354 Analysis of the Mineral Waters [Nov. 
ral effect of the Bath waters ;—remarking, that though there i is 
only a grain of it in half a pint of the water, this forms no objec- 
tion, when the great powers of very minute quantities of active 
substances are considered; that neither is its insolubility in the 
animal fluids an objection, as it exists in the water in a state of solu- 
tion; and that though it has neither taste nor smell, it may be an 
active substance, since there are indisputably peurrion ‘medicines 
which have little of either of these qualities. 
All this, it is superfluous to observe, is extremely nbeatiafataing, 
With regard to the iron, the only active substance—allowing full 
weight to the observations that small quantities of active medicines 
under great dilation operate with increased power, and that a‘ high 
temperature may aid their operation on the stomach—still we ean- 
not believe that one-siatieth of a grain, the quantity in a pint of 
this water, can produce any important medicinal effect : and with 
regard to the other substances, the reasoning whence their possible 
operation has been inferred, instead of removing the egies 
rather places it im a clearer light. 
The view of the constitution of mineral waters stated above 
enables us to assign to the Bath water a much more active chemical 
composition. ‘There is every probability that muriate of lime is its 
powerful ingredient. ‘The principal products of its analysis ate sul- 
phate of lime, muriate of soda, and sulphate of soda. ‘The _pro- 
portion of sulphate of lime is such, that part of it must pre-exist in 
the water, but part of it, there is reason to conclude, isa product 
of the analysis; the muriate of soda is entirely so, and the quantity 
of sulphate of soda is larger than what the analysis indicates. In 
other words, there exist in it muriate of lime, sulphate of soda, and 
sulphate of lime; and during the evaporation, the muriate of lime 
being acted on by a portion of the sulphate of soda, muriate of soda 
and a corresponding portion of sulphate of lime are formed. 
On the probability of this view I need not, after the preceding 
illustrations, offer any observations. The obtaining certain saline 
compounds from a mineral water by evaporation leads no doubt at 
first to the conclusion that they are its ingredients ; it is the eonclu- 
sion, accordingly, which has hitherto been always drawn, and we 
are disposed to regard this as evidence establishing this conclusion, 
in some measure, in opposition to any different view of the co 
sition. But this is merely oversight or prejudice. If it can be 
shown that the elements of these compounds may equally exist in 
the water in a different state of combination, which the evaporation 
must change, the conclusion that they do exist in such a state is 
a priori as probable as the conclusion that they exist in the state in 
which they are actually obtained. It is demonstrable that if muriate 
of lime and sulphate of soda exist in a mineral water, or, what 4s 
even less ambiguous, if they be dissolved together in pure water, 
thev must by evaporation be obtained, as muriate of soda and sul- 
phate of lime. ‘The actual obtaining, therefore, of these latter 
eompounds is no proof that they pre-existed as such in the wates, 
