tin Laws of Affinity, 7 1 



Barytes forms with the fulphuric acid an infoluble fait : 

 when the folution of a fulphate is mixed with that of a fak 

 having a bafe of barytes, there is always formed and preci- 

 pitated a fait with a bale of barytes. 



As lime forms a fulphate very litlle foluble, and which is in 

 a great meafure precipitated if there be not a great deal of 

 water, it equally changes its bafe with all the foluble ful- 

 phates till the period.when precipitation ceales to take place 

 by the folubility of the fulphate of lime. Hie fulphate of lime 

 having {till much more folubility than fulphate of barytes, 

 falts with a bafe of barytes, which are mure foluble, decom^ 

 pofe the fulphate of lime. 



Oxide of lilver forms an in foluble fait with muriatic acid : 

 all falts of filver which are foluble being mixed with foluble 

 muriates, there is precipitated muriate of filver. Mercury, if 

 not too much oxidated, has a fimilar action. 



As muriate of lead is little foluble, the falts which the oxide 

 of lead forms with other acids, and which polfefs folubility, 

 produce a precipitate with foluble muriates ; but, as an info- 

 luble fait is made with fulphuric acid, the folution of muriate 

 of lead produces a folution of fulphate of lead when mixed with, 

 foluble ful phates. 



5th, When water, then, in which different falts have beea 

 put in folution is made to evaporate, thefe falts feparate ac- 

 cording to the order of their folubility, and it is by it that one 

 can judge of the changes of bafe which may take place. 



But the folubility of falts varies according to temperatures :- 

 it is therefore the relative folubility, according to the different 

 temperatures, that mud be conlidered. The nitrate of potaih. 

 mixed with the muriate of foda will cryftallize at a low tem- 

 perature, but the muriate of foda will feparate itfelf even during 

 the time of the evaporation: no exchange of bafes will take 

 place, becaufe the nitrate of foda is a little more foluble cold 

 than the nitrate of potaih ; and becaufe, on the contrary, the 

 muriate of potaih is a little more foluble warm than muriate 

 of foda. 



6th, I connder here only the principal refult, arifmg from 

 a force of cohefion, of fuch a nature, that it makes the effect 

 of the forces oppofed to it to difappear; but when there does 

 not exift a eontiderable cohefion in the combinations which 

 can be formed, the mutual aclion of the fubftances which 

 remain in the liquid Mate of the folvent, and of the propor- 

 tions which vary by the crvMalhzation of the newlv-fepa* 

 rated combination, mu(i produce different effects. The ex- 

 periments I have begun, will loon throw further lighten this 

 fitbjecf.. 



E 4 7 th > An- 



