169 TORPEDOES. By A. HILLIARD ATTERIDGE. [PLATE XCVIII.] TH HERE are few things more remarkable than the great revolution which science has effected in modern warfare. Within the last twenty years there have been hundreds of inventions and improvements in our means of attack and defence, and the result has been such a development of destructive power that in all but its great unalterable principles war has been completely changed. On the battle-field, before the deadly fire of the breechloader, the long line and the massive column have given way to clouds of skirmishers; huge guns, such as men only dreamed of a few years ago, are mounted in our ships and fortresses; and instead of the old three-deckers which carried our flag in the days of Howe and Nelson, our fleets are composed of ironclad monsters, any one of which could annihilate all the armadas of former times. A new feature, too, has been introduced into naval warfare-a new means of defence has been gradually devised—and now an armament, when it approaches a hostile shore, has to risk destruction from mines hidden deep below the surface of the sea. Torpedoes, once rude contrivances scarcely less dangerous to those who used them than to the enemy against whom they were employed, are now, thanks to the researches of our electricians, marvels of ingenuity, perfectly safe to handle, but fearfully dangerous to the aggressor. By their means coasts and harbours can be easily and cheaply placed in a thorough state of defence; and ports, while secure from the approach of a foe, can be still left open to friendly men-of-war and merchant ships. It is only of late years that torpedoes have been brought to this high state of perfection; they have hitherto been employed comparatively rarely in actual warfare, but there is little doubt that they will play a great part in future conflicts. In this paper we propose to give a short account of the various ways in which they are constructed; but as in a few pages it would be difficult even to enumerate all the methods which have been adopted, we can only describe the more important plans of action which have been used or suggested. A torpedo may be briefly described as a waterproof case of gunpowder, or some similar explosive, so arranged as to be fired close to a hostile vessel, with the object of sinking her. They may be at once divided into two great classes-stationary torpedoes, which are fixed at one spot and fired on the enemy's touching or approaching them, and locomotive torpedoes, which are either propelled against a ship by some mechanical contrivance or allowed to drift with the current. It would be difficult to say when or by whom torpedoes were first used; certain it is that the original idea must be an old one, for drifting fireships were employed at a very early date, and gunpowder could not be long invented before some one would think of making a fireship into a floating mine. The first attempts in this method of attack were of the rudest kind. Nearly a hundred years ago, in 1778, the Americans used drifting torpedoes against the English fleet in the Delaware. The plan adopted was to fill small kegs with gunpowder, and place in them a gunlock, so arranged that the collision with a ship's side would bring down the hammer and explode the charge. "Bushnell," says Fenimore Cooper, "made several unsuccessful attempts to blow up the ships of the enemy by means of torpedoes, a species of warfare which it can hardly be regretted has so uniformly failed." This was written in 1839, and up to that time it might be said with truth that torpedo warfare was an utter failure. But men worked on, improvements were suggested, new plans were invented, but still it seemed almost impossible to construct anything like a safe and at the same time efficient torpedo. In the Crimean war the Russians used drifting torpedoes against the allied fleets in the Baltic. Many of these were exploded mechanically by coming in contact with French and English men-of-war, but the charges were so small that no serious damage was done by them, and more than one which failed to explode was picked up and found to be quite incapable of doing harm, because the men employed to place it in the water had neglected to put the firing apparatus in working order by withdrawing the safety key, lest they should themselves be destroyed by an accidental explosion. Indeed the great defect of any torpedo fired in this way is the peril to which it subjects all who have to handle it, as any rough usage would ignite the charge, and moreover when once it is set adrift it is dangerous alike to friend and foe. It was in the civil war in America that torpedoes were first used to any great extent, and for the first time were really successful. The Confederates, in particular, were very active in this * "History of the Navy of the United States of America,' vol. i. p. 157. way; they succeeded in sinking many of the Federal ships; and at Charleston, though the guns of the blockading fleets again and again silenced the land batteries, the ships were kept out of the harbour by the lines of torpedoes moored at its mouth. It was during this conflict, too, that the first great step was taken towards making torpedoes at once safe and effective, by using electricity as a means of ignition, thus keeping those terrible weapons completely under the control of the defenders, so that by merely disconnecting the electric battery from the wires they can be rendered perfectly harmless, and by renewing the connection they can be in a moment again made ready for action. In this way friendly vessels can be allowed to get into a harbour in safety, while an attacking squadron is held at bay; but with the old plan of firing the torpedoes mechanically, when once they were laid down neither friend nor foe could enter the port; and, moreover, to remove them when the war was over would be an undertaking of such frightful peril that it would be hard to get anyone to attempt it, as an incautious touch would be enough to explode the mine and blow the working party into the air. By adopting electricity as the igniting agent all those disadvantages are obviated. Again, in the "Seven Weeks' War" of 1866 we see torpedoes once more employed, and now still further improved. In that year the Austrian engineers arranged and executed a complete system of torpedo defence for Venice and the Adriatic coasts of the empire. It was not, however, put to the test of having to resist an attack of the Italian fleet, for Tegethoff, by his splendid victory at Lissa, crushed for the time the naval power of Italy. This is, nevertheless, an important epoch in the history of this kind of warfare, as it was the first time that a regular system was adopted; for in America all that had been done was to use such materials and such forms of apparatus as came readily to hand; and almost every sort of contrivance was used at different times and places. At the great Paris Exhibition of 1867 the methods used in the defence of the Venetian coast were exhibited by the Austrian government, and the period between the wars of 1866 and 1870 was one of great activity in researches and experiments in this department. When war was declared by France, the Prussian government at once proceeded to put all their ports in a state of defence with the help of torpedoes. The most improved forms of apparatus were used, and there could not be a better example of the way in which an inferior naval power can now render itself secure from the attack of a much superior one. The Germans tacitly acknowledged their inferiority on the sea, for their men-of-war never left the protection of the forts of Kiel and Wilhelmshaven; yet the French fleet, from which so much had been expected, effected absolutely nothing. The German harbours, with this new defence, were almost impregnable, and they were not attacked. So well satisfied is the German government with the experience of 1870, that it is said that they have decided to build no more men-ofwar for the present, but to devote the funds which would otherwise be used for this purpose to the construction of floating batteries and the acquisition of torpedo matériel for the defence of their coasts and harbours. With this brief sketch of the history of torpedo warfare we must pass on to an account of how it is conducted. We shall speak first of fixed torpedoes, and the way in which they are secured in position and fired so as to do their work; then we shall go into the general principles of harbour and coast defence; and finally we shall briefly refer to the most successful efforts which have been made to construct effective locomotive torpedoes a branch of the subject which is not yet so far advanced. The first thing necessary in the construction of a torpedo is a case in which to place the charge. This case must be perfectly water-tight, otherwise the explosive will be rendered useless by the water leaking into it; and to secure this it must be strong enough to bear a good deal of rough handling, and also the pressure of the water at the depth to which it is to be submerged. When (as is usually the case) it is to be floated up from an anchor, it must have, when loaded, sufficient buoyancy to keep it steady at its moorings. It must be of such a shape that the charge may be readily and completely ignited with as few fuzes as possible; and as with gunpowder, or gun-cotton with an ordinary fuze, the explosion is not instantaneous in a charge of any size, but as it were runs through it, the case must be strong enough to hold together for a moment till the whole explosive force is developed; otherwise the first portion of the charge ignited will burst it, and admit the water to the rest. Various forms of case and various materials have been used or suggested. For their smaller torpedoes the Americans employed wooden barrels, and for the larger kind cases made of boiler-plate, and not unfrequently they used steam-boilers for this purpose. The barrels would of course be strengthened at the heads, and every kind of extemporised case would have to be made thoroughly water-tight by being coated either inside or outside with tar or some other waterproof material. The torpedoes for the defence of the Venetian coast in 1866 had either iron or wooden cases. (See figs. 1 & 2, Pl. XCVIII.) The former consisted of two cylinders, one within the other; the inner one contained the charge, and the space between them was left empty, to give buoyancy to the whole. The outer case was about 4 ft. high and 4 ft. in diameter, and the charge was 3 cwt. of gun-cotton. The wooden cases were also double, the space between them being filled with tar to make the torpedo water-tight. The inner case (about 4 ft. x 4 ft.) was further protected by being covered with plates of zinc, and contained a charge of 4 cwt. of gun-cotton, with air-spaces in the centre to make it buoyant. The form here adopted—a cylinder of equal height and diameter—seems to be the best. In theory the best form would be a globe, the charge to be ignited at the centre; but there would be a hundred difficulties in the manufacture and use of such a case in practice; and the cylindrical case of these dimensions, which is the nearest form to it we can conveniently use, gives us almost all the advantages which theoretically belong to the globular form, the greatest of which is that the thorough and uniform ignition of the charge is secured by its compact form, which brings all the outer portions within an equal distance of the point at which the ignition commences. A case of English invention consists of a cylinder of iron to contain the charge, protected by a thick outer covering of fir-wood soaked in tar and painted to make it water-tight. Besides wood and iron, a third material has been suggested; this is vulcanised india-rubber made into bags to hold the charges. It is found, however, that the bag gives way before the whole explosive force is developed, and thus a large portion of the charge is lost. To obviate this it has been proposed to place in the centre of the torpedo a long perforated brass tube containing the fuze and a small priming charge, so as to fire the explosive at several points, and thus ignite the whole of it before the india-rubber gives way. It is doubtful, however, if, even with this improvement, the india-rubber case is suitable for torpedoes, at least with charges of gunpowder. Its great advantage is the perfect security from water which it affords to the charge, but the difficulty of producing a complete and effective explosion quite outweighs this. It seems that the vulcanised india-rubber bag might be used with advantage in constructing wood and iron-cased torpedoes, as any defect in the tightness of the case would be neutralised by the charge being enclosed in such an inner covering. The form and material of the case having been decided upon, the next thing is to select the explosive best suited for the conditions under which it is to act. A few years ago there would have been little to be said on this point, for the only available explosive then known was gunpowder; but now there are a host of such compounds as gun-cotton, xyloidine, nitroglycerine, dynamite, picrate of potassium, glyoxyline, and more of less importance, and chemistry is continually adding to the number. The essential qualities required in an explosive for this purpose are great power, so that the space within which its explosion will be effective may be as wide as possible; and uniformity of action, in order that we may be able to reckon |