Philosophical Transactions. 125 
power about equal to that of water; it does not congeal at a tem- 
perature of 0°; its specific gravity is nearly 1-42, and it exerts a 
pressure of about two atmospheres at 45°. 
Sulphuretted hydrogen was generated and condensed in.an ana- 
logous way, from muriatic acid and sulphuret of iron. It was 
colourless, limpid, and excessively fluid. It was not rendered 
more adhesive by a temperature of 0°; its refractive power ap- 
peared to be rather greater than that of water, and the pressure of 
its atmosphere at 50, was equal to about’ 17 atmospheres. Its 
specific gravity about 0:9. 
Carbonic acid was also condensed, but it required great pre- 
cautions to effect the condensation with safety. It is a limpid, 
colourless body, extremely fluid, and floated, as did all the pre- 
ceeding liquids, upon the contents of the tube, without mixing. 
It distils readily at the difference of temperature between 32° and 
0°; its refractive power much less than that of water, and its va- 
pour exerts a pressure of 36 atmospheres at a temperature of 32°. 
In endeavouring to open the tubes which contained it at one end, 
Mr. Faraday states, that they uniformly burst with powerful 
explosions. 
Fluid enchlorine was also obtained, and proved to be a transpa~= 
rent substance, of a deep yellow colour, and highly elastic powers. 
Liquid nitrous oxide 1s limpid and colourless. It boils rapidly 
by the difference of temperature between 50 and 0°, and does not 
solidify at—10. Its refractive power is less than that of any known 
fluid, and the pressure of its vapour is equal to above fifty atmo- 
spheres at 45°. 
Liquid cyanogen is limpid, colourless, and very fluid, and does 
not alter its state at the temperature of 0°. Its refractive powers 
rather less than that of water; its specific gravity nearly 0-9, and 
the pressure of its vapour about 3°7 atmospheres. 
Mr. Faraday obtained dry ammonia from chloride of silver satu- 
rated with this gas*, and, by the usual process, succeeded in con- 
densing it. It was colourless, transparent, and very fluid. Its 
refractive power surpassed that of water, and all the other liquids 
hitherto described. The pressure of its vapour is equal to about 
6°5 atmospheres at 50°, and its specific gravity is 0°76. Attempts 
were made to obtain hydrogen, oxygen, fluoboracic, fluosilicic, 
and phosphuretted hydrogen gases in the liquid state; but though 
all of them have been subjected to great pressure, they have as 
yet resisted condensation, 
6. On the Application of Liquids formed by the Condensation of Gases 
as Mechanical Agents. By Sir Humphry Davy, Bt. Pres. R.S. 
In this paper Sir H. Davy anticipates the probability of the ap- 
* See Quarterly Journal, yol, y. p. 74. 
