572 
DE. H. DEBUS ON THE CHEMICAL THEOEY OF GUNPOWDEE, 
and 5*1 atoms of sulphur were transformed according to equation (VIII.). If in 
equation (IX.) for y the number 21 '35, and for z the number 5*1 is substituted, the 
volume of gas is found to be 47*73. 
16KN0 3 + 21‘35C-j-5*lS are equal to 2035*4 parts by weight, and 47*73 vJ§3. = 
534098*7 cub. centims., if the weight is expressed in grammes, therefore: 1 grm. of 
the powder yields 262*4 cub. centims. of gas. 
On an average, 93*75 per cent, of the weight of the powder was transformed, according 
to equation (VIII.), hence we have : 
262-4 x 93-75 
100 
= 246*0 cub. centims. 
"i 
for the theoretical volume of gas formed by the combustion of 1 grm. of powder. 
The mean of Noble and Abel’s observations is 268*7 cub. centims. From this 
number 14*5 cub. centims. must be subtracted for the volumes of sulphuretted 
hydrogen, marsh gas, and hydrogen, leaving 254*2 cub. centims. for the carbonic acid, 
carbonic oxide, and nitrogen. Therefore we obtain, for the volume of the gas 
produced by 1 grm. of service powder from Waltham Abbey, 
Experiment. Theory. 
254*2 cub. centims. 246 cub. centims. 
the difference between the two numbers is only 1*9 cub. centim. greater than the 
greatest difference between two observations made with B. L. G. powder. 
The three descriptions of powder, Bunsen and Schischkoef’s, Linck’s, and Noble 
and Abel’s, contain from 13 to 21 atoms of carbon, and from 6*3 to 8*4 atoms of 
sulphur for every 16 mols. of saltpetre, and are good representatives of gunpowder in 
general. 
The values calculated for the volumes of the gases furnished by these powders are 
near enough to those found by experiment to show the correctness of the theoretical 
considerations on which equation (IX.) has been framed, and to justify the use of this 
equation for the determination of the volume of gas produced by mixtures which 
contain saltpetre, carbon, and sulphur in proportions different from those of the 
Waltham Abbey, the Wurtemberg, or Bunsen and Schischkoff’s powder. 
The amount of heat generated by the combustion of a mixture of saltpetre, pure 
carbon, and sulphur can be found in the following manner: 
If we assume, as in the case of the calculation of the gas, that no carbonic oxide is 
formed, that is to say put a = 0, multiply the heat of formation of each product with 
its coefficient in equation (Till.), add the products thus formed and subtract from 
the sum the heat of formation of saltpetre : the difference will be equal to the heat 
generated by the combustion of the mixture. 
