On the Affinity of Rarths for each other. 343 



trailed from alum, it is difficult to free it entirely from ful- 

 phiirlc acid. 



By cxtrafting alumine from thofc natural ftoncs which 

 contain it, either by the nitric acid or the muriatic acid, it 

 will be eafy to difcover the error into which the author was 

 led by muriate of lime prepared with the earth of alum. 



Exp. IX. By combining muriate of lime, in folution, with 

 muriate of barytes, Guyton obferved an abundant precipitate, 

 which was not dilfolved by excels of muriatic acid. The fo- 

 lutions of thefe two nuiriates, whether concentrated, or diluted 

 with diftilled water, gave no fign of precipitation by mixing 

 together, nor a long time after their combination. In my 

 opinion, the muriate of lime employed by Guyton contained 

 fome atoms of fulphuric acid, which, with the barytes, mull 

 have formed fulphate of barytes. 



Exp. X. Muriate of lime mixed with that of magneiia 

 gave, as Guyton obferved, no fign of precipitation. 



Exp. XI. When folutions of muriates of lime and of ftron- 

 tian were mixed, no change was produced. This was ob- 

 ferved alfo by Guyton. 



Exp. XII. Guyton announces, that the mixture of folutions 

 of muriate of magnefia and muriate of alumine aifuiiied, at 

 the end of fome minutes, a Uight milky appearance. This 

 experiment, being carefully repeated, exhibited nothing of 

 the kind ; my licjuors retained their clearnefs and tranf- 

 parency. 



Exp. XIII. The thirteenth experiment, made with a mix- 

 ture of folutions of muriate of magnefia and muriate of ba- 

 rytes, formed no precipitate, either at the moment or long 

 after; yet Guyton fays he obtained an abundant precipitate. 

 It is probable that fulphuric acid was Hill concealed in the 

 muriate of magnefia. 



Exp. XIV. This experiment, which was made with mu- 

 riate of magnefia and muriate of ftrontian, gave no fign of 

 any new combination. The fame was remarked by Guyton, 



Exp. XV. Muriate of barytes and niuriate of alumine, 

 both difiTolved and even diluted in water, gave to Guyton an 

 abundant precii)itate. The fame experiment, repeated with 

 the lolutions concentrated or diluted with water, did not yield 

 Die the fame refuli : the mixture always remained clear, with- 

 out forming any precipitate. 



Exp. X\T, Jhe fixtccnlh experiment, made by the com- 

 bination of muriate of ftrontian with that of barytes, exhi- 

 bited no change. 



Exp. XVII. The feventeenth and laft experiment of 

 Guyton, on the affinity of earths in the humid way, wass 



Y 4 nude 



