pole of a very powerful battery to earth, and charge one end of
the defective cable, then immediately discharge it through a reflecting
galvanometer, and note the extreme limit of the swing of the needle, then,

charge the other end of the cable in a similar manner, and discharge it
through the same galvanometer, noting as before the swing of the needle.
This should be done three or four times, and the average of the deflections
taken. Then the position of the fault would be indicated by the proportion
between the average deflections in each case, and the cable might safely be
cut at that point. Should the precise position of the fault not be discovered
in thus cutting the cable, each section should be tested again for
conductivity, and that in which a fault was still found to exist should be
again tested by the discharge as before.
Test of Electrical Resistance of Cable.—This is effected by balancing it
against the Wheatstone balance, in a similar manner to that explained for a
fuze. The electrical resistance of the conductor of a cable affords a very
correct indication of the quality of the metal of which it is composed. For a
very delicate test the reflecting galvanometer should be used.
Electrical Test of Insulated Joints.—Insulated joints and connections,
whether of a permanent or temporary nature, should be tested electrically, in
a precisely similar manner to that explained for electric cables.
They should be soaked for forty-eight hours, and then tested for
insulation, conductivity, and electrical resistance.
In testing permanent joints special tests are carried out, which are
described by Mr. Culley in his 'Handbook of Practical Telegraphy.'
Voltaic batteries should be subjected to the following tests:—

1.—For potential.
2.—For internal resistance.
3.—For electromotive force.

For the purpose of testing the potential of a battery, one pole should be
put to earth, and with the other one pair of the quadrants of a Thomson's
reflecting galvanometer should be charged; when this is done, a certain
deflection of the spot of light will occur, and the amount of such deflection,
as compared with that produced by a standard cell applied to the instrument
in a similar manner, would give the relative value of the potential of the
battery.

The following method of determining the internal resistance of a battery
is that recommended by Mr. Latimer Clark in his book on electrical
measurements.
The instrument employed is a double shunt differential galvanometer, a
diagram of which is shown at Fig. 97. Connect the battery and a set of
resistance coils in circuit between the terminals A and D, and insert plugs in
the resistance coils so that they give no resistance; insert plugs at A and C,
and also both the shunt plugs at A and D. The current will now flow through
one half of the galvanometer circuit only, being, however, reduced to 1/100
of its amount by the shunt D; the deflection of the needle must be carefully
read. The plug A must now be removed to B, which causes the battery
current to flow through both halves of the galvanometer (each being
shunted). The circuit will now be as shown in the figure, and the needle will
of course be deflected somewhat more than before. Now unplug the
resistance coils which are in circuit with the battery until the deflection of
the needle is reduced to its original amount, and the resistances unplugged
will be equal to the internal resistance of the battery.
The following is another method of ascertaining the internal resistance
of a battery cell.
A circuit is formed, consisting of the battery cell, a rheostat, and a
galvanometer, and the strength C is noted on the galvanometer. A second
cell is then joined with the first, so as to form one of double the size, and
therefore half the resistance, and then by adding a length l of the rheostat,
the strength is brought to what it originally was, C.
Then if E is the electromotive force, and R the resistance of cell, r the
resistance of the galvanometer, and other parts of the circuit, the strength C
in the one case is C = E / (R + r), and in the other = E / ((1/2)R + r + l), and
since the strength in both cases is the same, R = 2l, i.e., the internal
resistance of the cell is equal to twice the resistance corresponding to the
length l of the rheostat wire.
The comparative electromotive force of a battery may be determined by
means of a double shunt differential galvanometer in the following method,
as recommended by Mr. Latimer Clark.

"This can only be done relatively in terms of some other standard
battery. First determine the resistance of the standard and of the other cells
to be measured; then insert the shunt plugs at A and D, Fig. 97, and also at
C and B, and join up the standard cell in circuit with a resistance coil to the
terminals A and D, and unplug the resistance coils until a convenient
deflection is obtained, say 15°; note the sum of the resistances in circuit,
including that of the battery galvanometer, resistance coil and connecting
wires; now change the battery for another, and by unplugging the resistance
coils bring the needle again to the same deflection, 15°; having again found
the total resistance in the circuit, the relative electromotive force will be
directly proportional to these resistances."
The electromotive force of a battery may also be measured statically by
means of Thomson's quadrant electrometer, the poles of the battery being
connected with the two chief electrodes of the instrument, in which
arrangement no current will pass, and the electromotive force will be
directly indicated by the difference of potential observed.
In the case of a quantity battery, that is, a battery capable of fusing a fine
platinum wire, its electromotive force and internal resistance may be
determined by means of the resistance coils K, and thermo galvanometer M,
shown at Fig. 95.
Tests after Submersion.—After an electrical submarine mine has been
placed in position, it should be immediately tested to ascertain that all is
right, and similar tests should be applied at intervals to ascertain that the
charge remains dry; that the insulation and conductivity of the electric cable
remains the same; and that its electrical resistance indicates a state of
efficiency.
The nature of the tests applied to determine these points will depend
upon the nature of the combination in which the mine is arranged.
The manner of applying the "sea cell" test, by which is ascertained the
condition of a system of electrical submarine mines, will be readily
understood from the following examples.
The arrangements for testing to ascertain whether a charge is dry, or wet,
is shown at Fig. 98.

z is a plate of zinc introduced in the circuit within the charge, and
between the fuze and the shore; another earth plate of carbon x is connected
with the electric cable beyond the fuze, forming the ordinary earth
connection of the system at that point; and at home a copper earth plate c is
used.
First, in the case of a dry charge with the insulation and conductivity of
the cable, good; under these circumstances there would be formed a sea cell
between the earth plates x, and c, which would produce a certain deflection
of the needle of a galvanometer g, which is placed in the circuit, and in a
certain direction.
Secondly, in the case of a charge becoming wet, through leakage, with
the insulation and conductivity of the cable, good; under these
circumstances, a sea cell would be formed between the plates c and z,
causing a different deflection of the needle in amount and in direction, by
which it would be at once indicated that the charge had become wet.
TEST TABLE, DIFFERENTIAL GALVANOMETER.

"Sea cell" Test for Insulation.—Again, in the case of the insulation of the
electric cable being damaged to such an extent as to expose the copper

conductor. Under these circumstances there would be formed a sea cell
between the copper earth plate c, and the exposed copper conductor of the
cable, by which a certain definite deflection of the galvanometer would be
observed, which deflection would differ in character from that produced by
the copper carbon sea cell, when the insulation of the cable was good, and
the system in working order, and therefore it would indicate that some
change in the electrical conditions of the system had occurred. The fact that
a leak existed in the insulation would be proved by changing the earth plate
at home from copper to zinc, carbon, tin, &c.
In the case of no deflection being produced on the galvanometer, on
applying the sea cell test, a want of continuity, or inefficient connections
would be indicated.
The foregoing afford examples of the vast utility of the "sea cell" in
connection with a system of electrical tests for submarine mines, numerous
variations of which may be effected by employing a series of earth plates,
of different metals, at the home end of the circuit, in connection with a
carbon and zinc earth plate at the other end. And the mode of manipulating
these tests may, by means of numerous switch plates, as shown at Fig. 95,
be made extremely simple and efficient.
Armstrong's System of Electrical Testing.—A very simple method of
testing electrical submarine mines, with which low tension fuzes are used,
has been devised by Captain Armstrong, R.E., and is shown at Fig. 99. a is
the electric cable leading from the shore; b the cable attached to a polarised
relay c, and connecting the charge through the fuze f to the earth; b' the
cable, attached to another polarised relay c', and connecting the mine with
the circuit closer; the polarised relay c, in the mine, is arranged to be
worked by a positive current, that is to say, the wire surrounding the core is
so wound as to increase the polarity of the electro magnet, near the
armature d, when a positive current is passed through it, and to diminish the
polarity when a negative current is passed through the wire surrounding the
core; the polarised relay c' within the circuit closer is arranged to be worked
by a negative current, the coil being so wound as to produce an influence
exactly the reverse of c.

Then, a positive current passing along the line wire a, the armature d in
the charge will be attracted, while d' will remain unaffected; again, if a
negative current be circulated, the armature d' within the circuit closer will
be attracted, while the armature d will remain unaffected. Two insulated
wires forked together are wound round each electro magnet, one a thin wire
(g and g') having a considerable resistance, about 1000 ohms, being
connected direct to the earth plates e and e', and the other a thick wire (h
and h') offering a very small resistance, and so arranged that when the
armature is attracted, they may be in contact with and complete the circuit
through the armature to earth.
The thin wire coils are so arranged that a certain number of Leclanché
cells (ten or twelve, as may be desired) will make the electro magnets act,
while with fewer cells the current would be too weak, and would therefore
pass through them to earth without affecting the armature.
By means of the three-coil galvanometer, a table of the deflections,
obtained by the foregoing system of testing, should be carefully recorded,
when the circuit is known to be in good working order, so that any defect in
the circuit would be at once indicated on the application of the various tests,
by the results so obtained differing from those originally recorded. When a
system of submarine mines is placed in position for the purposes of practice
and experiment, every trouble should be taken to endeavour to fix the exact
position of any defect that may exist, also to ascertain its magnitude, &c.,
but in time of war, should a defect exist in the system, no time must be lost
in such operations, but the mine at once lifted, and the fault repaired, or a
fresh one laid in its place, unless the presence of an enemy or other
imperative cause should prevent such work being done.
Austrian Testing Table.—The following is a description of the Austrian
testing table, and their mode of making electrical tests with it, in connection
with their system of self-acting electrical submarine mines.
METHODS OF TESTING.—ARMSTRONG,—AUSTRIAN.

Its design is shown at Fig. 100; c z represents the battery with one pole
to earth at e, and the other in connection with an intensity coil a, through
which the current passes to the contact plate b. When it is desired to put the

system of mines in connection with the table, in a state of preparation to be
fired by the contact of a vessel, a plug is inserted between the contact plates
b and f, and the current passes through the galvanometer g, and electrically
charges the conducting wires connecting the mines with the battery, through
the several binding screws on the contact plates, numbering 1, 2, 3, &c. The
fact that the charge has been fired is also at once indicated on the
galvanometer g.
Test to discover an Exploded Charge.—It then becomes necessary to
ascertain which particular mine of the system has been exploded; for this
purpose a separate circuit in connection with a single cell d is employed.
This cell is in connection through a galvanometer g' (a more sensitive
instrument than the galvanometer g) with the pivot of the key h, and
rheotome R, which latter is connected, as shown by the dotted lines, with
each individual mine of the system attached to the contact plates numbered
1, 2, 3, &c. The handle of the rheotome is moved round, to each number in
succession and directly it is placed in contact with that corresponding to the
exploding mine, the electrical circuit is completed through the exposed end
of the fractured wire, and this is indicated by the galvanometer g'. During
the testing process the firing battery c z must be disconnected; this is done
by raising one of the bridges i i with which each group of ten mines is
provided.
Insulation Test.—The rheotome and testing galvanometer g' are also
used to test the insulation of the electric cables connecting the mines to the
testing table. This is done in precisely the same manner as testing for an
exploded mine: the handle of the rheotome is turned round, and each cable
connected in succession with the testing circuit as before; should the
galvanometer g' remain stationary, the insulation is good; but should a
defect of insulation exist, the current passing through it would act on and
deflect the galvanometer, indicating the particular line in which it exists,
and, roughly, its extent in proportion to the deflection shown; should the
fault be considerable, the defective cable should be at once detached, as the
current lost through it might so diminish the working power of the firing
battery, as to prevent it exploding any of the fuzes attached to the group in
connection with it. By the above arrangement, the insulation of each line
can be tested at any moment required.

In making the delicate test for insulation, which should invariably be
done at leisure, and, if possible, when an enemy's vessels are not in the
vicinity of the mines, a large number of Daniell's or other cells of suitable
form should always be used. To do this, it would only be necessary to
connect such a battery in place of a single cell permanently arranged, as
described, in the testing circuit, and to proceed with the details of the
operation as before. As the cable would, in actual work, always be charged
with the full power of a firing battery, the value of its insulation to resist an
electrical charge at such a high potential would be an important point to
determine. The fuzes being entirely out of the circuit till the moment of the
action arrives, no danger of a premature explosion need be apprehended; if
a fuze were in such a position as to be fired prematurely, it would be
exploded, in connection with the firing circuit, independently of the
operation of testing the insulation of the cables.
To render a Channel Safe.—In order to render the channel safe for a
friendly vessel, it is only necessary to remove the plug from between the
contact plates b and f; this disconnects the firing battery from the circuit.
Defence of Harbours by Booms, &c.—Booms or cables supported by
rafts may also be employed in the defence of harbours, or rivers, either by
themselves, or in combination with submarine mines; in the latter case, the
booms, &c., may be moored either in advance of the mines, or in rear of the
front row, this last method of mooring them being the most effective one.
There are a great variety of forms in which a boom may be constructed.
The qualities essential for a good and practicable boom are:—

1.—Great strength.
2.—Great power of resistance.
3.—Convenience in handling.
4.—Easy to manipulate.
5.—Its materials easily procurable.

Construction of a Boom.—The general construction of a boom consists
of a main cable, buoyed up at intervals by floats. The main cable may be
either wire, chain, or rope, the former being very much superior for this
purpose to chain or rope. The floats consist of balks of timber built round

the main cable and bound together by means of iron hoops &c. A space is
left between each float, by which a certain amount of flexibility in the boom
is obtained, without which it would be of comparatively little use, as it
might be easily overrun.
It must be borne in mind, in constructing all such booms, that the smaller
the proportion of timber used in forming the floats to the cable, consistent
with buoyancy, the stronger will be the structure.
A very important feature in connection with such a mode of defence is
the manner of mooring it; for if it be moored so as to be unyielding, then its
sole power of resisting a vessel charging it is the actual strength of the
materials composing the structure, but if it be moored so that it is capable of
yielding to a sudden blow, this force will be to some extent absorbed, and
resistance of the defence greatly increased.
The raft employed to support the main cable should be moored by means
of very heavy chains (without anchors) in the direction of the attack, and
with ordinary anchors and cables on the other side.
As a rule, the booms should be moored obliquely to the direction of the
current, where there is any, as the tendency of the current to overrun the
boom when so placed will be less, and also a ship ramming it must place
herself athwart the current to attack the boom at right angles.
Clearing a Passage through the Torpedo Defences of an Enemy.—The
subject of clearing a passage through the torpedo defences of an enemy is
one fraught with innumerable difficulties, on account of the varied nature
and impracticability of obtaining accurate and certain information of such
defences, and thus it is impossible to lay down any fixed rule or plan for
carrying out such an operation.
In fact, it will be only under the most favourable circumstances that such
a service will be successfully accomplished, that is to say, in the case of a
harbour or river defended by submarine mines but unsupported by guns, or
guard boats, or where the electric light is used.
Numerous methods have been devised from time to time to effect the
destruction of an enemy's submarine defences, among which are the
following:—

1.—Projecting frames, &c., from the bows of a vessel.
2.—Creeping and sweeping by boats.
3.—Countermining.

Projecting Frames, &c., from the Bows of a Vessel.—This method was
adopted by the Federals during the American civil war of 1861-5, and in
many instances it was the means of saving their ships when proceeding up
rivers which had been torpedoed by the Confederates, though
notwithstanding this precaution several vessels were sunk. The submarine
mines against which this mode of defence was used, were in nine cases out
of ten mechanical ones, and therefore the framework defence afforded a
better means of protection then, than would be the case now that electrical
ground mines and circuit closers are used, as the framework would catch
the circuit closer only, and the vessel would probably be over the mine
when the explosion took place. The Americans moor their circuit closers in
rear of their mines, so that a vessel fitted with a bow frame or not, coming
in contact with the former must be right over the charge at the instant of
explosion.
Against ground electrical mines fired at will, the bow net, &c., is no
protection whatever, still under certain circumstances it would be found
extremely useful.
Sweeping for Submarine Mines.—This method of clearing a channel of
submarine mines could not possibly be carried out under artillery fire, but in
waters not so defended it would prove of some value.
Where only buoyant mines, or ground mines with circuit closers are to
be cleared away, two or more boats dragging a hawser between them would
be sufficient to discover them, and so lead to their destruction; but where
dummy mines and inverted creepers are moored in addition, another
method of sweeping must be resorted to, viz., that of bringing an explosive
charge of gun-cotton to act on the obstruction grappled, and thus destroy it.
This is effected by lashing a charge to each end of the sweep, so that
whatever is grappled may slide along it, until caught by hooks, which are
attached for this purpose to the centre of the charge. On grappling an
obstruction, the two boats drop their anchors, one hauling in, the other

veering out the sweep, until the charge is hooked by the obstruction; this
being effected, the boats move out of range, and the charge is fired.
Creeping for Electrical Cables, &c.—Creeping is the method employed
for picking up the electric cables of the enemy's submarine mines, and is
effected by boats towing an ordinary grappling iron, or specially prepared
creeper on the ground.
In both sweeping and creeping it would be found necessary to employ a
diver, who would ascertain the nature of the grappled obstructions which
could not be easily raised by the boats.
The Lay torpedo boat, which is fully described in the chapter on
offensive torpedoes, is capable of being used for the foregoing purposes.
Countermining.—Countermining, that is, the destruction of submarine
mines by the explosion of other mines dropped close to them, will under
certain conditions prove of great use in clearing harbours of mines. This
method could not be operated in waters properly guarded and swept by
artillery fire.
There are two distinct methods of laying out countermines, viz.:—
1.—In a boat, which may be either towed, or hauled out to its
destination, or may be steered, and controlled by electricity.
2.—By attaching them to buoys so that they are suspended at the
proper depths, and then hauled out by means of a warp to an
anchor which has been previously placed in position.
Both of the foregoing methods have been successfully manipulated in
practice, the first method, where the boat carrying the countermines is
towed either by a pulling or steam boat being the most practicable one. A
large amount of material would be required for clearing a channel by means
of countermines: for example, if the mines to be attacked require 500-lb.
gun-cotton charges to be used, 7-1/2 tons of the explosive, besides cables,
buoys, &c., would be required to clear a passage about one mile in length
and 200 feet in width.
A ship's launch will carry about twelve of these 500-lb. countermines,
with all the gear attached thereto.

Experiments to ascertain the effect of countermining have been carried
out in England and Europe for the last five years, some of which are given
at length in the chapter on "Torpedo Experiments." During the Turco-
Russian war, a portion of the Danube was swept in the ordinary and most
simple manner by the Turks, and five Russian electro contact buoyant
mines were picked up; one other exploded during the process of dragging it
to the surface, but no injury occurred to those at work.
Destruction of Passive Obstructions.—To clear away booms, or other
passive obstructions, if not possible to cut them away, they may be
destroyed by outrigger boats exploding their torpedoes underneath, and in
contact, or by attaching charges of gun-cotton at intervals, and then
exploding them simultaneously. When a chain is horizontal, and therefore
somewhat taut, a charge of 3-1/2 lbs. of gun-cotton (this explosive, being
the most effective and convenient for such purposes, should always be
used) will be found sufficient to destroy it, no matter what size, and whether
the chain is in or out of the water, the charge being of course placed in
contact with it. Great uncertainty must always attend the supposed
clearance of a channel, or passage of submarine mines, as was exemplified
during the American civil war, when most of the Northerners' vessels were
destroyed while moving over ground which had been previously carefully
dragged, and buoyed, and this fact, coupled with the tediousness and danger
of performing such a service, proves the enormous value of a system of
defence by submarine mines.

FOOTNOTES:
[J] 'Electricity and Magnetism,' by Professor F. Jenkins.
[K] See Appendix.
[L] As constructed by Mr. J. Mathieson, late R.E., at the Silvertown
Telegraph Works, Essex.

CHAPTER V.
OFFENSIVE TORPEDO WARFARE.

T HE term "Torpedo" is applicable more particularly to offensive
submarine mines than to those employed for the purposes of defence,
and therefore by torpedoes will be understood every kind of submarine
explosive weapon designed to be used for active attack against vessels, &c.,
no matter how they may be manipulated.
Offensive Torpedo Warfare still in its Infancy.—Though during the
seventeen or eighteen years that torpedoes have been considered as a
legitimate mode of naval warfare there have occurred three big wars, in
each of which submarine weapons, offensive and defensive, have played an
important part, still the subject of offensive torpedo warfare must be even
now considered as in its infancy, and therefore any opinions expressed as to
the merits and demerits of the various apparatus in connection therewith can
but be based on the theoretical capabilities of each torpedo, and on the
results of experiments carried out with them during peace time, which latter
as a rule are conducted under far too favourable conditions to be relied
upon.
Their Use during the Civil War in America.—During the American civil
war, the only offensive submarine weapon that was used was the outrigger
or spar torpedo, which in those days was a crude and imperfect machine,
and manœuvred from boats possessing all the features which a torpedo boat
should not possess. Still under these unfavourable conditions ships were
sunk by such means by both Federals and Confederates, proving that in
future wars this mode of attack, favoured by the vast and important
improvements that have lately been effected both in connection with the
torpedoes and torpedo boats, should play a prominent part, and prove a
most destructive mode of attack.
Their Use in the Franco-German and Russo-Turkish Wars.—In the
Franco-German war of 1870-1, offensive torpedo warfare was not resorted
to by either side, the French fleet being deterred from entering German

waters by the submarine mines placed, or at least supposed to be placed, in
position.
From the Russo-Turkish war much light was expected by torpedoists to
be thrown on the subject of torpedo warfare, but alas, little or nothing was
done to settle any of the many vexed questions which exist in regard to
offensive submarine weapons. The torpedo experience of that struggle
tended rather to prove that the vast importance hitherto attached to torpedo
attack was much exaggerated.
One of the causes which led to the failure of offensive submarine
weapons, when employed on active service, seems to be due to the fact that,
owing to the extremely small radius of the destructive effect of such
weapons, it is absolutely necessary for complete success to explode the
mine in actual contact with the attacked vessel; to ensure which, at night
time, in an unknown harbour, with the position of the vessel attacked
somewhat uncertain, and even without the additional obstacles of guard
boats, booms, electric lights, &c., is a service of infinite difficulty, and one
which may easily terminate in a failure. The foregoing would more
especially apply to the spar torpedo attack, but in an attack with the
Whitehead fish, or towing torpedo, there would be an additional cause of
failure, viz., the complicated nature of their manipulation.
Torpedoes may be divided into four classes, viz.:—

1.—Drifting or floating torpedoes.
2.—Towing torpedoes.
3.—Locomotive torpedoes.
4.—Outrigger or spar torpedoes.

Drifting or Floating Torpedoes.—By "drifting" or "floating" torpedoes
are meant all those submarine machines which are dependent on the tide or
current of a stream for their action and motion.
During the American civil war this mode of attacking vessels was
constantly employed by the Confederates, and though not successful in
destroying any of the Federal ships, was the means of considerably
hampering the movements of their river flotillas.

Drifting torpedoes might be advantageously used for the destruction of
pontoon bridges, booms, &c., and in this way, had the Turks in their late
war used them, the Russians would have found the crossing of the Danube a
matter of infinite danger and difficulty; in fact, by a systematic use of such
weapons, combined with a little dash on the part of the Ottoman flotilla on
the Danube, that river should have been to the Russians an impassable
barrier. To use these torpedoes most effectively, especially against a single
vessel, a thorough knowledge of the force and direction of currents should
be gained before proceeding to undertake an operation in which these
submarine weapons are used.
Another point to be remembered is, that if such a torpedo were started
with the flood, for example, towards an enemy, and did not explode, there
would be a chance of its being returned to the starting-place by the ebb tide.
In this class the following torpedoes seem the most practicable:—

1.—Lewis's drifting torpedo.
2.—McEvoy's drifting torpedo.
3.—American extempore drifting torpedo.

Description of Lewis's Drifting Torpedo.—"Lewis's" drifting torpedo,
designed for the express purpose of destroying booms or other floating
obstructions placed round a vessel at anchor for the purposes of defence, is
shown at Fig. 101. It consists of a box a, containing the charge and fitted
with several detonating fuzes. This box is attached to one side of a beam b,
and within 6 inches of one extremity, the beam being about 20 feet long and
7 inches square; to the opposite side, of the same end of the beam b a heavy
weight c, resting in a shoe d, is attached by a long iron rod e, which reaches
to the other extremity of the beam, and is there connected to a bell-crank
lever and spring f, a pressure on which detaches the weight c; a chain g, 18
feet long, connects the weight loosely with the upper end of the beam, and
another chain h, 9 feet 6 inches long, connects it with a point more than 2
feet below the centre of the beam. The apparatus is so constructed that it
floats nearly vertical with the top of the beam just above the surface of the
water.

On the machine drifting against the boom or other obstruction, the spring
or lever f at the upper extremity is pressed down, thus releasing the weight
c, which falling, becomes suspended by the two chains g and h, and brings
the beam into an inclined position. The weight of this mass of iron and the
chain suspending it are suddenly brought to bear on the top of the beam,
dragging it under water and clear of the boom, &c. At the same time the
lower end, released from the weight, rises, and the whole apparatus is
carried forward by the current against the side of the vessel, on striking
which the torpedo is exploded.
Description of McEvoy's Drifting Torpedo.—"McEvoy's" drifting
torpedo is intended to be floated, singly or in groups, by the aid of tides or
currents against vessels at anchor, bridges, &c.
At Fig. 102 is shown a plan of this form of drifting torpedo.
It consists of the body of the torpedo a, which contains the charge, at the
side of which is placed the loading hole b; c is the tube containing the
priming charge; d is the framework surrounding and protecting the wheel or
screw e; f is the fuze pillar, in the centre of which is a steel rod g, and on the
top a thin steel plate h is placed; i is the nipple for the percussion cap; k is a
horizontal bar, turning and resting on top of the fuze pillar f; m is the lever
for supporting the hammer n when it is set; l is the screw barrel supporting
the wheel or screw e; o is a safety pin; q is the supporting chain, and p the
spring for working the hammer n.
By means of a buoy or log of wood, from which the torpedo is
suspended, it can be adjusted so that the explosion shall occur at the
requisite depth.
To prepare the torpedo for use, unscrew the fuze pillar f, take off the
horizontal bar k, place a percussion cup on the nipple i, and screw it tightly
against the end of the steel rod g. The fuze pillar is then ready for use, and
should be screwed into the body a. Then fill the torpedo with the explosive
and close the loading hole b. The hammer n is then set by drawing it back
and bringing the end of the lever m against it, at the same time running the
screw barrel l under the lever m, so that its end catches the screw of the
barrel, as shown in the figure. The safety pin o is then put in its place and

secured by a few parts of thread, which by a sharp jerk on the safety line
will be easily broken.
DRIFTING TORPEDOES.

The horizontal lever k, which carries the lever m and propeller e, rotates
on the top of the fuze pillar f, and is prevented from rising by means of a
screw. The torpedo being let go, the safety pin o is pulled out by means of a
line which is attached to it. The propeller will not revolve whilst the torpedo
is drifting with the current, but the instant it is stopped by the action of the
current the wheel will be caused to revolve, and after a few revolutions it
will unscrew the barrel from under the end of the lever k, and the latter,
dropping the hammer n, will be forced by the spring p into contact with the
thin steel plate h on the top of the fuze pillar, which blow is transmitted by
means of the steel rod g to the percussion cap, and the torpedo exploded.
American Extempore Drifting Torpedo.—This form of drifting torpedo,
which is readily made, was used in great numbers by the Confederates, and
though not successful in sinking any Federal ships, caused their vessels
considerable annoyance and delay.
At Fig. 103 is shown a sketch of this torpedo. It consists of a tin case
containing about 70 lbs. of powder. A stiff wire a, b passes through a hole
punctured in a strip of tin c, and a stuffing box d; the end a of the wire is
covered with fulminate, and so arranged that the friction caused by its
passage through the strip of tin c will ignite it; a number of wires lead from
b to pieces of driftwood on the surface e, e, e, and the case is supported at
the proper depth by a line attached to a section of log.
Towing Torpedoes.—By towing torpedoes are meant those submarine
machines which are so shaped and arranged, that when towed from a ship
or boat in motion they will diverge to a considerable extent, thus enabling
the towing vessel to pass clear of the ship attacked, and yet near enough to
allow of the torpedo being brought in contact with some part or other of her
hull.
Towing torpedoes were for the first time employed on actual service
during the late Russo-Turkish war, when a modified form of the well-
known Harvey torpedo, designed by a German officer, was used by the
Russians, but in no case was it successful.
In this class of submarine offensive machines may be placed the
following:—

1.—Harvey's towing torpedo.
2.—Menzing's towing torpedo.
3.—The French towing torpedo.

Harvey's Torpedo.—This form of towing torpedo was invented
conjointly by Captain John Harvey and Commander Frederick Harvey,
R.N., and is intended to be used at sea both as a means of offence and
defence.
At Fig. 104 is shown in elevation the small sized Harvey towing torpedo,
in which all the latest improvements that have been devised are represented.
a is the case of the torpedo, formed of Muntz's metal, but not provided,
as the original ones were, with an exterior case of wood; by this alteration
greater capacity combined with extreme lightness is obtained, which
undoubtedly much enhances the value of the small size torpedo which is
intended to be carried by and manœuvred from boats; b is the principal or
after lever, hinged on the top of torpedo at c, and rests, when ready for
action, in a crutch formed in the top of the exploding bolt d; e is the
foremost lever, hinged at f, and kept in position on the after lever b by a
groove formed in it and a lashing which passes through a slot in the
principal lever, as at g; h is the side lever, pivoted at i, and exerting a
pressure on the firing bolt d by means of a lanyard which is passed through
the bolt k and over the principal lever b; l is the top lever, pivoted at m, and
exerting a pressure on the bolt d by means of a lanyard which is passed
through the bolt n and over the principal lever b; this top lever l has been
added to ensure the action of the torpedo, on its striking sideways against a
vessel; o and t are handles, to the former of which the lashings of the levers
h and l are secured; p is the ring used for attaching the buoy rope; r, r are
two loading holes, made in the side of the torpedo case, by which a charge
of gun-cotton may be quickly and efficiently stowed; this also is a new
feature in the small size torpedo; s is the rudder formed for the purpose of
controlling the direction of the torpedo when the tow line is suddenly
slacked.
In regard to the large size torpedo, the construction of the case remains
as in the original ones, the improvements being, the enlargement of the

loading and fuze holes, and the addition of the top lever l, as shown at Fig.
104.
The small size torpedo is capable of holding 47 lbs. of water, whilst the
large size one will contain 76 lbs. of water, or about 33 lbs. and 58 lbs. of
gun-cotton respectively.
The slings are made of best Italian hemp, and consist of a span of four
legs, which are secured to lugs at the corners of the torpedo and connected
to an iron thimble, which is shown at Fig. 105; this thimble is made suitable
for either wire or hemp rope, and is so arranged that should the seizing
become slack, the parts of the slings cannot become detached from the
thimble.
HARVEY'S TOWING TORPEDO.

The legs of the slings should be so fitted that when stretched alongside
the torpedo they extend 1 foot beyond the stem for the large torpedo and 8
inches for the small one; the four legs should be so fitted that when an equal
strain is brought on them, the thimble should be on a level with the upper
lugs, and the upper fore span form an angle of 80° to 85° with the side of
the torpedo; this is shown at Fig. 106. This arrangement gives the best

divergence with the least strain on the tow rope, and is suitable when the
torpedo is kept at short scope, as well as when a long length of tow line is
out.
The mode of attaching the foremost and side levers is shown at Fig. 107.
Before reeving the lanyards they should be well greased in the wake of the
fair leads, but not where they are made fast. The lanyards should be made
up like a reef point. Care should be taken that the short arm of the side lever
h is brought close into the fair lead, and its lanyard should be set up
sufficiently taut to give a slight spring in the principal lever b by the strain
thus brought on it. This lever b has a steel fish on the top, in order to
prevent it taking a permanent bend. If the side lever lanyard is properly set
up, the bolt will spring down about 1/8th of an inch when the safety key is
withdrawn, owing to the spring in the lever, and the shrinking of the
lanyard; this brings the muzzle 1/8th of an inch nearer the pin without
disturbing the side lever.
The bolt is so arranged that the torpedo can be fired by either of the
following methods:—

1.—Mechanically.
2.—Electrically at will.
3.—Electrically on contact or at will.

Mechanically.—In this case the bottom of the inner cylinder, as at a, Fig.
108, is fitted with the ordinary mechanical chemical fuze, ignition being
effected by the breaking of the glass vessel containing the sulphuric acid on
being forced into contact with the needle n, by the action of the levers on
the torpedo striking a vessel.
Electrically at Will.—For this purpose a platinum wire fuze is used, one
terminal being connected to earth through the bolt, the other to a wire
leading up through the core of the bolt, and connected by means of an
ebonite joint with a single cored electrical cable leading from the torpedo
vessel.
Electrically on Contact, or at Will.—In this case, a resistance coil is
inserted in addition to the fuze, and is so arranged that on the bolt being
forced down a short circuit is formed, cutting out the resistance coil (about

20 ohms), and thus enabling the battery to fire the fuze, which, owing to the
20 ohms resistance in the circuit, it was previously unable to effect. Should
the bolt so arranged be required to be fired at will, it is only necessary to put
a more powerful battery in circuit, and so fire the fuze through the 20 ohms
resistance.
Exploding Bolt.—The exploding bolt is fitted to act with a pressure of
from 30 to 40 lbs. on its head for the large size torpedo, and from 15 to 20
lbs. for the small size one.
The bolts are all the same size, and differ only in the direction of the slot
for the safety key k, being port or starboard bolts accordingly. The muzzle
of the exploding bolt stands 1 inch off the pin when in the safety position,
that is, when the safety key rests on the brass work of the priming case.
The safety key is secured in the slot of the exploding bolt, as shown at
Fig. 108, by eight or nine parts of strong whitey-brown thread secured to
the key, passed round the bolt, and securely knotted; the parts of the thread
should come away with the key, in order that none of the parts may be
worked down the tube by the exploding bolt.
In the event of the large torpedo being cut away in deep water after the
withdrawal of the safety key, it will explode by pressure on the head of the
bolt at about sixty fathoms depth; the small one at about thirty fathoms.
Buoys.—The buoys are of two sizes, and are made of solid cork (such
cork only being used as will ensure great floating power after being
immersed for a time); each buoy is built upon a galvanised iron tube
running longitudinally through; on the ends of the tube are screwed wooden
cones, which bind all together, and render the buoy indestructible.
Two buoys are used for each torpedo, the larger buoys for the large size
torpedo, and the smaller buoys for the small size torpedo. The buoy rope is
of hemp, about five or six fathoms in length and two inches in
circumference, an eye being spliced in the end nearest the torpedo; to this
eye is bent the tow rope, with a single or double sheet bend forming the
knot by which the torpedo is towed; the other end of the buoy rope is passed
through one of the rings in the stern end of the torpedo (according to
whether working in deep or shallow water), then through the tube of the

first buoy, and an overhand knot made in the rear; then through the next
buoy, and a knot in the rear of that. Recently, Captain Harvey has adopted a
large and a small buoy for each torpedo, the large one being practically
sufficient, the smaller one being added in the event of the other one
becoming sodden.
Brakes.—The brakes are used for the purpose of controlling the tow
ropes; they can be fixed by screws into the deck at the most convenient
place for command, and in a properly constructed torpedo vessel would be
placed below the water line, to prevent exposure of the men working them.
They are so arranged as to admit of the tow rope being quickly veered, and
at the same time are sufficiently powerful to bring the torpedo to the surface
when required. Success greatly depends on the skilful handling of these
brakes, for in conjunction with the cork buoys they give the operator
command of the depth at which the enemy is to be struck. Unless a very
high rate of speed is required, one handspike will control the tow rope; the
other strap can be thrown off the drum, and the handspike allowed to lie on
the deck ready to be thrown into gear, if necessary. The surface of the drum
in contact with the strap should be powdered with rosin to increase the
friction. The tow rope should be so reeled up that in veering the reel may
revolve towards the men at the handspike. The spindle will contain several
tow ropes, that, in the event of one torpedo being cut away, another can be
immediately bent.
The brake for small torpedo requires only one drum and handspike. It
can be fitted to a steam launch by placing an extra thwart across near one of
the others.
Care should be taken that the riding turns lie fairly over each other, to
prevent a jamb when veering.
The brakes, both large and small, are so made as to ensure durability,
they being considered a part of the ship's furniture.
Brake for safety key line is a small reel on the same principle. When
going a slow speed, it may not be necessary, as the safety key line can be
attended by hand; but when going ten or eleven knots, it will be found of
considerable advantage, both in keeping the bight of the safety key line

from dragging astern, thereby lessening the divergence of the torpedo, and
also in drawing the safety key when a strong stop is used.
Arrangements for Launching and Towing the Torpedoes.—A yard across
either the main or mizen mast of a torpedo vessel, from 20 to 25 feet above
the water line, is a very convenient method for launching and towing. The
leading block on the yard, through which the tow rope is rove, may be fitted
to a traveller on the yard with an inhaul and outhaul, that the distance out
from the ship's side may be regulated as convenient.
In a large vessel, the leading block for tow rope can be fixed to the end
of the quarter-boat's davits. The brakes for commanding the tow rope
should be screwed firmly to the deck. In a vessel properly constructed for
the service, they would be on the lower deck, the tow rope having been led
along the yard, and down each side of the mast.
A leading block for the tow rope is placed on the deck by span or bolt a
few feet in front of the brake. The safety key reel, if used, must be fixed in a
convenient position on deck, that the man attending it can see how to
control it; in a properly constructed vessel he would be in the pilot house.
The safety key line leads through a small leading block on the ensign staff
or some convenient point abaft the lead of the tow rope, 15 to 20 feet above
the water. The leading block on the yard may be fitted with a lizard, if
thought necessary. A sharp instrument should be kept by the brakes ready to
sever the tow rope.
In large men of war, arrangements are made for carrying a loaded
torpedo and two buoys in a convenient position on each side of the vessel,
in such a manner that the tow line can be bent, the exploding bolt screwed
in, the levers adjusted, and the torpedoes and buoys dropped simultaneously
when required.
Preparing the Torpedoes for Use.—The torpedoes, port and starboard,
loaded and ballasted, having been hoisted out of the torpedo room, are
placed on the deck on their own sides, with their heads forward under the
leading block, and the buoys placed abaft them and strung together; the
exploding bolts are now entered into the torpedoes, and forced down until
their safety keys rest on the brass work, taking care that each safety key
points in the direction of the eye through which its lanyard has to pass; the

levers are now secured by their lanyards, as explained at pages 120 and 121.
The eye at the end of the buoy rope is now rove through the large or small
ring in the stern end of the torpedo. The tow rope having been previously
rove through the leading block on the deck and on the yard, is rove through
the thimble of the slings from forward aft, and bent, with a single or double
sheet bend, to the eye of the buoy rope. The safety key line having been
previously rove through the leading block on the ensign staff, and the
lanyard on the safety key having been led through the eye of the handle,
making a fair lead with the slit in the bolt, are bent together with a double
sheet bend, and stopped to the eye of the handle by a split yarn of suitable
strength, the yarn having been first secured to the line by a round turn
outside the bend.
The line should also be stopped with another split yarn round all parts of
the slings close up to the thimble, having first made an overhand knot in the
line at a distance a few inches longer than that between the eye bolt and the
thimble.
The crew having been stationed at their respective posts, the handles
having been shipped on the tow reel, the tow line is then reeled up until the
torpedo will launch clear, and swing out under the leading block on the
yard. Hold the torpedo by the handspikes, and take off the handles of the
brake. In swinging out, care should be taken that in starting from the deck
the fore slings do not foul the fore top lever. The stern of the torpedo can be
steadied by keeping a slight strain on the buoy rope. The safety key line
must be kept clear, and not checked, or it might break the stop and draw out
the key before intended. The buoys must be placed in a proper position and
hands stationed by them to launch them overboard the instant the torpedo
takes the water. It would be better to stop the screw, if circumstances would
allow of it, when lowering the torpedo and buoys into the water, to prevent
the chance of the buoys fouling the screw. The torpedo, on reaching the
water, will immediately diverge clear of the ship; the buoys being launched,
as the strain comes on the buoy rope, they will be towed clear away from
the screw, and full speed may be put on at once. The men at the handspikes
must veer steadily, occasionally checking the torpedo, that it may be kept
near the surface, and not allowed to dive, which it will do if the tow rope is
slacked up altogether, and then a sudden strain brought on it.

Eventually it will come to the surface, when the bow is pointed up by the
strain on the tow rope; greater the speed the more quickly will it be brought
to the surface. In shallow water this should be particularly attended to, as in
diving it might strike the bottom and injure the levers, and, if the safety key
has been withdrawn, explode; moreover, it brings an undue strain on the
tow rope. The torpedo can now be gradually veered out to the distance
required, the safety key line so attended that a sufficient strain is kept on it
as not to allow of a long bight of line dragging astern of the torpedo; at the
same time having due regard to the strength of the yarn by which the line is
stopped to the handle of the torpedo. The distance veered must depend upon
the nature of attack. The tow line should be marked with knots every 10
fathoms: under some circumstances the torpedo would be close to the ship
until passing the enemy; at other times veered to 40 fathoms it will be found
most suitable.
The full divergence of 45° is obtained up to 50 fathoms; beyond that the
bight of the tow rope in the water drags the torpedo astern, unless the tow
rope is triced much higher up, which has its disadvantage; 40 to 50 fathoms
of tow rope gives the best command of the torpedo, veering 2 or 3 fathoms
of tow line suddenly will always sink the torpedo some feet below the
surface. Should it become necessary to use the torpedoes with a stern board,
they can be so used, but in this case the port torpedo is used on the
starboard, bow and starboard on the port; all other arrangements being
exactly the same. In rough weather, advantage should be taken of the roll,
and the torpedo allowed to swing out from the yard, and be let go by the
run, checking the tow rope immediately the torpedo is in the water. It is not
absolutely necessary to ease the vessel when launching; the torpedo can be
launched at full speed. In the event of its being found necessary to cut adrift
the torpedo, in consequence of coming suddenly across a friendly vessel,
the tow rope should be cut near the brake, and if the buoy rope has been
rove through the large stern ring, the torpedo will sink and be lost, the buoy
only remaining. If the buoy rope has been rove through the small stern ring,
the torpedo will be suspended by the buoy rope; and should the safety key
not have been withdrawn, can be recovered with safety.
In the event of wishing to recover it when the buoy rope has been rove
through the large ring, a toggle must be lashed on the tow rope abaft the
leading block on the yard, when it can be recovered by the buoy rope; as a

general rule, however, it will be found best to expend the torpedo, and not
attempt its recovery.
HARVEY'S TOWING TORPEDO.

SYSTEMS OF ATTACK WITH HARVEY'S TOWING TORPEDO.

Recovering the Torpedo.—Should the safety key have been withdrawn,
great caution is necessary. Tongs, shown at Fig. 109, for going round the
upper part of the bolt, to take the place of the safety key, when once clasped
and secured round the bolt, render the torpedo safe to handle; this could
only be done from a boat. With the safety key in, there is no danger in
hoisting it inboard again by its own tow rope, and hoisting up the buoys at
the same time with a grapnel.
Different Methods of Using the Torpedo.—There are two methods of
employing the torpedo, either of which may be adopted, according to
circumstances.
1.—When it is towed with a length of line varying from 25 to 60
fathoms, and dipped when in position to strike the attacked
vessel.
2.—When it is kept suspended from the yard, &c., and dropped at the
spot, where according to the first method it would have been
dipped.
In the first method, it is not necessary to withdraw the safety key till just
before dipping; in the second method the safety key line is belayed at about
twenty fathoms, and the key withdrawn when the line is tautened by the
ship going ahead.
Tactics.—Description of the various attacks that may be made with the
Harvey torpedo against a ship at anchor or under way. In the following
diagrams T is the torpedo vessel, S the ship attacked.

Attacking a Vessel moored Head and Stern.—In this case the torpedo
vessel steers in for the bow or quarter of the vessel attacked, according to
the direction of the current, and on the side approached launches the
torpedo between the moorings, as at A; leaving the tow rope slack, the
torpedo vessel proceeds ahead or astern against the current, and when at a
sufficient distance off, the tow rope is held fast, which will cause the
torpedo to diverge into contact with the vessel attacked, as shown by Fig.
110.

Attacking a Vessel at Anchor by Crossing her Bow.—In this case the
torpedo is sufficiently diverged when near to the vessel with a good scope
of tow rope out. After having crossed her bow, proceeding onwards, the tow
rope will be brought obliquely across her cable, and the torpedo will swing
into her, as shown at Fig. 111. It may be here remarked, that in all cases the
depth of the explosion can be obtained by the sudden slacking of the tow
rope; and the tow rope once under the keel, causes the torpedo to be hauled
down near to it before exploding.
Attacking a Vessel at Anchor by coming up from Astern on either Side.—
In this case the torpedo is launched when on the quarter of the vessel
attacked, as at A, the tow rope left slack. After steaming ahead some
distance, hold fast the tow rope, when, by continuing to steam on, the
torpedo will diverge into contact with the bottom of the vessel attacked, as
shown at Fig. 112. When skilfully performed, the total destruction of the
enemy is certain, since the torpedo is springing from a depth to the surface,
and will, in consequence, strike near her keel. The torpedo vessel can pass
at her greatest speed, and, if thought necessary, near enough to clear away
any of the ordinary obstructions, such as booms, nets, &c.
Passing Down between Two Lines of Vessels at Anchor.—In this case it
would be impossible to fire at the torpedo vessel, for fear of injury to their
friends. Two or more torpedo vessels following each other with
preconcerted signals would cause great destruction. See Fig. 113.
Attacking a Vessel in Motion from Right Ahead.—In this case two
torpedoes are launched, port and starboard, each diverging to its full extent;
when passing the vessel attacked, one or the other of the tow ropes is
brought across the cut-water, and by the simultaneous motion of the two
vessels in opposite directions, the torpedo is brought alongside of or under
the bottom of the vessel attacked, as shown at Fig. 114. The torpedo vessel
should keep the masts of her enemy in one until close to, when either
torpedo will be used, according to the movement of the enemy. At the time
of the tow rope taking the cut-water, the brake is suddenly eased up; the tow
rope will then pass under the bottom, when by checking the tow rope the
torpedo will be hauled under the bottom.

To execute this attack, judgment, skill, and nerve of the highest order
will be required, as the risk of being run down will be imminent.
The Attack from Astern.—In this case two torpedoes are launched, and
diverged as in the previous case; it is assumed in this instance that the
torpedo vessel can outspeed the vessel attacked, which will enable her to
bring a torpedo under the run of the attacked vessel, as shown at Fig. 115.

SYSTEMS OF ATTACK WITH HARVEY'S TOWING TORPEDO.

If Chased by a Hostile Vessel, and unable to Face her.—In this case veer
a torpedo astern, having first obtained a position a little on the bow of the

chasing vessel. When it is known by the length of the tow rope out that the
torpedo is about abreast of her bow, hold fast the tow rope, which will cause
the torpedo to diverge, and be brought into contact, as shown at Fig. 116. As
a last resort drop spanned torpedoes.
Torpedoes can be used with a stern board, if necessary. The port torpedo,
in this case, will be launched on the starboard side, and the starboard on the
port side.
It should be here remarked that, although great speed is essential in the
torpedo vessel to come up with the enemy and choose an advantageous
position, it is not advisable to tow the torpedoes, if it can be avoided, at a
greater speed than 11 knots; because the strain brought upon the towing
gear is excessive, and the torpedo would require a large addition of ballast
to keep it sufficiently immersed to attain the full divergence.
There is, however, one style of attack in which the highest speed can be
maintained, viz. by dropping the torpedo alongside in passing.
This mode of attack is one of the best, particularly under cover of
darkness, against a ship at anchor.
The position of the torpedo is known, and the tow line is never in contact
with the enemy during the operation; a skilled hand at the brakes is all that
is required, the vessel keeping a straight course at the highest speed, passing
as close as possible to the enemy, in order to clear away all obstructions.
The tow rope must not be checked by the brake too suddenly.
Defensive Purposes.—The Harvey torpedo may be used as a means of
defence by large ships against a torpedo vessel attacking with that species
of submarine weapon, as the latter would be forced to pass outside the
former vessel's torpedo, and thus decrease the chance of a successful dip.
Again, in the case of an attack by the ram, these torpedoes afford some
protection, as a deterrent.
Night time.—Though a dark night and tempestuous are favourable to a
surprise, yet in the case of a Harvey torpedo attack it is essential that the
weapon should be seen to dip it at the proper time, therefore daylight is
necessary to this species of torpedo attack.

Value of the Harvey Torpedo.—The Harvey torpedo is undoubtedly of
considerable value when ably handled, yet the skill and judgment required
is very great, and can only be acquired by constant practice.
Description of the Menzing Towing Torpedo.—This modified form of the
Harvey towing torpedo was designed by Captain Menzing, of the German
navy, to remedy what is considered by the Germans as the chief defect of
that weapon, viz. its liability to injure friendly vessels, and also to do away
with the necessity of using two torpedoes, one for each side of a ship.
At Fig. 117 is shown a plan and elevation of this towing torpedo. a is the
body of the torpedo, somewhat similar to the Harvey, but narrower at the
stern, and bevelled on both sides towards the bow; b is an iron frame placed
in the bow, capable of being turned either to the right or left; c is the hole
for the introduction of the fuze, and d is the loading hole; e is a rudder
placed at the stern of the torpedo; f, f are levers, by pressure against which
the torpedo may be fired mechanically, or electrically at will; these levers
are connected to a block of wood fitted with stops to prevent them being
pushed too far over; s and p are two towing ropes, one on each side of the
torpedo, which pass from its stern through the point of the frame b, and
thence to the vessel, these are also connected to the rudder e in such a
manner that on either of the ropes s and p being tautened the rudder e is
turned in the opposite direction; w is an electric cable, strong enough to
bear the whole pressure of the torpedo when being towed right aft.
To diverge the torpedo on the starboard quarter of the ship, the line s
must be slackened, and the whole towing strain brought on the rope p,
causing the frame b to be pulled over to a knot k in the rope p, made at the
proper position to ensure the torpedo towing at the correct angle from the
course of the vessel, and at the same time causing the rudder e to be turned
to starboard; this is shown at Fig. 117 by the dotted lines.
To diverge the torpedo on the port quarter, the towing rope p would be
slackened and the whole strain brought on the rope s, and an action opposite
to that already described would be the result.
Two cork buoys are used, similar to those employed with the Harvey
torpedo; one being attached at a distance of 10 feet from the stern of the

torpedo, and the other at such a distance astern that the torpedo would be
placed at a distance below the surface to allow of safety to a friendly vessel.
GERMAN AND FRENCH TOWING TORPEDOES.

The torpedo is manipulated in a similar manner to the Harvey, the circuit
being closed at the moment of the first buoy disappearing, at which time the

torpedo would be about ten feet below the surface. The two buoys are
together capable of supporting the torpedo, and thus by means of the second
one it may be picked up, should it be necessary to cut the towing ropes.
Description of the French Towing Torpedo.—The towing torpedo used
by the French is represented in section and plan at Fig. 118.
a is the body of the torpedo, formed of wood enclosed in a thin steel
case; b is the head made of cork; c is the case containing the charge, which
is generally 33 lbs. of dynamite, this case is supported by the bolt d resting
on the plate e; f, f are whiskers, which are connected to the plate e; g and h
are hollow tubes, one end of g being attached to the case e, and one end of h
to the rear end of the body of the torpedo a, and they are so arranged that
when the case c is released, its weight will draw out the tube g, which slides
along the tube h to nearly the full extent of the latter; k, k are bolts, to which
the towing sling is attached; l is the fuze, and n is a small gun used for
firing the torpedo at will. The hole in the plate e through which the bolt d
passes is larger than the latter, so that when the plate is moved backwards
by pressure being applied to the whiskers the bolt is freed from support, and
case c attached to it falls.
The modes of firing are as follows:—
1.—The automatic plan of firing is effected by the tube h, after it has
fallen a certain distance, corresponding to a depth of 9 feet for
the case c, drawing down by means of a line attached to it a
plug contained in the body a, which completes the circuit of the
firing battery.
2.—The plan of releasing the charge at will is effected by means of the
small gun n, which is fired by electricity, and by its firing
forces back the plate e, thus releasing the charge, which is then
exploded, as previously explained.
Locomotive Torpedoes.—By "Locomotive" torpedoes are meant those
that possess within themselves the power to move through the water, when
once started in a given direction.
Of this species of submarine weapons, the following are the most
efficient and are the ones most generally used:—

1.—The Whitehead fish torpedo.
2.—The Lay torpedo.

Invention and Adoption of the Fish Torpedo.—The idea developed by
the fish torpedo is due to an Austrian marine artillery officer, who is now
dead. In 1864, Mr. Robert Whitehead, then superintendent of iron works at
Fiume, acting upon the suggestions of a Captain Lupuis of the Austrian
army, commenced a series of experiments to ascertain the practical value of
the above idea, the result being a fish torpedo, commonly called "The
Whitehead," which though far inferior to the fish torpedo of the present day,
was then considered to be a fearful and wonderful weapon.
The Austrians were the first to purchase this weapon, and two years later,
in 1870, Mr. Whitehead came to England, and prosecuted numerous
experiments with his fish torpedo under the supervision of several English
officers, and on the 8th of October of the same year he succeeded in
completely destroying an old hulk moored at the mouth of the Medway. The
fairly successful results of these experiments induced the English
government to purchase the secret and several of Mr. Whitehead's fish
torpedoes, under the following conditions:—
1.—The right of manufacturing them in England.
2.—To be kept fully informed of all improvements, as soon as made.
3.—The right of using all such improvements.
And the total amount paid to Mr. K. Whitehead at that time was the sum
of seventeen thousand five hundred pounds, which did not include the sum
of two thousand five hundred pounds claimed for the expenses attendant on
the Medway experiments. Since then a large number of Whitehead's fish
torpedoes have been purchased from time to time, especially during the
Turco-Russian war, when some two hundred were ordered, also great
numbers have been manufactured at Woolwich. The English fish torpedo, as
far as can be ascertained, is a vastly superior weapon to the Whitehead fish
torpedo, possessing as it does increased speed, and therefore far greater
accuracy.
Besides Austria and England, nearly all the European governments have
purchased the Whitehead secret and torpedoes, but in the case of some of

them, the last two clauses of the English conditions of purchase were
omitted.
WHITEHEAD'S FISH TORPEDO.

The Turkish is the only government that has obtained the Whitehead
secret and torpedoes without paying for it. This was managed as follows:—

"On the night of the 20th of December, 1877, the Russians made an
attack with Whitehead torpedoes on an Ottoman squadron lying in the
harbour of Batoum, but owing to a want of practical knowledge of the
manipulation of such weapons, no vessels were sunk or damaged, but two
fish torpedoes, one in perfect condition, were found the next morning high
and dry on the beach at that place."
The American government have up to the present time not sanctioned
the purchase of the costly Whitehead torpedo, preferring their own
locomotive torpedo, which will be fully described further on. On a
government purchasing the fish torpedo, a certain number of their naval or
military officers are sent to Fiume in Austria, where Mr. R. Whitehead's
manufactories are situated, and where the necessary very exhaustive
experiments with his torpedoes are carried out, and are there thoroughly
instructed in the manipulation of these machines, and are also supplied with
a double set of drawings of the various parts of the torpedo. These officers,
and all others whom it may be necessary to initiate into the mysteries of the
Whitehead secret, are bound on their honour not to divulge it.
Employment of Fish Torpedoes in War.—The fish torpedo has been
employed on actual service on three known occasions only, in two of which
it failed to fulfil its deadly mission.
On the 29th of May, 1877, a Whitehead fish torpedo was fired by H.M.S.
Shah against the Peruvian ironclad Huascar, but failed to strike her, owing
to the latter vessel altering her course at the moment of the torpedo being
discharged. The next instance of the employment of the Whitehead torpedo
was that one mentioned at page 132. The last and only successful attempt
yet made occurred on the 26th of January, 1878, when the Russian steamer
Constantine fired a Whitehead torpedo against a Turkish guard vessel off
the harbour of Batoum, and completely destroyed her.
Description of Torpedo.—A general view of the Whitehead fish torpedo
is shown at Fig. 119. It is divided into three parts, connected together by
screws.
1.—The charge chamber.
2.—The adjustment chamber, in which is placed what is known as the
secret.

3.—The air and engine chamber.
Vertical and horizontal steel fins are fitted for the purpose of maintaining
the torpedo in an upright position whilst passing through the discharge tube,
or frame; the former fins run nearly the whole length of the weapon, while
the latter are considerably shorter. The motive power of the torpedo is
compressed air, forced by means of a powerful steam air compressing pump
into a portion of the steel chamber (3) at a tension of upwards of 1000
pounds to the square inch, which is equivalent to about sixty atmospheres,
and which by means of a set of small three cylinder Brotherhood engines,
contained in the steel chamber (3), drives two screw propellers. These
engines are capable of exerting a force of forty indicated horses, and yet
only weigh about thirty-five pounds, from which it will be understood that
to attain these results the workmanship and materials employed in their
manufacture are of the very highest order and fineness.
The torpedo is made of various sizes, ranging from 14' long and 14"
maximum diameter to 19' long and 16" maximum diameter.
Capabilities of the Fish Torpedo.—The capabilities of the fish torpedo
are as follows:—
1.—If adjusted for a certain depth, from 5 to 15 feet, and projected
from above water, or if started from the surface, or if
discharged from a submerged tube, it will rapidly attain that
depth, and maintain it during the run.
2.—If fired in still water, it will make a straight run in the line of
projection, provided that an allowance has been made for the
deflection due to transverse currents.
3.—It can be adjusted to stop after having run any distance up to its
extreme range, and after stopping to sink, float, or explode.
4.—Its range and speed vary considerably, according to the pattern of
the torpedo.
Woolwich Fish
Whitehead Fish Torpedo.
Torpedo.
14' long, 16" 14' long, 16" 14' long, 14" 14·5' long, 14"
Yards. max. diam. max. diam. two max. diam. two max. diam. two
one screw. screws. screws. screws.

200 .. .. 20 knots. 25-1/4 knots.
250 9-1/2 knots. .. .. ..
300 .. 12-1/4 knots. 19-1/4 knots. 24-1/2 knots.
400 8 knots. .. 18 knots. 23 knots.
600 .. 11 knots. .. 20 knots.
750 .. 10-1/2 knots. .. ..
800 7 knots. .. 16-1/2 knots. 18 knots.
1000 .. 9 knots. .. 15-1/2 knots.
Pressure of air in engines varies for distance and speed from 40 atmospheres to 140 atmospheres.

Placing the Charge.—The explosive is generally placed in what is
termed the cartridge case, which case is similar in shape to the interior of
the charge chamber (1), and is fixed thereto by means of wooden wedges.
Ignition.—The method of ignition is mechanical, and is arranged as
follows:—Extending from the nose of the torpedo to the cartridge case is a
tube terminating in a copper case, in which is placed the priming charge and
detonating composition; within this tube is a steel rod some 2 feet long,
fitted with a needle point at its inner end, and its outer end screwed into a
frame; this frame is capable of moving in and out, and is connected with a
spiral spring which tends to force it, and consequently the steel rod, or
striker, inwards. By compressing this spiral spring, the inner end of the
frame is butted against a catch, by which it is prevented from acting. On
this catch being released, no matter by what means, the spring is brought
into action and forces the frame and steel striker inwards, the needle point
of the latter coming into contact with the detonator fires the priming charge,
and so explodes the torpedo. The foremost extremity of the torpedo, which
is termed the nose piece, is so fitted that it is capable of being forced
inwards, but in a position of rest its inner edge is just clear of the catch. On
a pressure being brought on the nose piece in a direct line with the length of
the torpedo, it will be forced inwards, the result being the releasing of the
catch and explosion of the torpedo. In addition to the nose piece, horizontal
and vertical levers, or whiskers, may also be used, a slight pressure on
either of which will similarly effect the explosion of the torpedo; also
cutters for penetrating nets, &c., are fitted to the nose piece when desired.

Safety Wedge and Key.—For safety purposes a wedge is employed,
which when in the safety position prevents the catch from acting; this
wedge is so arranged that it may be withdrawn by the action of the
machinery after the torpedo has run a certain distance, and also may be
replaced by similar means in the safety position on the completion of the
run. As an additional precaution a safety key is used, which is inserted in
the head of the torpedo through the spring of the frame.
Description of Adjustment Apparatus.—For adjusting the length of range
for withdrawing and replacing the safety wedge, &c., the following
apparatus is employed.
Two cog wheels, a large and a small one, are fixed on the upper part of
the after end of the torpedo, just in front of the screw propellers: the small
wheel is fitted with a certain number of teeth, thirty for instance, which
gears into an endless screw attached to the propeller in such a manner that
one revolution of the propeller moves the wheel one tooth, therefore thirty
revolutions would turn the wheel one complete revolution. The big wheel is
fitted with much larger teeth than the small one, and by means of a pin on
the latter wheel is moved round one tooth for every complete revolution of
the small wheel, and clamped in this new position by a spring catch, which
is also worked by the pin on the small wheel. In front of these wheels is a
stud which works fore and aft in a slot, and attached to a spring which tends
to draw it to the after end of the slot. This stud is connected by means of a
wire rod to the valve that admits the compressed air to the engines; when
the stud is in the fore part of the slot the valve is open, and when in the after
part it is closed.
Adjusting Length of Range.—By means of a lever the spring of the stud
is compressed, and the stud moved to the fore part of the slot; then the big
wheel is moved round until a stud on its face is the required number of teeth
above the lever. For every thirty revolutions of the propeller, and
consequently one tooth of the big wheel, a certain known distance is
traversed, which varies according to the pattern of the torpedo.
Adjusting Apparatus.—When the propeller has made the number of
revolutions corresponding to the length of range required, and consequently
has moved the big wheel the number of teeth it was set above the lever, the

stud on the big wheel presses against the lever and so releases the spring in
the slot, causing the slot stud to fly from the fore part to the after part of the
slot, by which action the valve admitting the compressed air to the engines
is closed, and consequently the engines cease to work.
Attached to the axle of the big wheel is a small brass arm, which is
connected by means of a brass rod to the safety wedge, and is so arranged
that after the required number of revolutions of the propeller, the safety
wedge will be drawn out; or it may be drawn out at the instant of the
torpedo leaving the tube, carriage, &c. Also by means of an additional lever
at the fore part of the torpedo, which is connected by means of a wire rod to
the valve that admits the air to the engines, and by arranging the attachment
of the safety wedge to the brass rod from the big wheel, so that on the
wedge being withdrawn it is released from that brass rod, on the torpedo
having completed its run, the action of closing the valve which admits the
air to the engines causes the additional lever to force the wedge into the
safety position.
Torpedo to Float at End of Run.—This is due to the difference of
buoyancy at the end of a run from what it was at the commencement, owing
to the compressed air being used in working the engines.
Torpedo to Sink at End of Run.—This is effected by means of the
adjustment chamber (2), in the after end of which there is a spiral spring
valve, which can be attached to the brass rod on the outside of the torpedo
that works the valve which admits air to the engines, in such a way that on
the valve being closed, and therefore the run of the torpedo completed, the
spiral spring valve is opened, admitting water to the adjustment chamber (2)
of sufficient amount to sink the torpedo.
To Explode the Torpedo at End of Run.—This is effected by connecting
the vertical firing whisker to the rod which otherwise would be connected
to the safety wedge lever, by which means, on the valve admitting air to the
engines being closed, a force is transmitted to the vertical whisker instead
of to the safety wedge lever, and consequently the torpedo is exploded.
Adjusting the Depth.—A small wheel, the face of which is marked in
feet, is placed on the left side of the fore part of the adjustment chamber (2).

To adjust for depth, by means of a key turn the wheel until the number
corresponding to the depth of run required is opposite the pointer.
The torpedo is maintained at the desired depth by means of certain
mechanical apparatus contained within the adjustment chamber (2), and
which constitutes what is termed the secret of the fish torpedo. This
chamber is connected by screws to the foremost and after chambers of the
torpedo, in such a manner that by means of a number of small holes bored
round the circumference, as shown at (2), Fig. 119, the faces of the chamber
are exposed to the pressure of the water, which varies with the depth to
which the torpedo descends. Within the adjustment chamber is an endless
strong spiral spring, attached to the after face of the chamber, and so
arranged that after being set to a certain tension, capable of resisting an
equivalent pressure on the outside of the aforesaid face, any increase or
decrease in this exterior pressure will cause the spiral spring to work a rod
by which the horizontal rudders of the torpedo are regulated, and thus the
desired depth for which the spring is set is maintained. The course of the
torpedo is represented by a series of curves, above and below the line,
representing the depth it is set for, these curves gradually decreasing until at
100 yards' distance from where the torpedo was started the curves are so
small that the path of the torpedo is almost identical to that of a straight
line.
Within this adjustment chamber is also placed an automatic balance,
which also assists to maintain the torpedo at the desired depth, by reason of
its swinging forward on the torpedo descending, and swinging aft on its
rising, which motion is used to regulate the horizontal rudders. The above is
merely a general idea of the arrangement used in the Whitehead fish
torpedo, to enable it to reach and maintain whatever depth it may be
necessary to use it at from 5 to 15 feet.
Projecting the Torpedo.—The fish torpedo may be projected in various
ways, viz.:—

1.—Through a submerged tube in the stem, or on the broadside.
2.—From a carriage above the surface.
3.—From the surface.
Discharging Torpedo through a Submerged Tube in the Stem.—In this
case a tube is fitted to an orifice in the stem; this opening is as far below the
water line as possible, and is closed by a watertight cap and a sluice valve;
the inner end of the tube is fitted with a watertight door; the torpedo being
prepared for action is placed inside the tube, the inner door closed, and the
tube filled with water; then the watertight cap and sluice valve are opened,
and the torpedo started by means of a piston which is worked by
compressed air. This piston can be worked from deck, and so the torpedo
fired at the proper instant. To prevent the torpedo from slipping out of the
tube, a stop is placed in the fore end of it, which can be withdrawn at the
same time as the compressed air is admitted behind the piston. The torpedo
being clear of the tube, the sluice valve and watertight cap are closed, and
the tube emptied of the water, the projecting piston being at the same time
forced back.
On the Broadside.—In this case, the discharging tube works inside an
iron casing, through a stuffing box at the inner end, and in a shield attached
to the outer end of the tube. This shield, placed on the fore side of the
orifice, is of such a length as to protect the torpedo from the pressure of the
water passing the vessel. The mode of discharging the torpedo in this case is
similar to that used when projecting it through the stem.
Comparison of the Stem and Broadside Methods of Projecting the
Torpedo.—The former method of projecting the torpedo seems the most
suitable to specially built torpedo vessels, but not so to large ironclads, on
account of the difficulty of fitting a tube to the stem of such a ship, and also
that in so doing the efficiency of the vessel as a ram would be impaired.
In regard to the accuracy of the firing of the above methods, both seem
equally good, though in the case of firing on the broadside it would be
necessary to prepare carefully calculated tables of deflection, any mistake in
the using of which would be fatal to a successful torpedo shot.
Projecting a Torpedo from above Water.—In this case an iron carriage is
used, which is fitted with a frame, in which the torpedo rests; the outer end

of this frame is provided with a lip, some few feet long, by which means the
rear end of the torpedo is slightly canted up on leaving the frame, and any
undue strain on the tail of the torpedo is prevented. The frame is mounted in
the iron carriage in such a way that it can be elevated or depressed by
means of a screw, as in the case of a gun mounted in an ordinary carriage.
The torpedo is ejected from the frame by means of a piston as previously
explained, a small reservoir of air being attached to the carriage, so that it
can be used at any port.
Firing a Torpedo from the Surface.—The torpedo possesses sufficient
buoyancy to float with a small portion of its upper surface above water;
such being the case, it is only necessary to set the various adjustments, point
it in the required direction, and by hand turn back the lever on the upper
part of the weapon (which opens a communication between the air chamber
and the engines), when it will instantly dart off and very rapidly attain the
depth it is set for.
Method of Firing a Fish Torpedo from a Boat.—To manipulate a fish
torpedo from a boat, it may be carried in a light frame, which can be
lowered or raised by means of a pair of davits. When required to discharge
the torpedo, the frame containing it is lowered into the water, so as to bring
the torpedo about two feet below the surface, the head being somewhat
lower than the tail.
Thornycroft's Method of Firing Fish Torpedoes from a Boat.—Another
method, which has been patented by Mr. J. I. Thornycroft, of the firm of J.
I. Thornycroft and Co., steam launch builders, and which is fitted to the
torpedo boats built by them for foreign governments, is shown in elevation
and plan at Fig. 120 and 121.
The apparatus consists of two or more bent levers A securely and rigidly
fixed on a shaft B, which works in bearings fixed on the deck of the vessel
C from which the torpedo is to be discharged. On the ends of the levers A
furthest from the shaft B are pivoted other levers D, to which the cradle or
case E for sustaining the torpedo is suspended. The other ends of each of
these levers are connected to the vessel by means of rods or tubes F, jointed
at each end in such a way that when the shaft B is made to revolve in its
bearings, the case containing the torpedo is guided over the side of the

vessel and close to it, and is held in a position convenient for discharging
the torpedo, as shown at Fig. 120.
The shaft B may be made to revolve by means of ropes G and pulleys H
attached to the levers A, or by hydraulic or steam pressure, as may be found
most convenient.
The torpedo case can be towed alongside the vessel if necessary without
deranging the apparatus. The torpedo case is carried in the angles of the
bent levers, and is stowed away so that neither it nor the suspending levers
project at all beyond the hull of the vessel; also when lowered, the levers
and suspending rods fold over one another so as to occupy very little space,
and the torpedo is suspended close to the hull.
Also the torpedo during the operation of lowering as well as when in a
firing position remains close to the side of the vessel, thereby obviating any
risk or inconvenience from excessive leverage which would have a
tendency to capsize the boat.
For especially built torpedo launches, the above mode of carrying and
launching the fish torpedo is certainly the best yet devised.
Woolwich Fish Torpedo.—In the Woolwich torpedo, the engines exert a
force of nearly 60 indicated horses, and work up to 1000 revolutions per
minute; the total weight of the torpedo fully charged (33 lbs. of gun-cotton)
is about 500 lbs.
THORNICROFT'S BOAT APPARATUS FOR FISH TORPEDOES.

The Whitehead fish torpedo costs about 380l., while the Woolwich one
costs only 300l.

The Lay Torpedo Boat.—Priority of invention of this torpedo was on the
13th of June, 1873, awarded by the Commissioners of Patents to Mr. John
Louis Lay, several other persons having claimed the invention, among
whom was Colonel Von Scheliha, an officer of the Russian army.
This locomotive torpedo, or more properly called torpedo boat, has been
for several years adopted by the American government, during which time
it has undergone a series of exhaustive experiments, which has proved it to
be a most valuable and efficient weapon of offence and defence. Lately the
Russian government have adopted it, and intend using it extensively in the
defence of their harbours, &c.
General Description of the Torpedo.—At Fig. 122 is shown a
longitudinal section of a Lay torpedo boat constructed and provided with
guiding and controlling apparatus, and with means for propelling it by
ammoniacal gas. Fig. 123 is a horizontal section of the same; A is the hull
or body of the boat, which has conical ends A1, A2, and is formed of thin
plate iron, or steel, or other suitable material. The section in the end A1
forms the magazine containing the charge of dynamite or other explosive
material; A3 is the section containing the gas reservoir or holder; the
compartment A4 contains the apparatus for holding and paying out the
electric cable; the compartment A5 in the end A2 contains the motor engine,
the steering apparatus, and other parts to be hereinafter described. All of
these compartments or sections are separated from each other by means of
air-tight bulkheads A6. The torpedo boat may be propelled by means of a
single screw, double screw, or two screws. In the latter method, which is
shown at Fig. 122 and 123, the propellers B and C are made to revolve in
opposite directions; the shaft D of the propeller B is hollow or tubular, and
the shaft E of the screw C passes through the same; these screws are
actuated by an engine shown at F. H, H are the horizontal rudders, or side
wings, two forward and two aft; these wings are mounted on shafts or
spindles passing transversely through the boat; these rudders may be set to
occupy a horizontal position, or a more or less inclined position in the
proper direction, to cause the submerging of the boat by the action of the
water on the said rudders as the boat moves forward, and they are adjusted
before starting. N, N are two guide rods, one aft and one forward, which
project up from the boat to enable the operator to determine its position at

any part of its run, and in the case of a night attack they are provided with
lights; the said rods can be raised or lowered at the will of the operator. Q is
the electric cable, which affords a medium of communication between the
operator on shore, &c., and the torpedo boat, whereby it may be started,
stopped, steered, fired, and has her position ascertained; this cable is carried
in the boat in a coil arranged longitudinally in the air-tight chamber A4 in
the reel frame R, and is payed out as the torpedo progresses through a tube
S, projecting aft under the boat and beyond the rudders and propellers, so
that the said cable will not be fouled by the same; or it may be payed out
through a hollow shaft in the centre of the boat. One end of this cable is
connected to a keyboard at the station on shore or on board of the ship or
other structure from which the torpedo boats are controlled. This keyboard
is provided with a suitable battery or other means for generating the electric
current, as hereinafter described.
The said cable is composed of several wires, each of which is insulated
from the others. One of these wires is connected with the mechanism for
starting and stopping the boat, one is connected with the steering apparatus,
one serves for indicating to the operator at all times the exact position of the
rudder, one is connected with mechanism for elevating and depressing the
said guide rods, and one serves for firing the charge in the magazine.
The motive power for effecting the necessary movements of the
mechanism or apparatus in performing the above operations is obtained
from the aforesaid engines, which are provided with suitable valves
arranged in combination with electro magnets, shunts, and the devices
connected with the said wires of the cable, as hereinafter set forth.
This form of cable has since been replaced by one which consists of two
wires only, the one for performing all of the necessary operations, exclusive
of the firing or exploding of the magazine, and the other exclusively for this
latter purpose. This improvement is effected by employing a series of relays
or resistance coils, or a multiple, or compound relay in the boat. The
advantages gained by this improved form of cable are:—
1.—Increased flexibility.
2.—A greater length of cable may be coiled in a given space.

3.—A thicker coat of insulating material may be used, thereby more
perfectly insulating it.
4.—It is much cheaper.
Two rudders are generally used, one below and one above the boat, as
shown at U, Fig. 122. These rudders are operated and controlled by means
of a small auxiliary engine T, Fig. 122, which is started, stopped, and
reversed by the electric current conducted through the cable Q in
connection with magnets attached directly to a valve forming part of the
said engine. This valve is so actuated by the magnets that when the current
passes in one direction the engine T will move the rudder to starboard, and
when the current acts in the opposite direction it will turn the rudder to port.

The mechanism for firing the charge in the magazine A1 is clearly shown
in Fig. 124, and operates as follows:—Projecting from the front extremity
or stem of the boat is a rod or pin V, which extends through a suitable
packing box W into the said magazine or charge chamber; when the boat
strikes an object, the said rod is forced inward into contact with the springs
or points X, thereby closing an electrical circuit and igniting a cartridge,
shown at Y, in the magazine.
The charge in the magazine can also be fired at any moment by the
operator on shore closing a circuit on the keyboard and thereby cutting out
one of two resistance coils placed in the circuit to prevent accidental or
premature discharge—that is to say, there are two resistance coils. The
battery is not sufficiently powerful to fire through both resistance coils at
the same time. When the boat strikes an object, the resistance coil in the
magazine is cut out by the driving inward of the rod V, as above described;
the battery then fires through the one on the keyboard. On the other hand, if
the operator desires to fire the torpedo boat before she touches the object of
attack, he manipulates the switch to cut out the coil in the keyboard, the
charge then being fired through the coil in the magazine. This arrangement
of the two resistance coils is very effectual in preventing accidents.
In some instances the magazine is made detachable from the hull of the
boat, so that on striking an object it will descend or drop down in the water
before exploding. This modification is shown at Fig. 125 and 126.

The magazine A* is attached at its lower side to the boat by a chain or
other suitable connection. At its upper edge it is held by a rod a*, as shown
in Fig. 125. This rod is fitted to slide in dovetailed bearings, as shown at b*,
and when this magazine is in its place on the boat the said rod is engaged
with a catch or stop c*, but when the said rod is driven against any object it
is forced back and released from the said catch or stop, and the magazine
then drops, as in Fig. 126, and is fired.
To effect the firing a ball d* is used and placed in a tube containing two
springs or plates e* and arranged in an upwardly inclined position, as
shown in Fig. 125, one of the said springs being connected with the cable
and the other with a wire that passes through the cartridge to earth.
While the magazine is in the position shown in Fig. 125 the circuit is
incomplete, but when the magazine drops the said ball falls into the position
shown in Fig. 126; the circuit is then completed, and the magazine is fired.
The electrical or electro-magnetic apparatus for generating, directing,
and controlling the currents, whereby the above-described operations are
effected, may be of any suitable kind, the following being the form of
apparatus usually employed.
A battery r, shown at Fig. 127, consists of any desired or requisite
number of cells constructed and arranged in any suitable manner, and
connected by proper conducting wires with the keyboard s. The latter is
provided with a series of pole changers s1, s2, s3, s4, and switches s5, s6, and
is shown in Fig. 128.
Each of these pole changers is arranged to effect and control one of the
above-named operations, and is therefore connected with one of the
aforesaid insulated wires forming the cable. For instance, the pole changer
s1 effects the starting and stopping of the propelling engine; s2 controls the
steering apparatus; s3 is connected with the steering index; s4 operates or
adjusts the aforesaid guiding rods; and the switches s5, s6 control and effect
the firing of the charge in the magazine.
LAY'S LOCOMOTIVE TORPEDO.

LAY'S LOCOMOTIVE TORPEDO.

The connections between these pole changers and switches, and the
apparatus they operate or control on board the boat, are as follows—that is

to say, the said propelling engines have a throttle valve, which controls the
admission of the gas from its generator or reservoir to the cylinders of the
said engine, and in combination with this valve in the boat there is a shunt
and set of electro magnets. The armature of the latter is connected with a
lever, which is pivoted so that the action of the electric current in one
direction through these magnets will pull one end of the said lever down,
and the action of the current in the other direction will pull its other end
down—that is to say, by reversing the current through these magnets the
movement of the said lever is reversed; and this lever, connected by suitable
means with the slide of the said throttle valve, will open or close the same,
and thereby start or stop the engine as required.
For operating and controlling the above-described steering apparatus,
and indicating the position of the rudder to the operator on shore, the
following devices are employed, in combination with the pole changers s2,
s3 on the keyboard:—The pole changers are geared together by insulated
toothed wheels, which are fixed on the spindles or axes of the said pole
changers, so that the latter work accurately together and maintain the same
relative positions to each other. The pole changer s2 is connected by one of
the said insulated cable wires with a shunt on board the boat, which shunt is
connected with a set of magnets arranged in combination with the valve of
the engine that drives the steering apparatus, and which valve is reversed or
opened and closed by the reversal of the currents through the said magnets,
as above described, and the said engine moves the rudder to port or
starboard at the will of the operator. In order that the operator may know the
exact position of the rudder at any moment, a series of pins or projections
fixed on an arc or other portion of the rudder stock, and arranged in
combination with an insulated spring projecting into the path of the said
series of pins, are employed. This spring is connected by one of the cable
wires with the pole changer s3 on the keyboard, which is geared with and
moves in unison with the pole changer s2, so that the electric current that
controls the steering engine, and the current that returns the indication of
the rudder's position, will both be reversed simultaneously. A separate
battery is connected with the index on the said keyboard, whereby a
constant current is maintained between this index and the indicating
apparatus on the boat.

The current passing from the said spring to the shore is made to indicate
the position of the rudder by the index on the keyboard by the contrivance
shown in Fig. 129. This contrivance consists of a set of magnets w, which
have a vibrating armature w1 pivoted to oscillate between them. One end of
the armature lever is provided with insulated spring pawls w2, which take
into ratchet wheels w3. On the same shafts on which these ratchet wheels
are fixed are wheels w* formed with insulated teeth and geared with each
other. The shaft of one of these wheels is geared by bevel pinions w4 with a
vertical shaft w5, to which is attached the index needle or finger x**, Fig.
128. Therefore it will be obvious that this index finger is placed in
connection with the aforesaid spring and series of pins attached to the
rudder yoke on board the boat.
Now it will be obvious that when the rudder is turned in either direction
these pins will come successively in contact with the said spring, and at
each contact and separation the circuit will be made and broken, and an
impulse will be transmitted through the cable, whereby a corresponding
movement will be transmitted to the said index finger or pointer x** on the
keyboard.

The pole changer s4 is connected with another of the insulated wires of
the cable, which on board the boat is connected with a shunt and set of
magnets arranged in combination with the aforesaid cylinders that operate
the said guiding rods, so that by sending the current in one direction the said
rods will be raised, and by sending the current in the opposite direction the
said rods will be lowered.

The switch s5 is connected with another of the said insulated wires of the
cable, which forms the circuit, including the aforesaid two resistance coils.
By adjusting this switch the operator completes the circuit through the
two resistance coils, and then, but not till then, the charge can be exploded,
either by the operator, or by the action of the firing pin or rod when the
same is driven in and cuts out the other resistance coils as above described.
The resistance coil X1, Fig. 124, is connected to the binding screws 9, 10 by
the wires 7 and 8. These binding screws are in metallic connection with the
two springs X, but otherwise they are carefully insulated. One pole of the
fuze Y is connected to the binding screw 10, the other put to earth through

the body of the boat, as at E; the main wire 11 is connected to the binding
screw 9. Now when the operator cuts out the resistance coil at the firing
station, which is done by moving the switch s6, the electric current is
sufficiently powerful to ignite the fuze Y through the resistance coil X1, so
that at any moment the torpedo may be exploded by the operator on shore,
or by the contact between the torpedo and the attacked vessel the rod V will
be driven in, and, coming in contact with the springs X, will bridge over the
space that originally existed between them and so cut out the resistance coil
X1, and the torpedo will be exploded automatically.
Capabilities of the Lay Torpedo Boat.—The capabilities of the Lay
torpedo boat are as follows:—
1.—It may be launched from the shore, a vessel, or a structure, and be
kept under observation, and accurately guided or directed to the
ship or other object to be attacked; and it may be exploded at
any desired moment, or it may be caused to return to the
original point of departure without being fired.
2.—It may be totally and instantaneously submerged to prevent its
destruction or capture by the enemy, and it may be raised to the
surface, as soon as the danger has passed, in a condition fit for
immediate action.
3.—It may be used as a tug or towing boat to take out a number of
torpedoes, which may be sunk and exploded when desired.
4.—It may be used in connection with certain apparatus to clear away
obstructions found to prevent the entrance of ships into
harbours, and it may also be used to clear harbours of mines,
&c.
Launching the Lay Torpedo Boat.—For facilitating the launching and
controlling of the Lay torpedo boats, a structure or submarine fort is used.
This structure may be square, or oblong, and may be made to carry any
number of the torpedo boats. The body is constructed of plate or sheet iron
of suitable strength and stiffened with angle iron, or otherwise, and divided
longitudinally or transversely into watertight compartments, into which the
water is admitted to sink the said structure. At the top or upper side,
cylinders or tubes are placed, each of which is capable of containing and
launching one of the torpedo boats. At the forward end of each tube is a

door, or cover secured to a rod or shaft fitted to turn in suitable bearings;
this rod or shaft is provided with an arm which is connected to the piston
rod of an engine worked by gas contained in a reservoir, or by other suitable
means. The slide or other valve which controls the admission of the gas,
&c., to this engine is arranged in connection with electro magnets,
connected by a suitable cable with a keyboard on shore, or wherever the
operator's station may be. By sending an electric current through this cable
in one direction through the electro magnets, the door is closed; and by
sending such a current in the opposite direction it is opened. The cables
carried in the torpedo boats, and through which the mechanism on board
each torpedo boat is operated and controlled, are also in this case connected
with the keyboard, which must be provided with a number of sets of pole
changers and switches, or equivalent devices, corresponding with the
number of boats to be controlled by means of the said keyboard.
This apparatus will form a very convenient adjunct to fortifications or
stations liable to be attacked by sea. The said fort may be prepared for use
by placing torpedo boats in the said tubes, and may be kept floating until
the enemy's ships have arrived closely enough to permit the determination
of the point where the said fort can be most advantageously located for
operating against the said ships. The fort is then towed to this point, or
taken as near as possible thereto on rails, and towed the remainder of the
distance. It is then submerged, and will be ready for immediate operation.
The said fort is provided with suitable valves for the admission of water to
sink the same, and with means for forcing in air through the pipe P* to
expel the water when the fort is to be raised.
When it is desired to launch either of the said torpedo boats, the door of
its tube or cylinder is first opened by sending a current through the cable
that controls the door, as above described. Then the current is sent through
the boat's cable to start her propelling engines. The said boat will then
emerge from the cylinder or tube and will rise to the surface, or as near the
surface as may be desired, and may then be directed and controlled by the
operator at the keyboard, as previously described. And one after another of
the said torpedo boats may be thus launched and exploded, without giving
to the enemy any clue to the point or position from which they are being
sent.

LAY'S LOCOMOTIVE TORPEDO.

Launching the Torpedo from a Ship.—The method of launching the Lay
torpedo boat from an ironclad or other large ship is shown at Fig. 130. The
tubes or cylinders S in which the torpedo boats A are held are, in the
apparatus shown at Fig. 130, closed at their inner ends by plates, or covers
S1, which are provided with suitable water-tight and insulating packing
boxes S2 for the passage of the electric cables of the said torpedo boats,
each cable being connected with the keyboard, which is placed in any
convenient part of the ship, and at their outer ends the said tubes are
furnished with strong and well-fitted slide valves, or sluice gates S3, which
are opened by screws, connected by gearing with a hand wheel, and shaft
S4, S5, for the admission and exit of the said torpedo boats. Also these
cylinders are provided with packing pieces at their sides, arranged to be
pressed by screws or otherwise up to the sides of the torpedo boats in these
cylinders, and thereby hold them firmly and immovably in rough weather.
The Method of Sinking and Raising a Lay Torpedo Boat.—The apparatus
by which this is effected is shown at Fig. 131, which is a longitudinal
section of a portion of a torpedo boat. The hull A of the torpedo boat is
provided with a water chamber l, which has holes or apertures l1 in the
bottom of the same, and is also provided with an air cock at l2. In
connection with this chamber is arranged a small cylinder m, provided with
a piston m1, whose rod m2 is attached to the lever of the said cock. A spiral
spring m3 is provided to resist the inward movement of the said piston. The
said small cylinder m is connected by a pipe m4 with a valve chest, in which
is arranged a slide valve m5. The said slide valve is connected by a rod or
rods to the lever or levers m6, whose fulcrum is at m*, and the said levers
are connected by the links or rods m7 with the armatures of electro magnets
n, which are included in the circuit of the cable, whereby the boat is
controlled from the keyboard at the station; o is a pipe extending from the
said valve chest to the aforesaid water chamber l; p is a feed pipe by which
gas is conducted from the reservoir or generator to the valve chamber.
When it is desired to sink the torpedo boat an electric current is sent in
one direction through the said magnets, and thereby operates the slide valve
to admit gas to the cylinder m in front of the piston m1, which is thus forced
inward and opens the air cock l2. The opening of this cock permits the

escape of the air from the water chamber l, and consequently the entrance
of water through the apertures l1, and the boat then immediately sinks.
When it is desired to raise the boat a current is sent in the opposite
direction through the said electro magnets, thereby operating the said valve
and piston in such a manner as to close the cock l2 and open the port o1 and
the pipe o, thereby allowing the gas to pass from the valve chamber into the
compartment l; this gas by its pressure expels the water from the said
compartment, and the boat then having its normal buoyancy restored
immediately rises to the surface.
The Lay Torpedo Boat used as a Tug to take out a Number of Small
Torpedoes.—This arrangement is shown at Fig. 132 and 133. The small
vessels or torpedoes are designed to be first sunk and then exploded, chiefly
for clearing harbour or the like of mines or other obstructions. These results
are accomplished by means of the following devices and arrangements, that
is to say, each of the small vessels or torpedoes F is provided with apparatus
which is included in an electrical circuit formed by a suitable insulated
cable G, extending throughout the train of small vessels or torpedoes F.
One vessel of this train, preferably the rear one, is connected with the
station by an electrical cable H, which is payed out from a coil or coils, or a
reel or reels, in the said vessel as the same travels through the water. This
cable H connects with the cable G, which is connected with the towing boat
A, and passes through the series of boats F to the said cable H. One wire of
the said cable is arranged in combination with sealed or covered apertures
in the bottom of a compartment or compartments of these small vessels F,
as shown at I, the covers of these apertures being so formed as to be
ruptured or destroyed by the explosion of a cartridge or cartridges placed in
the said compartment or compartments. When a current of electricity is sent
through the aforesaid wire of the cable it will explode the said cartridges
and open the apertures, thereby admitting water into the said compartments
so that the vessel F will sink.
The cable G that passes through the train of torpedoes or vessels F is so
arranged that when a current passes through the other wire of the said cable
it will fire cartridges placed in the charge chambers or magazines of the said
small vessels, as shown at J. The part of the cable or towing line G, which
connects the towing boat A with the train of small boats or torpedoes F, is

attached to a hook or other device, which can be disengaged by sending a
current through the cable K, connecting the boat A with the shore or other
station. It will be understood that when being used for this purpose the said
boat A is not or need not be charged with explosive material.
LAY'S LOCOMOTIVE TORPEDO.

The aforesaid towing boat A takes the train of torpedoes F to any
required position. It is then disengaged from the train, leaving the said small
vessels or torpedoes F floating in such position. Then by sending a current
first through one wire of the cable H the boats F are first sunk by the
explosion of the cartridges and opening of the apertures, as above
described. They may then be discharged immediately by sending a current
through the other wire of said cable H and firing the cartridges in their
magazines, or they may be left submerged to form mines which may be
exploded at any desired moment.
The said small vessels or torpedoes may be provided with vertical rods
to indicate their position to the operator at the station; these rods are shown
at L, and they should be made hollow to allow the air in the water
compartments or chambers to escape to permit the water to enter the same

when the vessels F are to be sunk; or other suitable provision may be made
for the escape of the air from these compartments.
The said vessels F are preferably made cylindrical with conical ends,
and are provided with suitable insulating and water-tight packing boxes, as
shown at F1 for the cable G to pass through at the stem and stern of each
vessel.
The Lay Torpedo in Clearing Obstructions.—For this purpose the
torpedo boat is provided with an apparatus, shown at Fig. 134 and 135, in
combination with the electric cable, whereby the said boat is controlled and
guided, and there is arranged in the boat A a compartment A3, from which
extends down into the water a line or rod U, provided at its outer end with a
hook or claw U1, properly formed to take hold of any chain or bar with
which it may come in contact. In the said compartment A3, and upon the
upper end of the said line or rod U, is placed a small case or cylinder U2
containing a charge of dynamite or other explosive material and a cartridge
or fulminating cap, or a bottle of sulphuric acid, surrounded with a certain
quantity of chlorate of potash and sugar. This case or cylinder U2 is shown
detached and drawn to an enlarged scale at Fig. 135, and it will be seen that
the said case is provided with a tube 1 containing a cartridge, or a phial
filled with explosive substance at 2, and a ball or weight at 3. The said case
is fitted to slide upon the said line or rod U, and when placed at the upper
end thereof and not held or retained will slide to the lower end of the same.
In the said compartment A3 is arranged at U4 an electro-magnetic apparatus,
included in the circuit of the said cable, and connected with a bolt or catch
which in its normal position holds the said explosive case and prevents its
running down on the grappling line or rod U. This explosive case is also
provided at its lower end with a grappling hook U5.
When the grappling hook U1, on the lower or outer end of the line or rod
U, engages with any obstruction the boat will be stopped, and this stoppage
will be indicated on the keyboard. The operator by this indication is
apprised of the stoppage of the boat by an obstruction, and by sending a
current through the cable by means of a switch provided for this purpose on
the keyboard he can immediately release the explosive case U2, which runs
down the line or rod U, and engages by its grappling hook U5 with the hook

U1. The line or rod U is then disengaged from the boat A, and the explosive
case U2 turns or falls over. As it turns over the ball or weight 3 contained in
the tube 1 drops on the said phial 2, fractures it, and thereby allows the acid
to mix with the explosive or fulminating charge and explode the case U2.
This explosion will rupture or destroy the obstructing chain or bar, so that
the ironclad ships or other vessels can pass freely and safely into the
harbour or beyond the point where it was intended to stop them.
Used to clear away Mines and Electric Cables.—For this purpose there
is an implement V provided, Fig. 136, somewhat of an anchor form, but
with four or any desired number of arms V2 extending outward at a suitable
angle from its shank V1. In the neck of each of these arms are fitted two
small plain or toothed discs V3, which are so arranged as to present their
teeth to any object lying in the angle or corner formed by and between the
arms V2 and shank V1 of the said implement, as shown at W.
In using this implement it may be attached to a line or cable coiled in the
torpedo boat, which, in this case, is used without being charged with
explosive material, and is sent in advance of any ship that has to enter or
pass through the suspected water. This line must be arranged in combination
with a detaching apparatus controlled by electro-magnetic apparatus
included in the circuit of the cable which connects the torpedo boat with the
keyboard at the operating station.
LAY'S LOCOMOTIVE TORPEDO.

By sending a current from the station the operator releases the said
implement or its line from the detaching hook or holding device. The said
implement then sinks to the bottom; then the said boat returns to the ship,
paying out the said line as she so returns. The end of this line is then taken
by a steam tug or other vessel, and the said grappling implement is thereby
dragged along through the water over which the ships are to advance, thus
breaking any wires or cables that may be in its course. This operation is
shown at Fig. 137, in which A is the towing boat, K the controlling cable, V
the said implement, V* the line attached to the implement V, X X submerged
mines, and X1 X1 are the mine cables.
In some instances it may not be practicable to reach the enemy's ship or
other object of attack directly from the station to which the torpedo boat is
connected, and from which it is controlled. In this case a small boat, &c., is
used in addition, which should be so arranged as to present to the enemy's
view as slight a surface as possible. This mode of attack is shown at Fig.
138, where A is the torpedo boat, and N is the small auxiliary boat. This
boat N is provided with a keyboard and battery like that described at page
144, and the electric cable L, carried on and payed out from the torpedo
boat A, is connected with the keyboard. The boat N is also attached to and

towed by the torpedo boat A by the tow line O; and the torpedo boat is
steered and guided by means of the said keyboard in the boat N. The
auxiliary boat is designed to contain two men, who lie down, one at the
bow, the other in any convenient position abaft him; the latter has control of
the keyboard, while the former by the aid of a telescope keeps the torpedo
boat in view, and transmits his orders to the man at the keyboard. On
arriving at such a distance from the enemy as to render an attack
practicable, the tow line O is disengaged, and the torpedo boat A, guided
and controlled, and fired from the boat N. The torpedo boat being exploded,
the auxiliary boat can be rowed back to the station or ship to which it
belongs. By this means the range of action of the torpedo boat is greatly
extended, and with comparatively slight danger to those employed in
making the attack.
A more recent form of the Lay torpedo boat is shown at Figs. 139, 140,
and 141, where Fig. 139 is a plan or top view of such a boat, Fig. 140 is a
side elevation of the same, and Fig. 141 is a midship section on the line x x.
A is the hull of the boat, a is the main or central portion of the said hull, b, b
are side or auxiliary portions of the same. These parts a and b may be oval
or circular in transverse section; they are constructed of thin steel or other
suitable sheet metal, and secured together by riveting or bolting. The side or
auxiliary portion b form the reservoirs or chambers for the gas; they also
serve to contain the propelling engines. c is the magazine, d the chamber or
compartment for containing the coiled cable, e is the compartment
containing the electrical steering and other apparatus, f is the firing rod or
pin, g is the water ballast chamber, h is the cable, i the paying-out tube, j, j
are the screws or propellers which rotate in opposite directions, and k, k are
the sight or guiding rods.
The parts of the apparatus or mechanism whereby the various operations
of the torpedo boat are effected are connected to the cable and controlled by
electric currents transmitted from the station through the cable, as
previously described. The Lay torpedo boat weighs about 1 ton, its length is
23 feet, and speed 12 knots per hour.
Spar or Outrigger Torpedo.—By a spar or outrigger torpedo is meant a
torpedo which is carried at the end of a pole or spar projecting from a boat
or vessel, and which may be fired either by contact or at will.

This system of submarine offence has up to the present time been the
only one that has successfully stood the crucial test of actual warfare.
During the civil war in America the spar torpedo attack was resorted to
by the Confederates and Federals, principally by the former, the result being
the loss of two large men of war and severe injury to several other ships
composing the Federal fleet, and the loss of one vessel of war belonging to
the Southerners.
The spar torpedo was also used on several occasions by the Russians in
their attacks on the Turkish ships in the war of 1877-8, but in only one
attempt was it the means of sinking a Turkish vessel.
Description of McEvoy's Duplex Spar Torpedo.—At Fig. 142 is shown a
sketch of Captain McEvoy's improved patent duplex spar torpedo, which is
the form most generally used at the present time, and which seems to fulfil
all the requirements of such a submarine weapon, viz.:—
1.—Handiness, at the same time capable of containing a charge of
gun-cotton sufficient in contact to destroy the most powerful
vessel afloat.
2.—Certainty of action.
3.—Capable of being fired either on contact or at will.
4.—Mode of attaching the spar simple and very secure.
LAY'S LOCOMOTIVE TORPEDO.

In Fig. 142, a is the case, capable of containing some 33 lbs. of gun-
cotton; b is the tube through which the three wires w, w1, and w2 are led; c
is the socket in which the wooden or steel spar is introduced and secured, d
is the striker, which is attached to a brass contact plate within the head of
the case a in such a manner that any pressure either on the head or side of
the striker d will force the aforesaid plate in contact with the two studs to
which the battery wires are attached; e is a cradle affixed to the striker d to
ensure its action on contact being made by the torpedo with the attacked
vessel; the explosive is inserted at f, the socket c being made to screw on
and off.
When a hollow steel spar is used, the battery wires are sometimes led
through the interior of the torpedo and the spar, by which means they are
well protected; the only objection to this method of leading the wires being
the probability of injury to them, should the spar be broken on contact, or
by a shot.
McEvoy's Arrangement of Torpedo Wires.—At Fig. 143 is shown the
arrangement of wires as devised by Captain McEvoy, whereby the spar
torpedo may be exploded at will or on contact. c and z are the poles of the

firing battery, to which are attached respectively the wires d and d2; f is the
fuze, which is placed in the centre of the charge, and to the poles of which
the wire d2 is attached, the other end of this wire being connected with the
stud s; to the stud s1 is attached the other end of the wire d, and at the point
c in the same wire is inserted a contact breaker; another wire d1 is
connected to the wires d and d2 at the points r and r2 respectively, and at the
point k in this same wire is inserted a firing key, which latter is shown in
section at Fig. 144, from which the mode of connecting the two ends of the
wires and of using the key will be at once apparent. The contact breaker is
somewhat similar to the firing key, but there is no spring in it, contact being
made or broken by screwing the two parts together or apart. The object of
the contact breaker is to prevent the torpedo being exploded by contact, and
so to place the control of the weapon entirely in the hands of the operator.
As will be seen from Fig. 143, if contact is broken at c, it is impossible to
fire the torpedo unless the firing key k be pressed in; but should contact be
made at c, then either by means of the firing key k, or by the torpedo
striking the hostile vessel, its ignition will be effected.
The foregoing method of arranging the spar torpedo wires is certainly
very neat and effective, and is at the present time in extensive use. As yet it
has not been adopted by the English government, they still preferring to fire
the spar torpedo at will alone.
The different methods of manipulating the spar torpedo from boats will
be described in the following chapter.
General Remarks on Offensive Torpedoes.—The torpedoes that have
been described in this chapter are the only ones that at the present time can
be considered as having been proved to be practically useful, and which in
future wars may be employed against ships with some chance of success.
The spar, the Whitehead fish, and the Harvey towing torpedo have each
been subjected to the test of actual service, the former weapon being the
only one that has under those conditions been successfully used. Taking this
fact into consideration, also the high pitch of excellence that has been
attained in the construction of steam torpedo boats, and also the results of
the numerous exhaustive experiments that have been from time to time
carried out in England, America, and Europe, with various modifications of

the locomotive, towing, and spar torpedoes, there can be no two opinions as
to which of the numerous species of offensive submarine weapons is the
most practicable and effective, and that is the spar or outrigger torpedo.
To manipulate successfully locomotive and towing torpedoes in an
attack against hostile vessels, the operators must be not only unusually
fearless and self-possessed, but also must possess a thorough practical
knowledge of the complicated method of working and manœuvring those
weapons—in fact, they must be specialists; whilst in the case of the spar
torpedo, which may be fired by contact, it is only necessary to employ men
capable of handling a boat well, and possessed of dash and pluck, to ensure
an attack by such means being generally successful. Of course under some
circumstances, such as in a general action, when the locomotive and towing
torpedoes are manipulated from specially constructed torpedo vessels, they
will prove of great value, and the fish torpedo fired from a boat, in close
proximity to the attacked vessel, in smooth water, and unmolested, would
sink a vessel which under the same circumstances, owing to her being
protected by booms, might prove impregnable to a spar torpedo attack; but
such favourable conditions will not often occur in war time.
Mc. EVOY'S DUPLEX SPAR TORPEDO.

As an offensive submarine weapon of defence, the Lay torpedo boat
should prove of real value; and also manœuvred from specially constructed
vessels, it seems capable of being used in a variety of ways. As yet little is
known of this weapon, all the experiments carried out with it having been
confined to America; but now that Russia has adopted it, and one or two
have also been secured by the Peruvians, its practical value will become
more generally known.

CHAPTER VI.
TORPEDO VESSELS, BOATS, AND
SUBMARINE BOATS.

E MPLOYMENT of Torpedo Ships.—Torpedo ships, that is to say, sea-
going vessels, very fast, handy and impregnable, specially designed to
carry and operate offensive submarine weapons, such as locomotive,
towing, and the spar torpedoes, especially the former, are now considered as
a necessary and valuable adjunct to a fleet, their special work being to give
the coup de grâce to disabled ironclads in a general action; they will also be
used to attack the ships of a blockading force, and against rival torpedo
vessels. As a general rule these torpedo ships will be armed with the ram
and torpedoes only, heavy guns being dispensed with, though the
Nordenfelt and other machine guns will be considered necessary.
The German Torpedo Vessel Uhlan.—This torpedo vessel was built in
Germany by the Stettin Engine Company, and launched in 1876.
She is armed with a contact torpedo charged with dynamite carried on a
10-foot ram, lying deeply under the water line. To protect the vessel from
the effects of the discharge of the torpedo, she is built with two complete
parts, sliding one within the other, and having a considerable extent of
intermediate space between them. This space is filled with a tough and
elastic material (cork and marine glue), which even in the case of the bows
being carried away, would afford a second line of resistance. The Uhlan
carries an engine of one thousand indicated horse power. The steam is
supplied by Belleville's tubular generator. These engines occupy by far the
greater space of the vessel, only a very small portion being left for her crew
and coal. This great power of the engines is necessitated by the fact that she
has to be driven at a very high speed, at the same time she has a very great
draught, also the greatest facility of steering has to be attained; hence the
proportion of width to length, 25 to 70 feet. In order to save the crew at the
worst, a raft is constructed, which is also filled with a mixture of cork and

marine glue, and is placed near the helm. The mode of operating with the
Uhlan is as follows:—
The dynamite torpedo is affixed to the point of the ram by the aid of
divers. The rudder is then fixed, and the crew opening a wide port on the
vessel's side, jump on the aforesaid raft. The steamer then rushes forward,
and explodes its torpedo in contact with the hostile vessel. The crew hold on
to the torpedo ship, and in case she is not injured board her again and repeat
the manœuvre, if necessary.[M]
This is a novel form of torpedo boat, but does not seem to be a very
practicable method of torpedo attack.
Admiral Porter's Torpedo Ship Alarm.—The Alarm torpedo ship was
built from plans designed by Admiral David D. Porter, U.S.N. Her total
length, which includes a ram 32 feet long, is 172 feet; her beam is 27 feet 6
inches, and her draught of water is 11 feet. She is built of iron on the
bracket plate system, that is to say, she has a double hull, one shell being
constructed inside the other. Her double bottom is divided into a number of
water-tight compartments. The whole interior of the vessel is also built in
compartments, which may be hermetically closed, so that in case of both
the shells being ruptured, it would still be impossible to fill the entire ship
with water. She is steered by the same apparatus which propels her, viz. the
Fowler wheel, which is illustrated at Fig. 145.
This wheel turns on a vertical shaft, and its paddles are feathered by an
eccentric cam in such a manner that at one part of their revolution they have
a pushing and drawing action on the water, while at another part they
present only their edges. In fact it is simply a feathering paddle wheel,
turned horizontally instead of vertically. By suitably turning the cam wheel,
which is done from the helm, the feathering of the paddles is caused to
occur at different points; and in this way the vessel may be turned, or rather
her stern twisted around, as if on a pivot. At the same time, by suitably
adjusting the paddles, the ship goes ahead, or astern, the engine meanwhile
running in the same direction.
By the apparatus above described it is considered that the Alarm is
afforded not only a means of speed, but of being handled with the utmost

readiness, which latter is absolutely essential in such a vessel, as she must
always meet her antagonist bows on.
The steering is accomplished from the wheel house located aft on the
deck, or below deck, as all the appliances in the wheel house for steering,
&c., are duplicated below. By means of a hand lever beneath the wheel,
steam is admitted to a small auxiliary engine which works the cam that
adjusts the paddles. Then by turning the horizontal hand wheel in either
direction, the helmsman controls the movement of the cam, as desired. Just
above the wheel is a dial with a pointer, which enables him to note the
position of the paddles, and so adjust them as ordered. Inside the wheel
house there are also devices for communicating with the men working the
bow gun, and with those managing the torpedoes.
Her Armament—Engines.—At Fig. 146 is shown the spar and mode of
working it. It consists of a long hollow iron cylinder lying on its supports
between decks. Its outboard end rests in a kind of trough, and to this
extremity the torpedo is fixed. The spar is controlled by means of tackles
and a steam winch. The side spars are 18 feet, and the bow spar 32 feet in
length. If the hostile vessel is defended by torpedo guards, by means of a
mechanical contrivance the torpedo signals the fact, and is not exploded
until the vessel has forced the obstructions. The engines of the Alarm are
compound, with four cylinders, the condenser being placed between them.
There are four cylindrical tubular boilers with an aggregate heating surface
of 4,600 square feet. Her speed is about 16 knots. Her upper deck is only 3
feet above the water. She is fitted with an electric light, and also with
machine guns on her broadside.[N]
This is undoubtedly a most formidable vessel, both as a ram and a
torpedo ship, and if capable of performing all that is expected of her, will
prove a valuable addition to the United States Navy.
THE "ALARM" TORPEDO SHIP.

Captain Ericsson's Torpedo Vessel "Destroyer."—This torpedo vessel
was devised and built by Captain John Ericsson. The Destroyer is 130 feet
long, 11 feet deep, and 12 feet beam, extreme; both ends of her hull are
precisely alike, and terminate with very fine wedges. The rudder is attached
to a vertical wrought iron post welded to a prolongation of the keel, just
abaft the propeller, as shown at Fig. 147. The tillers consist of thin plates of
iron riveted on opposite sides of the rudder, a few inches from its bottom.
These tillers are operated by straight rods connected to the pistons of
horizontal hydraulic cylinders of 5 inches diameter, which are attached to
the sides of the keel. The steering gear by the above arrangement is placed
10 feet below the water line, while the top of the rudder is 6 feet below the
same, and thus perfect security is afforded to this most important feature of
a torpedo vessel. The intention of the designer in constructing this vessel is
to render her so far impregnable, that in attacking bow on she can defy the
opponent's fire, at the same time offering absolute protection to her
commander and steersman, and also protecting the base of her funnel. The
leading feature of the construction of the hull of the Destroyer is its being
provided with an intermediate curved deck, which extends from stem to
stern, and which is composed of plate iron strongly ribbed, and perfectly
water-tight. This intermediate deck supports a heavy solid armour plate,
fixed transversely to the line of keel, and 32 feet from the bow, inclined at
an angle of 45°, and supported on its after side by a wood backing 4 feet 6
inches in thickness. Behind this formidable shield the steering wheel is
manipulated, a wire rope extending from its barrel to a four-way cock
placed near the stern, by means of which water pressure is admitted
alternately to the hydraulic cylinders, previously mentioned, the motion of
whose pistons actuate the rudder. The lower division of the vessel is
ventilated by powerful blowers, and contains the machinery; it also affords
a safe retreat for the crew during the attack. The upper division is filled with
blocks of cork, excepting a small part near the bow, occupied by the
aforesaid armour plate and wood backing.
The deck house is 70 feet long, and composed of plate iron, riveted
water-tight to the upper part of the hull. As there are no openings in the
sides of this deck house, the vessel may be run with her upper deck under
water.

Armament of the "Destroyer."—The Destroyer is to be armed with
torpedoes somewhat similar to the projectile torpedo, drawings of which
were submitted by Captain Ericsson, the inventor, to Emperor Napoleon III.
in 1854. The present weapon is composed of a solid block of light wood,
the explosive charge being contained in a metallic vessel inserted at its
forward end. Instead of being circular, as was the case with the original
torpedo, its transverse section is square, with parallel top and bottom and
vertical sides, forming very sharp wedges at both ends, cased with steel
plates. The extreme length of the Destroyer torpedo is 23 feet. Ignition is
effected by means of a percussion fuze placed in the head of the weapon.
Operating the Torpedo.—The method of operating the torpedo is that of
inserting it into a horizontal tube near the bottom of the vessel, provided
with valves for keeping out the sea during the process of insertion, as
shown at Fig. 148. When near the hostile vessel, this valve is opened, and
the torpedo expelled by a piston actuated by steam power, the expulsion
being effected without recourse to gunpowder or other explosive agent. The
area of the actuating piston of the Destroyer is 314 square inches, while the
sectional area of the projectile is only 196 square inches; this difference in
size of the two areas is a special and important feature of the invention, as
will be understood from the following: the tension of the acting medium in
the Destroyer exceeds 200 lbs. per square inch, therefore the torpedo will be
pushed out by a force of (314 × 200) / 196 = 320 lbs. per square inch, and
as the distance passed by the piston while impelling the torpedo is 30 feet,
an energy of nearly 2,000,000 foot-pounds will be imparted to the
projectile.
When making an attack, it is intended that the vessel should at the
instant of firing her torpedo reverse her engines, this retrograde motion
being greatly assisted by the recoil, which must attend the discharge of a
body weighing some 1,400 lbs. impelled by the aforesaid enormous force,
and moving through a distance of 30 feet before reaching the water.[O]
Certainly this new system of submarine attack seems feasible, but it has
yet to prove, in common with all other new inventions, whether its
theoretical capabilities are also practical ones. At Fig. 149 is shown a
general view of this novel torpedo vessel under weigh.
THE "DESTROYER" TORPEDO SHIP.

Torpedo Boats.—In offensive torpedo warfare, whether using the spar,
locomotive, or towing torpedo, especially in the case of the former class of
submarine weapons, to ensure a successful attack it is absolutely essential
to operate those weapons from steam boats, which are capable of fulfilling
as near as possible the conditions herein enumerated:—
1.—They should be capable of steaming at least 18 knots per hour.
2.—Their engines should be noiseless, and easily managed.
3.—They should be extremely handy.
4.—No smoke should enable their approach to be detected, or glare
from their fires.
5.—That it should be possible to raise steam in them in a few minutes.
6.—They should be built in water-tight compartments, and covered
fore and aft to prevent being swamped.
7.—The crews should be protected as far as practicable from rifle fire.
In addition to the foregoing, for the purpose of rendering these craft
capable of defending themselves against the attack of guard boats, and also
of being employed as such, and on river expeditions, &c., they should be
built sufficiently strong to enable them to carry a small gun either in the

bows or stern; this would apply more especially to those torpedo boats
which are part of a ship's stores.
During the last four years a very large number of torpedo boats have
been built, which more or less fulfil the aforesaid conditions, nearly the
whole of which have been constructed by the two English firms, viz.
Messrs. Thornycroft and Co. and Messrs. Yarrow and Co., and to the latter
firm is due the honour of constructing the fastest vessel as yet in the world.
Up to the present time, a specially built torpedo boat has on only one
occasion been used on active service, viz. at the attack on a Turkish monitor
on the 20th of June, 1877, which is detailed at length in the following
chapter. This boat was one of Messrs. Thornycroft and Co.'s launches, and
from all accounts she behaved wonderfully well under the most untoward
circumstances.
Thornycroft Torpedo Launches.—Messrs. Thornycroft and Co., of
Chiswick, London, have during the last six years built a large number of
torpedo launches for the English government and for several of the
principal European governments.
Norwegian Launch.—The first torpedo boat ever built by this firm was
the one shown at Fig. 150, for the Norwegian government. This boat was 57
feet in length by 7 feet 6 inches beam, drew 3 feet of water, and the
stipulated speed was 16 English statute miles, or nearly 14 knots per hour;
which speed was not to be ascertained by a mere measured mile trial, but
was to be 16 miles through the water in a run of one hour's duration.
The hull of the vessel was constructed entirely of steel plates and angle
bars, and, as may be seen from the diagram, was divided into six water-tight
compartments, A, B, C, D, E, F.
The compartments marked A and F in the stem and stern were for stores;
those marked B and E were fitted with seats for the crew, and were provided
with movable steel covers, so that on going into action, or during rough
weather, they might be completely covered.
The compartments C and D are for the steersman and the machinery
respectively, and were covered completely by steel plating 3/16 of an inch

in thickness—a thickness sufficient to withstand Snider or Martini-Henry
bullets, fired from a distance of twenty paces.
The compartment D was furnished with a hood, having slits 1/4 of an
inch wide, all round, through which the steersman could see with sufficient
distinctness to direct his course easily. Motion was communicated from the
wheel to the tiller by means of steel wire ropes, which it was originally
intended should be encased in wrought iron tubes.
The possibility however of these tubes being bent by a shot, and so
jamming the wire ropes, led to this arrangement being abandoned, and the
ropes were simply run through eyes at intervals along the side.
The armament consisted of a cylindro-conical shaped torpedo towed
from the top of the funnel, round which a ring was fitted with two pulleys
for the towing rope, the strain being taken off by means of two stays
attached forward.
The length of this torpedo was 13 feet and the diameter 9 inches, and
with a speed of 11 knots it has diverged to about 40 degrees from the
direction of the boat's motion when running in smooth water.
The torpedo is worked by means of a small winch and brake fixed on the
after part of the engine room skylight; davits are provided for dropping the
torpedo overboard.
The engines were compound, of the usual inverted double cylinder direct
acting type, capable of developing about 90 indicated horse power, and
were fitted with a surface condenser, so that the vessel could run in salt
water, without danger of injuring her boiler.
A small tank contained a supply of fresh water, to make good
deficiencies arising through leakage, and from steam escaping at the safety
valves, &c.
The circulating, air, and feed pumps were driven by a separate engine.
The boiler was of the locomotive type, the shell being made of Bessemer
steel; the fire box and its stays of copper, and the tubes of solid drawn brass.

On the official trial, which took place on the Thames on the 17th of
October, 1873, the number of revolutions done in the hour was found to be
27,177, and the number required to do a mile in still water was 1578. The
distance run in the hour was then, 27,177/1578 = 17·22, or very nearly 17-
1/4 miles.
The steam pressure during the trial averaged 85 lbs. per square inch, and
the vacuum 25-1/2 inches.
Swedish and Danish Boats.—Boats of the same size and similar in all
particulars to the foregoing one—excepting the engines, which are
improved by driving the air pump, feed pump, and circulating pumps off the
main engines, and abolishing the auxiliary engine, which performed these
duties in the case of the Norwegian boat—were made for the Swedish and
Danish governments. The result was an increase of speed to 17·27 miles in
the case of the Swedish boat, and to 18·06 miles, or 15-5/8 knots, in the
case of the Danish boat.
There is no information regarding the armament of the Swedish boat, but
the Danish boat was armed with two spindle-shaped torpedoes 12 feet long
and 11-1/2 inches diameter, somewhat like the Whitehead torpedo. They
were placed on deck longitudinally near the funnel, so as to facilitate
launching, and were arranged to be towed from an upright pole 8 feet high,
placed about 6 feet from the stem.
A small winch was fixed on either side aft, to pay out the towing line,
and to bring back the torpedo. By these arrangements the torpedo could be
projected at a large angle from the direction of the boat's motion, and at
considerable velocity. The speed of the boat when towing one of these
torpedoes is about 10 knots.
Austrian and French Boats.—The next size of torpedo vessel is that
supplied to the Austrian and French governments, which is shown at Fig.
151. The dimensions are:—length, 67 feet; beam, 8 feet 6 inches; draught of
water, 4 feet 3 inches. The guaranteed speed in the case of the Austrian boat
was 15 knots in a run of one hour's duration, and in the case of the French
boats 18 knots, in a run of two hours' duration. These boats were built of
somewhat thicker plating than the 57 feet type, and the armour was
extended.

They were divided into six water-tight compartments, and they differed
from the Scandinavian boats in having the spaces forward and aft of the
machinery permanently decked, instead of being covered with movable
steel covers only.
The machinery was somewhat similar to that in the Scandinavian boats,
excepting that the engines were capable of developing 200 indicated horse
power, and that the air was supplied to the furnace by being forced into an
air-tight stoke hole, instead of being forced directly under the fire grate.
The armament of these vessels consisted of two torpedoes attached to
the end of wooden poles, 4-1/2 inches diameter and about 43 feet long,
connected to the battery by insulated wires, and arranged to be fired either
by coming in contact with the enemy's vessel or at any distance from it, at
the will of the operator.
The torpedoes themselves were simply copper cases, of sufficient size,
in the case of the Austrian boat, to contain 11,000 cubic centimetres of
explosive, and in the case of the French boats, to contain 25 kilogrammes of
dynamite.
The mode of arranging the wires is similar to that explained at page 155.
The method of manipulating the torpedo poles consists of two tubes riveted
together at right angles, so as to form something like the letter T. The
torpedo pole is put through the horizontal tube, which is free to move round
the centre of the vertical tube, and the vertical tube is free to move through
a quarter circle at right angles to the centre line of the vessel.
In attacking in front, the vertical tube is laid over till it is parallel to the
water surface, and the horizontal tube is allowed to incline sufficiently far
to allow of the end of the pole, when run out, to be depressed from 8 to 10
feet below the water-line. It is held in this position by a pair of blocks
attached to the top of a short mast.
In attacking on the broadside, the vertical tube is laid over till it assumes
a position such as to allow of the pole, when swung round, to touch an
enemy's vessel at about 8 or 10 feet below the water line.
The speed trials of the Austrian boat took place on the 11th of
September, 1875, when she did 24,700 revolutions on her hour's run on the

Thames, and the number of revolutions required to do a knot in still water
was found to be 1357. This gives the distance run in the hour as 18·202
knots, or 3·202 knots over the contract speed. The steam pressure averaged
105 lbs. per square inch, and the vacuum 25-1/2 inches during the run.
In the case of the French boats, the total number of revolutions done in
the two hours' run in the roadstead off Cherbourg was 49,818, and the
number required to do a knot in still water was found to be 1382, so that the
distance run in the two hours was 36·05 knots, or just over the contract
speed. During the two hours, the average steam pressure was 108 lbs. per
square inch, and the vacuum 25 inches.
The Austrian boat was sent to her destination on board a steamer, but the
French boats, under the command of an experienced captain, steamed by
themselves from Chiswick to Cherbourg, not crossing at the nearest points
and running along the shore, but going boldly from Dover direct to
Cherbourg.
Shortly after the arrival of the French boats in Cherbourg, they were
altered so as to attack in front only, as the French authorities found that
these small vessels were better adapted for resisting the effects of an
explosion at the bow than at any other part.
The arrangement adopted is shown at Fig. 152, and consisted of a steel
pole about 40 feet in length, having one end about 6 inches diameter, and
solid, and the other about 1-1/2 inches diameter, and hollow; this pole was
mounted at its solid end on small pulleys, which ran upon two ropes
stretched fore and aft of the vessel; the other end, to which the torpedo was
attached, was led over a pulley fixed on the bow. Ropes passing over
pulleys to a windlass in the after compartment were attached to the inboard
end, and by turning the windlass the pole was drawn backwards or forwards
as required.
It will be observed that as the pole is drawn forward, the inboard end
being constrained to move in a line parallel to the deck, the outer end is
depressed in the water, and is so adjusted that when the pole is run out to its
full extremity, the torpedo is depressed to about 8-1/2 feet below the water
level.

Dutch and Italian Boats.—The third size of boat built by this firm for
the Dutch and Italian governments are 76 feet long and 10 feet beam, and
are guaranteed to do a speed of 18 knots. These boats are similar in design
to the Austrian and French boats previously described, but differ from them
in having engines of 250 indicated horse power, and in having more free
board forward, so as to make them better sea boats.
The Dutch type are armed with the outrigger torpedo, as fitted to the
French boats, and the Italian type with the Whitehead fish torpedo.
The "Lightning" Type of Boat.—Now comes the Lightning type of
vessel, which is shown at Fig. 153. This vessel, built for the English
government, is 84 feet long over all, 10 feet 10 inches beam, and draws
about 5 feet of water. The machinery on board the Lightning is similar in
design to that already described, and is capable of indicating 350 horse
power. The hull of the Lightning is made of heavier plating than usually
employed, and her lines are fuller, as she is intended for use in a tolerably
rough sea if necessary; and in order that she may be able to remain at sea
for some time, cabin accommodation on a scale larger than in any of the
other boats is provided for the officers and crew. The steering gear is
arranged so that the vessel may be steered from the deck, or from the
conning tower, and the usual telegraph gear is fitted to communicate from
the deck, or from the conning tower, to the engine room.
The top of the conning tower is supported on three screws, so arranged
that it may be raised or lowered, and the space for sight adjusted according
to the range of vision required, or the risk to be run from the enemy's
missiles.
The Lightning is armed with fish torpedoes, which are discharged from
her deck forward by means of a discharging apparatus.
The torpedoes are charged with air, by means of one of Mr.
Brotherhood's air-compressing pumps.
The Lightning on her preliminary runs attained a speed on the measured
mile of 19·4 knots per hour, a speed which will be somewhat reduced when
she has her torpedoes, &c., on board, but which will then be over 18 knots
per hour.

Several torpedo boats have been built and are in process of construction
by this firm for the English government.
THORNYCROFT'S TORPEDO BOATS.

French Boats.—The next size of boats is the 87 feet type, as shown at
Fig. 154. Of this type of torpedo launch several have been built and are now
under construction for the French government.
These vessels are 10 feet 6 inches beam; draught of water about 5 feet.
They are built of heavier plating than the Lightning, and are guaranteed to
maintain a speed of 18 knots. The propellers in these boats are placed in
front of the rudder, so as to give increased readiness in steering. In order to
prevent oxidation as far as possible, the plates and frames below the water
line are galvanised. A spark-catching apparatus is fitted to the base of the
funnel, so as to prevent the position of the boat being betrayed to the enemy
at night.
The armament of these vessels consist of an outrigger arrangement
similar to that described at page 167. They are also well adapted for the
Whitehead torpedo. They are also provided with a strong buffer in the bows
for deadening the shock, in the event of their coming into contact with an
enemy's vessel at too high a rate of speed.
"Second Class" Boats and Mode of Manipulating the Fish Torpedoes
from them.—Another type of Thornycroft torpedo boats, several of which
have been built for continental governments, and which is termed "Second
class," is shown at Fig. 155. These boats are 60 feet long, 7 feet 6 inches
beam, and draw some 3 feet of water; their guaranteed speed being 16 knots
per hour. The mode of carrying the Whitehead fish torpedo, and
manipulating it from such a boat by means of Mr. J. I. Thornycroft's
invention, which has been fully described at page 140, is shown at Fig. 155
and 156, where Fig. 155 represents both torpedoes housed, and Fig. 156 one
torpedo in the firing position, the other one being housed.
Four of this type of Thornycroft torpedo boats were attached to H.M.S.
Hecla during her recent cruise in the Mediterranean, and have been very
favourably reported on as follows:—They do not suffer from the blows of
the sea, nor from the strains incident upon hoisting in and out; nor yet when
they are suspended ready for lowering, in which latter position they have
frequently remained for twenty-four hours; that under careful management
they are perfectly safe in a heavy sea, and they possess good manœuvring
powers.

The Thornycroft torpedo frames were found to perform well the services
for which they are intended. When proceeding at ordinary speed they are
nearly noiseless, and cannot be seen on a dark night at a distance of 100
yards.
The Thornycroft Propeller.—All the torpedo boats built by this firm are
fitted with the propeller invented by Mr. Thornycroft, and which bears his
name. It is a modification of what is known as the Dundonald propeller, the
principal difference being that in the Dundonald propeller the blades are
inclined backward in straight lines, while in the Thornycroft propeller they
are curved.
Experiment at Cherbourg.—The following account of an experiment
which took place at Cherbourg in March 1877, whereby to test the
efficiency of a Thornycroft torpedo boat in exploding a spar torpedo under
the bottom of a vessel proceeding ahead at the time, is taken from the
Times, under date the 13th of March, 1877.
THORNYCROFT'S TORPEDO BOATS.

"Admiral Jaurez, who commands the squadron, ordered a disabled ship,
the Bayonnaise, during a rather rough sea, to be towed out by a steamer

belonging to the navy. A second lieutenant, M. Lemoinne, was sent for, and
informed that he had been selected to make the experiment of launching the
Thornycroft against the Bayonnaise while both were in full sail. He
accepted the mission without hesitation, picked out two engine men and a
pilot, and went down with them into the interior of the Thornycroft, of
which only a small part was above water; this visible portion being painted
of a greyish colour, so as to be easily confused with the sea. The torpedo
was placed so as to project from the bow of the vessel, at the extremity of
which were two lateen sailyards about three metres in length. The towing
steamer then took up its position in front of the squadron, and the
Thornycroft also assumed the position assigned for it; an interval of three or
four marine miles separating the torpedo boat and the Bayonnaise. On a
signal being given, both were set in motion, the steamer advancing in a
straight line, and the Thornycroft obliquely, so as to take the Bayonnaise in
flank. The steam tug went at 14 knots an hour, going at full speed in order
to escape the Thornycroft. The latter went at 19 knots an hour, a rate not
attained by any vessel in the squadron. The chase lasted about an hour, the
squadron keeping in the rear, so as to witness the operations. At the end of
that time the distance between the Thornycroft and the Bayonnaise had
sensibly diminished, and at a given moment the former, in order to come up
with the latter at the requisite distance, had to slacken speed to 8 knots an
hour. The whole squadron watched this last phase of the struggle with
breathless interest, and people asked themselves whether the shock of the
torpedo would not infallibly destroy the little vessel which bore it. It was
feared that the lives of the second lieutenant, Lemoinne, and his three
companions were absolutely sacrificed. However, the two vessels got
visibly nearer. All at once the Thornycroft put on a last spurt, and struck the
Bayonnaise with its whole force on the starboard bow. The sea was terribly
agitated, a deafening report was heard, and the Bayonnaise, with a rent as
big as a house, sank with wonderful rapidity. As for the Thornycroft,
rebounding by the shock about fifteen metres off, even before the explosion
occurred, it went round and round for a few moments, and quietly resumed
the direction of the squadron. No trace remained of the Bayonnaise; it was
literally swallowed up by the sea."
The experiment was a most complete success, the torpedo boat not being
in the least degree injured.

The Power of Flotation of a Thornycroft Boat after being pierced by a
Rifle Shot.—On the 5th of July, 1877, Messrs. Thornycroft and Co. made an
experiment with one of their torpedo boats to ascertain under what
conditions flotation is still retained after the boat has been pierced by a rifle
shot.
The torpedo boat experimented on was similar to the one which has been
described at page 169. A Martini-Henry was fired through her side, about a
foot under water in the stoke hole. Whilst at anchor the water entered in
sufficient quantity to fill an ordinary size bucket in twenty-five seconds, but
when she was driven ahead less water entered, and on the speed of 10 knots
being reached, little or no water entered. The hole was a little more than
three quarters of an inch in diameter.
The engagement on the Danube between the torpedo boat Schootka and
some Turkish vessels, in which the former vessel was pierced by bullets,
but yet did not sink, led to the above experiment being carried out.
Efficiency of Thornycroft's Engines.—As a practical proof of the
efficiency of the engines supplied by Messrs. Thornycroft and Co. to their
torpedo boats, a similar engine has been used for over two years to work the
various machines in connection with their works at Chiswick.
Torpedo Boats built by Messrs. Yarrow and Co.—Messrs. Yarrow and
Co., of the Isle of Dogs, London, are also very well-known torpedo boat
builders, and have during the last four years constructed a considerable
number of such vessels for the English and different continental
governments, and, as has been before stated, they are the constructors of the
fastest vessel in the world.
Dutch Torpedo Launch.—In 1875 this firm built a torpedo launch for the
Dutch government, specially designed for ocean purposes. It was 66 feet
long, 10 feet beam, and 5-1/2 feet deep. She was driven by a pair of
inverted direct acting engines. The boiler was of the locomotive type, with a
working pressure of 140 lbs. per square inch, and capable of exerting a
force of some 200 indicated horses.
Russian Torpedo Boat.—This firm also constructed for the Russian
government two torpedo steamers 85 feet in length. The guaranteed speed

of these vessels being 20 knots per hour. In 1878 the Russian government
ordered one hundred exactly similar boats to be constructed, mostly at St.
Petersburg, thus proving the high estimation held by that government of
Messrs. Yarrow and Co.'s torpedo boats.
Description of a Yarrow Torpedo Launch.—Figs. 157, 158, and 159
show an elevation, section, and plan of a torpedo boat, Yarrow type, a large
number of which have been built for the Russian and other continental
governments.
The length of this boat is 75 feet, its beam 10 feet, and draught of water
3 feet. She is built of steel of the best quality, no other metal possessing the
requisite strength and stiffness for scantling, and plates of such lightness. It
is divided into eight compartments by seven transverse bulkheads, the
forward and after compartments being used for stores, the two central ones
enclosing the machinery, while the steersman and operator are placed in the
compartment immediately abaft the engines.
The steersman's head projects above the deck, and is protected by a rifle
proof steel truncated cone, the top part of which is movable like the visor of
a helmet. The hull is decked over from end to end with a curved shield, the
midship plating of which is capable of resisting rifle shots, even at close
quarters; its curved form being well adapted for giving the maximum
strength to the structure, and quickly frees itself from any large body of
water.
YARROW'S TORPEDO BOATS.

The propelling machinery consists of a pair of inverted compound
condensing engines. The revolutions per minute at full speed are about 470,
and the indicated horse power about 280. The propeller is of steel. The
funnel is fixed at one side of the centre line, to be out of the way of the bow
torpedo pole and gear.
This type of torpedo boat attains a speed of from 17-1/2 to 18-1/2 knots
per hour.
The armament of some of these boats consists of three spar torpedoes, a
bow, and two quarter ones. The bow pole, which is strong and heavy, is
hauled out and in by means of a small auxiliary engine.
Boats similar to these, but of larger dimensions, viz. 84 feet long and 11
feet beam, have also been constructed by this firm. Speed from 19 to 20
knots per hour.
English Torpedo Boats.—The following account of two torpedo boats
which had been originally built by this firm for the Russian government,
but, owing to the proclamation issued by the English government at this
time prohibiting torpedo boats leaving England, were seized by the

Customs authorities when on the point of completion, and were ultimately
purchased by the English government, is an extract from the Times under
date the 4th of July, 1878.
"These vessels are each 85 feet long with 11 feet beam, and draw, when
fully equipped for service, an average of 3 feet of water. They are strongly
constructed of steel, and are fitted with compound surface condensing
engines capable of indicating 420 horse power. The high pressure steam
cylinder of these engines is 12-1/2 inches in diameter, and the low pressure
21-1/2 inches, both having a 12 inch stroke. These boats are at present
known by their builders' numbers, one being No. 419 and the other No. 420.
The former is propelled by a three-bladed screw, 5 feet 6 inches diameter
and 5 feet pitch; and the latter by a two-bladed screw of similar proportions.
Messrs. Yarrow adopt supplementary engines for driving the air pump,
circulating pump, and feed pumps; they consider this plan preferable to that
of working these pumps direct off the main engine, as is sometimes done.
One advantage in having separate pumping engines is that, whether the
vessel is in motion or stationary, a powerful means is available for pumping
her out, should the necessity arise. It is estimated by her builders that if the
air pump and circulating pump were both utilised for this purpose, the water
could be pumped out as fast as it could enter either of these vessels through
one hundred holes made in the skin by Martini-Henry rifle bullets. If this is
the case, these craft may be deemed safe from sinking so long as their
machinery is working efficiently. The boiler is of the locomotive type,
placed in the forward part of each vessel, and has a closed stoke hole. In
connection with the boiler a very important improvement has been
introduced by Messrs. Yarrow. This consists in a means of rendering the
closed stoke hole safe for the men in the event of the collapse of a boiler
tube—a contingency which cannot be absolutely guarded against. Its
efficiency was proved beyond all question upon a previous trial of one of
these boats. This was No. 419, which was tried on the 24th of May last
under the supervision of the Admiralty officials. Upon that occasion an
accidental rupture of one of the boiler tubes occurred nearly at the close of
the runs over the measured mile, which so far had been very successful.
When the boiler tube gave way the steam rushed out of the foremost
hatchway from the compartment in which the smoke box end of the boiler
is situated, and soon after from the two funnels. The men in the stoke hole,

however, being shut off from the boiler, were uninjured, and remained at
their post several minutes after the first outburst of steam. The accident,
although an untoward event, was considered by the Admiralty officials as
affording a highly satisfactory proof of the efficiency of Mr. Yarrow's
invention.
"The engines are placed amidships, and each vessel has spacious cabin
accommodation aft, as it is intended that they may be used either as
despatch or torpedo boats. For the latter purpose the cabin framings above
deck are removed and replaced by steel plating. They are steered from the
cabin, there being a look-out for the steersman just above deck level. The
deck is clear of all obstructions, the two funnels being placed one on either
side. They are fitted with balanced rudders and steer well, answering their
helms very quickly."
The trials of these two torpedo boats are taken from the Engineer under
date the 19th of July, 1878. At that time these boats completely eclipsed in
speed everything that had hitherto been done. At Fig. 160 is shown in
elevation this type of torpedo launch.
"The trials were personally conducted by Mr. Yarrow, under the
superintendence of the authorities from Whitehall, and consisted in a two
hours' run without stopping, during which time the boats were tested at the
measured mile at Long Reach. Each boat was run six times over the mile,
three runs with the tide and three runs against it. The boats and machinery
are similar in every respect, excepting that No. 419 is fitted with a three-
bladed propeller, and No. 420 a two-bladed one, their diameters and pitch
being the same in both cases. The weights on board were accurately
weighed, and amounted to 6 tons in each boat, including coals, water, crew,
and ballast.
"Trial of No. 419.
Min. Sec. Knots per hour.
1st run down occupied 2 36 23·076
1st run up " 3 20 18·000
2nd run down " 2 35 23·226
2nd run up " 3 16 18·367
3rd run down " 2 32 23·684

3rd run up " 3 14 18·557
Mean of the six runs, 20·818 knots per hour.
Mean steam pressure, 115 lbs. per square inch.
Vacuum, 23½ inches.
Mean revolutions of main engines per minute, 456.

"Trial of No. 420.
Min. Sec. Knots per hour.
1st run down occupied 2 33½ 23·452
1st run up " 3 25½ 17·518
2nd run down " 2 32½ 23·606
2nd run up " 3 21 17·910
3rd run down " 2 32 23·684
3rd run up " 3 24 17·647
Mean of the six runs, 20·636 knots per hour.
Mean steam pressure, 115 lbs. per square inch.
Vacuum, 24 inches.
Mean revolutions per minute, 466.

"The highest speeds were obtained by No. 419, during the third runs up
and down, the mean of which give 21·12 knots, which is equal to 24-1/3
statute miles per hour, during which time the engines were making 470
revolutions per minute. At the close of the runs, the bearings were found to
be in first-class condition, and there was not the least sign of anything
getting warm during any part of the trials."
Spanish Torpedo Boat.—The following description of a torpedo boat
built by this firm for the Spanish government, enumerating all the
improvements that have of late been effected in the construction of such
vessels by members of this firm, is taken from the Engineering under date
the 21st of February, 1879.
"The alterations have a twofold character, and have reference to the
arrangements for discharging the products of combustion from the furnaces
and to those for steering the vessel. In brief, the boat is funnelless and is
fitted with two rudders, one at each end. The main object in dispensing with
the funnel is to enable the torpedo boat to approach as closely as possible to

an enemy without being seen, a secondary, although still an important,
consideration, being the absence of any obstruction to the steersman's view,
such as a funnel on deck. The outlets for the smoke in the present instance
are two ports, one on either side of the vessel, and placed about 15 feet in
from the bow. Each of these smoke ports is fitted with a damper, and the
smoke can be turned through either or both of the passages as desired. The
control of these dampers is given to the steersman, who, on approaching an
enemy, can direct the products of combustion through the port on the
unexposed side of the vessel. The emission of smoke by day and of the
glare and sparks by night are thus to a very large extent hidden from view,
thus enabling the torpedo boat to approach very closely to the point of
attack without being observed. The outlets are fitted with valves which are
kept open by the blast, but which close on being struck by a passing wave.
Should the vessel have to be out when a heavy sea is running the ports are
closed, and a spare funnel is rigged up on deck, on one side. Although the
smoke ports are placed forward in this boat, it is intended to place them aft
in the next that Messrs. Yarrow build, as that arrangement will obviate the
inconvenience at present experienced by those on deck from the heated
gases of the furnace being carried along it at times by the wind, when on a
certain course.
YARROW'S TORPEDO BOATS.

"The steering powers of the boat have next had attention from Messrs.
Yarrow, and they have sought to remedy the defective steering common to
these large quick-speed torpedo craft. To do this they have fitted the vessel
under notice with two balanced rudders, one of which is placed forward
about 10 feet from the bow, and the other in its usual position at the stern
with the screw abaft it. Both rudders are connected with the same steering
gear, and are operated simultaneously by one steersman. The forward
rudder can be raised out of the water into a casing inside the boat if desired
by means of a screw cut on the upper part of its spindle. By the same
means, by unscrewing the collar on the spindle, the rudder can be released
and dropped into the water should the necessity arise for so doing, by
reason of its becoming fouled or damaged. In trials which have been made
with this double-steering system, it has been found that when steaming at
high speeds the forward rudder has a much greater control over the motion
of the boat than the stern one. The reason assigned for this is that at high
speeds the forward part of the boat is lifted out of the water, and
consequently offers a diminished side resistance to any turning motion
brought to bear upon it.

"The boat in which these improvements have been introduced is 86 feet
long by 11 feet beam and 5 feet 6 inches deep. She is fitted with compound
engines having 22 inch and 12-1/2 inch cylinders, with a 12 inch stroke, and
making 520 revolutions per minute when running at full speed. She is
propelled by a three-bladed screw 5 feet 6 inches in diameter and 5 feet
pitch. Put through some evolutions with the view of testing her steering
powers, the double rudder arrangement was found to answer exceedingly
well, and she turned a circle of a diameter equal to about three times her
own length in 1 minute 15 seconds. She turned equally well either going
ahead or astern, and in fact her steering capabilities were satisfactorily
demonstrated. The new arrangement for carrying off the smoke also
answered very well, with the exception that the heated gases occasionally
swept the deck, which objectionable result will be avoided in future boats."
These boats are to be armed with spar torpedoes, and with the Whitehead
fish torpedo, the cradles and fittings for which are shown at Fig. 161.
The Fastest Vessel in the World.—Another type of torpedo boat, of
which one of the same dimensions has been built by this firm for the
English government, is shown at Fig. 162. This vessel is as yet the fastest
vessel in the world. The trials with this boat were made in March of this
year, and were as follows:—
Time, Knots Knots
Runs.
Min. sec. per hour. per hour.
First 2 37 = 22·93
Mean of first pair = 21·35
Second 3 2 = 19·78
Third 2 33 = 23·53
Mean of second pair = 22·05
Fourth 2 55 = 20·57
Fifth 2 30 = 24·00
Mean of third pair = 22·23
Sixth 2 56 = 20·45
giving as a mean 21·93 knots per hour, or 25-1/4 statute miles. The boat
was fully equipped for active service, i.e. with a load of 6-3/4 tons on
board. It was found during the trial that at speeds of 17 and 19 knots the
vibration of the boat was considerable, but when running over 20 knots it
was hardly perceptible; the excessive vibration taking place when the

revolutions of the engines became a multiple of the natural vibration of the
boat.
Torpedo boats are at the present time being built by this firm for the
English, French, Spanish, Austrian, and Italian governments.
Russian Torpedo Boats, built by Mr. S. Schibau, Prussia.—Mr. S.
Schibau, of Elbing, Eastern Prussia, in 1878 constructed ten torpedo boats
for the Russian government, similar to the one shown at Fig 163.
These boats are each 66 feet long, and 11 feet 3 inches beam. They are
built of steel plates about an eighth of an inch thick. Their engines consist
of three cylinder compounds, with surface condensers; and they run at 380
revolutions per minute, at full speed, driving a screw 4 feet in diameter.
They have been variously armed, some with the spar, some with the
Whitehead fish, and some with the Harvey towing torpedo. Their speed is
about 18 knots per hour.
Messrs. Herreshoff's Torpedo.—Messrs. Herreshoff, of Rhode Island,
U.S.A., have also constructed several torpedo boats. One of these, built for
the English government, is shown in section at Fig. 164. This boat is 59 feet
6 inches long, 7 feet 6 inches beam, and 5 feet 6 inches deep; she draws
about 1 foot 3 inches of water.
RUSSIAN TORPEDO BOAT, HERRESHOFF'S TORPEDO BOAT.

"The vessel is constructed with five water-tight bulkheads, and her hull
is of composite construction below the water line, having a steel framing

covered with wood planking. The upper part of the hull is wholly of steel,
the plates being 1/16 inch thick, the top sides sloping inwards and the upper
work forming a protective superstructure for the crew and machinery. She is
propelled by a screw which is placed beneath the vessel in a central
position, and which is driven by a direct acting condensing engine placed in
the forward part of the boat. The diameters of the steam cylinders are 10-1/2
inches and 6 inches respectively, with 10 inch stroke, and they are of 100
horse power estimated. There is an independent feed pump and air pump.
The stoke hold is enclosed and is supplied with air by a Sturtevant blower,
which is driven by an independent engine of 2-1/2 horse power. The
propeller is a two-bladed screw 38 inches in diameter and 5 feet pitch, the
screw shaft being 23 feet in length. The vessel is steered by means of a
balanced rudder placed a short distance from the stern and under the ship,
the helmsman being located in a stern cabin with a protected look-out raised
just above the deck. The hull and machinery together weigh 6 tons, but with
the working crew of four men and fuel, stores, and two torpedoes on board,
boat weighs about 7-1/2 tons.
"Steam is supplied by a Herreshoff coil boiler, which constitutes another
novelty in this boat. This boiler consists of a circular combustion chamber,
which in the present instance is 4 feet in diameter internally, and within
which is a coil of about 300 feet of 2 inch pipe coiled to nearly the diameter
of the chamber. This coil is continued at the top so as to form a kind of
dome under the cover of the combustion chamber. By the side of the boiler
is a separator, into which the steam passes before it goes to the engine. The
water from the feed pump is admitted at the top of the coil, and during its
course to the bottom the greater portion of it becomes converted into steam.
Having passed through the entire length of the coil, the steam and water are
discharged together into the separator in such a manner that the water is
entirely separated from the steam, and can be blown off as required. The
steam is taken from the top of the separator, and returns through a short coil
placed inside the combustion chamber, where it becomes superheated, and
is led thence to the engines. It is claimed for this boiler that it cannot
explode destructively, inasmuch as there is but a very small quantity of
water in it at any time, and that it is distributed along the entire length of the
coil. A rupture at any point would only be attended by a moderate blowing
off of steam. The rapid circulation of the water is found to prevent the

deposit of salts, the surplus water not converted into steam carrying with it
all impurities. A good working pressure can be obtained within a few
minutes of lighting the fire, and the boiler can be blown off in a few
seconds. The large combustion chamber enables the full economy of the
fuel to be realised."[P]
This vessel is guaranteed for a speed of 16 knots per hour. She can be
propelled ahead or astern with equal speed, and can be brought to a dead
stop when going full speed within a distance equal to her own length. Her
turning powers are equally good. Her armament will probably be the fish
torpedo.
Ordinary Torpedo Boat.—The most efficient and simple method of
fitting and working a spar torpedo from an ordinary steam launch or
pinnace is shown at Fig. 165. This method will be readily understood from
the figure; the dotted lines show the position of the spar and upright, when
rigged in. The speed of this type of torpedo boat ranges from 6 to 9 knots.
Occasions would no doubt occur in time of war when a torpedo attack by
such boats would be a feasible matter, and therefore everything should be
done to render these boats fit for that special service.
Defects.—The most important defects of such craft are:—
1.—The noise created by their engines, thus rendering an undetected
approach to a hostile vessel impracticable.
2.—Their liability to be swamped by the explosion of the torpedo.
Of course there are many minor defects, but above are the principal
ones, both of which might, to a considerable extent, be modified.
Torpedo Boat Attacks.—It is impossible to attempt more than a very
general idea of how to conduct a torpedo boat attack, as so much depends
upon the circumstances, ever changing, under which each particular attack
would have to operate.
The spar and the fish torpedo are the submarine weapons that can best be
manipulated from boats, the towing torpedo requiring a more roomy craft
than the torpedo boat generally is to operate it from with any chance of
success.

Methods of Protecting Ships from Boat Torpedo Attacks.—The principal
methods that exist at the present time of protecting a ship from a boat
torpedo attack are as follows:—
1.—Booms by themselves, or supporting nets hung vertically,
surrounding the ship at a distance of 10 or 15 feet from the side
of the vessel.
2.—A crinoline of wire, or chain, fixed by stays to the vessel's side,
but capable of being lifted out of the water if required.
3.—The above methods supplemented by guard boats, and a cordon of
boats.
4.—A cordon of boats, that is, boats connected at certain distances by
means of hawsers, or chain cables, and at a distance of some
200 or 300 yards from the vessel, supplemented by guard
boats, but without other protection.
5.—Electric lights and torpedo guns. These latter are small guns
capable of penetrating the side of a torpedo boat and of being
depressed at a very small angle.
As it is against these defences that torpedo boats would have to contend,
therefore they have been described previous to explaining the mode of
conducting a torpedo boat attack.
The first two methods of defence are of course quite impracticable when
the attacked vessel is one of a blockading squadron, and it is against such
vessels that a torpedo boat attack will generally be used and oftenest be
successful.
In the case of a vessel forced to anchor in a harbour which is accessible
to the torpedo boats of the enemy, by the application of either of the first
two methods, supplemented by guard boats and electric lights, she would
undoubtedly be almost impregnable against a torpedo boat attack, even
were the boats armed with the fish torpedo, though she would of course not
be in that state of readiness which is essential to a man-of-war's efficiency.
As a general rule, no man-of-war should anchor unless absolutely necessary
in the vicinity of an enemy's ports, and then should retain the power of
moving in any direction in the quickest space of time possible, using the
electric light and guard boats as a means of protection.

An attack by boats armed with the spar torpedo must always partake of
the nature of a forlorn hope, this especially applying to the boats
themselves, the crews of which, provided they are supplied with good life
belts, would seem to run a far greater risk of a wetting and a prison than of
being shot.
Not less than four torpedo boats should compose the attacking force. The
crews of the boats, consisting of only those actually required, should fully
understand "that the hostile vessel is to be torpedoed," i.e. they are not to
give up the attack on the vessel opening fire, nor in the case of one or more
of the torpedo boats being sunk, but to remember that one boat is sufficient
to effectually carry out the object of the attack, viz. the sinking of the ship.
In making the attack, one boat should be directed on each bow, and one
on each quarter, the final rush being as combined as possible. There must
not be the slightest hesitation, and each boat must make direct for her point
of attack.
The cause of the Russians failing so often in their torpedo boat attacks
during the war of '77 may be traced to the absence of anything like a
system, and to their giving up the attack directly they supposed themselves
discovered.
When using the towing torpedo, two boats only could be used, and they
should make the attack, either coming down from ahead, one on each side
of the vessel, or coming up from the stern, one on each side of the vessel, or
by the boats crossing the bow and stern of the vessel in different directions.
In the case of the fish torpedo the attack must be conducted in a different
manner, the object in this case being to get within a certain distance only of
the vessel undetected, and from thence send the missile on its deadly
course. The distance should not be more than 500 yards; the closer up to
200 yards the better. In connection with such an attack, the torpedo boats
might be supported by guard boats, whose particular duty it would be to
engage the enemy's guard boats and so leave the torpedo boats free to do
their particular work.
It has been suggested to use the electric light from the bows of torpedo
boats, but this would do away with one of the chief characteristics of such

boats, viz. their invisible and unknown approach, on which the whole
success of the attack in a great measure depends.
Fosberry's Patent Torpedo Boat Protective.—To enable torpedo vessels
and boats to remain afloat after being struck by shot from mitrailleuses,
rifles, and other arms usually employed against such craft, and at the same
time to retain their structural lightness, Colonel G. V. Fosberry, of the
English army, has designed the following method, which is based upon the
discovery that when india-rubber or the like is placed and secured on a
metal plate, and is penetrated or punctured by a rifle bullet or similar
projectile, which also passes through the metal plate, the hole or orifice so
formed in the india-rubber will, after the projectile has passed through it
and the metal plate, immediately be closed by the elasticity of the
surrounding portions, so that no water can follow the projectile through the
said hole or orifice. India-rubber or other elastic material, or a combination
of such materials, in the form of sheets, belts, or coats, is placed upon or
around those portions of the hull of the boat which are to be protected.
Vulcanised or mineralised india-rubber is the material usually employed by
Colonel Fosberry. Between the metal plates and the india-rubber covering
an intermediate substance, generally kamptulicon, is interposed, which is
cemented or riveted to the said metal plates, and to which the india-rubber
is attached. This intermediate substance, which is the feature of the
invention, must be of such a nature that it may be caused to adhere closely
and tightly to all parts of the metal, and also to the india-rubber covering,
while the same are unperforated, but when the said india-rubber covering
and the metal plate under the same are perforated by a bullet, the portion of
the said intermediate substance adjacent to the perforation must be detached
from the elastic covering and metal plate, and leave the former free to act
like a valve, and close up over the hole so that no water may enter; and this
intermediate substance, as applied by the inventor in the immediate vicinity
of the perforation, will by the effect of the shot be so broken up and
detached from the india-rubber covering as to allow the same to recover its
original position independently of the new shape or position of the injured
and deformed metal plate.
Should the india-rubber be placed upon the metal plates and be so
attached to the said plates as to adhere and conform to them in or after their
deformation, a hole made in the india-rubber would remain open; on the

other hand, should the india-rubber without any intermediate substance be
attached to the metal plate in such a manner that it will recover its position
after perforation, water would penetrate between the metal and the india-
rubber, and by the pressure of this water the india-rubber would be liable to
be detached from a large area of the metal plate, and so become ineffective
or even dangerous to the boat. Moreover, if the india-rubber is fixed directly
upon the metal plates, in the case of a shot passing completely through the
boat, that is to say, passing into the boat at one side and out at the other
side, a large portion of the india-rubber adjacent to the hole made by the
shot in leaving the boat will be torn or destroyed, but this will not be the
case in boats constructed according to Colonel Fosberry's patent.
The French government have recently applied this invention to one of
their torpedo boats with very successful results, thereby proving that it is
not merely a theoretical idea.
Submarine Boats.—Submarine boats, if they could be constructed to
fulfil the conditions hereinafter enumerated which are essential to a perfect
boat of that nature, would for many reasons be a very important point
solved in connection with torpedo operations, and therefore it is most
extraordinary that a practicable submarine boat has not yet been designed
and built.
Bushnell's Submarine Boat.—The first submarine vessel built for
torpedo purposes was designed and constructed by David Bushnell in 1775.
This vessel, operated by a Sergeant Esra Lee, was employed in an attempt
in 1776 or thereabouts on the Eagle, an English man-of-war, which proved
unsuccessful, owing to the sergeant not being thoroughly versed in the
management of his curious craft. She was soon afterwards sunk in the
Hudson river, but was subsequently recovered by the inventor, though never
used again. This vessel was capable of holding one person, and air
sufficient to support him thirty minutes without receiving fresh air, and is
fully described in 'Barnes's Submarine Warfare.'
Qualifications essential to a Submarine Boat.—A submarine boat should
possess the following qualifications:—
1.—It should be of sufficient displacement to carry the machinery
necessary for propulsion, and the men and materials for

performing the various operations.
2.—It should be of such a form that it may be easily propelled and
steered.
3.—It should have sufficient interior space for the crew to work in.
4.—It should be capable of carrying sufficient pure air to support its
crew for a specified time, or of having the means of purifying
the air within the boat, and exhausting the foul air.
5.—It should be able to rise and sink at will to the required depth,
either when stationary or in motion.
6.—It should be so fitted that the crew possess the means of leaving
the boat without requiring external assistance.
7.—It should carry a light sufficient to steer by, and to carry on the
various operations.
8.—It should possess sufficient strength to prevent any chance of its
collapsing at the greatest depth to which it may be required to
manipulate it.
The results of former experiments with such boats prove that manual
power, which was the original mode of propulsion, is not the motive power
best adapted to such a boat; compressed air, gas as used in the Lay torpedo
boat, and steam, are all of them far preferable to the original method, but
which of these modern ones is the most practicable has yet to be decided.
The most difficult point to be overcome in connection with a submarine
boat is that of steering it correctly when beneath the surface of the water.
Confederate Submarine Boat.—The Confederate submarine torpedo
boat that sunk the Federal vessel of war Housatonic on the 17th of
February, 1864, was built of boiler iron, 35' long, 3' beam (extreme), 5' high
in the centre. She carried a crew of nine men. She was propelled by means
of a screw propeller worked by eight of the crew, her greatest speed being
four knots an hour in smooth water. She carried a sufficient quantity of air
to enable the crew to remain submerged for the space of two to three hours.
Two fins were fitted on the outside for rising and falling at will, when in
motion. There were two manholes provided, fitted with bull's-eyes. This
boat was intended to pass under a vessel's bottom, towing a torpedo after
her, which was arranged to explode on contact. She was the means of
drowning fourteen men before she made her last attempt, when nine others

were added to the above list. In her successful attack on the Housatonic, she
was armed with the bow spar torpedo, and was sunk, owing to her running
into the hole formed by the explosion of her torpedo. About three years
after the American civil war was over, this submarine boat was recovered.
Divers went down, and found her lying alongside the hull of the
Housatonic, with the remains of the nine men in her.
French Submarine Boat "Plongeur."—The boat termed the Plongeur
was designed by Admiral Bougois and M. Brune, and was exhibited at the
Paris Exhibition of 1867. She was 26' long, 9' deep, and fitted with centre
and bilge keels. She carried two small tanks containing compressed air, and
four large tanks were placed at the bottom of the boat for the purpose of
sinking her, these latter tanks communicating with the water outside and the
air tanks. She also was fitted with a compass for steering by, a water gauge
to show the depth of submersion, and an air gauge to show the pressure of
air in the boat. Rectangular valves were placed at the bottom of the boat for
entrance or exit therefrom, for the use of divers, and to affix torpedoes to a
ship's bottom. On the top a circular opening for entrance and exit was
arranged, also an iron cupola fitted with bull's-eyes. She was also fitted with
an apparatus for spraying water through the air in the interior of the boat on
its becoming foul, and escape valves for releasing any foul air were placed
at the top of the boat. The water tanks were filled by means of pumps, and
emptied by means of the compressed air. She was propelled by a three-
bladed screw worked by four men. Her rate of progression was about four
knots per hour. The anchors consisted of two 15 inch shot, fitted with wire
rope cables, working through watertight stuffing boxes.
This vessel has been subjected to some experiments, but with what
results is not generally known.
One of the most important uses to which a submarine boat would be put
in connection with torpedo operations would be "to discover the exact
position and number of an enemy's submarine mines, and if necessary
destroy them," the former being an operation in the present day quite
impossible to perform, and the latter one rarely to be depended on.

FOOTNOTES:
[M] Extract from 'European Ships of War,' &c., by J. W. King, U.S.N., page
312.
[N] Extract from Engineering, under date April 13, 1877.
[O] Extract from letter of Captain Ericsson that appeared in Engineer, under
date Nov. 8, 1878.
[P] Extract from the Engineering of the 10th of January, 1879.

CHAPTER VII.
TORPEDO OPERATIONS.

A REVIEW, however brief, of the numerous torpedo operations that
have of late years been carried out in actual war, must prove not only
of great interest, but of material aid to those who may be desirous of
studying this branch of naval warfare, for the experience so gained ought
alone to be the basis on which a system of submarine offence and defence
should be constructed.
No new torpedo invention should be adopted, however theoretically
perfect it may be, until it has been subjected to a very severe practical test,
under conditions as nearly analogous to those that would occur on active
service as it would be possible to obtain. The vast importance of a carefully
planned and executed system of submarine defence is an established fact,
and it only remains to discover what are the best weapons for, and most
practicable mode of manipulating a system of submarine offence, to
establish torpedo warfare in all its branches as a necessary function of naval
warfare.
It would be a mere waste of time to dwell on the Anglo-French and
American wars of the beginning of this century (1797-1812); though during
that period various attempts were made by Fulton and others to destroy
hostile vessels by means of submarine infernal machines, inasmuch as they
all partook more or less of the nature of experiments, and were all failures,
but come at once to the Crimean war (1854-1856), when what may be
termed a systematic employment of torpedoes for harbour defence was first
employed.

Crimean War (1854-56).

Defence of Sebastopol Harbour, &c.—The Russians employed a large
quantity of submarine mines, both electrical and mechanical, principally the

latter, in their defence of the harbours of Sebastopol, Sveaborg, and
Cronstadt.
According to General Delafield, U.S.A., the arrangement of the
mechanical mines was entirely new, the conception and idea of an eminent
Russian chemist, Professor Jacobi.
Electrical Mines.—No mention is made by the General of the
employment of electrical mines, but the fact of a hulk being captured by the
Allies at Yenikale, with a number of torpedoes on board, and all the
arrangements necessary to explode them by electricity, such as Voltaic piles,
electric fuzes, several miles of conducting wire, &c., is sufficient proof of
this type of submarine mine being extensively used by the Russians in their
harbour defences.
Many of their mechanical mines were picked up by the Allies, several of
which were found to have their safety caps on. Owing to this neglect, and
the smallness of the charge of the torpedoes (only some 25 lbs. of
gunpowder), it is not to be wondered at that no serious injury was done to
any ships of the allied squadron.
Deterred most probably by the failures of Bushnell, Fulton, and others in
previous years with the submarine and other torpedo boat attacks, nothing
of this description was attempted by either side.
Russian Mechanical Mines.—The Russian mechanical mines consisted
of barrels of powder fitted with fuzes, so arranged that a blow would smash
a glass tube containing sulphuric acid, causing the acid to mix with some
chlorate of potash, resulting in combustion and the explosion of the mine.

Austro-Italian War (1859).

Defence of Venice by Von Ebner.—During this brief struggle, defensive
torpedo operations were carried out under the direction of Colonel Von
Ebner, of the Imperial Austrian Engineers.
The harbour of Venice was protected by a most elaborate system of
submarine mines, devised by the above-named officer. Though the
importance of his system was proved by the fact of no attempt being made

on Venice, yet no opportunity was afforded of practically testing its
efficiency.

American Civil War (1861-65).

Cause of the Present Importance of the Torpedo.—The prominent
position the torpedo now holds as a most important and legitimate function
of naval warfare is owing without doubt to the successful and extensive
employment of them on the part of the Confederates during this long and
bloody struggle.
Reasons which induced the Confederates to employ Torpedoes.—The
numerous harbours and navigable rivers in the possession of the
Southerners, the few ships of war at their disposal, the overwhelming fleet
of the Northerners, and the introduction for the first time of ironclads in
naval warfare, are the principal causes which forced the Confederates to
resort to torpedoes as a means of offence and defence.
Though a few rude and extempore submarine mechanical mines were
met with by the Federals during the earliest part of the war, it was not until
many months after the commencement of hostilities that the Confederates,
finding themselves quite unable to cope with their rivals on the sea, set to
work in earnest to organise a system of submarine warfare on a grand scale.
Torpedo Corps formed, &c.—Loss of "Cairo."—By October, 1862, a
secret service torpedo corps, with headquarters at Richmond, was in full
swing, and the principal harbours and rivers of the Confederates were
systematically protected by means of electrical and mechanical mines, also
a scheme of offence by drifting and spar torpedoes was in preparation, and
in December of the same year they experienced the first-fruits of their
labour by the total destruction of the Federal war steamer Cairo.
The following brief review of the numerous torpedo operations carried
out by both sides, and the effect their use had on the war, will be sufficient
to enable the general reader to gain some idea of the vast importance of this
submarine weapon in future warfare.
Fuller and more detailed accounts will be found in Commander S.
Barnes's, U.S.N., Colonel Von Scheliha's, and Captain H. Steward's torpedo

works.
Every Species of Torpedo used—Frame Torpedoes at Charleston, &c.—
Federal Ship Disasters—Small Effect of Electrical Mines—Loss of the
"Commodore Jones," &c.—Every species of submarine mine seems to have
been used by the Southerners for their harbour and river defence, the most
effectual of which were the barrel, frame, and Singer's torpedoes. These
were all mechanical, fired by means of sensitive concussion fuzes. At
Charleston and elsewhere the frame torpedo, which also acted as an
obstruction, was largely used, and where this species of mine was known to
be laid, the Northerners never attempted to force a passage. Out of some
thirty or forty Federal ships sunk or injured by torpedoes, by far the larger
proportion of such disasters was effected by means of the barrel and
Singer's mines. Though electrical mines were very extensively used on the
St. James River and at Charleston, &c., yet only one Federal steamer, the
Commodore Jones, was sunk, and only one other, the Commodore Barney,
was injured.
Case of the "New Ironsides."—The Federal ship New Ironsides, at the
attack on Charleston in 1863, was anchored for one hour and a half exactly
over a 5000 lbs. electrical mine, which despite all the efforts of the
Confederates could not be exploded. The reason of this was owing to the
deterioration of the primer, due to too constant testing.
Welden Railway.—A notable instance of the effect of torpedoes on the
war was the saving of the Welden line of communication in December,
1864. The Welden Railway was the principal artery of communication to
Richmond for the Confederates. To intercept this, by destroying the railway
bridges, a fleet of nine Federal gunboats was sent up the Roanoke river;
when nearly arrived at their destination, and though every precaution in the
shape of bow projecting spars, creeping, &c., was taken, seven of the
vessels were either sunk or severely injured by submarine mines. Thus the
expedition ended in a most disastrous failure.
General Butler's Attack on Richmond.—Again, in April, 1864, General
Butler's attack on Richmond utterly failed, owing to the Federal fleet being
unable to co-operate with him, the destruction of the Commodore Jones
completely checking any further advance of Admiral Lee's ships, thus

allowing the Confederates to employ the garrisons of their river batteries in
their land line of entrenchments.
More than One Line of Torpedoes required.—The capture of the Spanish
fort at Mobile in April, 1865, by a Federal fleet under Admiral Lee, proves
the necessity of employing more than one line of torpedoes, where the
safety of a position depends almost entirely on those means of defence, as
this one did. Here, though several Federal vessels were either sunk or
severely damaged, yet the fort was captured.
Boat Torpedo Attacks.—In regard to boat torpedo attacks, the
Confederates were only successful in two out of many attempts made by
them to sink Federal vessels.
The "Housatonic" and "Minnesota."—These successes were the
complete destruction of the Housatonic by a submarine boat, fitted with a
spar torpedo, and serious injury caused to the Minnesota by the explosion of
a contact spar torpedo, carried by an ordinary gig, commonly termed
"David's." In the former instance the attacking boat was sunk,[Q] in the latter
instance she was uninjured.
Destruction of the "Albemarle."—On the part of the Federals, Lieutenant
Cushing with a steam launch fitted with a Wood and Lay torpedo,
succeeded in sinking the Confederate ram Albemarle. The boat in this
instance was swamped by the column of water thrown up on the explosion
of the torpedo, she having been driven full speed at the Albemarle.
Ship Spar Torpedoes.—On both sides, spar torpedoes fitted to the bows
of ships, and also on rafts slung over the bows, were somewhat extensively
used, but on no occasion were they the means of injuring or sinking any
vessels.
To increase the difficulties of the Northerners in searching for submarine
mines, the Southerners laid down a great number of dummy torpedoes, also
erected false torpedo stations, and laid false wires.
It must always be borne in mind, in connection with the torpedo
operations above detailed, that the apparatus were very crude, and the
operators at the commencement inexperienced.

Paraguayan War (1864-68).

Torpedoes employed by the Paraguayans.—During their protracted
struggle with the Brazilians, the Paraguayans employed submarine mines
for the protection of their river forts, &c.
Loss of the "Rio Janeiro"—Brazilian Fleet entrapped.—On the 2nd of
September, 1866, the Brazilian ironclad Rio Janeiro, after being well-
battered by the guns of the Curupaity fort, was sunk by a torpedo. Later on,
near the same place, a whole fleet of Brazilian war ships were entrapped by
the Paraguayans, between two rows of submarine mines, but owing to
faulty arrangements they escaped unharmed.

Austrian War (1866).

Venice, Pola, &c., protected by Torpedoes.—During this war, torpedoes
for the defence of Venice, Pola, &c., were extensively used by the
Austrians, under the direction of Baron von Ebner, but as in '59 no
opportunity was afforded of proving their practical worth, though morally
they were of great value, the Austrian harbours so defended being
considered impregnable by the enemy, and therefore no attempt was made
to force them.

Franco-German War (1870-71).

Little or nothing in the matter of torpedo operations was attempted by
the Germans, and on the part of the French nothing whatever.
Germans employed Submarine Mines.—Electrical and mechanical mines
were placed in several of the German harbours, the former containing about
200 lbs. of dualine, the latter some 80 lbs. of gunpowder. The only attempt
to destroy French ships by means of offensive torpedoes was made by the
German vessel the Grille, off Rügen, which resulted in failure.
In laying down and in picking up after the war was over their
mechanical mines, several exploded, killing some ten to fifteen men.

Boats necessary.—Towards the end of the war, the Germans were
constructing special torpedo boats, believing that such were necessary for
the complete defence of harbours. This war added another proof of the
moral worth of submarine mines; the French fleet not daring to approach
German waters supposed to be defended by such means.

Russo-Turkish War (1877-78).

Superiority of Turkey to Russia in the matter of Ships.—On the Danube,
in the Black Sea, and Mediterranean, where the principal naval portion of
the war was carried out, Turkey was possessed of a fleet of ships infinitely
superior to Russia, both in point of numbers and strength, and therefore, to
enable her to hold her own against this vast superiority of the Turks, the
Russians resorted to an extensive employment of torpedoes, for both
offensive and defensive purposes.
Russian Torpedoes.—For many years previous to the outbreak of
hostilities in April, 1877, the Russians had been studying the subject of
torpedo warfare in all its branches, a certain number of their naval and
military officers and men having every year passed through a regular course
of torpedo study, at a school specially formed for such a purpose; they had
also laid in large stores of submarine mines, spar torpedoes, and were in
possession of the Whitehead and towing torpedoes, and also several electric
lights, and a few months after war was declared they obtained a fast
Thornycroft torpedo boat.
Turkish Torpedoes.—On the other hand, the Turks were only in
possession of a number of those huge, unwieldy 500 lbs. buoyant mines,
and one electric light; circuit closers, contact mines, boats (steam or
otherwise) fitted for use with torpedo, or offensive torpedoes, being
conspicuous by their absence.
Thus it will be seen that in the matter of submarine offence and defence,
the Russians were as superior to the Turks as the latter were to the former in
the matter of ships.
Turkish Defensive Torpedo Operations.—The defensive torpedo
operations carried out by the Ottoman naval officers and men were as

follows:—
The harbour of Batoum in the Black Sea was protected by a few 500 lbs.
buoyant mines, arranged to be fired by observation.
The mouth of the Bosphorus and the Dardanelles were similarly
defended. For this work great praise is due to those who executed the work,
for the very strong current and great depth met with in those waters would
render such a service a work of great difficulty, even when properly
constructed mooring boats, and men trained to such, were employed, both
of which in this particular instance were absent.
Soulina, one of the mouths of the Danube, and Suda Bay (Candia) were
also protected by similar means.
Russian Defensive Torpedo Operations.—The Russian defensive torpedo
operations were very extensive, their principal harbours in the Baltic, as
well as those in the Black Sea, were carefully defended by electro-contact
mines of the latest type; so also they protected their numerous bridges
across the Danube, double and sometimes treble rows of such mines being
moored on either side, and in addition they also placed several mines in the
Danube, on the chance of destroying the Turkish Danube flotilla.
Destruction of Turkish Gunboat "Suna" by a Russian Submarine Mine.
—The only instance that occurred during this war of a vessel being sunk by
a stationary submarine mine was that of the Turkish gunboat Suna, at
Soulina, in October, 1877, on the occasion of the unsuccessful attack on
that place made by the combined Russian and Roumanian flotilla.
About 6 A.M. on the morning of the attack, a "loftcha" containing two of
the enemy's electro-contact mines, fitted for laying down, was captured by
the Turks, from which it was evident that the Russians had been employed
during the night in torpedoing the reach immediately above the Turkish
defences. However, not heeding this very practical warning, the Pacha in
command of the Soulina squadron ordered the Kartal (a paddle-wheel tug
vessel) and the Suna (an old wooden gunboat) to reconnoitre up the river;
they accordingly started, the Kartal leading the way. At 8.5 A.M., about
fifteen minutes after the two vessels had left their moorings, an explosion
was heard, and almost at the same instant the unfortunate gunboat Suna was

observed to go down head foremost, her masts only remaining above water.
The Kartal, which at the time of the catastrophe was some distance in
advance, at once turned back to the assistance of her consort, and managed
to save a number of the gunboat's crew, this work having to be performed
under a galling fire from the allied flotilla. Owing to this day being the
"Feast of Bairam," the unfortunate gunboat was dressed with masthead
flags, thus four Turkish ensigns fell into the hands of the enemy, the Pacha
refusing permission for any attempt to be made to save them. The reason
that the Kartal escaped the fate of her consort was due to her only drawing
some 5 feet of water, while the Suna drew at least 8 feet.
The gunboat struck the mine that sunk her on her port bow, the effect of
the explosion being to completely smash in that side of her bow, dismount
her foremost guns, and carry away her foremast just above the deck (the
mast remained standing, though inclined forward); the second lieutenant of
the Suna, who was at the time of the explosion standing on her fore bridge,
was thrown off and killed, and some twelve of the crew were killed and
wounded. To complete the destruction of the Suna, another torpedo was
exploded under her port quarter by the Russians. The torpedo that was used
on this occasion is detailed at page 68.
Offensive Torpedo Operations.—The numerous boat torpedo attacks
made by the Russians against the Turkish fleet will now be considered. The
following accounts have been carefully compiled from two sources, viz. an
article written by Captain Chardonneau, which appeared in the 'Revue
Maritime et Coloniale,' 1878, and which has been recently translated for the
Journal of the Royal United Service Institution by Lieutenant J. Meryon,
R.N., and notes taken by the author during his service with the Imperial
Ottoman Navy (1877-78).

1st Affair.

The Batoum Attack.—The first torpedo boat attack occurred on the night
of the 12th-13th of May at Batoum.[R]
On the night of the attack there were lying in the harbour several vessels
of the Ottoman fleet, including ironclads, transports, despatch-boats, &c.
These vessels were totally unprotected by guard boats, booms, electric

lights, &c., and only the usual number of sentries were posted, the Turks at
that time not quite believing in such boat attacks, thus offering peculiar
advantages for a torpedo attack.
Four torpedo boats formed the attacking force, viz. the Tchesme, Sinope,
Navarino, and the Soukoum Kalé.
These boats were carried by a ship of the Maritime Company of Odessa,
named Grand Duke Constantine. She was an iron screw steamer, able to
steam about 10 knots per hour, and fitted to hoist up the above-mentioned
torpedo boats. She was armed with four 4-pounders, and torpedoes.
Early in the evening of the 12th the Constantine left Poti, and proceeded
off the harbour of Batoum, her captain (Lieutenant de Vaisseau Makaroff)
deeming it advisable to lay to seven miles from the harbour, the supposition
that the Turks had placed submarine mines off the entrance being the cause
of his so doing.
About 11 P.M. the four torpedo boats started to the attack, Makaroff being
in command of one of them. They were all painted sea green, and possessed
a high speed. The night being dark, and having been despatched some
distance off, they reached the entrance in somewhat straggling order. The
Tchesme, commanded by Lieutenant Zatzarennyi, and armed with a towing
torpedo, was the first to enter the harbour, and, without waiting for her
consorts, dashed at the Ottoman fleet, and succeeded in getting close to a
large Turkish paddle-wheel transport, and her commander dipping his
torpedo, struck the ship under her quarter; but that little something which so
often causes a failure in this mode of warfare occurred, and no explosion
followed the pressing down of the firing key, much to the chagrin and
disgust of Zatzarennyi. As might be supposed, by this time an alarm had
been raised, and guns, rifles, &c., were fired in and from every direction,
causing the torpedo boats to beat a precipitate and hasty retreat. Fortunately
the Turks were not possessed of any steamboats, nor were any of their ships
ready to dash out, or the defeat would have been a far more disastrous one
than was the case. Neither of the boats were damaged, nor any of the crews
injured.
The failure of this first attempt was due in a great measure to the mode
of attack, no system or unanimity of action on the part of the four

commanders being observable; and also to the somewhat half-hearted
support given to the Tchesme, for had her three consorts only dashed at the
Turkish ships as boldly, one at least of the Ottoman fleet would have been
sunk, the only defence resorted to being their guns and small arms.
The moral effect of torpedoes was displayed here, causing the
Constantine to lay too far off the entrance to the harbour, thus decreasing
the chance of her boats making a successful attack.
The Russian version finishes up by saying, "although this first endeavour
was unsuccessful, the authors of it were received at Sebastopol with
enthusiasm."

2nd Affair.

The Matchin Attack.—The second attempt was made on the 25th-26th of
May on two Turkish monitors, the Fettu Islam and the Duba Saife, and a
small river steamer, the Kilidj Ali, lying at anchor off Matchin.[S]
Four Russian torpedo boats were sent to the attack, viz. the Czarowitch,
Lieutenant Doubasoff; the Xénie, Lieutenant Chestakoff; the Djiquite,
Midshipman Persine; and the Czarevna, Midshipman Bali. The total
number of officers and men carried by these boats on this occasion was
forty-six.
The night of the attack was rainy, but not completely dark, since the
moon was above the horizon during nearly the whole of the expedition.
The force left Brailoff at one o'clock on the morning of the 26th, and
advanced in two columns up the river, finding great difficulty in stemming
the strong current.
A boat from the Duba Saife, rowing guard some 500 yards in advance of
the squadron, observed the approach of the Russian boats, but allowed them
to pass on their voyage of destruction without attempting to stop them, or
alarm the vessels. On reaching within 150 yards of the Duba Saife,
Dubasoff in the Czarowitch was challenged, and failing to give the correct
answer was immediately fired at; but, nothing daunted by the hail of shot
and bullets, he dashed on, and succeeded in exploding one of his spar

torpedoes on the port side of the Duba Saife, just under her quarter, a
column of water and débris being thrown up to a height of 120 feet, which
partly filled his boat, but notwithstanding managed to get safely away. The
monitor not sinking as soon as expected, Chestakoff in the Xénie dashed in,
and completed the work of destruction, the unfortunate ship sinking in a
very few minutes after this last explosion. The Djiquite was struck in the
stern, and had to be run ashore for repairs, but eventually all four boats
reached Brailoff in safety. The Russians allowed to neither killed nor
wounded, which, when the time they were exposed to the fire of the three
Turkish ships (about twenty minutes), the number of men (forty-six)
engaged, and their very close quarters, seems miraculous.
The Duba Saife, thus lost to the Turks, carried two 12 cm. Krupp guns,
and a crew of some sixty officers and men, few of whom were saved.
Lieutenants Dubasoff and Chestakoff were decorated with the 4th Class of
the Cross of Saint George, and three seamen received the insignia of the
Order of Military Merit.
This attack was conducted in a most gallant manner, and far more
systematically than the Batoum affair. If instead of holding one of the boats
in reserve, which was part of Dubasoff's plan, and the remaining three
attacking one vessel, the force had divided itself into two parties, and had
made a simultaneous attack on both the monitors, the probability is that the
Fettu Islam would have shared the fate of her consort.
The officer of the Turkish guard boat was tried by court-martial, but
what his ultimate fate was is not generally known. He certainly deserved
nothing less than death.

3rd Affair.

The Soulina Attack.—The third attempt took place on the 9th-10th of
June, 1877, on a Turkish squadron lying at anchor off Soulina.[T] This
squadron consisted of the three ironclads Feteh Bulend, Moocardemikhair,
and Idglalieh, and a tug, Kartal.
The Russian attacking force consisted of six torpedo boats, viz. the No.
1, Lieutenant Poutschin; the No. 2, Lieutenant Rojdestvenski; the Tchesme,

Lieutenant Zatzarennyi; the Sinope, the Navarino, and the Soukoum Kalé.
The No. 2 was a specially constructed torpedo boat, 68 feet long, and very
fast. All were armed with spar torpedoes, with the exception of the
Tchesme, which carried a towing torpedo. The boats were convoyed from
Odessa by the Constantine, some being carried, and some being towed;
another steamer, the Vladimir, supported her. The Turkish squadron were
anchored in quarter line, about one mile from the harbour; the Kartal, under
weigh, being used as an advance guard, and a few boats rowing guard close
to the ships being the only means of protection adopted by the Turks.
Passive obstructions, such as booms, nets, crinolines, &c., were not thought
of, much less used.
On arriving about five miles from Soulina, the boats were formed into
two groups, the first consisting of the No. 1, the No. 2, and the Tchesme,
and despatched on their way. The working of their engines was scarcely
heard, and all lights were carefully hidden by tarpaulins.
The first casualty that happened was the disabling of the Tchesme, by the
electric wire of her towing torpedo fouling the screw, this obliging her to
return to the Constantine. Aided by good fortune, and by the darkness of the
night, the No. 1 and the No. 2 succeeded in getting close to (30 yards) one
of the Turkish vessels, the Idglalieh, before being discovered, when they
were at once hailed, and, not answering, a tremendous fire of big guns and
rifles was directed on them from the Idglalieh, which was promptly
followed by that of the whole squadron, though from the other ships
nothing of the boats could be seen.
According to the Russians, the No. 2 succeeded in exploding her torpedo
close to, if not in contact with, a Turkish vessel, but from eyewitnesses on
board the squadron only one explosion was heard, viz. that of Lieutenant
Poutschin's torpedo. Any way, no damage whatever was experienced by the
Ottoman squadron. The No. 1 came down on the Idglalieh's starboard bow,
fouled her cable, and swung alongside, exploding one of her torpedoes in so
doing, but with no other result than a wetting to those of the ironclad's crew,
who were on the forecastle. Alongside Poutschin remained for some
minutes, but at last managed to get clear, and then was either sunk by the
Idglalieh's fire, or, as he avers, on finding his screw foul, he sunk his boat,
rather than let her fall into the hands of the Turks. Poutschin and four of his

crew were picked up, after being some hours in the water, by the squadron's
boats.
The No. 2 seems to have suffered severely, her funnel being bent, the
axle of the steering wheel damaged, sixteen rivets were started, and the iron
keel plate had dropped some 18 inches, and finally the lower part of her
rudder broken, and one of the blades of her screw bent aft; part of this
damage was no doubt the effect of the explosion of her torpedo, which was
probably not in position, but unless she ran over some loose stones of the
Soulina breakwater, the damage to her keel and rudder cannot be accounted
for.
The second group of boats had followed up the first, but on hearing the
noise of the explosions and roar of the guns and rifles they returned to the
Constantine.
That ship, on observing the firing, endeavoured to close the land, but she
grounded, and remained until daylight in a difficult position, but at last got
afloat, and returned to Odessa with five out of her six torpedo boats.
Lieutenant Rojdestvenski, the Commander of the No. 2, received the 4th
Class of the Cross of Saint George, and three seamen the insignia of the
Order of Military Merit.
On the part of the No. 1 and No. 2, this was a most gallant affair, though
unsuccessful, but as regards the remainder of the boats the less said the
better.
Had the Turkish squadron slipped the instant the alarm was given, and
steamed full speed in the direction of Odessa, the Constantine and her
convoy might have been cut off. Both the Moorcademikhair and Feteh
Bulend were 13 knot ships, and therefore considerably faster than the
enemy. But, as usual, the Turks were far too dilatory to take advantage of
the occasion.

4th Affair.

The Rustchuk Attack.—The fourth torpedo attack was made on the
afternoon of the 20th of June, 1877, on a Turkish monitor off Rustchuk.

The only Russian torpedo boat sent to the attack on this occasion was a
Thornycroft named the Choutka, commanded by Lieutenant Skrydloff, and
accompanied by a celebrated Russian artist, Verechtckaguine by name. The
instant the torpedo boat was observed, so well directed and steady a fire
was kept up by the monitor that both the lieutenant and the artist were badly
wounded, and the electric wires of the torpedo severed, thus obliging the
Choutka to beat a retreat. According to the Russian account, the monitor
was struck by the boat's torpedo spar, but the above seems the more likely
version. This was certainly a most audacious attack, and had the Turks only
succeeded in hitting the Choutka with her big gun, it would have ended
fatally for the Russians; as it was, the boat was struck by several bullets, but
none of the crew were wounded.

5th Affair.

The Aluta Attack.—The fifth attack was made on the 30th of June, 1877,
on a Turkish monitor off the mouth of the Aluta, in the river Danube. This
attempt, like the last, took place in broad daylight. Four Russian boats were
sent forward, but in spite of the captain of the Turkish vessel doing all he
could to run the boats down, none of them succeeded in getting sufficiently
near the vessel to enable a torpedo to be placed in contact. The captain of
the monitor took the precaution to rig his lower booms out, and so managed
to keep the enemy's boats at a respectful distance, they imagining that mines
were fixed to the ends of the booms. After two hours of this dodging about,
the Russians, finding the case hopeless, abandoned the attack.
The Russian account states—1st, that the captain of the monitor was an
Englishman; 2nd, that the vessel was protected by nets and torpedoes lashed
to the extremities of her booms—both of which statements are radically
wrong.
The torpedo boats forming the attack were the Choutka, Midshipman
Niloff, and the Mina, Sub-Lieutenant Arens, both armed with the spar
torpedo.
Unless indeed the Russians acted up to the old proverb which says
"Discretion is the best part of valour," it is difficult to understand how four
small easily handled boats could have been for one hour endeavouring to

strike a ship (which ship was at the same time being manœuvred with a
view of running them down) without either effecting their object or being
sunk or damaged in the attempt.
The Russians, though unsuccessful, behaved gallantly. Midshipman
Niloff was severely wounded, but no mention is made as to the number of
the crew that were killed and wounded, or of the damage received by the
boats. Niloff received the 4th Class of the Cross of St. George, and Arens
the Order of Military Merit.
The Turkish captain, Ali Bey, behaved most pluckily and skilfully. The
only wonder is that both the boats were not sunk by the monitor's fire.

6th Affair.

The Soukoum Kaleh Attack.—The sixth attempt was made on the 23rd-
24th of August, 1877, on a Turkish ironclad, the Assari Shefket, at the time
lying at anchor off Soukoum Kaleh.[U] Four torpedo boats composed the
attacking force, viz. the Sinope, Lieutenant Pisarefski; the Torpedoist,
Midshipman Nelson Hirst; the Navarino, Lieutenant Vichnevetski; and the
Tchesme, Lieutenant Zatzarennyi, the latter officer being in command.
These boats had been brought to the entrance of the harbour by the
Constantine, and were despatched on their mission of destruction about half
past ten.
An eclipse of the moon occurred on this night, and, taking advantage of
this fact, the four Russian torpedo boats dashed into the harbour at full
speed and made for the Turkish vessel.
Fortunately for the safety of his ship and lives of his crew, the captain of
the Turkish ironclad had several boats rowing guard round his ship, and
otherwise everything on board in readiness for immediate action. On the
attacking flotilla nearing the guard boats, blue lights were burnt, rifles fired,
&c., and the alarm given to those on the look-out in the Assari Shefket. The
moment the enemy were within range, such a well-directed and heavy fire
was poured on them that the attack was completely foiled. One of the
Russian torpedoes was exploded, but failed to do more than throw a
quantity of water up. The next morning a pole with torpedo fixed on it was

found by the Turks, and on the strength of this and the numerous fragments
of wood similarly found, one if not more of the enemy's boats it was
supposed must have been sunk, or much knocked about.
This was a much better planned and executed attack, but was
unsuccessful owing to the extreme vigilance of the Turks.
This attempt will always be remembered by the Turks, on account of the
general order that appeared in the papers on the part of the Russians, in
which "the brilliant exploit and successful destruction of the Turkish
ironclad Assari Shefket" was set forth at great length; she at the time that
this appeared being quietly at anchor off the dockyard at Stamboul, not
having received any damage whatever.

7th Affair.

The Second Batoum Attack.—The seventh attempt was made on the
night of the 27th-28th of December, 1877, on several Turkish men-of-war
anchored in the harbour of Batoum (the scene of the first Russian torpedo
attempt and failure). Four boats composed the attacking force, viz. the
Tchesme, Lieutenant Zatzarennyi, in command, armed with a Whitehead
fish torpedo, containing 32 kilog. of gun-cotton, fitted to fire from a tube
under the boat's keel; the Sinope, Lieutenant Stchelinski, armed with a
similarly charged fish torpedo, fitted to fire from a raft, which was towed by
the boat, and two other boats, armed with spar and towing torpedoes.
The means employed at Batoum for the safeguard of the Ottoman fleet
there against such an attack was that of guard boats and a barrier formed of
logs of wood, with planks secured to them, so arranged by means of
weights that the planks remained perpendicular to the surface of the water
when in position.
Owing to the extreme darkness of the night, the Russians managed to
evade the guard boats, and when, as they imagined, some 60 to 65 yards
from a Turkish ironclad, the Tchesme and Sinope's Whitehead fish
torpedoes were started on their deadly mission; but, owing most probably to
the want of practice of manipulating these somewhat delicate instruments,
also to the darkness, and the slight swell there was on at the time, both

missed their mark, and were landed high and dry on the beach astern of the
ship.
One of these weapons was perfect, the other minus her fore
compartment, this having been knocked off by the torpedo colliding with
some hard object. No explosion was heard or seen by the Turks.
This was the second time that the fish torpedo had been employed on
actual service, and, as in the previous instance, failed.
The guard boats and barrier of the Turks seem to have been of little
avail.

8th Affair.

The Final Attack.—The eighth and last attempt was made on the night of
the 25th-26th of January, 1878.
This was originally intended to be an attack on the Turkish fleet at
Batoum, but on entering that harbour the two Russian torpedo boats, the
Tchesme, Lieutenant Zatzarennyi, and the Sinope, Lieutenant Stchelinski,
were met by a Turkish revenue steamer, against which the boats discharged
their Whitehead torpedoes, resulting in her complete destruction, at the
same time arousing the squadron, and causing the boats to beat a retreat.
Though the vessel destroyed was not a frigate, yet the expedition was
successful in so far as proving that it is possible to project Whitehead fish
torpedoes from boats at a distance of 70 to 90 yards from an enemy's ship,
on a dark night, and strike her with them.
This concludes the whole of the offensive torpedo operations that were
carried out during the war, of which two out of eight attempts were
successful, which is without doubt a fair percentage.
There seems every probability that the present struggle between Chili
and Peru, in the Pacific, will afford torpedoists further experience of the
various offensive torpedoes, when subjected to the test of active service.

FOOTNOTES: