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ANALYSIS OF MINERAL WATERS. 277 
magnesia. Its quantity may then be estimated from its preci- 
pitation by carbonate of ammonia, or by other methods usual- 
_ly employed. Silica will also be precipitated in the same 
stage of the process ; its separation from the alumina may be 
effected by submitting the precipitates, thoroughly dried, to 
the action of diluted sulphuric acid. Potash when present, 
which is very seldom to be looked for, will remain at the end, 
in the state of muriate of potash. Muriate of platina will de- 
tect its presence, and the muriate of potash may be separated 
by crystallization from the muriate of soda. 
. Ture is another mode in which part of the analysis may 
be conducted, which, although perhaps a little less accurate 
than that which forms the preceding formula, is simple and 
easy of execution, and which may hence occasionally be admit- 
ted as a variation of the process ; the outline of which, there-- 
fore, I may briefly state. | 
- The water being partially evaporated, and the sulphuric and 
carbonic acids, if they are present, being removed by the addi- 
tion of muriate of barytes, and the conversion of the whole 
salts into muriates effected in the manner already described ; 
the liquor may be evaporated to dryness, avoiding an excess 
of heat, by which the muriate of magnesia, if present, might be 
decomposed ; then add to the dry mass six times its weight of 
rectified alcohol (of the specific gravity at least of .835); and 
agitate them occasionally during twenty-four hours, without 
applying heat. The muriates of lime and magnesia will thus 
be'dissolved, while any muriate of soda will remain undissol< 
ved. 
