the cables were all led to a casemate. The preceding sketch, found among Colt's papers after his death, and bearing the date 1836, shows one of his devices for igniting the mines at the proper instant; it is of course only applicable to an elevated site. A secret believed to relate to a method of making the vessel telegraph her own position died with him. This sketch explains itself. One set of conductors from all the cables are united and permanently attached to a single pole of a powerful battery. The other conductors lead to a map of the channel, and each is secured at the point corresponding to the known position of its mine. The reflector is arranged to throw the image of the hostile ship upon the map, and as it passes over a wire terminal the operator with his other battery-wire closes the proper circuit and explodes the torpedo. Colt's experiments extended over a period of about fourteen years, the latter part of the time under the auspices and at the expense of the government. He destroyed several vessels at anchor, and finally, on Apr. 13, 1843, accomplished the feat of blowing up a brig under full sail on the Potomac, operating his battery at Alexandria, 5 miles distant. This decisive trial was witnessed by many members of Congress and by the President, and its success at that date stamps Col. Colt as a man of extraordinary ability. The time, however, was not yet ripe for the introduction of the new weapon, and, like those of his predecessors, Col. Colt's plans were ultimately rejected by the government.

The Anglo-French war with Russia in 1855 furnished the next occasion for the application of submarine mines to harbor defence. Sebastopol, Cronstadt, and Sweaborg were protected in this manner by devices of Prof. Jacobi. Unfortunately for the success of his system, the charges were too small (8 or 9 pounds), and although explosions occurred under two or three English frigates, no serious damage was done. The fuze consisted of a small bottle of sulphuric acid imbedded in a mixture of potassium chlorate and sugar; the mechanical breaking of the bottle by contact

with the vessel effected ignition. The great improvement of placing the igniting apparatus within the torpedo, independent of external levers, is due to Prof. Jacobi, who also made use of electrical mines to be fired by an operator on shore. The Italian war of 1859 gave occasion for Col. von Ebner of the Austrian engineers to employ in the defence of Venice a system of electrical mines more carefully elaborated than any which had preceded it, but no opportunity for practically testing its merits occurred.

In fine, it was reserved for American engineers to demonstrate upon a grand scale the important part which the modern torpedo can be made to play in maritime warfare. The civil war of 1861-65 offered conditions peculiarly favorable to its development. The Southern Confederacy was possessed of no fleet worthy of the name, while a long line of seacoast and many navigable rivers exposed its territory to easy assault by water. It could, therefore, well afford to sacrifice most of those routes of communication, provided they could be closed to the war-vessels of the Union. Every variety of torpedo became, therefore, admissible. After some preliminary trials, the service was formally legalized in Oct., 1862, and an efficient bureau was established at Richmond, which continually extended the scope of its operations until the end of the war. Seven U.S. iron-clads, eleven wooden war-vessels, and seven armytransports were destroyed by torpedoes, and many more vessels were more or less injured. The Confederates lost three vessels by their own mines, and a fine iron-clad, the Albemarle, by the counter-operations of the U. S. fleet. This wholesale destruction occurred chiefly during the last two years of the war; and if at its beginning the system had been as well organized as at its close, the influence which might have been exerted upon the naval operations of the Union forces can hardly be estimated. The details of the Confederate system were published to the world soon after the end of the war, and they have formed the common basis upon which different nations have begun the investigations now actively prosecuting for perfecting appliances in submarine warfare. For this reason they will be considered somewhat in detail. The several devices may be grouped in five distinct classes-stationary torpedoes or submarine mines, automatic drifting torpedoes, infernal machines, offensive spar torpedoes, and submarine boats.

Stationary Torpedoes, often called Sea-Mines.-To form an obstruction in the channel which shall stop the enemy, either by his actual destruction or by his fear of it, is the object of this class. Several types were used. The frame torpedo was one of the most simple. Each shell weighed about 400 pounds, and contained 25 pounds of gunpowder. The fuze, consisting of a vial of sulphuric acid imbedded in potassium chlorate and sugar, was placed in the loadinghole, protected by a thin lead cap to be crushed by the vessel. The pile torpedo, a similar pattern of mine, also shown

FIG. 2.

on the figure, was found in the water-approaches to Savannah. The swaying boom torpedo was a marked improvement upon this device, since, being free to move, it was not so easily discovered by dragging. To render it still more effective, it was often attached by a line to a "turtle" containing a fuze made upon the principle of an ordinary cannon-primer. The attempt to grapple Iand raise the boom torpedo exploded this auxiliary, which was planted in front, so as to be well under the bottom of the enemy. The charge of the boom torpedo was about 70 pounds, and of the turtle 100 pounds; the whole device was

Frame and Pile Torpedoes,

FIG. 3.

FIG. 4.

called the "devil-catcher." Another approved pattern was known as the Singer or Fretwell torpedo, invented by Singer and introduced by Fretwell. The principle of its action was similar to that of the "turtle," the charge (50 to 100 pounds) being fired by a percussion-cap acted upon by an external plunger released when the inverted saucer-cap was thrown off by the touch of the enemy. The weakening

Swaying boom and turtle Torpedoes. of the spring under continued tension, and the growth of seaweed and shellfish, were found to destroy efficiency after the torpedo had remained a few weeks in position. Το obviate this difficulty-which is inherent to all mechanism acting externallyGen. Rains, when in charge of the laboratory at Augusta, Ga., devised a fuze priming said to consist of fulminating mercury and fulminating silver, which was exceedingly sensitive, 3 slight blow being sufficient to cause detonation. Fuzes containing it, protected against moisture by a lead cap easily crushed by contact, were used in his barrel torpedoes. These torpedoes contained from 70 to 120 pounds of gunpowder, conical ends of light wood being added to increase flotation and to strengthen the case. The Rains fuze served its purpose well, and was used in landmines, in hand-grenades, and in several types of torpedoes.

Singer's Torpedo.

FIG. 5.

Lastly, electrical mines,

to be fired by the act of an operator on shore, were employed; but the difficulty of procuring the requisite insulated cable restricted their use, and it is worthy of note that no attempt was made to make them automatic. The charges employed were usually enormous, amounting to 2000 pounds of gunpowder. The Commodore Jones was destroyed on May 6, 1864, by a torpedo of this type. It was planted in a narrow part of the channel of James River, in about 35 feet of water, and was operated from a pit on the river-bank containing a small Bunsen battery. The Commodore Jones was allowed to advance safely over the mine, which was reserved for

TH

Barrel Torpedo.

the flag-ship, but the operator hearing the order given to return preparatory to a more thorough search for torpedoes, the vessel was blown up as she backed down stream. She appeared to be lifted bodily by the explosion, and was utterly destroyed, more than three-quarters of her crew being killed or wounded.

FIG. 6.

Automatic Drifting Torpedoes.-This class was especially designed for rivers where the current, setting in one direction, could be depended upon to sweep the apparatus down to the hostile fleet, and perchance to bring it into contact with some vessel. Night was often selected for the attempt, but the ease with which a ship at anchor may be protected by nettings rendered the several devices of little avail. The simple form shown in the figure was used in great numbers on James River. A piece of slow-match was arranged to burn down the tube to the charge. These torpedoes were often caught by nets, but did no damage. A more complex arrangement is shown in Figure 7. This torpedo was often set adrift, connected to a log by a knotted line, which, fouling the anchorchain, would bring the former to rest under the bottom, when the current acting on the wheel would release the plunger and determine an explosion.

Drifting

pedo.

Tor

Infernal Machines.-This class of torpedoes is not generally considered to come within the limits of legitimate warfare as practised at the present day, because it subjeets non-combatants to great peril without any previous warning. It was designed to be smuggled on board the Union war-vessels or transports, and thus to effect their destruction. Two types were employed. The most simple was known as the "coal torpedo." It consisted of a metal FIG. 7. ease containing several pounds of gunpowder, cast and colored to closely resemble a lump of coal. When ignorantly thrown into the furnace, it caused the explosion of the boiler. The Greyhound was destroyed in this manner on James River, as were also several transports on the Western waters. The other type was known as the "horological torpedo." It consisted of a case containing a large charge of gunpowder and a clockwork arrangement set to run for a certain time, at the expiration of which it released a plunger and fired the charge. A dis

Current Torpedo. astrous explosion was caused in the army powder-fleet at City Point in 1864 by an arrangement of this character, which was placed on board one of the barges by a spy. At Mound City a similar explosion was effected.

Offensive Spar Torpedoes.- This form of the new weapon afforded the best opportunity for the display of personal gallantry, and several officers won distinction in its use. An outrigger spar, from 20 to 30 feet in length, carried a torpedo designed to be brought in contact with the enemy's hull and exploded in a hand-tohand conflict. The Confederates early supplied ram torpedoes to their ironclad fleet, but a lighter pattern was chiefly used, operated from a special craft termed "Davids," by reason of their small size and insignificant appearance as compared with their adversaries. The type used at Charleston was built of boiler iron, and was about 35 feet long, shaped like a cigar, with a low combing to exclude the waves. Small engines driving screwpropellers gave a maximum speed of about 7 knots per hour. The torpedo

FIG. 8.

Spar Torpedo.

51

was of copper, charged with about 50 pounds of fine gunpowder. Under cover of the night these boats approached the hostile fleet, trusting to suddenly dart alongside and discharge the torpedo with impunity in the confusion and alarm created by their sudden appearance. Another type of this class of boats consisted of an ordinary steam-launch equipped in a similar manner. Several of the Union warvessels-the New Ironsides on Oct. 5, 1863, the Memphis

FIG. 9.

on Mar. 6, 1864, the Minnesota on Apr. 8, 1864, and the Wabash on Apr. 18, 1864-narrowly escaped destruction, and the Confederate ironclad Albemarle was sunk at her moorings by this mode of attack. The latter feat was performed by Lieut. Cushing, U. S. N., and for its exceptional gallantry it deserves a special description. The boat was an ordinary steam-launch equipped with a Wood and Lay torpedo and a brass howitzer. This torpedo was provided with an air-chamber, and at the proper moment was to be detached from its boom and allowed to rise under the enemy. A strong pull upon the lanyard then released the ball, which, falling on the percussion-cap, ignited the charge. Lieut. Cushing with a crew of thirteen officers and men advanced 8 miles up Roanoke River, passing the Confedcrate pickets undiscovered. On apWood and Lay Tor- proaching the Albemarle, moored to the wharf and protected by a pen of logs about 30 feet from her side, he suddenly darted upon her, and under a heavy fire exploded his torpedo against her bottom, thus sinking her. Most of his party were captured, and some were drowned; Lieut. Cushing himself and one man escaped by swimming and threading the swamps to the Union lines.

pedo.

Submarine Boats.-But one boat of this character won a record during the war, and hers was sufficiently tragic to deter imitation. She was of boiler iron, 35 feet long, was propelled by hand at a maximum speed of 4 knots, and could remain submerged to any desired depth for half an hour. Her crew consisted of nine men. In the preliminary trials (see SUBMARINE NAVIGATION) she sank three times, drowning 23 men. Finally, under Lieut. Dixon, C. S. N., she sailed out of the harbor, attacked and sunk the Federal steam-sloop Housatonic, and disappeared for ever with her crew. She was designed to pass under the enemy, drag ging a floating torpedo, which would explode when brought in contact with his hull, but on this occasion she was used like an ordinary David.

The Schleswig-Holstein war of 1864, although short, afforded an opportunity for employing defensive mines, and one of the invading vessels was sunk through their agency. The Paraguayan war of 1864-68 furnished the next occasion for submarine warfare. Immediately after the Brazilian fleet entered the waters of that little state, a fine iron-clad, the Rio Janeiro, was sunk by two torpedoes against which she had struck. Subsequently, a division of the fleet ran past the batteries of Curupaity, only to find itself entrapped between two lines of torpedoes, one in front and the other planted in rear, after the passage, to bar the retreat; the defective nature of these obstructions alone prevented a serious disaster. Later in the war the Tamandaré was crippled by a submarine mine. The Paraguayan torpedoes belonged to the anchored or drifting class, and the sulphuric-acid fuze was largely used. During the Franco-German war of 1870-71 no conspicuous use was made of torpedoes, but the German ports were protected by them, and the French contributed a new device to the list. It is known by the name of the "ball of Verdun," devised by Capt. Bussière of the engineers to destroy a military trestle-bridge thrown by the Prussians over the Meuse a short distance below the fortress. It consisted of a large sheet-iron sphere, over 3 feet in diameter, heavily charged with gunpowder, and provided with a clockwork train, which after a certain time was to discharge a pistol and thus ignite the mine. It was but little heavier than water, and was carefully adjusted so as to make the centre of figure and of gravity coincident. A body fulfilling these conditions will be rolled along the deepest part of the channel by the current, and will, of course, be far more difficult of detection than a floating object. The capitulation of the fortress prevented a trial of its efficiency, but many letters were introduced into Paris during the siege by similar balls caught by nets spread for the purpose.

Torpedo Warfare in the Future.-It is apparent, from

the foregoing historical résumé, that torpedoes are no longer to be regarded as experimental devices, but that they have become recognized weapons of maritime warfare, admitting of very varied applications. They may be employed offensively in the combats between hostile vessels, or they may be used defensively to repel an apprehended attack upon a harbor or district by preventing the passage of the enemy's squadron through the channel of approach. Entirely different principles of construction and of manipula-, tion mark these two classes of the weapon. The former requires the technical skill of a sailor to move the charge into position and explode it within destructive range. The latter differs in no essential respect from the mines so long employed in the defence of land fortifications. Accordingly, in the U. S., England, and some other countries possessing an extended seacoast, the service of torpedoes has been divided between the navy and the engineers of the army-the former operating offensively afloat, and the latter defensively from the shore. Our naval station is at Newport, R. I., where the needful investigations are conducted, and where classes of officers now receive regular instruction in the use of the new weapons. The army school is at Willet's Point, New York harbor, where the subject is experimentally studied, and where the officers and the enlisted men of the engineers are exercised in all the duties of defensive submarine mining. While, in general, the line of demarcation between the two services is thus plainly marked, some of the weapons-such, for example, as fish torpedoes stoored by electricity-may be conveniently operated either from land or from shipboard, and they would be used in war either by army or navy as occasion might offer.

All maritime nations are now carefully investigating the subject of submarine warfare, but the greatest secrecy is thrown around these studies. Enough, however, has transpired to enable the following imperfect résumé of the principal results to be given:

Offensive Torpedoes.-In offensive torpedo warfare many new devices have been proposed from time to time, and subjected to systematic FIG. 10. trial by naval officers. The Harvey torpedo belongs to this type. The charge is contained in ก narrow Copper vessel, encased in wood strapped with iron, and so ballasted as to ride vertically in the water. A tow-line of wire rope passes from the slings of the torpedo through a

Harvey Torpedo.

block on the yard of a fast steamer to a reel fitted with a brake on her deck. The enemy is passed at full speed, with the torpedo diverging at an angle of about 45° from the quarter, and the course is so directed as to bring the weapon in contact with his hull. Just before striking him the torpedo is made to dive by suddenly slacking the tow-line, and then to rise under his bottom by checking it with the brake. Explosion is effected through the agency of the projecting levers, which when struck either detonate a contact fuze or close an electric circuit, and thus cause the passage of a powerful current through a platinum fuze. These torpedoes are made of various sizes, one of the largest patterns being 4.5 feet long, 2 feet deep, and 6 inches wide, designed to contain 100 pounds of gun-cotton or dynamite. The requisite flotation is given by the cork buoys a a', as when at rest the torpedo sinks by its own weight. This weapon was devised by a skilful sailor, Capt. Harvey of the Royal navy, and he claims that it can be successfully used on the high seas even during a gale. Official trials in 1870 at Portsmouth, England, caused it to be adopted in the English service. The torpedo was operated from a steam-tug against the iron-clad Royal Sovereign. At first the latter remained at anchor, and thus received ten attacks from different directions. In every case the torpedo struck her at depths varying from 1 to 16 feet. The iron-clad fired blank cartridges, and succeeded in discharging seven and four shots in two of the trials, and only two shots in the others. The Royal Sovereign then got under way at a speed of 8 or 9 knots, the tug moving at about 11 knots. Six attacks were thus made, all of which were successful, although every effort was made to avoid the blows. From two to twelve shots were fired at the tug in each attack while manoeuvring to effect her object. The Harvey torpedo, although formerly adopted by several nations of Europe and highly commended, failed in the late Russo-Turkish war.

Another new type of offensive torpedo is that known as the Luppis Whitehead. The idea developed by this weapon is due to an officer of the Austrian marine artillery, now

dead, but the first practical trials were made in 1864 by Robert Whitehead, superintendent of ironworks at Fiume, acting upon the suggestions of Capt. Luppis, an officer of the Austrian navy. The torpedo has undergone great improvements between that date and the present time, and the right to use it has been purchased by many European nations. The latest type consists of an iron and steel vessel in the shape of a spindle of revolution. It is driven by a propeller moved by compressed air, and it is claimed to be capable of maintaining a speed under water of 22 knots for a distance of 1200 feet, or 12 knots for 6000 feet. It can be projected from a launching-tube or started by hand, and is capable of regulating and preserving its depth and direction, within narrow limits, in still water; but crosscurrents or seaweed may introduce large variations. It can be set to explode on contact or after a definite time, and either to sink or rise to the surface after finishing its course. Great secrecy is preserved as to details.

Submarine rockets, carrying explosive charges and started from submarine guns, have received and are now receiving attention, both in this country and in Europe. Such a weapon, if its course can be successfully controlled, will be especially dangerous in the combats of iron-clad vessels at short range, since the blow, being delivered under the armor, cannot fail to achieve decisive results.

Submarine boats now appear to be passing out of favor with all nations, partly because their history in former wars has been nearly uniformly tragic, and partly because the necessity for their use has been done away with by the invention of the fish torpedo steered and controlled by elestricity. This idea was first patented by Lieut.-Col. Ballard, Royal Engineers, in Aug., 1870, and again by Lieut.-Col. Foster, U. S. Engineers, in 1872. It has been independently elaborated by Mr. Lay and Mr. H. J. Smith in this country, and by Col. von Scheliha in Russia. The claim to priority in the invention has been the subject of litigation; but the decision of the commissioner of patents (June 13, 1873) has awarded it to Mr. Lay, whose boat has also been brought most conspicuously before the public. This type of torpedo consists essentially of a boat of the Luppis Whitehead class, which carries and unreels a coil of insulated wire through which the electric current from a battery on shore or on shipboard can be passed at will to certain electro-magnets. By closing and breaking the circuit, and reversing the direction of the current, valves connected with the motive-power are controlled, and thus the rudder may be put to starboard or port, and the engine may be started or stopped. In this manner the motion of the fish is under perfect control from the instant of starting. The motive-power may consist of liquefied carbonic acid, or ammonia, or compressed air, or steam peculiarly applied. The boat may be made to move at the surface or below it. Her position is known to the operator from two small flags carried near the water-level, which at night are replaced by two lanterns shaded in front so as not to be seen by the enemy. A speed of about 12 miles for 1 miles has been obtained. Any of the modern explosives may be employed, and detonation results from the action of mechanical faze or of a circuit-closer and battery. A modification of this torpedo is proposed by Capt. Ericsson, who supplies his motive power to the engine by a flexible tube drawn after the boat. This motive-power is compressed air generated by an engine near the operator; and by regulating the supply the boat is steered without the aid of electricity. A movable torpedo invented by Mr. Sims has been developing at Willet's Point since 1879. All parts vulnerable to machine-guns are submerged. It is moved and controlled by electricity conveyed by a cable from a dynamo on shore to an electric motor on board. The speed for a run of 2 miles is at the rate of about 10 miles per hour. increasing toward the end. The charge is 400 pounds of explosive gelatine. The Brennan torpedo is developing at Chatham, England. The motive power is supplied by unreeling piano-wire from two drums on board to two on shore.

But it is not exclusively to new inventions that attention is now directed. The offensive spar torpedo, as already stated, has made a brilliant record in actual battle, an i continues to be favorably regarded both in our own and foreign navies. It furnishes better opportunities for dashing exploits than any other type of the weapon, and thus naturally commends itself to gallant seamen eager for distinction. Speed and the cover of night or fog are conditions highly favorable to success. The circumstances characterizing a contest with this weapon are dramatic in a high degree; for size, heavy armament, massive iron plating, and the close vicinity of friendly ships are of little avail in repelling the dash of the tiny antagonist, which suddenly appears out of the darkness, spreading confusion on every side. Hurried slipping of cables and getting under way, accompanied by random, desperate firing, last for an

instant, and then the blow is received, or the assailant is again lost to view in the surrounding gloom. It is the fight of the sword-fish and the whale introduced into modern warfare. The tendency at present seems to be toward a more general use of this type of torpedo; for while during the late war it was chiefly operated from steam-launches or similar craft, the larger vessels of our navy are now provided with it. In Europe vessels are specially constructed for the purpose, the essential conditions being high speed, noiseless machinery, and invulnerability to small projectiles. A special torpedo-vessel, the Alarm, was constructed under the direction of Admiral Porter for our own service. She is 166 feet long on the water-line, with a height of side of 10 feet forward and 8 feet aft. She is plated with iron, and carries a formidable ram and a 15inch gun, trained to fire forward in the direction of her keel. Four Gatling guns are mounted to repel boat-attacks, and she can employ four spar torpedoes on iron booms shoved out through ports below the water-surface, on her bow and broadsides, to a distance of fifty feet. She is provided with a Mallory wheel, which both propels and steers the ship, giving great power of rapid manoeuvring. All her movements are controlled by one man in the pilothouse, and electricity is skilfully used for conveying orders and exploding the torpedoes.

Defensive Torpedoes.-To understand the full importance of the submarine mine in defending our great seaports against hostile fleets, it is necessary to consider the changes in ships of war which immediately preceded its introduction. Before the invention of the screw-propeller, vessels in attacking forts were at the mercy of winds and currents; and long experience proved that one gun ashore was more effective than many afloat. Moreover, since stone walls were more resisting to shot and shell than bulwarks of oak, the rule introduced into land defence soon after the invention of gunpowder, that no masonry must be exposed to a direct fire of artillery, could be ignored in water-batteries, thus rendering it easy to mass the guns and provide a heavy fire against hostile shipping, even where the site was restricted. The screw-propeller, followed shortly after by armor-plating and big guns afloat, effected a radical change in the conditions of the problem. The fleet was now free to steam rapidly past the batteries under favorable conditions not before practicable. The new class of guns required to assail the armor-plating with a reasonable chance of success was far more bulky and difficult to manoeuvre than the former armament of the forts; moreover, it was discovered that earthen parapets and substantial traverses must take the place of the compact masonry casemates heretofore in use. The defence thus found itself at great disadvantage. The hostile ships of war, more under control, less vulnerable, and possessed of much higher speed, were to be encountered by guns more unwieldy, and, in most of our harbors, much fewer in number from the naturally contracted sites available for the earthen batteries. The attention of military engineers was thus urgently directed to the devising of some obstruction which by holding the enemy under fire, and depriving him of the comparative immunity resulting from a high rate of speed, should restore to the defence its lost superiority. The modern submarine mine has accomplished this vitally-important object. Evidently, if through its influence the guns can be fired 100 times at a slowly-moving ship, instead of once at a rapidly-passing enemy, the effective power of the battery is multiplied more than 100 times. Independently, therefore, of its own destructive power, the defensive torpedo has become an essential auxiliary of the land gun. Indeed, they are inseparable in a judicious system of harbor defence, for, while the former is necessary to developing the full power of the latter, the latter is no less essential in protecting the former against the operations of the enemy; for it is an admitted principle that electrical submarine mines cannot defend themselves without the aid of flanking guns to keep off boats, and of a fort secure against assault wherein to place the necessary batteries and operating apparatus. The trifing expense and superior power of this combination as compared with monitors for harbor defence has effectually disposed of the latter, which at one time were popularly believed to be our only dependence in the future for protecting our great seaboard cities against the dangers of a bombardment. They are now reduced to the grade of a useful auxiliary reserve force, which should not be neglected in a few of our large harbors. The navy is thus released from an irksome confinement to a defensive warfaro in our ports, and is free to strike effective blows where the enemy may be most vulnerable to attack, and where he will fear something more than a simple repulse as the result of an unfortunate naval action.

Some of the more important of the recent improvements in submarine mining are the following: The modern explosives (see EXPLOSIVES) have largely superseded gunpowder,

53

because greater power with less bulk may thus be secured. The latter is an important matter, since upon the size of the torpedo depends the depressing effect of the current, and hence the amount of buoyancy necessary to keep the case always high enough to be touched by the enemy in passing. This buoyancy, of course, regulates the weight of the anchors and the size of the mooring connections, and, in fact, the principal dimensions of the system. The increase in intensity of explosive action is also important, for efforts are now making to give increased strength to the hulls of war-vessels by employing iron in the form known as the double-cellular bottom, thus reducing the destructive range of the torpedo, and exacting the employment of more powerful charges. In England experiments upon the Oberon, a vessel of this type, have shown that the horizontal destructive range of gun-cotton in charges even as large as 500 pounds is restricted to a few feet. This charge was fired on the bottom in 48 feet of water at horizontal distances from the ship of 100, 80, 60, 50, and 30 feet, and finally vertically under her side. Although she was much shaken and injured by some of these shots, only the last burst through the double bottom and sunk the vessel. At our own engineer school of defensive submarine mining at Willet's Point, N. Y., a long series of trials has been conducted to determine the effective range of different charges of different explosives sunk at different depths below the surface; and by the careful measurements of several hundred explosions the matter has been successfully brought within the scope of mathematical analysis. The formulæ and results are now all made public, and they confirm the fact of restricted destructive range. The subject is full of interest in a scientific point of view. To illustrate one striking feature developed-viz. the effect upon the jet

FIG. 11.

Torpedo practice at Willet's Point, New York harbor. caused by varying the depth of submergence-the figure is given. The original picture was made by the instantaneous photographic process by Lieutenant James Mercur, corps of engineers, and advantage was taken of the passing of an unsuspecting schooner to obtain a convenient scale of comparison. Both charges consisted of 100 pounds of mortar powder, the one on the apparent right sunk 4 feet, and the other 10 feet, below the surface. The height of the columnar jet exceeded 400 feet by accurate measure

ment.

Electricity is now chiefly used as the igniting agent in submarine warfare, because this enables the obstructed channels to be safely traversed by friendly vessels. The mines are usually arranged to be fired at will, or automatically by the touch of the vessel. The best systems are designed to work cither on an open or closed circuit at pleasure, because this largely increases the danger of tampering with the torpedoes. By the use of proper fuzes (see FUZES) ignition may be effected with certainty. To cause the explosion to occur automatically by the touch of the vessel, a device called a circuit-closer or circuit-breaker, according to the circuit chosen, is employed. Many ingenious devices have been proposed. The figure shows the most improved form of the Mathieson arrangement, now adopted in the English service. The lead ball a, supported

с

by the coil b, is caused to vibrate by its inertia when the torpedo is struck by the vessel. The contact-disk c is thus made to close or open the circuit FIG. 12. through the agency of the surrounding springs d. More simple contrivances than this are in use in some other services. Even for contact-mines unconnected with the shore, and hence under no control, electricity is now available for ignition; and its use largely reduces the danger of handling and planting the mines. A small battery is placed in the torpedo or in a hollow anchor under it, and when everything is in position the circuit to the circuit-closer is completed after the boat has reached a safe distance from the mine.

In the matter of torpedo cases, experience has shown that metal, usually iron, must be employed

where the mines are to remain sub- Mathieson's Circuitmerged for long periods. Wood in

closer.

such cases cannot be trusted to exclude water, although lager-beer kegs supply a good temporary expedient. It is an essential condition that the form shall be symmetrical, in order to reduce the tendency to rotary motion to a minimum. Wire rope is found to supply the best moorings. The electric current is conveyed by armored cable, not unlike that employed for the Atlantic telegraphs; but indiarubber is superior to gutta-percha as an insulator, becauso less likely to be injured by changes of temperature in storage and laying. To avoid a multiplicity of cables, as well as to reduce cost, several different cores are often united in a bundle and included in a common armor.

FIG. 13.

While the details of our own system of submarine mines, as elaborated by the writer at Willet's Point, are not made public, its general features were exhibited at the Centennial Exhibition at Philadelphia in 1876, and are as follows: Two types of electrical mine are in use, the ground and the buoyant. The former is employed in comparatively shallow water, and consists of a case resting upon the bottom and containing a large charge of dynamite. Floating near it, but so far below the water-surface as to be concealed from view, is a buoy carrying a circuit-closer or breaker to regulate the current through a fuze embedded in the former. The buoyant mine is designed for use in deep water, and consists of an anchor holding in position a torpedo floating just below the surface; the latter contains the charge of dynamite, the fuze, and the circuitcloser or breaker. If desired, the latter may be carried by a separate buoy so placed that when touched by outriggers or other torpedocatchers, the mine will be directly under the vessel. The channel to be defended is thickly studded by lines of these mines, so arranged with respect to each other that no vessel can pass without coming in contact with one or more of them. Single-conductor electric cables running from each mine combine in multiple cables, and

are extended through a subterranean gallery to a secure bombproof casemate within the fort, where is placed the apparatus by which, at the will of the operator, the mines may be fired by judgment, or be rendered either inert or automatically explosive when struck by a vessel. The system is arranged to permit easy electrical tests, by which any injury at once becomes known, as well as its nature and locus. Wires also extend from the casemate to flanking guns, so that if a boat succeeds by night in cutting a cable or in disturbing a mine, by so doing it draws upon itself a heavy automatic discharge of canister, grape, or case shot, according to its distance from the fort. Electric lights are arranged to sweep the lines of mines, and thus give additional security against hostile operations conducted under cover of the darkness. The casemate is connected by telegraph with a lookout, so that the whole system is under the perfect control of an officer who can see what is required, and instantly give the needful orders. For instance, one of our vessels might be chased by a cruiser. She could pass with absolute safety the mines,

which for her pursuer would at once become deadly engines of destruction.

Detailed maps and plans for the torpedo defence of all our most important channels have been carefully prepared by the board of engineers for fortifications, and are now on file in the engineer department at Washington. The casemates and galleries for the introduction of the cables have been actually constructed at several of our forts. Large stores of torpedo material are accumulating at the engineer dépôt at Willett's Point, where, as already stated, our engineer troops receive the training needful to prepare them, in case of sudden war with a maritime power, to rapidly plant and operate the defensive mines along our extended seaboard. HENRY L. ABBOT.

Torpedo, Torpedo-Vessels. See SHIPS OF WAR. Torqua'tus (TITUS MANLIUS), a member of the celebrated patrician family, the Manlia gens, of ancient Rome, received his surname TORQUATUS in 361 B. c. for slaying a gigantic warrior among the Gauls in single combat on the Anio, and ornamenting himself with the neck-chain (torques) of the fallen foe. He was several times consul and dietator, and finished the wars with the Latin League. During one of his campaigns he forbade all single combats. His son, nevertheless, fought with a Latin warrior and slew him, but when he returned to the camp and laid the spoils at the feet of his father, he ordered him to be punished with death; hence the expression, Manlia imperia, common in the Latin literature.-Another member of the same family, LUCIUS MANLIUS TORQUATUS, became very conspicuous in the civil war. He was prætor when the war broke out in 49 B. C., and as he belonged to the aristocratic party, he was apposed to Cæsar. He was stationed at Alba with six cohorts, but on the fall of Corfinium he abandoned Alba, and his soldiers went over to Cæsar. He subsequently joined Pompey in Greece, and in 48 had the command of Oricum, but was compelled to surrender to Cæsar, who, however, sent him away unmolested. He immediately joined Pompey again, and fought under him at Dyrrhachium. After the battle of Pharsalia he went to Africa, and here he was taken prisoner by P. Sittius at Hippo Regius, and slain. He was well versed in Greek literature, a man of elegance and taste, and a pupil of the Epicurean school of philosophy. He was a friend of Cicero, and is introduced by him in his dialogue De Finibus as the advocate of the Epicurean philosophy. In his letters to Atticus, Cicero calls the first book Torquatus in his De Finibus, and speaks of him with much respect.

Tor'quay, town of England, county of Devon, is handsomely situated on the Torbay, an inlet of the English harbor. P. 24,765. Channel, and frequented as a bathing-place. It has a good

Torque [Lat. torques; Celtic tore], a spirally and almost circularly bent rod of gold, worn as a personal ornament upon the neck by the ancient Celts and other rude races of the Old World.

Torquema'da [Lat. Turrecremata], de (JUAN), CARDINAL, b. at Valladolid, Spain, in 1388; entered the Dominican order of friars in Valladolid 1403; was present at the Council of Constance 1417; afterward pursued the study of theology at the University of Paris, where he graduated 1424; became an instructor there; was successively prior of the Dominican convents at Valladolid and Toledo; was called to Rome by Pope Eugenius IV., by whom he was made "master of the sacred palace" 1431; was papal theologian at the Council of Bâle, where he contributed to the condemnation of the doctrines of Wycliffe and Huss, and advocated the doctrine of the Immaculate Conception; participated in the same capacity in the Council of Florence 1439, where he drew up the project of union between the Greek and Latin churches, for which he received from the pope the title of "defender of the faith" and the rank of cardinal; attended the Council of Bourges 1440; became bishop of Palestrina 1455, and of Sabina 1464. D. at Rome Sept. 26, 1468. Author of Meditationes (1467), Expositio brevis et utilis super toto Psalterio (1470), which were among the earliest productions of the press at Rome, Quæstiones Spiritualis Convivii Delicias præferentes super Evangeliis (1477), Commentarii in Decretum Gratiani (Lyons, 6 vols., 1519), and of several other works, as yet unprinted.

Torquemada, de (Tomas), b. at Torquemada, Spain, about 1420; became a Dominican monk and prior of the monastery of Santa Cruz at Segovia; was appointed by Ferdinand and Isabella first inquisitor-general of Spain 1483; was confirmed in that post Oct. 17 of that year by Pope Innocent VIII., who gave him the title of "confessor of sovereigns:" labored with great vigor and success in organizing the Inquisition throughout Spain, especially at Seville, Córdova, Jaen, and Ciudad Real; drew up the code of procedure subsequently followed; was influential