FARADAY'S EXPERIMENTS. 2il 



the air contains oxygen, which was never observed to unite with 

 the liberated hydrogen under the same circumstances, although 

 its affinity for that element is infinitely greater than for nitrogen. 



According to this supposition, the nitrogen of the air must 

 have formed ammonia by uniting with the hydrogen of the 

 decomposed water, although at the same time there was present 

 oxygen, for which hydrogen has a much greater affinity. 



The experiments were repeated in an atmosphere of pure hy- 

 drogen, prepared from water which was previously freed from 

 all air by long-continued boiling. But in this case also, where 

 all nitrogen was excluded, the presence of ammonia was observed. 

 Hence, Faraday concluded that there must be an unknown 

 cause of the formation of ammonia. 



Now, when it is known that ammonia is a constituent of the 

 air ; that it is present wherever the air is found ; that it is itself 

 a coercible gas, which is condensed on the surface of solid bodies 

 in much larger proportion than air ; and further, when it is 

 known that it exists in distilled water, these, and other still more 

 incomprehensible experiments of Faraday, are explained in a very 

 simple manner. 



Fine and bright iron wire, introduced into fused potash, causes 

 the evolution of ammonia, which soon ceases ; but a new evolu- 

 tion takes place when a second portion of polished iron-wire is 

 introduced (Faraday). 



Zinc introduced into potash in a state of fusion, occasions an 

 immediate evolution of ammonia and hydrogen gas ; but although 

 the conditions for the possible formation of ammonia continue 

 (zinc, air, and nascent hydrogen), the quantity of ammonia gene- 

 rated does not increase ; but, by the addition of fresh zinc, or 

 of hydrate of potash, a new quantity of ammonia may be 

 detected. 



Some potash and zinc were heated together ; a part of the mix- 

 ture was then placed in a flask, which was immediately closed, 

 while another part was dissolved in water, the clear solution dried, 

 and laid aside for 24 hours. After this time had elapsed, the 

 first portion cave scarcely perceptible t; aces of ammonia. The 

 other gave very appreciable indications of its presence, apparently 



