766 



GUNPOWDER 



to^which the powder is subjected is glazing. Its object is to render it less liable to 

 injury, by absorption of moisture or disintegration during its carriage from place to 

 place. The glazing is effected by causing the grained powder to rotate for somo 

 time in a wooden drum or cylinder, containing rods of wood running from end to end. 

 The grains as they rub against each other and against the wooden ribs, have their 

 angles and asperities rubbed off, and at the same time the surface becomes harder and 

 polished. It is finally dried by exposure to a stream of air, heated by means of 

 steam. 



A vast number of experiments have been made, at various times, to discover the 

 proportions of nitre, sulphur, and charcoal best adapted for the production of 

 gunpowder. It has been found, as might have been anticipated, that no general rule 

 can be given, no admixture can bo made which shall fulfil every requirement. 

 Those powders which contain the largest quantities of charcoal are, it is true, as 

 powerful as others in projectile force ; but they have the disadvantage of attracting 

 more humidity from the air. It is very singular that all nations appear to have found, 

 by trial, the proportions most generally useful for ordinary purposes, and it is worthy 

 of remark, that they all approximate to the percentages required by the very simple 

 formula, KO,N0 5 + S + 30. In fact, the Prussian powder approaches so closely 

 the theoretical numbers, that they fall within the limits of the errors of analysis, 

 thus : 



Prussian powder. Theoretical proportions. 



Nitre . . 75-0 KO,N0 5 93 or 1 equivalent 74'8 



Sulphur . 11-5 S 16 11*9 



Charcoal .13-5 C . 18 or 3 equivalents 13 '3 



100-0 



127 



100-0 



When a powder constituted as above is fired, the decompositiou is probably as 

 follows (represented in symbols) : 



KO,N0 5 + S + 30 = 300= + N + KS. 

 [2(XWO) + S + 3C = 3C0 2 + 2M- + K 2 S] 



That is to say, the explosion of one equivalent of powder results in the formation of 

 three equivalents of carbonic acid, one of nitrogen, and one of sulphide of potassium. 

 It is evident that these theoretical relations are not absolutely the true expression of 

 the phenomena ; because, in the first place, gunpowder is merely a mechanical mixture, 

 and not a definite chemical compound ; and, in the next, the charcoal is repre- 

 sented by the symbol C as if it were pure carbon, whereas, in fact, even the purest 

 and best-made charcoals contain variable amounts of hydrogen, ashes, and oxygen. 

 The hydrogen is partly converted into water and partly into hydrosulphuric acid 

 (sulphuretted hydrogen). 

 The following are the proportions of the ingredients used in various countries : 



Table of the Composition of various Gunpowders. 





Blasting powders contain less nitre than others, the combustion is therefore less 

 perfect, and if used for artillery or small arms, not only is the piece very soon ren- 

 dered foul, but the ball is projected to a much less distance than is required in prac- 



