Smokeless and even noiseless powders seem to have been sought for during the whole gunpowder period. In 1756 one was experimented with in France, but was abandoned owing to difficulties in manufacture. Modern smokeless powders are certainly less noisy than the black powders, mainly because of the absence of metallic salts which although they may be gaseous whilst in the gun are certainly ejected as solids or become solids at the moment of contact with air.
Brown Powders.—About the middle of the 19th century guns and projectiles were made much larger and heavier than previously, and it was soon found that the ordinary black powders of the most dense form burnt much too rapidly, straining or bursting the pieces. Powders were introduced containing about 3% sulphur and 17-19% of a special form of charcoal made from slightly charred straw, or similar material. This “brown charcoal” contains a considerable amount of the hydrogen and oxygen of the original plant substance. The mechanical processes of manufacture of these brown powders is the same as for black. They, however, differ from black by burning very slowly, even under considerable pressure. This comparative slowness is caused by (1) the presence of a small amount of water even when air-dry; (2) the fact that the brown charcoal is practically very slightly altered cellulosic material, which before it can burn completely must undergo a little further resolution or charring at the expense of some heat from the portion of charge first ignited; and (3) the lower content of sulphur. An increase of a few per cent in the sulphur of black powder accelerates its rate of burning, and it may become almost a blasting powder. A decrease in sulphur has the reverse effect. It is really the sulphur vapour that in the early period of combustion spreads the flame through the charge.
Many other powders have been made or proposed in which nitrates or chlorates of the alkalis or of barium, &c., are the oxygen providers and substances as sugar, starch, and many other organic compounds as the combustible elements. Some of these compositions have found employment for blasting or even as sporting powders, but in most cases their objectionable properties of fouling, smoke and mode of exploding have prevented their use for military purposes. The adoption by the French government of the comparatively smokeless nitrocellulose explosive of Paul Vieille in 1887 practically put an end to the old forms of gunpowders. The first smokeless powder was made in 1865 by Colonel E. Schultze (Ding. Pol. Jour. 174, p. 323; 175, p. 453) by nitrating wood meal and adding potassium and barium nitrates. It is somewhat similar in composition to the E. C. sporting powder. F. Uchatius, in Austria, proposed a smokeless powder made from nitrated starch, but it was not adopted owing to its hygroscopic nature and also its tendency to detonate.
Bibliography.—Vanucchio Biringuccio, De la pirotechnia (Venice, 1540); Tartaglia, Quesiti e invenzioni diversi (lib. iii.) (Venice, 1546); Peter Whitehorne, How to make Saltpetre, Gunpowder, &c. (London, 1573); Nic. Macchiavelli, The Arte of Warre, trans. by Whitehorne (London, 1588); Hanzelet, Recueil de plusiers machines militaires (Paris, 1620); Boillet Langrois, Modelles artifices de feu (1620); Kruger, Chemical Meditations on the Explosion of Gunpowder (in Latin) (1636); Collado, On the Invention of Gunpowder (Spanish) (1641); The True Way to make all Sorts of Gunpowder and Matches (1647); Hawksbee, On Gunpowder (1686); Winter, On Gunpowder (in Latin); Robins, New Principles of Gunnery (London, 1742) (new ed. by Hutton, 1805); D’Antoni, Essame della polvere (Turin, 1765) (trans. by Captain Thomson, R. A., London, 1787); Count Rumford, “Experiments on Fired Gunpowder,” Phil. Trans. Roy. Soc. (1797); Charles Hutton, Mathematical Tracts, vol. iii. (1812); Sir W. Congreve, A Short Account of Improvements in Gunpowder made by (London, 1818); Bunsen and Schiskoff, “On the Chemical Theory of Gunpowder,” Pogg. Ann., 1857, vol. cii.; General Rodman, Experiments on Metal for Cannon, and Qualities of Cannon Powder (Boston, 1861); Napoleon III., Études sur le passé et l’avenir de l’artillerie, vol. iii. (Paris, 1862); Von Karolyi, “On the Products of the Combustion of Gun Cotton and Gunpowder,” Phil. Mag. (October 1863); Captain F. M. Smith, Handbook of the Manufacture and Proof of Gunpowder at Waltham Abbey (London, 1870); Noble and Abel, Fired Gunpowder (London, 1875, 1880); Noble, Artillery and Explosives (1906); H. W. L. Hime, Gunpowder and Ammunition, their Origin and Progress (1904); O. Guttmann, The Manufacture of Explosives (1895), Monumenta pulveris pyrii (1906); Notes on Gunpowder and Gun Cotton, published by order of the secretary of state for war (London, 1907). (See also [Explosives].)
(W. R. E. H.)
[1] These words were emended by some authors to read luru mope can ubre, the letters of which can be arranged to give pulvere carbonum.
[2] This represents the composition of English powder at present, and no doubt it has remained the same for a longer time than the above date indicates.
[3] Brown or coco-powder for large charges in guns. The charcoal is not burnt black but roasted until brown, and is made from some variety of straw, not wood.