Biography of Berzelius. 217 



of ordinary chemical processes, in which bodies act upon 

 each other only when in immediate contact, are different from 

 those which occur during the discharge of an electric pile 

 where bodies act at a distance. It is only in some chemical 

 processes, such as the arborescent deposition of metals, that 

 there is a resemblance to the decompositions effected by the 

 pile 



Much later Berzelius assumed the existence of another 

 force, although only as regarded some special chemical 

 changes — the catalytic force. The evolution of light and 

 heat according to the electro-chemical theory could only result 

 from the combination of bodies opposite in their characters ; 

 but when they occur on the decomposition of bodies, or when 

 compounds are decomposed and new ones formed, without 

 the body, whose presence causes this change, taking part in 

 it, Berzelius ascribed this effect to the force of catalysis. 



Much has been brought forward in opposition to the as- 

 sumption of this new hypothetical force. But it is not justly 

 censurable that, in an imperfect science like chemistry, all 

 phenomena which stand isolated, for which no suitable ana- 

 logues can be found, and which appear as it were wonderful, 

 should provisionally be ascribed to a peculiar cause or force, 

 so as openly to admit, that in the present state of the science 

 it is more appropriate not to explain a chemical process at 

 all than to do so in a forced and fastidious manner. With 

 the advance of the science the number of phenomena belong- 

 ing to such categories will always become smaller. 



After Berzelius had laboured uninterruptedly during a 

 space often years in the investigation of the atomic weights 

 of the elements and their compounds, and had these so far 

 established that all experiments corresponded to within small 

 and unavoidable errors, he was in a position in 1818 to pub- 

 lish tables containing the atomic weights of about 2000 simple 

 and compound bodies. 



Thus had Berzelius completed as it were the scaffolding 

 of his system, and he now commenced to supply the defi- 

 ciencies which he had previously been obliged to pass over, 

 and thus to plan out the whole. 



Some time before, in 1814, he had also extended his inves- 



