202 Scientific Intelligence — Chemistry and the Arts. 



ture was surrounded by the air, estimated by an alcohol thermome- 

 ter, was a temperature of — ■ 106° Fahr. But on placing the mixture 

 under an air-pump, and removing the atmospheric pressure, leaving 

 only that of the vapour of carbonic acid, which amounted only to 

 ^ijth of the former (that is, to the pressui-e of a column of 1*2 

 inch of mercury), the thermometer indicated a temperature of 166° 

 below zero of Fahrenheit's scale. In this state the ether was very 

 fluid, and the bath could be kept in good order for a quarter of an 

 hour at a time. 



The author found that there were many gases which, on being 

 subjected to cold of this extreme intensity, condensed into liquids, 

 even without a greater condensation than that arising from the or- 

 dinary atmospheric pressure, and that they could then bo preserved, 

 sealed up in glass tubes, in this liquid state. Such was the caso 

 with chlorine, cyanogen, ammonia, sulphuretted hydrogen, arseniu- 

 I'etted hydrogen, hydroiodic acid, hydrobromic acid, carbonic acid, 

 and euchlorine. With respect to some other gases, such as nitric 

 oxide, fluosilicoii, and olofiant gas, it was difficult to retain them for 

 any length of time in the tubes, in consequence of the chemical 

 action they exerted on the cements used in the joi)iings of caps and 

 other parts of the apparatus. Hydroiodic and hydrobromic acids 

 could be obtained eitlier in the solid or liquid state. Muriatic acid 

 gas did not freeze at the lov.'ost temperature to Avhich it could be 

 subjected. Sulphurous acid froze into transparent and colourless 

 crystals, of greater specific gravity than the liquid out of which they 

 were formed. Sulphuretted hydrogen solidified in masses of con- 

 fused crystals of a white colour, at a temperature of — 122° Fahr. 

 Euchlorine was easily converted from the gaseous state into a solid 

 crystalline body, which, by a slight increase in temperature, melted 

 into an orange-red fluid. Niti'ous oxide was obtained solid at the tem- 

 perature of the carbonic acid bath in vacuo, and then appeared as a 

 beautifully clear and colourless crystalHne body. The author con- 

 ceives, that in this state it might, in certain cases, be substituted 

 with advantage for carbonic acid in fi'igorific processes, for arriving 

 at degrees of cold far below those hitherto attained by the employ- 

 ment of the latter substance. Ammonia was obtained in the stato 

 of solid white crystals, and retained this form at a temperature of 



— 103°. The following liquids could not be made to freeze at 



— 166°, namely, chlorine, ether, alcohol, sulphuret of carbon, caout- 

 choucine, camphine, and rectified oil of turpentine. The following 

 gases shewed no signs of liquefaction when cooled by the carbonic 

 acid bath, even when subjected to great pressure, namely, 



Hydrogen and oxygen, at a pressure of , .27 atmospheres. 



Kitrogcn and nitric oxide, at a pressure of . 50 



Carbonic oxide, at a pressure of . . .40 



Coal gas, at a pressure of . . . .32 



