L 49 1 
with the ground, divided into five or iix -rooms, 
which are fo hot from the nature of the foil, that 
patients go thither to fweat by order of the phy- 
sicians. 
The grotto, of which I am to give an account, is 
not dug into a rock, but into a fandy earth, which 
however is of fufficient tenacity and confidence to 
keep together without tumbling down, tho’ the fides 
or walls are cut perpendicular. It is fomewhat 
more than three feet wide, near two toifes{or twelve 
feet) long ; five or fix feet high at the entrance, and 
a little lefs than three feet at the inner end. • 
Tho’ the ground is a little Hoping from within 
outward, and much more fo from the door to the 
road, which is about five yards from it, and runs 
along the foot of the little hill j yet one walks di- 
redfly into it, as upon level ground, without the af- 
fidance of fteps to go up or down : which thews, that 
the Hope is pretty even from the bottom or inner end 
of the grotto to its mouth, and from thence to the 
road. The knowlege of this particular is neceflary 
for better comprehending what I have to fay in the 
fequel. 
When a perfon places himfelf at the didance of 
fome few dcps without fide, and doops fo as to have 
the eye nearly on a level with the ground of the 
grotto, newly opened, and well illuminated, he fees 
a vapour within it, pretty much like that, which ap- 
pears over a chafing-difh of red coals, but with this 
difference, that it is more fluggifh and heavy ; for it 
does not rife above five or fix inches high. This 
fluid, which is hardly vifible, and feems fo fubtil to 
the eye, fpreads regularly, and feems to effedt an 
G asquilibrium., 
