﻿88 M. Dumas's Remarks on Affinity. 



of affinity would have seemed impossible so long as statical elec- 

 tricity alone was known to physicists; but Volta's discovery and 

 the investigation of the properties of dynamical electricity opened 

 out a new path. It seemed natural to suppose, for example, that 

 there was a close connexion, for instance, between the force of the 

 spark which determines the combination of oxygen and hydrogen 

 in the formation of water, and that of the battery which, effecting 

 in silence and without intermission the decomposition of this 

 liquid, transfers hydrogen to the negative and oxygen to the 

 positive pole. 



Reversing the decomposing mode of action of the pile, should 

 we not obtain the most natural representation of the attractive 

 force which unites the elements of water? 



Davy was the first to endeavour to give by means of electricity 

 an explanation of the permanent effects due to chemical attrac- 

 tion, and of the transitory phenomena which accompany the com- 

 bination of bodies. He supposed that at the contact of an acid 

 and a base theirparticlesbecome charged with contrary electricities, 

 and that at the moment of combination these electricities suddenly 

 reunite. The compound formed, the light or the heat developed 

 at the moment of combination are readily explained on this hy- 

 pothesis. Davy supposes, then, that it is attraction which unites 

 the particles of bodies, but that placing in contact sulphur and 

 copper, for instance, they take opposite electrical conditions, 

 that by heating them the electrical tensions are increased, that, 

 lastly, the two electrical fluids acquire so high a tension that 

 they attract one another and unite, producing heat and light, 

 while the sulphur and the copper, being approximated by this 

 contact, remain united by the attraction and thus form sulphuret 

 of copper. 



Ampere, modifying this hypothesis, regards the atoms as 

 being endowed with an electricity of their own, and as being 

 surrounded by an electrical atmosphere of the opposite kind. 

 These electrical atmospheres, when they neutralize one another, 

 produce heat and light; the electricities peculiar to the atoms 

 produce the combination by their mutual action. Ampere has 

 thus no need to bring into play general attraction ; he refers to 

 the operation of a single force both the transient and permanent 

 phenomena of chemical action. But Ampere would willingly 

 have sought in electricity the cause of universal attraction itself. 



Berzelius, finally, regards the molecules as being not merely 

 electrified but polarized. 



These various conceptions have had only one single practical 

 consequence. Davy, convinced that the force which united the 

 elements of compound bodies was of electrical origin, concluded 

 that, by opposing to the electricity of combination the electricity 



