540 



Prof. J. Dewar. 



[June 17, 



On again increasing the pressure so as to get a layer of carbonic 

 acid, and then releasing the pressure gradually, the liquid carbonic 

 acid on the surface first fell in oily streams through the saturated 

 benzol ; but when all this had disappeared, the carbonic acid then 

 commenced to boil from the bottom of the benzol, and continued to do 

 so until it was again entirely vaporised. 



At 35° C. liquid commenced to appear at 35 atmospheres, forming 

 a distinct layer on the surface of the benzol, which was not in the 

 least agitated. On further compression the liquid layer increased in 

 volume, but no oily streams were seen to fall through the benzol ; and 

 on leaving it for about ten minutes, the layer of liquid was almost 

 just as distinct, showing that it was not nearly so soluble in the benzol 

 at this temperature. 



On the pressure being now reduced, the liquid quietly evaporated 

 away from the surface ; but when all this had disappeared, carbonic 

 acid commenced to boil out of the benzol, showing that it had dis- 

 solved a considerable amount. 



At 52° C. the liquid appeared at 60 atmospheres, forming a layer 

 which mixed with the benzol on standing ; and at 70° C. and 85 at- 

 mospheres a distinct layer was also formed, which however rapidly 

 mixed with the benzol. 



4. Carbonic Acid and Ether. 



A tube was filled with carbonic acid and a little ether introduced. 

 At 20° C, and at a pressure of 20 atmospheres, the carbonic acid 

 liquefied and fell through the ether, mixing with it in all proportions. 



At 42° 0. liquid was condensed on the surface of the ether at a 

 pressure of 55 atmospheres, forming a distinct layer ; the upper sur- 

 face of the ether was, however, kept in continual oscillation from the 

 apparent solution of the carbonic acid in it. No currents due to the 

 falling of the carbonic acid through the ether were visible. At 68° 0., 

 and a pressure of 110 atmospheres, a perfectly separate layer of fluid 

 was formed on the surface of the ether, and no currents descended 

 through the ether. 



5. Carbonic Acid and Nitrous Oxide. 



When a tube was filled with equal volumes of carbonic acid and 

 nitrous oxide, and the gas liquefied, the fluids mixed together in all 

 proportions, no difference being perceptible ; but when the pressure 

 was suddenly withdrawn, the one gas boiled before the other, and for a 

 few seconds a distinct line of separation was seen. 



Liquefaction of Carbonic Acid with Trichloride of Phosphorus. 

 At 16 o- 20 C, and 42*95 atmospheres' pressure, the carbonic acid 



