RELATION OF NITROGEN TO HYDROGEN. 26 J 



quantity of nitrogen gas, which could not be the case if nascent 

 hydrogen were able to form ammonia. 



It has been considered as a certain proof of the formation of 

 ammonia from the nitrogen of the air, that peroxide of iron, 

 formed by the rusting of iron in the air, contains a certain quan- 

 tity of ammonia ; but air itself contains ammonia, which pos- 

 sesses a considerable affinity for peroxide of iron. Marshall 

 Hall has shown the inaccuracy of the view that water is decom- 

 posed in this case ; and further experiments, instituted in this 

 laboratory for the especial purpose of deciding this question, have 

 shown, that when air is freed from its ammonia, by being con- 

 ducted through concentrated sulphuric acid, before being brought 

 in contact with the rusting iron, the oxide then formed does not 

 contain a trace of ammonia. 



Braconnot* has shown that most basalts, trap, granite from 

 Rochepon, and from Bresse ; syenite, amphibolite, wakit (a lava) ; 

 basalt, from Baden ; quartz, from Gerordines ; pegmatite, and 

 many other minerals, yield, by dry distillation, water containing 

 a sensible quantity of ammonia. 



These facts cannot be explained by the interpretation above 

 given to the occurrence of ammonia in ferruginous tarth, namely, 

 the oxidation of iron at the expense of water ; but there cannot 

 be any doubt that the ammonia has had a similar origin in all 

 these cases, although that origin cannot be ascribed to an oxida- 

 tion of iron. 



The question — whether the nitrogen of the air possesses the 

 power of uniting with hydrogen at the moment of its liberation 

 from water ? has been lately made the subject of exact experi- 

 ments, although with very different objects in view. Will and 

 Varrentrapp applied to the quantitative estimation of nitrogen in 

 organic bodies the known fact, that the nitrogen of bodies con- 

 taining that element is evolved in the form of ammonia, when 

 they are heated to redness, mixed with potash. By combining 

 the ammonia with an acid, and converting it into the salt termed 

 chloride of platinum and ammonia, the ammonia generated may 

 be weighed with ease, and the quantity of nitrogen may 

 be calculated from the known composition of this salt. A great 

 * Annates de Chitnie et de Physique, tome lxvii., p. 104, &c. 



