112 On the Liquefaction and Solidification [1844. 



Hence it is probable that this substance may be used in 

 certain cases, instead of carbonic acid, to produce degrees of 

 cold far below those which the latter body can supply. Down 

 to a certain temperature, that of its solidification, it would not 

 even require ether to give contact, and below that temperature 

 it could easily be used mingled with ether ; its vapour would 

 do no harm to an air-pump, and there is no doubt that the 

 substance placed in vacuo would acquire a temperature lower 

 than any as yet known, perhaps as far below the carbonic acid 

 bath in vacuo as that is below the same bath in air. 



This substance, like olefiant gas, gave very uncertain results 

 at different times as to the pressure of its vapour; results 

 which can only be accounted for by supposing that there are 

 two different bodies present, soluble in each other, but differing 

 in the elasticity of their vapour. Four different portions gave 

 at the same temperature, namely 106 Fahr., the following 

 great differences in pressure : 1 '66 ; 4*4 ; 5*0 ; and 6*3 atmo- 

 spheres ; and this after the elastic atmosphere left in the tubes 

 at the conclusion of the condensation had been allowed to 

 escape, and be replaced by a portion of the respective liquids 

 which then rose in vapour. The following Table gives certain 

 results with a portion of liquid which exerted a pressure of six 

 atmospheres at 106 Fahr. 



Fahr. Atmospheres. Atmospheres. 



-40 . . . 10-20 

 -35 . . . 10-95 

 -30 . . . 11-80 

 -25 . . . 12-75 

 -20 ... 13-80 

 -15 ... 14-95 

 -10 ... 16-20 

 - 5 ... 17-55 



... 19-05 . . . 24-40 

 5 ... 20-70 . . . 26-08 

 10 ... 22-50 . . . 27-84 

 15 ... 24-45 . . . 29-68 

 20 ... 26-55 . . . 31-62 

 25 ... 28-85 . . . 33-66 

 30 ... ... 35-82 



35 . 38-10 



