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NATURE 



\A7tgnst 9, 1877 



of late attained to so important a position. In the White- 

 head, or fish-torpedo, the electric fluid, it is true, plays no 

 part, but this is the only notable exception. In the floating 

 torpedo, the moored torpedo, and the spar-torpedo, elec- 

 tricity is the life and soul ; at one moment the machine is 

 but a floating buoy or sunken impediment, the next it is 

 transformed into a terrible volcano. A feeble current of 

 electricity flashing along the wire, has on the instant 

 sufficed to bring about the fatal change. 



Passing from torpedo warfare and the recent attempts 

 that have been made to turn electricity to account in 

 the construction of self-steering launches, we come to 

 a scarcely less important matter, that of firing guns 

 by the electric spark. Not only are guns at proof and 

 those under experiment so ignited, but on board the 

 modern ironclad it is the custom now-a-days to fire 

 broadsides in this wise also. By leading wires from every 

 gun to one point, which is specially adapted for observa- 

 tion, the double advantage is secured of bringing about 

 the firing at the most opportune moment, and of securing 

 a simultaneous discharge. Some experiments made in 

 Germany have proved beyond doubt that an armour plate 

 struck instantaneously in this way by several shot, may be 

 effectively broken up, whereas the ordinary broadside fire, 

 brought about by gunners at word of command is incapable 

 of doing so. The wires may be led into an observing tower, 

 or half way up the mainmast if need be, and here the 

 firing officer can calmly consort his measures undisturbed 

 by the smoke, and noise, and bustle going on below him. 

 He is provided with proper sights, and the guns being 

 laid in accordance with his orders, he can watch the oppor- 

 tunity for firing as well as if he had his eye to the weapons 

 themselves. 



Finally, we have the use of the electric light in warfare. 

 It is the most recent application of all of this wonderful 

 agent, and we should hesitate to say how extensive may 

 hereafter be the employment of electricity in this connec- 

 tion. In the Franco-Gemian war, the first use of this 

 powerful source of illumination was made by the French 

 engineers, and from the forts around Paris the electric 

 rays were made to sweep in all directions, to watch for 

 hostile troops engaged in the operation of mining. Bodies 

 of soldiers upwards of a mile distant could be plainly seen 

 by the vivid light of the electric lamp, and working 

 parties were frequently compelled to abandon their object 

 in the presence of this powerful detector. As a means of 

 discovering the approach of torpedo launches at night, 

 the electric light will obviously be of value, and already a 

 trial of it has been made in several of Her Majesty's 

 ships. The Alexandra, the flagship of the Mediterranean 

 fleet, is provided with an electric lamp, worked by one of 

 Wilde's powerful machines, so that the efficiency of 

 the apparatus may be practically tested. Experiments, 

 however, have already shown what the electric rays 

 are capable of doing, and a low torpedo-launch cannot 

 approach within a thousand yards without detection, 

 while if painted of a neutral grey, so as the better to 

 escape observation by day, the vessel, it appears, is all 

 the more perceptible under electric illumination. Steamers, 

 we are told, are peculiarly liable to be detected by an 

 electric lamp, since the rays are reflected by the steam 

 and smoke as effectively as if the latter were a solid screen. 

 How valuable, too, the electric light on board ship must 



prove for signalling purposes may be gathered from the 

 fact that the Dungeness light, which was the first one of 

 an electric nature constructed in this country, can be 

 seen on a clear night at a distance of thirty miles with all 

 the brilliancy of a star of the first magnitude. 



H. Baden Pritchard 



THE GEOLOGY OF THE VIENNA WATER 

 SUPPLY 



Geologic dcr Kaiser Fyatiz-y osefs Hochqucllcn-Wasser- 

 leitiDig. Einc Studie in den Teriidr-Bildungen am 

 IVestrande des Alpmcn Thciles der N'iedeniii" von 

 Wicn. By Felix Karrer. (K.K. geolog. Reichsanstalt. 

 Vienna, 1877.) 



THE publications of the Austrian Geological Institute 

 are deservedly noted for their number, their fulness, 

 and the beauty of their illustrations. Especially are the 

 large quarto memoirs published under the name of 

 Ahhandlungen remarkable in the latter respects. Con- 

 sisting usually of complete monographs, sometimes purely 

 palffiontological, but more often blending stratigraphy 

 with pateontology in a manner which is too seldom 

 resorted to in this country, these handsome volumes are 

 quite independent of, whilst they frequently illustrate, the 

 maps issued by the same authority. 



The present work forms vol. ix. of this important series. 

 In many ways it is unlike its forerunners, but it resembles 

 them in its completeness and in the finished character of 

 its plates. Although eminently local in interest yet so 

 many points are touched upon — or rather fully discussed 

 — in Dr. Karrer's memoir that it appeals to the civil 

 engineer, the hydrologist, the archaeologist, and the 

 chemist in almost as great a degree as to the geologist 

 and the systematic palaeontologist. 



This great closely-printed book of more than four 

 hundred pages, with its numerous tables and large folding 

 plates, is strictly what its title implies, viz., an account of 

 the geology exposed by the engineering works recently 

 carried out in order to bring the waters of the Kaiser- 

 brunnen and Stixtenstein springs to Vienna, a distance of 

 some twelve Austrian or fifty-five English miles. 



All the leading features of this section could probably 

 have been described and commented on with apparent 

 fulness in a short paper in the Verhandlungen of the 

 Institute, but the aim of the author has been to raise the 

 character of his memoir from that of a passing pamphlet 

 to that of a thoroughly exhaustive record of all the facts 

 — the seemingly unimportant as well as the obviously 

 valuable — which could be brought within the natural 

 limits of his subject. In this object he has perfectly suc- 

 ceeded, and the result is an orderly collection of minute 

 stratigraphical and other details such as, we believe, have 

 never before been brought together with reference to so 

 small an area. 



From Kaiserbrunnen at the foot of the Schneeberg and 

 from Stixtenstein a little further north to the very streets 

 of the Capital, or, geologically speaking, from the triassic 

 heights of the Noric Alps to the drift and alluvium over- 

 lying the Tertiary beds of this Alpine portion of the Vienna 

 Basin, only those valleys across which the aqueduct 

 replaced the cutting and the tunnel were left unsearched 

 and unplotted by Dr. Karrer. Every bed, band, thinning. 



