MODERN TORPEDO WARFARE.

Globe, Volume IX, Issue 1275, 20 April 1878, Page 3

MODERN TORPEDO WARFARE.

[From “ Nature.”] Electric torpedoes may be broadly divided into two clasees, offnesive and defensive torpedoes. The latter are employed for the protection of harbors, channels, and roadsteads ; the former, in the shape of drifting or star torpedoes, are carried to the attack in small swift-sailing steam launches. In England compressed gun cotton is generally used, but on the continent dynamite is the favorite. The gun cotton is pressed into cakes of disclike form, and while still wet the slabs are stored away in the magazines. In this moist condition the compressed pulp is notonly nonexplosive, but actually non-inflammable, except one possesses the key to its detonation. This is nothing more than a dry cake of the same material, which on being detonated by a few grains of fulminate brings about the explosion of any -wet gun cotton in its immediate neighborhood. The possibility of communicating explosion in this way by vibration instead of by spark or flame is the germ of a system of counter-mining, or torpedo annihilation, which bids fair to develop into a particularly effective moans of defence against these terrible machines. Dynamite is similarly exploded to gun cotton. Dynamite and gun cotton explode with something like four or five times the force of gunpowder, and for this reason a very destructive charge may be confined within a comparatively small space. In the case of moored torpedoes there is no limit to size, but for a star torpedo the charge must be considerably smaller, or it would destroy both the attacking and the attacked. A big moored torpedo of 5001bs. of gun cotton has been found, when sunk in forty feet of water, to be fatal to a strong ironclad if the latter happens to bo within this distance. Probably no ironclad could withstand this terrible volcano if it were to erupt in contact with the vessel’s sides. Such a torpedo throws up a cone of water 60 feet in height., with a diameter at its base of no less than 230 ft,

The fish torpedo is of very elaborate construction. The long tube is divided into three compartments : the head, which contains the explosive charge, th’e reservoir, in which the compressed air is stored, and the machinery by means of which the stored-up energy is converted into a propelling force. The air is compressed to the extent of 680Ibs. on the square inch. The torpedo, when properly charged, will do a journey of a mile or a mile and a half under water, the first 1000 yards being got over at a rate of no less than 20 miles an hour, and if unaffected by tide or current, the mach ne will proceed in a perfectly straight direction,. It floats at any distance under water that may be desirable, but is usually made sufficiently buoyant to swim (at eight feet from the surface j it explodes on striking any object, but the machine is so contrived that if it fails to strike, then it floats to the surface, and a trigger guard renders the fish at the same time inactions, and permits of its recapture without risk. Ingenious as the little creature is there has been no authenticated employment of it during the present war. On the Danube the spar torpedo alone seems to have been used against Turkish monitors. The Turkish ironclad at Matchin was the victim of two torpedoes of this class, the first of which was ignited by the crew of the launch by electricity, and the other on concussion with the vessel attacked. These Russian torpedoes are said to bo innocuous at a distance of 10ft. from the seat of explosion, and hence those in the launch do not suffer much except frpm the water that is thrown into the air. From the fact that small batteries in the boat are used to fire the charges, we may safely conclude that their explosion is brought about by a platinum wire fuse, which, together with a few grains of fulminate, would determine the detonation of dynamite or gun cotton. In the case of moored torpedoes depending for their ignition upon electricity, many points of scientific interest have recently been brought to light. Some experiments undertaken in Denmark two or three years ago showed most conclusively that dynamite torpedoes cannot be placed close together without incurring the danger of one charge bringing about the explosion of others. A dynanfite torpedo of 1501bs. ignited in 10ft. of water yas found capable of exploding other charges at a distance of 300 ft. by the mere vibration imparted to the water ; so that in constructing coast defences with dynamite torpedoes it is absolutely necessary to keep them far apart from one another. Another point was also noted. A current of electricity, if it emanates from a powerful frictional electric machine, traversing one of a bundle of wires, will induce a current into the other wires, aud thus bring about the explosion of torpedoes other than that which the operator on shore desires to ignite. It is these facts particularly w'hich have led to the development of a system of counter-attack, and have enabled our sailors to devise a means of defending themselves from the terrible sea monsters. Both dynamite and gun cotton are pecularly sensitive to vibration —ipdee.d their detonation, as wo have seen, is brought about by po othpr cause—and hence a captain of a man-of-war by exploding counter mines in his vicinity may soon get rid of any lurking torpedoes lying in wait for him, at any rate if they contain a nitroglycerin compound, and so speedily clear a way for his ship. A crinoline of spars and wire rope may be employed to catch the fish torpedo, provided it is not a very large one, and the net is at some distance from the ship; but heavymoored torpedoes have been hitherto considered too dangerous to approach, so that marine countermining must prove invaluable. The spar of drifting torpedo cannot be dealt with by nets or booms alone, and ip this case the only plap woifld seem to bo to meet attack with attack and beat off launches with other small boats. That all ironclads in time of war will have to be surrounded by lesser craft as a protection is a matter that we may now take for granted, as also that such vessels must be provided with some powerful means of illumination —the electric light, for instance—to prevent swift, lowlying torpedo launches from approaching unperoeivad at night time. Special schools of instruction for acquainting officers with the science of electricity and explosives have for some time past been established, and there is indeed scarcely a naval power which has not paid attention to submarine warfare; consequently we may expect to see future battles upon the sea carried on just as much under the water as above it. In England, at the Royal Naval College at Greenwich, instruction in the experimental sciences now forms one of the most important items in the curriculum. France has its naval torpedo school at Boyardville, where both officers and seamen are made acquainted with the principles of submarine warfare. Germany practiced torpedo warfare to such good purpose seven years ago that the magnificent fleet of the French never once ventured to visit the coast of the Fatherland. Both at Kiel and at Wilhelmshaven are to bo found torpedo depots' and a well organised staff of instructors, Lastly the news comes to us from Russia that the Czar has sanctioned the organisation of a distinct torpedo service, and two depots and instructional schools are to be formed.