﻿M. Dumas's Remarks on Affinity, 91 



Their shock at the moment of contact would produce heat, light, 

 electricity. The union of atoms once produced, in order to se- 

 parate these, molecular forces must intervene capable of separa- 

 ting them and carrying them to the limit at which attraction, be- 

 coming null or even negative, would cease to act or be changed 

 into repulsion. 



Thus we are led to the simple views of Newton and of Lavoisier. 

 Chemical combination takes place between ponderable bodies ; 

 the permanent effects are due to attraction ; its transitory 

 effects are due to the losses of motion which the atoms experi- 

 ence at the moment of their union. 



However, general attraction being admitted as a necessary 

 and sufficient representation of the force which determines che- 

 mical combinations, are we not led to efface the line of sepa- 

 ration which has been assumed to exist between cohesion and 

 affinity ? Is it not convenient to see one and the same force 

 varying its effects in the three states of aggregation — cohesion, 

 solution, and chemical combination ? 



Not that we should confound them ; for, their first cause being 

 the same, it would be none the less indispensable to modify its 

 application in these three circumstances, each of them having its 

 own distinct and persistent character. Just as it would always be 

 necessary to distinguish between general and molecular attrac- 

 tion, it would be none the less necessary to maintain the dis- 

 tinction between the three forms of molecular attraction. I have 

 no doubt that, if once we knew the cause of affinity itself, we 

 should recognize in its mode of acting on bodies well-marked 

 modifications, as M. Chevreul long ago suggested. 



Yet, if chemical action, the force of solution, and cohesion are 

 mere modifications of general attraction, if they do not consti- 

 tute so many special and distinct forces, ought we not to expect 

 that the affinity of chemists more profoundly investigated would 

 lose its special character, become more mechanical, approach 

 little by little first its two congeners, and finally planetary at- 

 traction itself ? 



But cohesion and the force of solution, resembling in this re- 

 spect general attraction, form continuous phenomena ; the atomic 

 theory, on the contrary, ranges affinity amongst discontinuous 

 phenomena. 



Berthollet, guided doubtless in this respect by Laplace, him- 

 self familiar with Newton's philosophy, maintained for a long 

 time, as we know, that bodies can combine in all proportions. 

 He would willingly have applied to chemical phenomena, and 

 to the forces which determine them, Linnasus's axiom, Natura 

 non facit saltus, which is true of organized beings ; and if his 

 opinion had been confirmed, affinity would have been attached 

 mere closely to cohesion and general attraction. 



