SELECTED ARTICLES. 
ART. XLV. — ON THE LIQUEFACTION AND SOLIDIFICATION 
OF CARBONIC ACID. By J. K. Mitchell, M. D. 
In the year 1S23 public attention was strongly drawn to 
the subject of the liquefaction by pressure, of the, so called, 
permanent gases, by Mr., now Sir Michael Faraday.* Among 
the aerial fluids, carbonic acid was distinguished as requiring 
a force of 36 atmospheres at 32° F. to coerce it into the liquid 
state. His ingenious and hazardous experiments were con- 
ducted in glass tubes; and he depended on the accumulation 
of newly generated gas for the necessary pressure. 
Mr. Brunei,! in a subsequent endeavor to apply compressed 
gases to mechanical purposes, produced a pint and a half of 
liquid carbonic acid, which, even at high temperatures, he 
confined in a series of small brass tubes not above the of 
an inch in the thickness of their walls. 
This interesting subject was not again publicly agitated, 
until the appearance in December, 1835, of a report on the 
liquefaction of carbonic acid on a comparatively large scale. 
In the last number for that year of the Jinnales de Chimie 
et de Physique, M. Thillorier described the properties of 
liquid carbonic acid in detail. According to him this liquid 
demands for its existence at 32° F., a pressure, as stated by 
Sir M. Farraday, of 36 atmospheres. Its specific gravity is 
at the same temperature 0.830, at — 4° F e —0.900, and at 86° 
— 0.600. It is therefore enlarged by heat 3.407 times as much 
as its own or any other gas, when carried from 32° to 86°. 
* Philos. Trans. Lond. 
VOL. IV. — NO. IV. 
f Quart. Journ. Vol. XLI. 
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