1815.) of Dunblane and Pitcaithly. 359 
water and their proportions may be very different from those ob- 
tained by the direct analysis; for it is too obvious, after the pre- 
ceding observations, to require illustration, that the actual produc- 
tion of certain ingtedients by evaporation, or any other analytic 
process, is no certain proof that they pre-existed in the water. It 
is obvious, too, that if it were proposed to imitate the Cheltenham 
water by artificial preparation, it could be done much more easily 
according to this view than by attempting to dissolve the ingredients 
obtained by the analysis—an attempt, indeed, which would not 
succeed. ‘Lhe Dunbiane or Piteaithly water might be converted, 
so far as regards the saline ingredients, into a water similar to that 
of Cheltenham, by the addition of a little sulphate of magnesia, or 
more nearly by the addition of a little of the bitterm of sea water ; 
and where in the use of these waters a continued purgative opera- 
tion is required, such an addition might always be made with ad- 
vantage. They might even be made to receive the impregnation of 
carbonic acid of the Cheltenham water; by adding the magnesia in 
the state of carbonate, with the due proportions of sulphuric and 
muriatic acids in a close vessel. 
- The water of Harrowgate affords in its saline ingredients another 
illustration of the same views. The principal ingredient is muriate 
of soda, with which are present muriate of magnesia, muriate of 
lime, sulphate of magnesia, carbonate of magnesia, and carbonate of 
lime. Now nothing is more probable than that the last two sub- 
stances are not original ingredients, but are products of the analysis 
formed by the action of carbonate of soda existing in the water on 
portions of its muriate of magnesia.and muriate of lime, whence 
also the quantity of muriate of soda is increased. 
Lastly, a similar view may be extended to some of the most cele- 
brated foreign mineral springs. ‘Those of Spa, Pyrmont, and 
Seltzer, form a very valuable order of mineral waters, to which we 
have none analogous in this country—what have been called the 
alkaline carbonated waters, distinguished by the leading character 
of being largely impregnated with carbonic acid gas, and containing 
a considerable proportion of carbonate of soda. With this are 
associated carbonate of magnesia, carbonate of lime, and muriate of 
soda. Now this association of muriate of soda with these earthy 
carbonates, while there is also carbonate of soda present, leads 
almost necessarily to the belief that the real ingredients are car- 
bonate of soda, muriate of magnesia, and muriate of lime; that the 
carbonate of soda is in larger proportion than what is indicated by 
the analysis; that it acts during the evaporation of the water on the 
muriates of magnesia aod lime, and forms the carbonates of these 
earths which are obtained with corresponding portions of muriate of 
soda: and that it is only what muriate of soda there may be above 
this that exists as an original ingredient. 
The Seltzer water, which is the purest of this order of waters, as 
containing neither iron nor any sulphate, affords in particular a very 
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