( 54S ) 
when 'tis put into the Engine , and the Air that prefTes it ex- 
haufted. Meantime, I have fince made the fame Experiment wich 
a Ga^e, and I did not perceive , that all the bubbles that iffued 
out of the water, made the Mercury rife fo fenfe. 
. After this, I left my Receiver expofed to the Froft , and I 
found, that the Ice which was made therein was not yet quite 
free from bubbles , though the water thereof had boiled in the 
vacuum, which, one would think, fliould have driven out all the 
Air: Yet the bubbles were there far lefs numerous than in Ice 
made of ordinary water. I perceived nor, that the Quickfilver 
was much rifen in the G/g^^ Afterwards I melted this Ice , and 
put the water abroad to freez again, ftill without taking it out of 
the vacuum, and I found, that this fecond time it was very much 
freer from bubbles. The Glafs did not break; but becaufe it 
was fomewhat conical, we could not know, whether it remained 
whole upon the account of ns figure^ or becaufe that the waters 
which was frozen within, was freed of Air; And I xould not 
make the Experiment with glaffes of another figure, becaufe the 
Froft did ceafe. 
After this , I made Sfirit of Wine boil in vacuo in the fame 
manner I did the Water ; and I faw, that it boiled much fooner. 
It made the Mercury rife about an inch in the Gage^ Then 1 took 
it from the' fire , and faw it continue in its boilings and even 
finking the Receiver into cold water , it thereupon boiled much 
moreftrongly. One would think, this proceeded ftomzr\Anti' 
fetiftap ; but we have more ground to fay, it came from hence , 
that the vapours of the Spirit were condenfed, and fo made the 
Receiver more empty ; which is TufRcieat to make the Spirit of 
Wine boilj even though it were not hot. The Quickfilver did 
in two hours fubfidc again, to near half a line as low as it had 
been. Then I put the Receiver over the flame again , and made 
the Mercury rife more than two inches j but then the Receiver 
cracked. 
One day I took a tube of Plajler of Paris , open at one end , 
and clofe at the other. I applied the open end to the cement as [ 
was wont to do Receivers ; and I faw it was not pcfllblethus to 
exhauft it, becaufe the Air did eafily pafs through the Plafter. I 
put therefore a Tube of Iron on the Engln , fo as having filled ic 
with water, the Tube of Plafter was covered therewith; and 
[hen 
