SOLUTIONS AS A FUNCTION OF TEMPERATURE 171 



In this solution the amount of liquid in the tube was such that its 

 mean density was below the critical density. In such case the true 

 critical phenomenon does not occur since, if carried out under strictly 

 equilibrium conditions, the liquid disappears at the bottom of the tube. 

 In general, however, unless the amount of liquid is comparatively small, 



TABLE LXI. 



CONDUCTANCE OF 0.2245 PER CENT NH 4 C1 IN CH 3 OH IN THE 

 CRITICAL REGION. 



Temp. \i Liquid u Vapor V t/V 



234.0 1524.0 .4411 



236.9 1236.0 1.574 .4333 



239.0 930.3 2.177 .4261 



240.0 760.0 3.568 .4147 



241.0 605.7 6.381 .4000 

 241.9 469.7 14.64 .3707 

 242.5 257.7 38.66 .2806 



-* Crit. Pt. 



243.1 67.25 



245.2 54.36 

 247.1 47.62 

 249.0 41.33 

 254.0 30.19 



and is thoroughly stirred, it will be found that the meniscus fades away 

 at some point above the bottom of the tube at a temperature correspond- 

 ing to the critical temperature. At this temperature, the specific con- 

 ductance of the vapor phase was approximately one sixth that of the 

 liquid phase. The conductance of the vapor phase is readily appreciable 

 as much as 5 below the critical point. Above the critical point the 

 conductance of the solution in a gas below its critical density decreases 

 with the temperature, the decrease amounting to something over 50 per 

 cent for a temperature change of approximately 12. In the immediate 

 neighborhood of the critical point the conductance appears to change 

 somewhat more rapidly than at higher temperatures. 



The conductance of the vapor phase increases very rapidly with the 

 temperature, and the more rapidly the nearer the temperature lies to the 

 critical point. It is evident that several factors are here coming into 

 play. In the first place, the concentration of the salt in the vapor phase 

 increases with rising temperature; and, in the second place, the density 

 of the vapor increases with increasing temperature. As follows from 

 the results given below for the conductance of the fluid phase above the 

 critical temperature as a function of the concentration of the solvent, the 



