THE ACCOMPANYING SUBSTANCES* J7 



received among chemifts as an undoubted fact ; and, at the 

 end of Mr. Kirwan's Efay on the Analyfis of mineral Waters, 

 we find a lift of earthy falts which produce a re-action upon 

 one another, fuppofed to becaufed by an affinity that tends to 

 unite their bafes, in the form of a precipitate, infoluble in the 

 acids. Some other detached obfervations are to be found, in 

 the Journal de Phyfique, and in the Annates de Chimie. The 

 facl is certainly one of the moft important in the docimaftic art, 

 and merits all the attention of the fkilful in that branch. 



In the XLth volume of the Annates de Chimie, page 52, contefted by 

 Darracq has publifhed a paper, intended as a refutation of the arraC(l * 

 conclufions drawn by Guyton. I had myfelf repeated the 

 greater part of the experiments of the latter ; and the refults 

 I obtained were exactly fimilar to thofe of Darracq. In facl, 

 I had intended to continue the refearches ; but the very fatis- 

 factory paper of Darracq, appeared to me to render a further 

 profecution of them totally ufelefs. However, a paragraph 

 inferted in the Annates de Chimie, (Tom. XLI. p. 206*.) and 

 of which Guyton appears to be the author, fliews that he has 

 not derived from the Memoir of Darracq, that conviction 

 which it certainly conveys. The paragraph in queftion is 

 founded upon a letter, written from Freyberg, by Dr. G. M. 

 to Dr. Babington, dated December 17, 1800, and inferted in 

 the I Vth volume of Nicholfon's Journal, page 511. This let- 

 ter contains an opinion which deferves to be canvafTed, as it is 

 not perfectly juft ; and the ufe Guyton has made of it, has 

 determined me to add my obfervations to thofe of Darracq. 



I (hall follow the order of Guyton's experiments, in the Repetition of 

 enumeration of thofe I made. Guyton' s expe- 



rt ,-, - r .. , . nments. 



Lxp. 1. From a mixture of lime-water and barytes-water, Lime-water and 



Guyton obtained a precipitate. I obtained none. .barytes-water 



Exp. 2. A folution of alumina in potafh, mixed with a folu- jy,^, ' pl * e '~" 



tion of filica in the fame, gave a precipitate, after ftanding Alumina in pot> 



fome time. This had been obferved by Darracq, and by^^jjJM* 



Guyton, and agrees perfectly with the affinity which, before — Ascertained 



Guyton publifhed his paper, I had afferted to exift between beforc * 



thefe two earths. 



Exp. 3, 4, 5. Lime-water, ftrontia-water, and barytes- Water of lime, 



water, produce a fomewhat fimilar effect upon a folution of or °{ f lrontia » 

 ,,...- * or of barytes + 



fihca in potafh. to filica in pot- 



Vol. IV.— January, 1803. C Exp. *&ssF*k* 



