339 
some of the Substances which accompany it, & c. 
§ II. 
On the Affinities the Earths have been supposed to have for each 
other , in the humid way. 
In the course of the foregoing analysis, I had occasion to 
make some further observations concerning a subject upon 
which I had been formerly engaged, namely, on the affinities 
the earths have been supposed to have for each other, when 
held in solution by acid or alkaline menstrua. 
In the XXVUIth volume of the Annates de Chimie , page 189, 
I published a paper upon the analysis of some magnesian stones. 
In this paper, I took notice of the following affinities of the 
earths for each other, namely, the affinity of alumina for mag- 
nesia, of alumina for lime, and of alumina for silica. In the 
XXXIst volume, page 246, there is a memoir, by Guyton de, 
Mgrveau, upon a similar subject;* and he there reports some 
experiments of his own, by which he was induced to think* 
that the earths do really possess a chemical attraction for one 
another. Since that time, the affinity of the earths has been 
received among chemists as an undoubted fact ; and, at the end 
of Mr. Kirwan’s Essay on the Analysis of mineral Waters , we 
find a list of earthy salts which produce a reaction upon one 
another, supposed to be caused by an affinity that tends to 
unite their bases, in the form of a precipitate, insoluble in the 
acids. Some other detached observations are to be found, in the 
Journal de Physique , and in the Annates de Chimie. The fact 
is certainly one of the most important in the docimastic art, 
and merits all the attention of the skilful in that branch. 
In the XLth volume of the Annales de Chimie , page 52,, 
* He has taken no notice of any of the experiments contained in my paper. 
