Evolved gases black powder

Black powder, the oldest explosive and propellant kno wn, consists of a mechanical mixt of saltpeter, charcoal and sulfur in proportions varying with the purpose. Here, saltpeter is the oxygen producer, while charcoal is the combustible material. The object of sulfur is to make the powder readily inflammable and to form, on burning, K or Na sulfide (by reaction with K or Na nitrate) so as to prevent part of the C02 from forming K or Na carbonate, which would, of course, mean a reduction in the amt of gas evolved. Sulfur also imparts the neeessary tenacity and density to the powder mass(Ref 34,p 191)... 

Very etonoteristic derivatives off acetylene are the ex-plorive oomponnds whidi it Arms with certain metak or metallic salts. Tbmt if the gas is allowed to passover fused potassium, hydrogen is evolved, and bodies liavingthe composition C HK and C,Kj ate formed. Both of tliese substances are black powders, which are decomposed in contact with water with expletive violence acetylene Wng reproduced. A timilar calcium compound was obtained Wtihler on beating a mixture... 

A mixture of ThOg and calcined carbon black (0.24% ash) or graphite powder (0.33% ash), in quantities corresponding to the above equations, is made into a paste with a small amount of water and starch, and evaporated with stirring (graphite is preferred to carbon black because of its smaller volume). The lumps of dried material are placed in a crucible by means of a porcelain spatula their large size prevents them from being carried out of the crucible by the CO gas evolved in the process. 

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