Mr. Dutens in his “Inquiry into the Origin of the discoveries attributed to the moderns,” carries the antiquity of Gunpowder much higher; and refers to the accounts given by Virgil, Hyginus, Eustathius, Valerius Flaccus, and many other writers of the same date.
To close this tedious detail, we will mention one more work, which seems to confirm the antiquity of this composition, viz. the “Code of Gentoo Laws,” 1776; in the preface of which it is asserted, that Gunpowder was known to the inhabitants of Hindostan, far beyond all periods of investigation.
Having said thus much concerning the history and antiquity of this wonderful composition, it remains for us to describe the method by which it is now manufactured: but to retain that gradatum, or progressive order, with which we commenced our Work, it is necessary that we first describe the ingredients of which it is composed; for it is only by a knowledge of the parts of any composition, that we can gain a good understanding of the properties of the whole.
There are only three ingredients that enter into the composition of Gunpowder; these are Salt-petre, Sulphur, and Charcoal. The first is a combination of Nitric Acid[1] and Potash,[2] and is better known in modern chemistry by the name of Nitrate of Potash. The second is a substance very well known, from the inflammable properties it possesses; it is found alone, or combined with other bodies, in various situations; in volcanic productions it is found almost in its last degree of purity: it is found also, in the state of sulphuric acid; that is to say, combined with oxygen: it is found in this state in argil,[3] gypsum,[4] &c. and it may be likewise extracted from vegetable substances and animal matter. The third and last, is an article so well known in commerce, that it is almost needless to describe it; we shall therefore only observe, that the Charcoal found to be best for the composition of Gunpowder, is that made from the alder, willow, or black dog-wood.
This powerful composition is a mixture of these three ingredients, combined in the following proportions: for each 100 parts of Gunpowder, salt-petre 75 parts, sulphur 10, and charcoal 15. In some countries, the proportions are somewhat different; but this is the combination made use of by most of the English manufacturers.
The salt-petre is either that imported from the East Indies, or that which has been extracted from damaged Gunpowder. It is refined by solution, filtration, evaporation, and crystallization; after which it is fused, taking care that too much heat is not employed, or there is danger of decomposing the nitre.
The sulphur used is that which is imported from Sicily, and is refined by melting and skimming; the most impure is refined by sublimation.
The charcoal is made in the following manner. The wood is first cut into pieces of about nine inches in length, and put into an iron cylinder placed horizontally. The front aperture of the cylinder is then closely stopped: at the other end there are pipes connected with casks. Fire being made under the cylinder, the pyro-ligneous acid[5] comes over. The gas escapes, and the acid liquor is collected in the casks: the fire is kept up till no more gas or liquid comes over, and the carbon[6] remains in the cylinder.
The three ingredients being properly prepared, are ready for manufacturing. They are first separately ground into a fine powder, then mixed in the proper proportions, and afterwards committed to the mill for the purpose of incorporating their component parts. The powder-mill is a slight wooden building, with a boarded roof, so that in case of accidental explosions, the roof may fly off without difficulty, and in the least injurious direction, and thus be the means of preserving the other parts of the building.