1815.) . of Dunblane ana. Piicaithly. 349 
equally be the uncertainty, whether it had been previously com- 
bined with soda or lime. 
If sulphate of lime did not separate when the water was reduced 
by evaporation so far that, from the known solubility of the sulphate, 
the precipitation of it. ought to take place to a certain extent, it 
might be concluded that it did not exist. Yet even this conclusion, 
were the fact found to be so (which it is on making the experi- 
ment), is invalidated by the result, sufficiently established, that 
salts, by their mutual action, often increase the solubility of each 
other, and the sulphate of lime might, from this cause, be retained 
dissolved in a smaller quantity than it would require by itself for 
its solution. 
One ‘kind of proof may be given, that of showing that a much 
larger quantity of sulphate of soda than what analysis indicates in 
this water may exist in it, without any precipitation of sulphate of 
lime. I added to different portions of the water (four ounces each) 
5, 10, 15, 20, and 30, grains of sulphate of soda. In none of the 
experiments was there any immediate effect 5 and even after 24 
hours, there was no turbid appearance, or apparent change. In 
the greater number of these proportions, the quantity of sulphate 
of soda was more than: sufficient to convert the whole muriate of 
lime in the water into sulphate ; and, according to the known solu- 
bility of this sulphate, the quantity of water was not sufficient to 
retain it all dissolved. This quantity was even reduced to a certain 
extent by evaporation, without any precipitation. The result seems 
therefore to-prove, that sulphate of lime had not been formed, and 
that sulphate of soda may exist with muriate of lime in solution 
without decomposition, in the state of dilution which this mineral 
water affords. 
Another result which I obtained, and which so far favours the 
opinion that the sulphate of lime is formed in the progress of the 
evaporation by the reciprocal action of sulpbate of soda and muriate 
of lime, is, that when a small portion of sulphate of soda has been 
added, the quantity of sulphate of lime obtained is increased : when 
10 grains, for example, of crystallized sulphate of soda were added 
to a pint of the water, ‘after evaporation to dryness, four grains of 
sulphate of lime, which is double the proportion that the water 
would otherwise have yielded, were obtained—affording a proof that 
when sulphate of soda is dissolved in the water, it produces, in the 
progress of the evaporation, a corresponding portion of sulphate of 
lime, and of course also of muriate of soda. 
_ These results do not absolutely establish the conclusion, that the 
sulphuric acid exists in this water in the state of sulphate of soda 5 
yet on the while this is the more probable opinion. If it be ad- 
mitted, the preceding statement of the ingredients, and their pro- 
portions, must be altered. The sulphate of lime is of course to be 
omitted, ‘The sulphate of soda, which is to be substituted for it, 
cannot be obtained hy any method 5 but the quantity of it may be: 
inferred, from the quantity of sulphate of lime which is formed by 
4 
