10 Biography of Berzelius. 



theory of chlorine fell to the ground which he had derived 

 from the perfect analogy of muriates with salts, which con- 

 sist of an oxygen acid and an oxygenous base. 



With this investigation of alkaline sulphurets was con- 

 nected the equally important one upon the sulphur salts, 

 which, however, did not appear until several years afterwards. 



In the former paper Berzelius had directed attention 

 to the fact, that the sulphur compounds of alkaline me- 

 tals and of earthy metals combine with other metallic sul- 

 phurets in the same way as the oxides of these metals com- 

 bine with other oxides. Double sulphurets are thus formed 

 which admit of being compared with ordinary salts, inasmuch 

 as one metallic sulphuret constitutes the electro-positive, 

 that is, the basic part of the compound ; the other, on the 

 contrary, the electro-negative part, representing the acid. 

 But here only the lowest sulphurets of the alkaline metals, 

 that is, those corresponding as regards their composition 

 with the basic oxides of these radicals, will fill the place of 

 basic sulphurets ; the higher sulphurets behave, as it were, 

 like peroxides ; they may sulphurise other metals, but do 

 not combine with their sulphur compounds. 



The different stages of sulphuration of the electro-negative 

 metals which Berzelius called sulphides, and whose composi- 

 tion is analogous to that of the metallic acids, combine with 

 the electro-positive or basic sulphurets in such proportions, 

 that if the sulphur were replaced by an equal number of 

 atoms of oxygen, some one of the salts would be formed 

 which the same radicals would yield in their oxidized state. 



Of the sulphur compounds of the non-metallic elements, 

 those of carbon and hydrogen alone combine with the basic 

 sulphurets of the metals ; the latter class of compounds, — 

 those of sulphuretted hydrogen with alkaline sulphurets, — 

 were already known under the name of hydrothio-alkalies, 

 but their true composition was not recognised until now. 



Berzelius regarded this extensive series of sulphur com- 

 pounds quite appropriately as salts, and gave them the suit- 

 able name of sulphur salts, in order to distinguish them from 

 the oxygen salts, or those which had been long known, and 

 the so-called haloid salts, under which name Berzelius com- 



