20 G ELEMENTAEY PRINCIPLES OF GUNNERY. 



sulphur and chlorate of potass (or more frequently nitrate of 

 potass) are mixed with the fulminate of mercury, and the 

 powder being pressed gently into the cap, is secured there by 

 a drop of varnish. 



Chlorate of potass and 8ulplmr are sometimes used without 

 fulminate of mercury, or silver. Equal parts of these two 

 substances are carefully prepared, and mixed together with- 

 out any friction between hard substances, which would cause 

 an explosion. The mixture is then pressed into the caps 

 and secured as before described. Caps so prepared are, 

 however, very uncertain in their explosion, and they are 

 also highly corrosive in the action of their residuum on iron. 

 The Government caps are filled with a composition consisting 

 of chlorate of potass, 6 parts ; fulminate of mercury, 4 parts ; 

 and powdered glass, 2 parts. 



Whatever substance is employed it should be protected 

 externally by a copper cap or disk, and it should also be 

 covered with a layer of some varnish, which will defend it 

 from the effects of the atmospheric air. 



Messrs. Eley and Joyce are the only two makers of caps in 

 England, independently of the Government, and it would be 

 hard to say which is entitled to the pre-eminence, for the 

 productions of either may be taken as approaching so nearly 

 to perfection as to leave little to be asked for. At present 

 they each make two kinds one small, and adapted to ordi- 

 nary guns, and the other larger and stronger, as ordered by 

 the Government, and suited for rifles, especially when a 

 cartridge paper has to be pierced. Eley's caps are coated 

 with a metallic foil, which is intended to prevent decompo- 

 sition by contact with air or moisture, while those made by 

 Joyce are covered with " a highly waterproof substance, 

 burning with the same facility as the powder itself, and in 

 no degree detracting from that certainty and sharpness of 

 fire, as well as anti-corrosive property, so necessary for the 

 convenience and comfort of those who use them." These 

 words are from Mr. Joyce's circular, but I can speak to 

 their correctness from experience. The price of the sporting 

 caps by either of these makers is Is. 0>d. per box, containing 

 250, or 5s. Qd. per 1000. In all cases the caps ought to fit 

 the nipples with which they are used, and in ordering a lot 



