Theory of Gunpowder. 499 



oxygen by pyrogallate of potash. The residual gas is then 

 transferred into a eudiometer, exploded with excess of hydrogen 

 and electrolytic detonating gas, and the oxygen remaining after 

 the combustion, exploded by excess of hydrogen. 



If the required volumes of carbonic acid, sulphuretted hy- 

 drogen, oxygen, carbonic oxide, hydrogen, protoxide of nitrogen, 

 and nitrogen, be designated respectively by k, w, s, k^, h, Uq, and 

 n, we have first, if Aq be the volume in the absorption-tube taken 

 for analysis, 



k + iv + s + kQ + h + 7iQ + n = Aq ; 



k, w, and s are obtained directly by absorption. If A, be the 

 volume remaining after this absorption, we have 



kQ + h + nQ + n-=k^. 



If Ag volumes of the volume Aj be taken for analysis in the 



eudiometer, we have, setting ~=ol, 



ctk^ + uh + ««Q + «w = A^. 



If K be the carbonic acid formed by burning this volume Ag 

 with oxygen, and C the contraction observed in the combustion, 

 we have 



ukQ=K, 



, 2C-K 



ah= -g— . 



If be the volume of oxygen admitted into the eudiometer for 

 the combustion of A^, the volume of oxygen remaining after 



K -i-C 

 explosion and absorption of carbonic acid is ^— • Further, 



if V be the volume remaining after the combustion and absorp- 

 tion of carbonic acid of A2 + 0, we obtain 



«no + a«=V-0+— |— (<^) 



If the volume V be exploded with excess of hydrogen, a contrac- 

 tion C ensues, which is caused on the one hand by the combus- 



K 4- f ' 

 tion of oxygen present =0— — ^ , and on the other, by the 



o 



combustion of protoxide of nitrogen. Now as the contraction 



K -<- C 

 corresponding to this ^ — oxygen is 30 — C — K, the 



contraction corresponding to the ctn^ protoxide of nitrogen must 

 be C, — 30 + C + K. And further, since one volume of gas dis- 

 appears by the explosion of one volume protoxide of nitrogen 



