[ r 37 ] 
35. A quantity of the water being kept boiling 
for five minutes, and afterwards allowed to ftand till 
it became clear, was carefully filtrated from its 
ochrous fediment : after which, upon its mixture 
with fyrup of violets, it turned of a faint reddifii 
colour. 
From thefe experiments we infer, that this mine- 
ral water contains both an alkaline and an acid prin- 
ciple ; the former confiding of the ochrous and fer- 
rugineous parts, which are feparated from the water 
by elixation ; and the latter of the aluminous fait, 
which remains in the water after elixation. 
The following trials were made in order to know 
what effects are produced in the water by being ex- 
pofed to the air ; and in what refpe&s the waters of 
the two fprings differed from each other. 
Exp. 37. An English quart of the water of each 
of the fprings being fully expofed to the air in tw'o 
China bowls, the next day that of the under fpring 
was neither altered in its tafte, colour, or tranfparency, 
nor in any other fhape whatever ; but that of the 
upper fpring appeared of a yellowifh colour, altho’ 
it was clear, and tranfparent as the other. 
On the fecond day the tafte of the waters fcarcely 
appeared to be any way diminished. No fenfible 
change could be obferved in the lower water \ but 
the upper water was become more yellow than it 
was the day before, yet without any lofs of its tranf- 
parency. They both tinged of a deep blue colour 
with galls ; which tindtures appeared equally deep 
Vol. 50. T and 
