[ 467 ] 
by drinking more freely they foon go off. Thefe 
fymptoms feem to arife from fome matter being re- 
pelled and taken up into the circulation ; but as the 
water is fo pure, it is foon wafhed off by it, and 
carried out of the habit. 
Indeed the efficacy of thefe waters feems to be 
owing chiefly to their extreme purity and lightnefs,. 
by which they are enabled to pervade the fineft vef- 
fels, and not being loaded with any earths or falts, 
are capable of diffolving more than thofe waters 
which are already impregnated with them. And if 
we conflder the ill effedts, which waters full of ftony 
or ftyptic particles have on the conftitution, produ- 
cing glandular obftrudtions and the like, we may in 
fome meafure conceive, how waters, which are pure 
and almoft elementary, may affift in removing fuch 
difeafes. But beiide this extreme purity, the effi- 
cacy of this fpring muft be greatly affifted by the 
elaftic fluid, which it appears to contain from Exp. 
2, 3, 4, as well as by its bituminous or fulphureous 
parts, 9, 14, 15. It may alfo be expedted to adfftill 
more powerfully (both externally and internally) if 
it be impregnated with any fubtle tindture from 
copper ; as is probable, not only from Exp. 5, but 
from the effedts fometimes obferved upon its fir ft 
ufe. Befides thefe qualities, I fuppofe part of its 
efficacy in external application may arife from its. 
coldnefs. 
But whether, by any' chemical analyfis we can 
difcover its principal contents, or not, fo long as it 
is found to produce fuch extraordinary effedfs, we 
may there reft fatisfled ; experience being the beft 
teft of the nature of any fpring. For however the 
methods- 
f 
