214 lliognvphy of Berzeliu*. 



correct statement of Stadion, that hyperchloric acid contained 

 seven atoms of oxygen. 



The examination of the oxides of nitrogen presented consi- 

 derable difficulties to him. As ammonia was analogous to the 

 fixed alkalies, and, under the influence of galvanic electricity 

 yielded an amalgam with mercury, there was a possibility of 

 assuming that this was a process of reduction, and that ammo- 

 nia consisted of a metal and oxygen. But when ammonia was 

 decomposed, no oxygen was obtained, but only nitrogen and 

 hydrogen ; the oxygen must therefore, Berzelius inferred, be 

 concealed in these gases ; and one or both must be oxides of 

 the same radical, and this radical the metal ammonium. But 

 if nitrogen alone were the oxidised body, then the metal am- 

 monium must consist of the radical of nitrogen and hydro- 

 gen. Then, again, at that time several chemists, especially 

 Gay-Lussac and Thenard, assumed that potassium and so- 

 dium contained hydrogen ; however, in the controversy which 

 arose on this point between these chemists and Davy, who 

 sought to disprove their view, Berzelius immediately decided 

 in favour of the latter, and supported him with very strong 

 arguments. He also assumed, on this account, the presence 

 of oxygen in hydrogen, and this as well as nitrogen were, 

 according to his view, oxides of the metal ammonium. The 

 different stages of oxidation were, according to him, the fol- 

 lowing : hydrogen, protoxide of ammonium (the present ami- 

 dogen combined with potassium), ammonia, nitrogen, nitrous 

 acid, nitric acid, and finally water, the highest oxide of the 

 radical, which, however, must, on this view, have contained 

 72 times as much oxygen as the lowest oxide hydrogen. 



Berzelius was led to adopt this extravagant but ingenious 

 view by too great faith in the doctrine of proportions in 

 the form in which he then conceived it. Somewhat later he 

 retracted the opinion that hydrogen was an oxide, and de- 

 monstrated the elementary nature of this body by weighty 

 arguments ; but he still continued to regard nitrogen as con- 

 taining oxygen, and endeavoured afterwards to prove this by 

 means of its oxides. Even in 1818, in a paper upon the na- 

 ture of nitrogen, hydrogen, and ammonia, he said, " I ven- 

 ture to assert, that the compound nature of nitrogen must 



