COMPOSITION OF GUNPOWDER, ETC. 203 



Gunpowder is sold in. paper at 2s. 3d. per lb., and in 

 canister at 2s. Qd. If large quantities are taken a reduction 

 is made in the price; but it must be remembered that fire 

 insurances are rendered invalid by keeping a stock of this 

 dangerous substance on the premises. 



When gunpowder has become damp it is readily and safely 

 dried by placing the canister or flask in a jug of boiling 

 water with the mouth open, and occasionally taking it out 

 and shaking its contents. This is much safer than the ordi- 

 nary plan of drying it before the fire, and with a little care 

 answers equally well. 



Gtmcottun consists of finely carded cotton wool which has 

 been submitted to the following process : Nitric acid of spe- 

 cific gravity 1 'O is mixed with concentrated sulphuric acid, and 

 in this mixture the cotton is steeped for a few minutes; it is 

 then taken out and squeezed, after which it is carefully 

 washed in pure water and dried by a very gentle heat, when 

 it will have increased in weight seventy per cent., but in 

 appearance it is unchanged. It explodes at a much lower 

 temperature than gunpowder, that is, at a little above 300 

 Fahr., so that it requires much greater care to avoid acci- 

 dents, and on that account alone is objectionable as a sub- 

 stitute for it. It burns without smoke or -residue, but the 

 explosion is so rapid that the projectile power of this sub- 

 stance is not so great as that of gunpowder, while, at the 

 same time, the recoil caused by it is increased. It has also 

 the disadvantage attending on it that the charges must be 

 weighed, as they cannot be measured by bulk as is the case 

 with the powder in common use. Jt is not, therefore, sur- 

 prising that, in spite of its greater cleanliness, it has not 

 come into general use, being much more dangerous with less 

 power of projection, more recoil, and the above-mentioned 

 difficulty as to the calculation of the charge. 



In spite of these objections, however, guncotfcon has been 

 recommended by Captain Norton to be used, in particular 

 where it is desired to have a cartridge without the neces- 

 sity of biting it, as is now done in the army and navy. 

 By enveloping the cotton in a fine net, which is tied to the 

 base of the bullet, and may also be rendered explosive in the 

 same way as the cotton, the flame of the cap readily fires it, 



