LUEDEKING — CHEMISTRY OF COMBUSTION. 37I 



the mode of formation of cyanide of Potassium in iron blast fur- 

 naces, as was demonstrated by the same authors. 



By passing ammonia gas over red-hot charcoal cyanide of Am- 

 monium and Hydrogen are formed, according to Langlois, thus : 



2NH3 XC = NH^ CN X 2H. 



Here Hydrocyanic acid is formed probably by the dissociation of 

 the ammonia and a reaction upon one another of the nascent 

 elements. 



Again, the cyanogen Titanium compound is formed by heating 

 Titanic acid and Carbon in an atmosphere of Nitrogen to the tem- 

 perature of fusion of platinum according to Wohler and Deville 

 (Annal. d. Chem. u. Pharm. vol. ciii. p. 231). 



Here, then, vv^e have an experiment under conditions similar to 

 those in our own. In the reducing flame we have nitrogen of the 

 atmosphere, free carbon shown by the luminosity, and Titanic 

 acid and a very high temperature. The formation of the cyano- 

 gen Titanium compound in the reducing flame is brought about 

 chemically in exactly the same manner as in the Wohler & De- 

 ville experiment. 



The general assumption is that Carbon and Nitrogen cannot 

 unite directly without the inducing action of another substance. 

 On the basis of the mechanical data we should also expect this to 

 be the case. The heat of formation of Cyanogen gas out of Car- 

 bon (Diamond) and Nitrogen is — 3S300 calorics. The heat of 

 formation of Hydrocyanic acid out of Carbon (Diamond) and 

 Nitrogen and Hydrogen is — 30200 calorics. The heat of forma- 

 tion of Cyanide of Potassium solid out of Carbon (Diamond) and 

 Nitrogen and Potassium is -|- 30300 calorics. Whilst the forma- 

 tions of Cyanogen and Hydrocyanic acid are accompanied with a 

 disappearance of heat, are endothermic reactions, the formation 

 of Cyanide of Potassium is accompanied with powerful evolution 

 of heat, it is an exothermic reaction. 



There is, however, one experiment byMorren, C. R. 48, p. 342, 

 demonstrating the direct union of carbon and nitrogen, in passing 

 electric sparks bitweei electrodes of carbon in an atmosphere of 

 nitrogen. The reasons for this result, so antagonistic to thermo- 

 chemical expectitions, we shall enter upon later. 



