78 HISTORY OF GALVANISM. 



and were metallic, yet there were some circum- 

 stances in the mode of their formation, which led 

 to the supposition that they were a compound of a 

 metal and hydrogen; but this opinion is now 

 abandoned. 

 Attempts The analogy which exists between the proper- 



to decom- 



pose am- ties of the fixed and the volatile alkalies, led Sir 

 H. Davy to apply his powerful means of decompo- 

 sition to ammonia. The analogy of properties, 

 however, which causes them to be placed in the 

 same class of bodies, seemed to be counteracted by 

 the experiments of Berthollet, who, as is well 

 known, had resolved this latter substance entirely 

 into hydrogen and azote. Accordingly the me- 

 tallic nature of ammonia has not yet been proved ; 

 and although Sir H. Davy, in his earlier experi- 

 ments, conceived that he had procured oxygen 

 from it, and Berzelius obtained a species of amal- 

 gam, by exposing it in contact with mercury to the 

 galvanic influence, yet subsequent experiments by 

 Dr. Henry, and MM. Gay-Lussac and Thenard, 

 appear to explain these appearances on other 

 principles, and to restore the original conclusion, 

 that ammonia is a compound of azote and 

 hydrogen alone.* 



Decompo- Sir H. Davy next turned his attention to the 

 ?he earihs. earths. He found them more difficult to decom- 

 pose than the alkalies, and many arrangements 

 were employed without success. The object was, 



* Phil. Trans, for 1808, p. 1. 



