AMMONIA TYPE. 



II 



ammonia gas to the action of the electric spark, it undergoes de- 

 composition into its elementary constituents, as you perceive. 

 We have here two volumes of ammonia gas, which, by the con- 

 tinued action of the electric spark is decomposed into its con- 

 stituent nitrogen and hydrogen and the two volumes of ammonia 

 become gradually increased into four volumes of hydrogen and 

 nitrogen, mixed in the proportion of three volumes of the former 

 to one volume of the latter gas. But in this case, as in the 

 previous two, the information afforded by a determination of the 

 specific gravity of ammonia renders a direct experiment of any 

 kind unnecessary. We find that the weight of two litres of am- 

 monia gas, for instance, is identical with the conjoint weight of 

 one litre of nitrogen and of three litres of hydrogen ; so that 

 while from two litres of hydrochloric acid gas we can extract 

 one litre of hydrogen, and from two litres of steam we can 

 extract two litres of hydrogen, so from two litres of ammonia we 

 can extract three litres of hydrogen, in addition to the one litre 

 of chlorine, oxygen, and nitrogen respectively. Or from double 

 volumes of chloride of hydrogen, oxide of hydrogen, and nitride 

 of hydrogen, we may obtain one volume of hydrogen, two 

 volumes of hydrogen, and three volumes of hydrogen respectively, 

 in addition, in each case, to the one volume of chlorine, the one 

 volume of oxygen, and the one volume of nitrogen, as illustrated 

 by these models. 



Ammonia 



Hydrochloric acid 



Steam 



(10.) You will observe that all I have hitherto said with 

 regard to these three hydrides is simply a matter of experiment 

 or observation, uncontrolled by any theory whatever. It is a 

 matter of fact that if we take equal volumes of hydrochloric acid, 

 steam, and ammonia gases, we can extract from the ammonia 



