GUNPOWDER.
Gunpowder is a mixture of nitre, sulphur, and charcoal, and the more completely they are mixed, the more finely ground, and the purer they are, the more perfect will be the gunpowder. The proportions used of these ingredients differ slightly in different powder mills; but the average is about seventy-four parts nitre, ten sulphur, and fourteen charcoal, by weight; the sulphur and nitre can easily be completely purified, but the charcoal differs very much in almost every specimen, and charcoal that has been burnt long ago and exposed to the air and moisture is almost unfit for the purpose, that charcoal which has the least ash when burnt is found to be the best, and the charcoal which has been made in iron cylinders, is better than that made in the usual way, when each of the ingredients are separately powdered and sifted through a kind of sieve of silk called a bolting machine (such as is used in dressing flour), they are mixed in the proper proportions and taken to the mill, where they are moistened with water and ground to a smooth paste, this is pressed hard and then broken up into pieces which are put into a copper sieve, the bottom of which is perforated with small hole; a flat wooden ball is put into each sieve with the pieces of damp powder, and the sieves are all put into a circular motion by machinery, this causes the wooden ball to turn round in the sieve and so rub the damp powder through the little holes; it is collected below in small grains or “corns,” this process is called “corning,” this is now dried, and then put into a “reel” (a sort of barrel which turns round) and the grains, by rubbing against each other, become smoothed on the surface; the dust is now removed by a sieve, too fine to let the grains through; the powder is now fit for use.
Gunpowder was first known in England about five hundred years ago. It is not only used to discharge firearms, but in the more peaceful occupations of quarrying stone, mining, and to get rid of rocks both below and above water; these processes are called “blasting.”
GUN COTTON.
To prepare gun cotton, make a mixture of three parts sulphuric acid and one part nitric acid; when this has cooled (for it becomes hot on mixing), put into it some cotton wool, and let it be stirred about with a glass rod, then taken out, and all the superfluous acid strained from it; it is then to be covered up for an hour or so. It should now be thoroughly washed in cold water, so that all the acid be removed; to ensure this completely, let it be afterwards washed in a very weak solution of potash, and then dried by a very gentle heat, produced by either steam or hot water; when dry, soak it in a solution of nitre and dry it again. It is now so explosive that great care is required in its management, being about three times as explosive as gunpowder.
PHOSPHORUS.
This substance, since the general use of lucifer-matches, has become an important article of manufacture; whereas, but a few years ago, it was a mere chemical curiosity. It is prepared by mixing bone ashes with sulphuric acid, straining off the liquid part, and evaporating it to a syrupy consistence; with this, about a quarter of its weight of powdered charcoal is mixed, and the whole stirred and evaporated to a dry powder; this is put into earthenware retorts, which are connected by copper tubes to receivers filled with water; the retorts are raised to a white heat and maintained at this high temperature as long as any phosphorous passes into the receivers, the water in which is kept warm, so that the phosphorous melts and runs to the bottom, from whence it is taken and strained through chamois leather bags, under warm water, and then cast in glass tubes into sticks. Phosphorous is of a whitish color, like wax, is easily melted, readily takes fire even by slight friction, and, in the air, gives off fumes which in the dark appear luminous. It is chiefly used in the manufacture of lucifer matches, and, mixed with flour, butter, or sugar, is used to poison rats, mice, and other vermin, under the name of “phosphorous paste.” Phosphorous is poison, and most dangerous stuff to handle, minute particles often getting under the nails and causing painful sores.