EXPLOSIVE MIXTURES OF THE NITRATES. This class consists of those compounds which are me chanical mixtures of nitrates with some base, and contain charcoal or other substance yielding carbon, also usually containing sulphur. The nitrates are the source of the oxygen which on explosion combines with the carbon of the char coal, producing large volumes of gases, so that the mixture when confined will at the time of ex plosion be accompanied by a violent disrupting action. The typical representative of this class is black gunpowder, for a description of the manu facture of which, see GUNPOWDER. The standard composition of gunpowder is potassium nitrate (saltpetre) 75 parts, charcoal ]5 parts, and sulphur 10 parts; although these ingredients necessarily vary according to the uses for which the powder is desired: that is, whether Tor blast ing, sporting, or warfare. They must also be combined so that (1) the combustion may be complete and little residue left after explosion; (2) that the powder should not readily absorb or retain moisture; (3) that its explosive properties should not be greater than required; and (4) it should be hard and dense enough to bear trans portation without disintegrating. Excess of carbon and sulphur prevents perfect combustion and lowers the explosive force, while too great an amount of potassium or sodium chloride in the saltpetre will make the powder hygrometric. Disintegration may be prevented by proper stamping. Good gunpowder should have a den sity between 1.5 and 1.55. and the most powerful powders are those that are time most dense. Its exploding point ranges from 270° O. for blast ing-powder, 275° C. for rifle-powder, and 315° C. for the best sporting-powder.
Among the more important explosive com pounds in this class may be mentioned time fol lowing: Amide powder. consisting of a mixture of ammonium and potassium nitrates with char coal: az-otinr, consisting of sodium nitrate 69.04 parts, carbon 15.23 parts, sulphur 11.43 parts, and petroleum. 4.29 parts; earbo-asothw, con sisting of potassium nitrate 6].04 parts, ferrous sulphate 13.58 parts, soot 24.65 parts, and sul phur 13.58 parts: diorexine, consisting of potas shun nitrate 50 parts, sodium nitrate 25 parts. sulphur 12 parts, and sawdust from hard wood 1:3 parts; johnitr, consisting of potassium ni trate 75 parts, sulphur 10 parts. lignite 19 parts, sodium picrate 3 parts, and potassium chlorate 2 parts; pc/ratite, consisting of potas sium nitrate 64 parts, impregnated wood or charcoal 30 parts, crude antimony 6 parts; purolitc. consisting of potassium nitrate 51.50
parts, sodium nitrate 6 parts, sulphur 20 parts, sawdust 11 parts, and charcoal 1.50 parts: and saxifrayinr, or poudre barytique, mixture of barium nitrate and charcoal with a small portion of potassium nitrate.
Exem.osivE MI:ci1ia:8 OF TII E rIILORATES. On account of the readiness with which potassium ehlorato lends itself to the production of powerful explosives, it has been frequently used by in ventors to produce explosive mixtures. it will eon:bine with almost any ea rhonaosms material, and will readily explode by friction. The lend eney of such mixtures ti) spontaneous ignition, as well as their sensitiveness to percussion. has pre vented their extensive adoption. Among the mix tures in this class that may be mentioned are the following: Asphaline, consisting of potassium chlorate 54 parts, potassium nitrate and sulphate 4 parts, mixed with bran 42 parts; Ehrhardt powder, consisting of a mixture of tannin, pow dered nutgalls, or cream of tartar, with potas sium chlorate; Fontaine powder, consisting of a mixture of potassium chlorate and potassium pierate; florseley powder, consisting of potas sium chlorate 6 parts, nutgalls 1 part, and charcoal 1 part, mixed with 72 parts of nitro glycerin (this may also be classed as a dyna mite) ; helloes safety powder, consisting of spent tan and sawdust saturated with potassium or sodium nitrate and a little potassium chlorate, and then mixed with sulphur ; blast ing-powder, consisting of potassium chlorate 50 parts, manganese dioxide 5 parts, and finely pul verized organic matter, as bran. 45 parts; Orien tal powder. consisting of potassium nitrate and crude gamboge mixed with potassium chlorate; pyronoine, consisting of potassium nitrate GO parts, sulphur 9 parts, charcoal JO parts, metal lic antimony 8 parts, potassium chlorate 5 parts, rye flour 4 parts, and a small quantity of potas sium chromate; rachurock, consisting of potas sium chlorate 79 parts. and mono-nitrobenzine 21 parts, which are prepared separately and com bined only when about to be used tutonite, con sisting of potassium chlorate mixed with sulphur and metallic sulphides; and white powder, con sisting of a mixture of sugar, potassium ferro cyanide, and potassium chlorate.