Biography of Berzelius. 203 



with the mercury in such a quantity as to obtain a result. 

 He then endeavoured to attain his purpose by the direct de- 

 termination of the oxygen supposed to exist in ammonia. He 

 wished to make an application of the discovery made by 

 Bergman in his work " De di versa phlogisti quantitate in 

 metallis, 1 ' that when one metal separates another in a metallic 

 state, from solution in an acid, the metal suffering solution 

 yields precisely the same amount of phlogiston as the one pre- 

 viously dissolved requires in order to assume the metallic 

 form ; that a certain acid in dissolving metals expels equal 

 quantities of phlogiston from the different metals ; or to ex- 

 press the same in the language of the antiphlogistic system, 

 that when a certain quantity of any acid combines with dif- 

 ferent metallic oxides, forming neutral salts, the oxides must 

 contain an equal and invariable quantity of oxygen. 



But in order to be able to apply this law of Bergman with 

 perfect certainty, unassailable proofs of its perfect accuracy 

 were necessary. Those, indeed, which Richter had given 

 could not be regarded as at all admissible. Berzelius now 

 compared his analyses of potash, soda, and lime with Bucholz's 

 analysis of oxide of silver, and that made by my father of 

 oxide of mercury ; and he found in fact that the quantity of 

 these bases which saturate the same quantity of hydrochloric 

 acid, forming a neutral salt, contained, with very slight devia- 

 tions, the same quantity of oxygen. But w r hen he came to 

 examine other metallic oxides and combinations with muriatic 

 acids, the results obtained were so much at variance (perhaps 

 on account of many erroneous premises which he assumed) 

 with the principle of Bergman, that he was compelled to 

 ascribe the want of correspondence either to his own want of 

 dexterity in experimenting, or to an erroneous application of 

 Bergman's laws. Since, however, careful repetition of his 

 experiments gave results corresponding closely with those 

 first obtained, he began to entertain doubts of the correctness 

 of Bergman's law. When, again, he subsequently found that 

 metallic sulphurets, on being perfectly oxidised by nitric acid, 

 yielded neutral sulphates of the oxide, without any excess 

 either of metallic oxide or sulphuric acid, he felt compelled 

 to return again to the opinion which he had abandoned. At 



