58 ANNUAL OF SCIENTIFIC DISCOVERY. 



applied with equal certainty to the discharge of a considerable number of 

 mines. The great clement of success in the fuse-composition employed is to 

 be found in the circumstance that it combines a high degree of sensitiveness 

 with considerable conducting power. The substitution of the magnet for" 

 the voltaic and other arrangements hitherto used will greatly facilitate min- 

 ing operations; the soldier requires but little instruction in its use; with ordi- 

 nary care it is not liable to derangement; it is very transportable, and ready 

 for application at the shortest notice. 



In connection with submarine operations, vulcanized India-rubber bags 

 have become valuable substitutes for the wooden and metal receptacles hith- 

 erto employed for the charges of powder. The numerous applications which 

 India-rubber, especially in its vulcanized form, now receives in connection 

 with military equipments, render it a most indispensable material. Thus it 

 has been applied to the preparation of waterproof linings for powder-barrels, 

 waterproof cases for cartridges, convenient holders and waterproof coatings 

 for percussion caps. It is used in the form of springs and buffers in connec- 

 tion with gun-carriages and the beds of heavy mortars ; ambulance wagons 

 are supplied with efficient and easily applicable springs of India-rubber; and 

 one of the most important additions recently made to the comfort of troops 

 has been the general supply to them, when on active service, of waterproof 

 clothing and covers, to be used in camp. 



The protection of camp-erections from fire has also received attention, with 

 successful results. A cheap and ready mode of applying a coating of insol- 

 uble silicate of lime and soda to the surface of camp huts, whereby very 

 important protection against fire is attained, received application a few years 

 ago; and quite recently a method has been devised, by Mr. Abel, of impreg- 

 nating tent-cloth with silicates to such an extent as effectually to prevent fire 

 from spreading, when applied to any portion of it, and in such a form as to 

 enable them to resist the solvent effects of drenching rains. 



The application of soluble silicates to the preparation of very porous arti- 

 ficial stone has enabled Mr. Ransome to produce portable filters, by the aid 

 of which the soldier may frequently be enabled to partake of water which 

 otherwise would be unfit for use. A still more efficient portable filter is now, 

 however, prepared of carbon, in a porous condition, which not only has the 

 property of retaining the mechanical impurities of water in its passage 

 through it, but also will purity it to a very considerable extent from injurious 

 organic matters and gases Avhich it may contain. 



One of the most important improvements which has yet been effected in 

 the purification of water, and one which has already received important ap- 

 plication in connection with the military sen'ice, is presented in the appara- 

 tus contrived by Dr. Normandy for the preparation of wholesome and pleas- 

 ant water from sea or other water unfit for consumption. The apparatus 

 consists, in the first instance, of a great improvement on the condensing 

 arrangement contrived by Sir T. Grant, which has been for some time used 

 in the navy. The heat abstracted from the steam first consumed is applied 

 to the distillation of a second similar quantity of water, and the arrange- 

 ment employed for condensing this second product is of such a nature as to 

 ensure a very gradual but continuous replacement of the condensing water. 

 In this manner the latter becomes sufficiently heated, before it passes out of 

 the apparatus, to part with the gases which it contains in solution, and which 

 are made to pass into the distilling apparatus and mix with the steam. The 

 condensed product is thus thoroughly aerated; it is then, finally, made to 



