308 



Mr. J. B. Hannay. 



Table VII. 

 Alcohol with. Hydrogen. 



T. T'. t. t'. P. F. t". t'", 



230 231 75 76 226 191 16 16 



230-5 231 80 82 227 192 17 17 



231 -5 232 82 80 226 *6 191 '4 15 15 



232 232 92 90 226 *4 191 *6 15 15 



233 231 85 85 226 '4 191*2 15 15 



232-5 233 90 92 226 '5 191 15 15 5 



232 231 82 80 226*2 192*2 15*5 16 



229 230 *5 78 77 227 191 *8 16 16 



230*5 230 76 76 226*8 192 16 16*5 



231*5 231*5 77 77 227 191 4 15*5 15*5 



232 230 82 82 226*2 191 16 16 



231 *8 232 80 82 226 191 *2 17 17 



230 *4 232 73 72 226 *4 191 *4 18 17 *5- 



232*5 231*3 72 75 226*6 191*3 17 17 



231 232 80 80 226*9 192*1 15 15 



Average T 231 '351 n , -, 10 . OA ^ 

 mi r di on-, \ Corrected mean 23o *04. 



,, 1 'Zoi. '01 J 



Average P 226-58 1 ColTected mean i;8 .g atmos . 

 x 191"oo J 



Probable error of mean temperature 3 '18. 

 „ „ pressure 0*07. 



From these tables we see clearly that the critical temperature is not 

 materially altered by a very large increase of pressure ; in fact, in the 

 last case the pressure is nearly three times as great, and yet we have 

 only a lowering of the critical temperature by about one degree. It 

 was found, however, that as the pressure was increased the solubility 

 of the hydrogen in the alcohol also increased, so that at high pressures 

 a very considerable lowering of the critical temperature takes place, 

 When the two fluids have thoroughly mixed at a temperature over the 

 critical point, the passage of the mixture through the critical tempera- 

 ture downwards is not attended with immediate liquefaction ; in fact, 

 this does not take place till a temperature 10° lower is reached, the 

 hydrogen preventing the alcohol from assuming the liquid condition. 

 At a pressure of 250 atmospheres the meniscus disappeared, or rather 

 became broad at 225° ; but diffusion did not take place completely ; the 

 surface seemed to be destroyed, but the action did not go deeper, 

 while at 300 atmospheres the meniscus was lost at 220°. This is 

 plainly owing to the action of the compressed hydrogen, and could we 

 have a gas quite insoluble in the liquid, this lowering would not take 



