THE 



POPULAR SCIENCE 

 MONTHLY. 



SEPTEMBEE, 1904. 



THE DEVELOPMENT OF THE THEOEY OF ELECTEO- 



LYTIC DISSOCIATION.* 



By Professor SVANTE ARRHENIUS, 



STOCKHOLM, SWEDEN. 



A T first sight nothing seems to be more evident than that every- 

 -*--*- thing has a beginning and an end, and that it is possible to 

 divide everything. Nevertheless, the philosophers of antiquity, espe- 

 cially the Stoicist, concluded, on purely speculative grounds, that 

 these opinions are not at all necessary. The wonderful development 

 of science has reached the same conclusion as these philosophers, espe- 

 cially Empedocles and Democritus, who lived about 500 years B. C, 

 and for whom the ancients had already a vivid admiration. 



Empedocles professed that nothing is made of nothing, and that it 

 is impossible to annihilate anything. All that happens in the world 

 depends upon a change of form and upon the mixture or the separa- 

 tion of bodies. Fire, air, water and earth are the four elements of 

 which everything is composed. An everlasting circulation is charac- 

 teristic of nature. 



The doctrine of Democritus still more nearly coincided with our 

 modern views. In his opinion bodies are built up of indefinitely 

 small indivisible particles, which he called atoms. These are distin- 

 guished by their form and magnitude, and also give different products 

 by their different modes of aggregation. 



This atomic theory was revived by Gassendi about 1650, and then 

 accepted by Boyle and Newton. The theory received a greatly in- 

 creased importance by the discovery by Dalton of the law of multiple 

 proportions. For instance, the different combinations of nitrogen with 



* Address before the Royal Institution of Great Britain, June 3, 1904. 

 VOL. lxv. — 25. 



