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CHAPTER III. 



DOCTRINE OF ELECTIVE ATTRACTIONS. 

 GEOFFROY. BERGMAN. 



THOUGH the chemical combinations of bodies 

 had already been referred to attraction, in a 

 vague and general manner, it was impossible to ex- 

 plain the changes that take place, without suppos- 

 ing the attraction to be greater or less, according 

 to the nature of the body. Yet it was some time 

 before the necessity of such a supposition was clearly 

 seen. In the history of the French Academy for 

 1718 (published 1719), the writer of the intro- 

 ductory notice, (probably Fontenelle,) says, "That 

 a body which is united to another, for example, a 

 solvent which has penetrated a metal, should quit 

 it to go and unite itself with another which we 

 present to it, is a thing of which the possibility 

 had never been guessed by the most subtle philo- 

 sophers, and of which the explanation even now is 

 not easy." The doctrine had, in fact, been stated 

 by Stahl, but the assertion just quoted shows, at 

 least, that it was not familiar. The principle, how- 

 ever, is very clearly stated 1 in a memoir in the 

 same volume, by Geoffroy, a French physician of 

 great talents and varied knowledge. " We observe 

 in chemistry," he says, " certain relations amongst 

 1 Mem. Acad. Par. 1718, p. 202. 



