122 LIQUEFACTION, ETC., OF GASEOUS BODIES. 
tour's experiment), and applied to it heat, the ether would rise 
in vapor, and so would continue until the vapor was much con- 
densed. At last, the liquor below and the vapor above would 
be of as nearly the same weight as possible, and the least de- 
gree of additional heat would turn the liquor into vapor, or, 
if taken away, convert the vapor into liquor. Observe what 
happened. At that temperature of ether no pressure could 
bring the ether into a liquid state ; at a lower temperature it 
would. He believed, then, the reason why so many had fail- 
ed in liquefying and solidifying gases was, that although they 
could procure the immense pressure he had mentioned, they 
could not obtain a degree of temperature sufficiently low. He 
would explain in what manner he had succeeded. He had 
taken as his basis carbonic acid gas in its solid state as produc- 
ed by Thillorier. A quantity of carbonic acid, in partly a 
liquid and partly a vapor state, being confined in a tube, the 
expansion of the vapor forced the liquid through an orifice in 
the side into a cylindrical brass box, and being acted on by a 
rapid current of air the liquid carbonic acid was immediately 
converted into a solid substance like snow. Its temperature in 
that state was 70° below of Fahrenheit ; but though he took 
that as his basis, it was not low enough for the purpose of his 
experiments. The temperature must, therefore, be further 
decreased. It had been demonstrated by Thillorier, that if 
ether were applied to solid carbonic acid, the temperature 
could be reduced to even 105° below Fahrenheit; but a lower 
degree was still required, and that was obtained by exhausting 
the air. His object, then, was to combine this extreme de- 
gree of cold with great pressure in his experiments on gases. 
The means by which he effected it he thus described : — A 
quantity of gas in a glass vessel was forced by a condensing 
pump into a tube inserted in the receiver of an air pump ; that 
part of the tube inserted in the receiver was made of common 
bottle glass (the strongest kind for experiments, and capable 
of bearing an enormous pressure) in the shape of a retort, and 
the bent or lower part of the tube lying immersed in the cold 
