346 = Liquefaction and Solidification of Carbonic Acid. 
it was done but yesterday. The limbs are very much flattened, 
but otherwise, their external appearance is the same as usual in 
the species, which can easily be determined, being oak, walnut, 
hickory, &c. ~ The larger logs and fragments have undergone the 
transformation in various degrees, some being of a soft and spongy 
texture. Many aré in the state of perfect coal at one end, or on one 
side, ci have undergone no chan ge except SER: at the other. 
Art, XVI.—On the ES ahioion and Selidfoation of Carbonic 
Acid 5* by i. K. ‘Mircuet, M. D- 
In the year 1823, public: attention was eae drawn to the 
‘subject of the liquefaction by pressure of the, so called, perma- 
nent gases, by Mr., now Sir Michael Faraday. + Among the 
aerial fluids, garbonic 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 conducted in 
_ glass tubes; and he depended on ee accumulation of newly 
generated ous for the necessary pressur 
_ Mr. Brunel,{ in a subsequent ack to apply compressed 
gases to mechanical purposes, produced a pint and a half of liquid 
carbonic acid, which, even at high op aaa 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 
e in December, 1835, of a report on ‘the liquefac- 
tion of Sarbonis acid on a comparatively large scale. In the last 
number for. that year of the Annales de Chimie et de Physique, 
M. Thilorier described the properties of liquid carbonic acid in 
detail. According to him, this liquid demands for its existence 
as such at 32° F’., a pressure, as stated by Sir M. Faraday, of 36 
atmospheres. Its specific gravity is at the same temperature 
0.830, at —4° F.—0.900, and at 86°—0.600. It is therefore en- 
larged by heat 3.407 times as much as its own or any other gas, 
when carried from 32° to 86°. From —4° to 32°, its expansion 
is almost exactly equal to wees of the gases.$ _ 
* From the Journal of the Franklin Tustitate, 
t Philos. Trans. Lond, t Quart.Jou wc: Vol. 
§ See at page 301 of this number, a notice of Mr. om caged experiments 
on this subject, and that of Dr. Torrey, in our miscellany.— ‘ 
ee ee ae 
