168 DR. FARADAY ON THE LIQUEFACTION AND SOLIDIFICATION OF 



namely, -106° Fahr., the following great differences in pressure, 1*66; 4*4; 5*0; 

 and 6-3 atmospheres, 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 por- 

 tion 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. 



p^HE. Atmosplieres. 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 



The second column expresses the pressures given as the fluid was raised from low 

 to higher temperatures. The third column shows the pressures given the next day 

 with the same tube after it had attained to and continued at the atmospheric tem- 

 perature for some hours. There is a difference of four or five atmospheres between 

 the two, showing that in the first instance the previous low temperature had caused 

 the solution of a more volatile part in the less volatile and liquid portion, and that the 

 prolonged application of a higher temperature during the night had gradually raised 

 it again in vapour. This result occurred again and again with the same spe- 

 cimen*. 



Cyanogen. — This substance becomes a solid transparent crystalline body, as Bunsen 

 has already stated-f, which raised to the temperature of — 30°Fahr. then liquefies. 

 The solid and liquid appear to be nearly of the same specific gravity, but the solid is 

 perhaps the denser of the two. 



* ITiis substance is one of those which I liquefied in 1823 (see Philosophical Transactions). Since writing 

 the above I perceive that M. Natterer has condensed it into the liquid state by the use of pumps only (see 

 Comptes Rendus, 1844, 18th Nov. p. 1111), and obtained the liquid in considerable quantities. The non-soli- 

 dification of it by exposure to the air perfectly accords with my own results. 



t Biblioth^que Universelle, 1839, xxiii. p. 184. 



