GUNPOWDER, is a compound of nitre, sulphur, and charcoal. The chemical action which these few elemen tary bodies exert on each other has many times determin ed the fate of nations. More human beings have fallen victims to its power than at present exist upon the face of the globe, and it is now considered as the most effective agent in modern warfare.
The history of this surprising substance is clouded with much obscurity, and this we deem sufficient for not enter ing minutely into this branch of our subject.
Polydore Virgil and Thevet attribute the discovery of gunpowder to a monk named Constantine Anelzen, who was a chemist of some celebrity in his time. Others assert, with much probability, that it was discovered by Barthol dus Schwartz about the year 1320.
The Venetians are said to have used gunpowder during a war with the Genoese, in the year 1330. In 1346, cannon and gunpowder were used at the battle of Cressy; and about the same time at the seige of Calais.
Long before any of these periods, gunpowder is said to have been discovered by Roger Bacon. Iu a work written by him in 1280, he points out the composition of gunpow der; and was so much aware of its importance, as to re commend its explosive powers as the means of destroying armies.
The Chinese, and probably other nations of the East, with whom most of the arts have originated, appear to have been acquainted with a variety of these explosive com pounds long before they were known to Europe. It ap pears almost impossible, that, in countries where nitre is found in the soil, the commonest people should have been ignorant of the action between carbon and nitre. If sul phur were not present, still the effects would be remark able.
The preparation of gunpowder is divided into three prin cipal departments. 1st, The choice and purification of the materials ; 2d, The adjustment of the proportions, by which a maximum of explosive power may be produced; and 3d, The incorporation of the materials, which is a mechanical process not of less importance than the other departments.
In the choice of nitre, no rule is so important as the form and size of the crystals. It is necessary first to ex
amine whether the nitre affords any foreign matter differ ent from nitric acid and potash. It sometimes contains nitrate or muriate of lime, magnesia, and perhaps muriate of potash. First dissolve a small portion of the nitre, and filtre the solution. To a little of this, add a few drops of might be used to separate the foreign matter ; but for ge neral use this would be too expensive ; and the only prac ticable method of purifying nitre, is by frequent solution, evaporation, and careful crystallization. When the crys tals are transparent, clear, and well formed into distinct prisms, the nitre may be looked upon as pure. It is well to test it after every fresh crystallization, to know when it may be relied upon. If nitre should contain any alkaline sulphate, the test for this substance will be a solution of nitrate of barytes. If a precipitate is produced, add more of the same substance carefully till no more is precipitated. By this means the sulphate of the alkali becomes a nitrate, which is nitre.
The French method of purifying nitre for the manufac ture of gunpowder is very simple, and has been practised with success. The nitrate or muriate of lime, or the same acids with magnesia and even common salt, arc more easily soluble in cold water than the nitre itself ; but par ticularly the earthy salts, which are most injurious. This property presents an easy means of separating them from the nitre.
The French, for this purpose, first coarsely pound the crude nitre, and put it into a copper, adding to it 20 per cent. of cold rain water. The mixture is then stirred, and allowed to remain for 6 or 7 hours. The liquid part is now drained off, and 10 per cent. more water added, which, after stirring as before, is allowed to remain one hour, and then drained off as formerly. Lastly, 5 per cent. of water is to be added, and drained off as before, leaving the whole to drain completely. By this means the deliquescent salts are carried off, and also a portion of nitre, which may after wards be separated for common purposes.