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XVIir. Uefcarchesrefpeaitig the Laws of Affinity. ^CBeR- 

 TiiOLLKT, Member of the National Infiitute, &^c, 



Vy liEMfSrS have long been looking for Berthollct's work 

 on this rubjee% which has at laft made its appearance, and 

 contains much new and ufeful matter. A mere analyfis of 

 the work would be of little ufe to our readers; we fliall there- 

 fore prefcnt extracts of fuch parts as may tend to make 

 them acquainted with tlie nature of the fa6ts on which hef 

 founds his theory, and which deferve the attention of every 

 cheniKL 



Berthollet divides his memoir into fifteen articles- 



I. In the fir(i, after an eulogy on Bergman, he dates his 

 intention to be^ " to prove that elective affinities do not a6t 

 like ablolute forces, by which one fubllance in a combina- 

 tion would be difpkced by another ; but that, in all the com- 

 poiitlons and decompofitions w^iich are produced by ele6live 

 affinity, there is a dirtribution of the combined fubllance 

 among thofe which exercife contrary affinities ; and the pro- 

 portions of this diftribution arc determined not only by the 

 energy of the affinity of thefe fubflanees, but alfo by the 

 quantity with which they a^l) fo that quantity can make up 

 for the force of affinity, in order to produce the fame degree 

 of faturation. 



*' If I eftabliffi," adds the author^ " that the quantity of 

 pt fublbmce can make up for the force of its affinity, the re- 

 fult will be, that its action is in proportion to the quantity 

 neceffiiry to produce a determinate degree of ftituratiori. I give 

 the name of f/ufs to that quantity which is the meafure of the 

 capacity of the faturation of the different fubitanccs. In com-, 

 paring, therefore, the affinities of fubilances, I Ihall pay at- 

 tention to the ponderable (juantitits, which in this comparifoii 

 ought to be equal ; but in comparing their aftion, which is 

 compofed of their affinity and their proportion, it is their 

 niafs that ought to be confidered." 



The author then announces, that in the following difcuf- 

 fions he will chiefly employ ^' acids and alkalies, (compre- 

 hending aifiong the latter thofe earths whidi have the fame 

 4 a(B:ioii,) 



