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Experiment 4. 
In order to determine the quantity and quality of 
the matter in the water, I put two drachms of fmall 
iron nails into three ounces of it, and let them ftand 
twenty-four hours ; then examin'd, and found the fur- 
£ ice of the water cover’d with a thick fcum, like that 
of a chalybcat Spa. It loft the blue colour, and fharp 
vitriolic tafte. It was quite tranfparent, and at the bot- 
tom there was a quantity of a brown ponderous pow- 
der, which, when dried, weigh'd 14 grains. This 
powder, melted without any flux, produced 1 1 grains 
of pure copper. The nails loft 8 grains in the water, 
and were, in feveral places, cover’d with a folid la- 
mina of pure copper. The water, in which the nails 
lay, after being filtrated and evaporated, afforded a 
green vitriol, which in every refpedt relembled J'al 
Martin and produced the fame effects, when dif- 
folved, and mix’d with any aftringent tindture. 
Experiment y. 
From the fpring- water treated in the fame man- 
ner, I obtain’d a blue vitriol, the bafts of which is 
copper. 
From all thefe experiments it appears, that a mi- 
neral acid is the adtive quality in this water ; which 
being diffufed thro’ the copper ore, unites itfelf with 
that metal, and forms a vitriol, which is diffolved 
by the water, and remains fufpended in it, till it 
meets with iron in the pits, by which this acid is 
more ftrongly attracted than by the copper > there- 
