On the Laws of Affinity. 6"o 



When the oil has been treated with two hundredth parts 

 of fulphuric acid, if it be fuffered to digeft for twenty-four 

 hours with the fourth of its weight of chalk or carbonate of 

 Hme, or of argil, you will obtain it almoil as clear as water. 

 Lime, however, cannot be employed with advantage, as it 

 would occafion too much wafte; but, in my opinion, argil 

 would give very advantageous remits : it retains, indeed, a 

 pretty large quantity of oil, but, by means of a prefSj thi 

 lalt portions of the oil may be extracted from the argil almoil 

 entirely. 



XII. Researches re/peeling the Laws- of Affinity. By 

 C. Burtholl^t, Member of the French National 

 JnjYitute, 



[Continued frorji Vol. IX. p. 35*t] 



ift,LL 



XII. Of Complex Affinities,. 



NDER the more general name of complex affinity. 

 I (hall examine that which has been confidered as arifing from 

 the concourfe of four affinities, and which is generally di- 

 ftinguiflicd by the name of double affinity. 



To give an idea of the action of four affinities, Bergman 

 examines what takes place when aiblulion of fulphateor pot- 

 am and muriate of lime are mixed together. This, fays he,. 

 is as if one mould put into the quantity of water employed 

 the proportions of fulphuric acid, muriatic acid, lime, and 

 potafh, which enter into the compofition of thefe lalts : the 

 two bafes act by their affinities on thefe two acids; but 

 though the affinity of the potafh for the fulphuric acid be 

 ftronger than that which it has for the muriatic acid, the 

 affinity of the muriatic acid for the potafh, however, added 

 to the affinity of the fulphuric acid for the lime, gives a funi 

 of forces greater than the affinity of the fulphurjc acid for the 

 potafh, and that of the muriatic acid for the lime, which de- 

 termines an exchange of bales ; fo that, inftead of fulphatc of 

 potafh and muriate of lime, there are produced fulphatc of lime 

 and muriate of potafh. This explanation is always founded 

 on the fuppdfition, that the affinities are conusant forces in- 

 dependently of the quantities and the flate of faturation. 



2d, When the two bales act conjointly on one acid, the latter- 

 divides itfelf, or rather divides its aelion, in the ratio of their 

 jnaftes. I n(tead of one acid there are here two; and if no fepara- 

 tion is effected, either bvprecipitationor cry Itallifation, theacids 



E 3 will 



