34* O'^ ^^^^ Affinity of Earths for each other. 



fequence of this experiment he admitted an affinity between 

 lime and bat^vtes. 



I repeated the fame experiment with great care ; but ob- 

 tained no change in the Hquors mixed, nor any fign of pre- 

 cipitation, even after five months. It is to be prcfumed thit 

 the precipitate formed in the experiment of C. Guyton arofe 

 from (.he impurity of the fubftances employed. In my opi- 

 nion, it was owing to the prefence of fome atoms of fulphuric 

 acid contained in the hme. It is almoft always found \x\ 

 common lime. 



Exp. II. By combining a folution of aluminated potafh 

 and filiciated potaili, I obtained, as Guyton did, a very thick 

 white precipitate, which foon after formed agelly. This pre- 

 cipitate, difperfed in water, and filtered, gave, by the tetts, 

 proper foralumine and filex, evident proofs of the affinity of 

 thefe two earths diflblved in potadi. 



Exp.Wl. Lime water, mixed with a folution of filiciated 

 potafli, gave alfo proofs of a real affinity between thefe earths 

 by the precipitation, which was inllantly eflecSled. Thi? 

 was confirmed alfo by an analyfis of the precipitate. 



Exp. IV. Stronlian water with filiciated potafli produced 

 tlie fame phainomenon as the preceding mixture. 



Exp. V. Strontian water and lime water mixed together 

 foraied no precipitate, as was obferved by Guyton. 



Exp. VI. Strontian water and barytes water, when com- 

 bined, formed no precipitate. 



Exp. VII. Carbonates of lime and barytcs, dilTolved in an 

 excefs of iheir acid, ffave no figu of a new combination. 



Exp. VIII. This experiment, which begins the fenes of 

 thofe made by Guyton on the folution of earths in acids, did 

 not affijrd me the refults announced by thatchcmift. Having 

 made a mixture of equal pai ts of a folution of muriate of lime 

 and a folution of muriate of alumine, he obferved, i ft. That 

 the liquor immediately became turbid, without the acid of 

 agitation : 2d, That foon after it was opake, and almoft ge- 

 latinous : 3d, and in the laft place, that this precipitate did 

 not difappear by the addition of an acid. 



I repeated this experiment, with all the care poffible, ta 

 obtain the fa-'/ie phaenoniena. Very pure muriate of lime, 

 mixed with muriate of alumine equallv pure, gave no fign of 

 precipitation : the mixed liquors conftantly remained clear. 



It is probable, according to fome eftays which are pe- 

 culiar to myfelf, tliat the precipitate obtained by C. Guyton 

 was oGcafioned by the fulphuric acid. contained in the mu- 

 riate of alumine, and which at the time of the mixture mu(^ 

 have re-a6ted on the lime; for when alumine has been ex- 

 4 traded 



