Inquiry inta the Laws of Affinity. ly 



their a£lion, which Is compofed of both their affinity and their proportion, I muft then 

 confidei the mafs. 



The author next obferves, that in the following difcuflions, he fhall principally mak« 

 ufe of acids and alkalis, among which he comprifes thofe earths which a6i: as fuch; becaufc 

 they exercife great powers, which may difpel the influence of flight caufes ; and becaufe 

 they often produce comparable degrees of faturation, and afford refults which may be cafily 

 obferved. But the confequences drawn from their properties by Clt. BerthoUet, are appli- 

 cable to all other combinations. It is proved by many examples, that the principle cfta- 

 blilhed by the author extends to the whole chemical aSiop of bodies. 



After having proved by dire£l experiments, that the chemical adtlon of fubftances, of 

 which the forces are oppofed, does not depend upon their affinity alone, but likewife on 

 their quantity, the author (lates that he fhall make choice of obfervations on different kinds 

 of combinations which will confirm this principle, and prove its extent. I fliall examine, 

 he continues, the circumftances which modify it, or thofe affections of bodies which 

 favour or diminifh their chemical adlion, and which caufe the proportions of the combi- 

 nations which they are capable of forming to vary : I fhall apply thefe confiderations to the 

 complex affinities, and to thofe of compound bodies ; and laftly, I (hall endeavour to 

 determine the bafis on which the general and particular theories of chemical phenomena 

 ought to be eftablifhed. 



ARTICLE II. 



Experiments luhich prove that in the EleBive Affinities^ the oppoftng Suhjlances divide that 

 Body which is the SubjeB of the Combination. 



To demonflrate the truth of this propofition, Cit. BerthoUet defcribes feveral experi- 

 ments, from which we fhall quote the following : I kept, fays he, in a ftate of ebullition 

 in a fraall quantity of water, an equal weight of pot-afh, purified by alcohol, and of ful*- 

 phate of barytes. The operation was made in a retort, and confequently without the 

 contadl of air, and continued till the mixture was evaporated to drynefs : the refiduum was 

 treated with alcohol, which diffolved the pot-afh, and afterwards with water. The latter 

 effected a folution which alfo exhibited alkaline properties. This alkali was faturated with 

 acetous acid, after which there was formed, by evaporation, a confiderable quantity of 

 fmall cryftals, which poffeffed all the characters of fulphate of pot-afh ; fo that the ful- 

 phate of barytes was partly decompofed by the pot-afh, and the fulphuric acid was 

 divided between the two bafcs. 



The other experiments were made, 



I. With fulphate of pot-afh and lime: 2. With oxalate of lime and pot-afh:, 31 With 

 oxalate of lime and nitric acid : 4. With phofphate of lime and pot-afh : 5. With pot-afh 

 and carbonate of lime : 6. With foda and fulphate of pot-afh. 



_ In the whole of thefe experiments it is feen that thofe bafes, which are admitted as 

 forming, with the acids, the ftrongeft and^ moft permanent combinations, were partly 



Vol. v.— Aprh» i8oi. D \ -extricated 



