Analyfis of the Air. 199 
the proportion of caput mortuum , or earth 
being very fmall. 
Experiment LXXVIIL 
One eighth of a cubick inch of Mercury 
made a very infenfible expanfion in diftil- 
lation, notwithftanding the iron retort had 
an almoft melting heat given it at a fmith’s 
forge, fo that it made an ebullition, which 
could be heard at fome diftance, and withal 
fhook the retort and receiver. There was 
no air generated, nor was there any expan- 
fion of air in the following Exper. viz. 
Experiment LXXIX. 
I put into the fame retort half a cubick 
inch of Mercury , affixing to the retort a very 
capacious receiver, which had no hole in 
the bottom. The wide mouth of the re- 
ceiver was adapted to the fmall neck of the 
retort (which was made of a musket barrel) 
by means of two large pieces of cork which 
entered and filled the mouth of the receiver, 
they having holes bored in them of a lit fize 
for the neck of the retort 5 and the junc- 
ture was farther fecured, by a dry fupple 
bladder tied over it 3 for I purpofely avoided 
making ufe of any moift lute, and took 
O 4 care 
