1882.] 



Chemical Theory of Gunpowder. 



365 



which a given weight of powder can produce by its explosion, from the 

 composition of a portion of the residue and the composition of the 

 powder. They assume that the portions of powder of the same 

 description nsed in different experiments, were of the same compo- 

 sition. This is, according to the statements under No. 5, not the case. 

 The calculated quantities of gas and solid residue which a given 

 weight of powder can produce, will, in consequence, be affected by 

 certain errors. These errors compensate each other if the mean of 

 many experiments is taken. 



10. Portions of powder taken from different parts of the same 

 barrel show, according to Noble and Abel's analyses, greater diffe- 

 rences in their composition than samples of different descriptions 

 manufactured at Waltham Abbey, pebble, rifle fine-grain, rifle large- 

 grain, and fine-grain powder ; hence, we are justified in taking the 

 mean of the analyses of these powders, and expressing thereby the 

 composition of the English Service powder. The mean of the analyses 

 of Noble and Abel, and Wills, can be represented by the symbols — 



16KN0 8 + 21-180 + 6-63S, 



if hydrogen, oxygen, and ash of the charcoal, and the hygroscopic 

 moisture of the powder are neglected. 



11. From evidence described in the paper it follows, with a high 

 degree of probability, that during the combustion of gunpowder 

 potassic disulphide, and not monosulphide, as is usually assumed, is 

 formed. 



12. If the errors arising from the analytical method are corrected as 

 explained in the paper, if allowance is made for the sulphur which has 

 united with the iron of the apparatus, and, finally, if, for the reasons 

 adduced under No. 9, the mean is taken of the thirty-one analyses 

 published by Noble and Abel, then the explosion of the powders of 

 Waltham Abbey, as conducted by Noble and Abel in a confined space, 

 can be represented very nearly, if not quite accurately, by the follow- 

 ing equation : — 



16KNO 8 + 210 + 5S = 5K«,C0 8 + KoS0 4( + 2K,S«, + 13CO a + 3CO + 8N 2 



(«). 



1*63 atoms of the sulphur contained in the powder have united 

 partly with hydrogen and formed sulphuretted hydrogen, partly with 

 iron and produced ferrous sulphide. The entire amount of the oxygen 

 contained in the charcoal is eliminated with hydrogen as water, the 

 rest of the hydrogen either remains free or produces methane with 

 carbon and ammonia with nitrogen. The composition of the powder, 

 calculated from the mean composition of the products of explosion of 

 thirty-one experiments, can be represented by the symbols 



I6KNO3+ 21-350 + 6-62S, 



