6 Biography of Berzelius. 



ceeded in discovering lithium, which, as it came so unex- 

 pectedly, justly created great interest. 



The following larger papers of Berzelius form, as it were, 

 a series of monographs upon separate and important branches 

 of chemistry, which were at that time still obscure. It was 

 natural, that when he commenced the demonstration of the 

 law of definite proportions by means of a succession of labo- 

 rious investigations, that he must throw aside much, in order 

 to sketch the groundwork of his system. The investiga- 

 tions which he now undertook, were all instituted in accord- 

 ance with a matured plan, and he had long meditated upon 

 them before actually entering upon them. 



The first of these investigations was upon the ferruginous 

 cyanogen compounds. Gay-Lussac had, in his very import- 

 ant paper upon cyanogen, neglected to study these com- 

 pounds. After him several chemists had occupied themselves 

 with their examination, but all obtained very different results, 

 the greater number, however, assuming that the iron in the 

 so-called ferro-prussic acid salts was an essential constituent 

 of the acid which was combined in the salts with an oxidized 

 body. 



Berzelius, however, shewed that these salts contained 

 neither prussic acid nor oxidized bases, but that they con- 

 sist of cyanide of iron combined with the cyanide of an alka- 

 line metal, and consequently were double cyanides. He also 

 extended his investigations to the so-called sulpho-cyanic 

 acid salts, and shewed that they consist of metal, sulphur, 

 and cyanogen, the latter two united to form a radical (which 

 he subsequently called Ehodan) ; and that in them likewise 

 there was neither prussic acid nor oxidized bases. 



These investigations, which fully confirmed the views of 

 Gay-Lussac regarding cyanogen, were, however, of still 

 greater importance to Berzelius in another respect. After 

 Davy had been induced, by his researches in 1810, to con- 

 sider that it was simpler and more correct to look upon 

 chlorine as elementary, and not, as he had formerly done, as 

 a compound of oxygen with a radical that had not been iso- 

 lated ; most chemists concurred with him in this view. Gay- 

 Lussac and Thenard, who, even before Davy, considered a 



