xvn MOLECULAR ARCHITECTURE 397 



two sulphides, were strictly analogous with the oxy-salts 

 formed by the combination of two oxides. 



Berzelius's electro-chemical theory (1819). Berzelius's 

 theory included one other unifying feature to which 

 attention must be directed. Berzelius arid Hisinger (p. 273) 

 had been the first to show that the electric battery could 

 produce, not only a decomposition of water, but also a 

 resolution of the dissolved salts into acid and base. This 

 observation^ was soon followed by Davy's discovery of the 

 decomposition of the alkalis and earths into metal and 

 oxygen when the same agency was applied to these sub- 

 stances in the absence of water. As the electric current 

 was thus proved to be the most powerful agency for resolv- 

 ing chemical compounds, Berzelius concluded that chemical 

 affinity was electrical in character. 



" We are now confident that substances on the point of 

 combining, exhibit opposite electric charges, increasing in 

 strength as they approach the temperature at which com- 

 bination takes place, until, at the moment of union, the 

 charges disappear with a rise of temperature which is often 

 so great that fire blazes out. On the other hand, we are 

 equally confident that compound substances, exposed in a 

 suitable form to the action of the electric fluid produced 

 by the discharge of the pile, are separated and recover their 

 original chemical and electrical properties, whilst the charges 

 acting on them disappear." 



" In the actual state of our knowledge, the most probable 

 explanation of combustion and of the ignition resulting 

 therefrom, is then : that in all chemical combination there is 

 a neutralisation of opposite electric charges, and that this 

 neutralisation produces fire in the same way as in the dis- 

 charge of a Ley den jar, an electric pile or lightning, although 

 not accompanied, in these last phenomena, by a chemical com- 

 bination" (Chemical Proportions , 1819, 72-73). 



Berzelius's ELECTRO-CHEMICAL THEORY, as thus enunciated, 

 accounted not only for chemical combination, but also for 

 the liberation of light and heat, thus destroying the necessity 



