LIQUID CARBONIC ACID. 
59 
ART. XI ON THE PROPERTIES OF LIQUID CARBONIC 
ACID. By M. Thilorier. 
Dilatation. — This liquified gas presents the strange and 
paradoxical fact, of forming a liquid more easily distilled than 
the gases from 0° to 30° C. Its volume augments from 20 to 
29, that is to + 30° C; this augmentation equals about half 
the volume this liquid presents at 0° C; in short, its dilatation 
is four times greater than that of air, which from 0° to + 30° C. 
dilates 2 3 6 ° y , whilst the expansion of liquid carbonic acid, 
between the same thermometrical limits is 
Vaporization. — If the temperature of a tube containing a 
small quantity of liquid carbonic acid be increased, this liquid 
boils, and the vacuum becomes filled with vapour, which 
increases in quantity in proportion to the elevation of the 
temperature. At -f- 30° C. the quantity of liquid at 0° re- 
quired to fill the vacant space, is equal to one-third of the 
length of the tube. At 0° the proportion of fluid is only -L 
of the space filled. 
Pressure. — From 0° to + 30° C. the pressure of the vapour 
furnished by the liquified gas rises from 36 to 73 atmospheres; 
this gives an augmentation of one atmosphere for each 
degree; it must be remembered that the weight or density of 
the vapour increases in a proportion far greater than that of 
the pressure, and that the law of Mariotte is not applicable 
after liquifaction has taken place. If the density of the vapour 
be taken as a basis to determine the degree of pressure, that 
at 36° C. would be 130 atmospheres, whilst the gauge only 
indicates 73. 
Thermoscopic effects. — If a glass tube containing a portion 
of liquid, and one of gas be subjected to the action of heat, 
two contrary phenomena will present themselves. 
