﻿THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



FEBRUARY 1869. 



XII. Remarks on Affinity. By M. Dumas*. 



WHAT is the force which causes simple substances to unite 

 with other simple substances to form compounds — acids 

 with bases to form salts, quicklime with water to form slaked 

 lime, carbon to burn in air, iron to become covered with rust ? 



This force we do not know. We are merely aware that it is 

 only exerted when bodies are in apparent contact, that it be- 

 comes inappreciable when the distance of the bodies is appreci- 

 able, that, although the mass of bodies may come into play in 

 the phenomena which it produces, their nature exerts the pre- 

 ponderating action. We designate it as affinity. 



I do not propose to retrace here the history of affinity since the 

 first appearance of this word in the doctrines of chemistry, now 

 more than two centuries ago. I have explained elsewhere the 

 successive interpretations which have been given to it by Barchu- 

 sen, who first used it, Boerhaave, who fixed the meaning, Geof- 

 froy, who thought he had discovered the laws, and Berthollet, who 

 did really formulate them for a great number of phenomena. 



I should even not have allowed myself to place before the 

 Academy this fragment borrowed from the exposition of the last 

 researches of French chemists, if, in order to show their import, 

 I had not been led to place them in parallel with the principles 

 established by Newton at the close of the long researches to 

 which he devoted himself to account for the nature of chemical 

 reactions. 



* Translated from the Comptes Rendus, September 21, 1868. 

 Phil. Mag. S. 4. Vol 37. No. 247. Feb. 18G9. G 



