ANALYSIS OF MINERAL WATERS. . 279° 
This method is equally proper to discover other ingredients 
which are more rarely present in mineral waters. Thus, alu- 
mina will remain in the state of sulphate of alumina along 
with the sulphate of magnesia, and may be detected by preci- 
pitation by bi-carbonate of ammonia. Silica will remain with 
the muriate of soda after the action of the alcohol, and will be 
obtained on dissolving that salt in water. And iron will be 
discovered by the colour it will give to the concentrated li- 
quors, or the dry residues, in one or other of the steps of the 
operation. . 
6 
Tue general process I have described may be applied to the 
analysis of earthy minerals. When they are of such a compo- 
sition as to be dissolved entirely, or nearly so, by an acid, that 
is, where they consist chiefly of lime, magnesia, and alumina, 
its direct application is sufficiently obvious; where they re- 
quire the previous action of an alkali from the predomi- 
nance of siliceous earth, on this being separated, the excess of 
alkali may be neutralised by muriatic acid ; and the remaining 
- steps of the analysis may be prosecuted, with any modification 
which the peculiar composition will require. As the quanti- 
ties of the ingredients are capable of being estimated with so 
much precision, it may be employed with more peculiar ad- 
vantage where a small quantity only of the mineral can be sub- 
mitted to analysis; and when it is employed, such a quantity 
only, ten grains, for example, ought to be made the subject of 
experiment. 
END OF PART FIRST. 
