C 2 5 ] 
Experiment IV. 
Six grains of the fame pellicles expofed on a teft 
to a reverberatory heat for the fame fpace of time ; 
the vitriolic acid being volatilized, by the reverberated 
flame, was expelled from its terrene bafts, fo that the 
refiduum, when cold, weighed but three grains, 
was acrid to the tafte, grew hot with water, and 
communicated the fame qualities to it that lime 
does. Hence the faline pellicles depofited by eva- 
poration, appear to be the felenites, or the vitrio- 
lic acid, united to a calcarious earth, with a little 
iron. 
Experiment V. 
The liquor in the cup being quite evaporated, there 
remained fome regular cryftals ftanding in a whitiili 
powder ; the cryftals weighed five grains, and 
proved on examination to be regular cryftals of 
allum. 
Experiment VI. 
The whitifh powder foon attracted moifture from 
the air, and in the fpace of 24 hours ran, per de- 
liquium , into a browniih fubacid auftere liquor, of a 
ferruginous and faline tafte. 
It appears from thefe experiments, that the con- 
tents of the Somerfham water are : Firft, Iron. 
Secondly, Selenite. Thirdly, Allum. Fourthly, 
From its tafte, and attracting the moifture of the 
air, fome marine fait, with a little allum and vitriol 
Vol. LVI. E 
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