Ligite ofaction ot Solidification ’ B55 
the latter. This. actually et ‘in the attempt to ascertain 
the pressure at 86°, when the natural temperature was 75°. 
Bubbles of gas were seen ascending through a liquid in M, up to 
its surface at a few inches below the mercurial cylinder. This 
as far as relates to the tubes may be avoided by prolonging the 
socket of M, down into the mercury of the cup, so as to include 
a cylinder of common air between two cylinders of mercury, and 
prevent any carbonic gas from entering either the socket, or the 
glass tube. A correction for the weight of this PINE. must in 
‘such case be made. 
When a glass tube, hermetically sealed at one a and cemen- 
ted into a brass socket and screw at the other, is attached toa 
charged receiver and cooled by snow or pounded ice, liquid car- 
bonic acid may be collected in it: It is perfectly colorless and 
transparent, and the specific gravity bulbs, previously introduced, 
are seen to ascend or descend, as the temperature is altered. 
When the tube so charged is opened, the liquid becomes vio- 
lently agitated, escapes rapidly, grows colder and colder, and 
finally the remainder’is-convertéd into a solid, more dense than 
the snow already described, but nearly white, and very porous. 
If the tube be exposed to a paste of carbonic snow and ether, the 
liquid is solidified into amass which is not porous but which sinks 
in the liquid as the latter is formed again by the melting of the solid. 
The analogy between liquid carbonic acid and water, is thus 
completed for we have liquid, vapor, snow, and ice, exhibited by 
both. 
By the previous earn of water, ether, alcohol, metals, 
oxides, or oils, &c. into such tubes, and then filling shins with 
liquid earbonie acid, the~ resulting phenomena may be. easily 
observed. Water-being-heavier rests below the. new liquid, and ~ 
does not appear to mingle with it even at the surface of contact, 
for when the latter is let off no bubbles appear in the water, aia 
it is frozen at the top into solid ice. 
When alcohol or ether is introduced, the new liquid falls 
through it in streams, as water would do, but soon renders it 
milky by mixture. The removal of the pressure causes a violent 
effervescence, and immediately the clear, colorless ether, or al- 
cohol, is seen alone in the tube; no solid being formed. When 
alcohol holds shell-lac in solution, the acid causes its precipitation 
in light whitish flocculi, which are immediately re-dissolved 
