60 
SELECTED ARTICLES. 
1st. The liquid will augment by dilatation. 
2d. It will diminish by vaporization. 
The thermoscopic phenomena are very different, according 
to the relative proportions of liquid and gas; the former will 
either dilate, or contract, or remain stationary. 
These anomalies have enabled me, says M. Thilorier, to 
verify the extent of the dilatation and vaporization of this 
substance. It would appear, that the point of equilibrium, 
above which the liquid augments in volume, and below which 
it diminishes is when the liquid occupies || of the tube at a 
temperature of 0° C. If it fills a third, it becomes a retro- 
grade thermometer, rising with an increase of cold and sinking 
on the application of heat. If it occupies two-thirds of the 
tube, it will have the properties of a mercurial thermometer. 
Its range, however, is limited to + 30° C; for above this 
temperature the tube will be entirely filled with the expanded 
liquid. 
A thermometer of this kind, for all temperatures below 
-f-30 C. would have a great advantage over those in common 
use. It has been shown that those instruments gradually un- 
dergo an alteration, which unfits them for accurate observa- 
tions. 
Specific gravity. This liquified gas, whose specific gra- 
vity at 0° C. is 0.83, presents the singular phenomenon of 
changing its density from 0.90 to 0.60 in a scale of tempera- 
tures from —20° to +30° C. 
•Action on external bodies. Liquid carbonic acid is abso- 
lutely insoluble in water, and is incapable of mingling with it. 
It is soluble in all proportions in alcohol, ether, oil of naphtha, 
oil of turpentine and carburet of sulphur. It is decomposed 
with effervescence by potassium; it exercises no action on 
metals belonging to the six last classes, neither has it any sen- 
sible action on lead, tin, iron or copper. 
Cold produced by its sudden and instantaneous change 
