t 186 ] 
This fa<fl alone would be fufficient to prove, that 
the iron is not converted into copper ; fince, accord- 
ing to Sir Ifaac Newton’s table, the fpecific gravity 
of copper is to that of iron as 9000 to 764.?. 
When I was at this fpring in Augud lad, it ran> 
at the rate of 1 2 ounces every fecond ; and by put- 
ting iron into the water of the dream running from 
the pits, I found, that every ounce contained three 
grains of copper. Hence by calculation it appears, 
that 129600 grains of copper are carried off every 
minute, and confequently 1 24100 pounds Troy 
weight in a year) fuppofing the quantity and quality 
of the water to continue the fame. 
Hence we may eadiy account for the death of the • 
fifh, and other phenomena in the river, which re- 
ceives this vitriolic dream. 
In a hot funny day, .when the water is exhaled, 
the heaps of mold, raifed out of the ore- pits, are co- 
ver d with a~ vitriolic efflorefcence : hence, in rainy 
weather, the water appears like a drong folution of 
verdemfe. 
O 
Whoever is defirous to imitate the procefs carried 
on in thefe pits, may readily gratify his curiofity, 
by putting pieces of iron into drong folutions off 
vitriol. 
It is a common experiment, to tinge polidfd iron 
by rubbing it with Roman vitriol ) which depends 
on the caufe before -mention’d $ viz. the acid in the 
vitriol penetrates the iron, and leaves the copper on 
the furface. This experiment is alfo taken notice of 
by that excellent chemid, and celebrated philofopher, 
Mr. Boyle, who calls it z jympatkctic precipitation, 
in his Effay on fpecific Medicines. 
As 
