[ 20 ] 
part, or black earth, fhould feem to be of the ab- 
sorbent kind, the other an infolubie earth, or a fe- 
lenite. Whether the fir ft earth was originally dif- 
folved in the water by means of air, or whether it was 
only light particles of earth, which had been blown 
into the well, and only fufpended, I fhall not take 
tspon me to determine ; but, in looking at the water 
of another bottle, which was not ufed" in this ex- 
periment, I obferved, that although the water ap- 
peared quite tranfparent, yet that it contained fome 
particles of light earth fufpended ; however, thefe 
might have been originally diftolved by means of air, 
but feparated afterwards. 
The remaining water was put into a fmall bafon, 
and fet again on a fand heat to evaporate ; when it 
was reduced to about three ounces, a pretty firm 
pellicle appeared, and it was fet in a cool place for 
twenty-four hours ; at the end of which time, it was 
examined ; and, befides the pellicle which had formed 
on the furface, a thin white lamellated and granu- 
lated cruft had formed, and attached itfelf to the 
bottom and fides of the bafon. Thefe being all fe- 
parated, the whole was thrown into a filter ; and 
when the water had pafled, and the coffin was dry, 
there was found remaining gr. xi. of a very white, 
inlipid gritty fediment. This fediment in the mouth 
feels gritty, and has no tafte, being quite infipid ; 
when fome of it was put into a glafs with diftilled 
water, and a few drops of oil of vitriol mixed with 
it, a very flight effervefcence enfued ; but almoft the 
whole remained undiffolved, and appeared to be fe- 
lenite. 
The 
