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I firft compared the tafte of thefe two fprings, I could 
plainly difcern, that the water of the lower fpring 
was more acid, and lefs aftringent, than that of the 
upper one ; and, on the contrary, the water of the 
upper fpring feemed more aftringent, and lefs acid. 
This induced me to think, that the mineral parts, 
which caufed the acid and aftringent taftes, were 
mixed in the waters of thefe two fprings in different 
proportions. And what 1 obferved of them after- 
wards ftill confirmed this conjecture. 
But, in order to give fome evidence for the exift- 
ence of the above-mentioned minerals in the waters 
of thefe fprings, we fhall confider them feparately, 
by relating the experiments, which feemed to indi- 
cate, that they are contained in thefe waters in a very 
confiderable proportion, and by offering fome con- 
clufions, which may be reafonably drawn from 
them. 
And as the firft trials were made in queft of iron, 
it may perhaps be moft proper to confider it in the 
firft place. 
Experiment i. Some pieces of galls being added 
to equal quantities of the water of the two fprings, an 
exceeding deep and bright blue colour was immedi- 
ately produced in the water of the upper fpring, 
which in a little time turned to a perfect black. The 
water of the lower fpring, tho’ indeed it was turned 
of the fame colour, yet was not of fo deep a ffiade, 
but was fomewhat lighter than the former. The 
tinCture of galls caufed the fame appearances. 
2. A tincture of balauftine-flowers produced the 
above blue colours in both waters. 
Vol, 50. R 3. A 
