CHEMISTRY SINCE TIME OF DALTON 



remained to be accounted for. Davy's classical expla- 

 nation assumed that different elements differ among 

 themselves as to their electrical properties, some being 

 positively, others negatively, electrified. Electricity 

 and "chemical affinity," he said, apparently are mani- 

 festations of the same force, acting in the one case on 

 masses, in the other on particles. Electro-positive par- 

 ticles unite with electro-negative particles to form 

 chemical compounds, in virtue of the familiar principle 

 that opposite electricities attract one another. When 

 compounds are decomposed by the battery, this mutual 

 attraction is overcome by the stronger attraction of the 

 poles of the battery itself. 



This theory of binary composition of all chemical 

 compounds, through the union of electro-positive and 

 electro-negative atoms or molecules, was extended by 

 Berzelius, and made the basis of his famous system of 

 theoretical chemistry. This theory held that all inor- 

 ganic compounds, however complex their composition, 

 are essentially composed of such binary combinations. 

 For many years this view enjoyed almost undisputed 

 sway. It received what seemed strong confirmation 

 when Faraday showed the definite connection between 

 the amount of electricity employed and the amount of 

 decomposition produced in the so-called electrolyte. 

 But its claims were really much too comprehensive, as 

 subsequent discoveries proved. 



ORGANIC CHEMISTRY AND THE IDEA OF THE MOLECULE 



When Berzelius first promulgated his binary theory 

 he was careful to restrict its unmodified application to 

 the compounds of the inorganic world. At that time, 



53 



