1815.J - of Dunblane and Pitcatthly. 35k 
trates some circumstances connected with the mutual action of the 
sulphate of soda, and muriate of lime, to which I shall afterwards 
have to refer. It affords, too, an excellent illustration of the defi- 
nite proportions in which many bodies combine, and the uniformity 
of results which are obtained from their action on each other, in 
consequence of this law. 
_ Supposing the sulphate of lime obtained from this water by 
evaporation to be formed by the action of sulphate of soda on a 
portion of its muriate of lime, it might be inferred, that by adding 
the due proportion of sulphate of soda, the whole muriate of lime 
it contains may be converted into sulphate of lime; and this, from 
its insolubility, being easily separated from the muriate of soda, the 
quantity of it, and of course the quantity of muriate of lime, will 
be ascertained. From the preceding analysis, 18 grains of muriate. 
of lime appear to exist in a pint of the Dunblane water. Now this 
quantity requires for its decomposition 23°1-of real sulphate of soda > 
and the products of this decomposition are 22°1 of real sulphate of 
lime, and 19 of muriate of soda.* The former of these products 
being collected and dried, may be weighed, and the latter being 
deducted from the whole quantity of muriate of soda obtained by 
evaporation, the remainder will be the quantity originally contained 
in the water. ‘The obtaining of these quantities, therefore, or near 
approximations to them, will be at once a confirmation of the pre- 
_ eeding analysis, and of the accuracy of these proportions. 
__A pint of the water was evaporated to about one-fourth; the 
‘quantity of real sulphate of soda required for the decomposition of 
its muriate of lime, it has been just stated, is 23'1 grains. But by 
previous trials I had found that a small excess of sulphate of soda 
renders the decomposition more complete; 24 grains, obtained by 
exposing crystallized sulphate of soda to a red heat, were therefore 
added. ‘The liquor soon became turbid and thick. I had also 
found, that to render the decomposition more complete, it is of 
advantage not to evaporate at once to dryness, but to add small 
quantities of water occasionally for some time duriug the boiling. 
The experiment having been conducted. in this manner, a precipi- 
tate of sulphate of lime was collected, which, when washed and 
dried, weighed 19 grains, ‘The liquor being evaporated, afforded of 
dry salt 51°6 grains. But on dissolving this salt in water, a deposite 
of sulphate of lime remained undissolved ; and even on again eva- 
porating to dryness, and re-dissolving in water, a small portion was 
deposited for three successive times. The whole quantity of sul- 
phate of lime thus collected amounted to 5:8 grains, and of course 
increased the former quantity of 19 to 24°8 grains. Supposing the 
quantity of sulphate of lime originally contained in the water, or 
what is the same thing, capable of being produced in its evaporation 
.* The inspection of the scale of chemical equivalents gives at once these num- 
bers; and this highly useful instrument, lately invented by Dr. Wollaston, facili« 
es greatly all such reseavches by the number of results itypresents without the 
necessity of calculation, en Gy 
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