the Sulphur Wells at Harrogate. 187 
briefly, thefe properties of fhale, becaufe there is a ftratum of 
fhale extended over all the country in the neighbourhood of 
Harrogate ; feveral beds of it may be feen in the ftone quarry 
above the fulphur wells ; many of the brooks about Harrogate 
run upon fliale, and the fulphur wells fpring out of it. They 
have bored to the depth of twenty yards into this (hale, in 
different places, in fearch of coal, but have never penetrated 
through it. Its hardnefs is not the fame at all depths. Some 
of it will ftrike fire, as a pyrites does, with fteel ; and other 
beds of it are foft, as if in a ftate of decompofition, and the 
fulphur water is thought to rife out of that fhale which is in 
the fofteft ftate. But whatever impregnation fliale when cal- 
cined, or otherwife decompofed to a particular degree, may 
give to the water which paffes over if, it muft not be concluded, 
that fhale in general gives water a fulphureous impregnation ; 
fince there are many fprings, in various parts of England, arifing 
out of fhale, in which no fuch impregnation is obferved. 
I forgot to mention, in its proper place, that having vifited 
the bog, fo often fpoken of, after along feries of very dry wea- 
ther, I found its furface, where there was no grafs, quite can- 
died over with a yellowifh cruft, of tolerable confiftency, 
which had a ftrong aluminous tafte, and the fmell of honey. 
Bergman fpeaks of a turf found at Helfingberg in Scania, 
confifting of the roots of vegetables, which was often covered 
with a pyritous cuticle, which, when elixated, yielded alum ; 
and I make no doubt, that the Harrogate morafs is of the fame 
kind. 
Whether nature ufes any of the methods which I have men- 
tioned of producing the air by which fulphureous waters are 
impregnated, may be much queftiotied ; it is of ufe, however, 
to record the experiments by which her productions may be 
B b 2 imitated ; 
