DECOMPOSITION OF DIAZOBENZENE NITRATE. 295 



residue was effected without heat by means of the Schloesing 

 process, when it was found to represent 'Oil grm. per gramme 

 of the explosive compound. In the gases themselves, we found 

 0*00042 grm. of ammonia. 



12. The following table sums up these results, the weights 

 being expressed in parts per thousand : 



The result, 769*7, is higher than the weight of gas given above 

 (758-6), as it includes the ammonia. 



13. Equation of decomposition. We see, from this table and 

 from the discussion that arose when these gases were being 

 studied, that, if we disregard the complications caused by 

 secondary formations (hydrocyanic acid, ammonia, marsh gas), 

 the principal reaction is reduced to the following : 



C 6 H 5 N 2 N0 3 = SCO + 3C + 5H + 3K 



In reality, about one-tenth of the carbon that is not combined 

 with the oxygen, remains united with the hydrogen and nitrogen, 

 in a gaseous form, constituting marsh gas and hydrocyanic acid. 

 One-third of the hydrogen goes to form these same gases, 

 together with ammonia and fixed compounds. Lastly, one- 

 fourth of the nitrogen goes to form ammonia, hydrocyanic acid, 

 and nitrogenised charcoal. 



14. The simple decomposition of diazobenzene nitrate so as 

 to give carbon monoxide and free elements 



SCO + 3C (diamond) + 5H + 3tf, 



should disengage 201*6 Cal. at constant pressure ; i.e. 204*7 Cal. 

 at constant volume according to the heat of total combustion, 

 instead of -f 114'8, which was actually found. This proves that 

 the formation of secondary products has absorbed 8 9 '9 Cal. 



Such an absorption of heat results principally from the forma- 

 tion of the nitrogenised charcoal ; the exothermal formation of 

 ammonia and marsh gas almost counterbalancing the endo- 

 thermal formation of hydrocyanic acid. 



