52 



NATURE 



{Nov. 15, 1877 



construction and fine workmanship may be imagined 

 when the reader is informed that the machines cost 500/. 

 a piece to manufacture. The long tube is divided into 

 three compartments : the head, which contains the 

 explosive charge, the 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 600 lbs. on the 

 square inch, and to bring about this result an exceedingly 

 powerful air-pump is necessary, which forms an addi- 

 tional item of expense in the case of this torpedo. The 

 latter when properly charged will do a journey of a mile, 

 or mile and a half, underwater, the first 1,000 yards being 

 got over at a rate of no less than twenty miles an hour, 

 and if unaffected by tide or current, the machine 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 ; 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 innocuous, and permits of its recapture 

 without risk. Ingenious as the little creature is, there has 

 been, we repeat, no authenticated employment of it during 

 the present war. 



On the Danube the spar-torpedo'alone seems to have 

 been used against Turkish monitors. As in the case of the 

 Thorny croft\aMn<^, of which we are to have a flotilla of thirty 

 in the British navy, the torpedo is projected at the end of a 

 spar, and is ignited either by concussion or by electricity. 

 The Turkish ironclad at Matchin was the victim of two 

 torpedoes of this class, the first of which, we are told, 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 be innocuous at a distance 

 of ten feet from the seat of explosion, and hence those in 

 the launch do not suffer much except from 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 fuze, which, together with a few grains of 

 fulminate, would determine the detonation of dynamite or 

 gun-cotton. Each launch is provided with a pair of these 

 spar torpedoes, carried, when not in action, on each side, 

 running the length of the boat, and only on making an 

 attack is one or other projected at the bow, the torpedoist 

 being stationed behind a shield, or under an iron screen, 

 where he can make his observations tolerably free from 

 danger. 



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 dyna- 

 mite torpedo of 150 lbs. ignited in ten feet of water, was 

 found capable of exploding other charges at a distance of 

 300 feet by the mere vibration imparted to the water ; so 

 that in constructing coast defences with dynamite tor- 

 pedoes 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 fric- 

 tional electric machine, traversing one of a bundle of 

 wires, will induce a current in the other wires, and thus 

 bring about the explosion of torpedoes other than that 

 which the operator on shore desires to ignite. It is these 

 facts particularly which 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 pecu- 

 liarly sensitive to vibration — indeed their detonation, as 

 we have seen, is brotight about by no other 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 nitro-glycerine compound, and so speedily clear a way 

 for his ship. 



This is certainly subject for ' congratulation, for it 

 seemed at one time as if the poor sailor was absolutely 

 defenceless against these submarine abominations. A 

 crinoline of spars and wire rope may be employed to 

 catch the fish torpedo and explode the vermin harmlessly 

 in its toils, provided the ingenious brute is not a very 

 large one, and the net is at some distance from the ship ; 

 but heavy moored torpedoes have been hitherto con- 

 sidered too dangerous to approach, so that marine coun- 

 termining must prove invaluable. The spar or drifting 

 torpedo cannot be dealt with by nets or booms alone, and 

 in this case the only plan would seem to be to meet a^ tack 

 with attack and beat off launches with other small boats. 

 That all ironclads in time of war will have to be sur- 

 rounded 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 illumina- 

 tion — the electric light, for instance — to prevent swift, 

 low-lying torpedo launches from approaching unperceived 

 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 

 water as above it. In this country we have a torpedo 

 school on board H.M.S. Vernon at Portsmouth, while 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, as all the world knows, practised torpedo war- 

 fare to such good purpose seven years ago that the mag- 

 nificent fleet of the French never once ventured to visit the 

 coast of the Fatherland. Both at Kiel and at Wilhelms- 

 haven are to be found torpedo depots and a well-orga- 

 nised 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 instruc- 

 tional schools are to be formed at Kertch and Cronstadt, 

 whence torpedo appliances are to be issued for the 

 defence of the Baltic and the Black Sea. 



NOTES 



Mr. Darwin will receive the honorary degree of LL.D. at 

 Cambridge on Saturday next, at 2 p.m., at a congregation 

 specially convened for the purpose. In the evening the annual 

 dinner of the Philosophical Society will take place in the Hall of 

 Clare College, when a brilliant gathering is expected to meet the 

 illustrious visitor, among the non-resident guests being Profs, 

 Huxley, Tyndall, and Parker, and Sir John Lubbock. 



The Postmaster-General of the German Empire is about to 

 have an extensive series of experiments made with a view to the 

 introduction of the telephone into the telegraphic service. Several 

 hundred specimens of the telephonic apparatus manufactured by 

 Siemens and Halske have been ordered. 



The French Ministry had granted a pension to the widow of 

 Leverrier. Unfortunately the lady died, as we mentioned in our 

 last number, before the first monthly instalment became due. It 

 is hoped that a part of the pension will go, against ordinary rules, 

 to the son and daughter of the astronomer. 



The Minister of Public Instruction has been authorised by si 



