( 1^4) 



viz. in the points d and c : the critical mixing-tcmporatuics of the 

 binary systems. 



If' we start with a mixture of phenol and aniline, adding water 

 to this binary mixture, two liquid phases are formed, passing into 

 one when heated ; this mixing-temperature depends upon the quan- 

 tity of water added. The highest mixing-temperature we are able to 

 reach by the addition of water, may be called the critical mixing- 

 temperature of water with the said binary mixture. In varying 

 the proportion of phenol and aniline in the binary mixture, another 



critical mixing-temperature 

 will be obtained by the ad- 

 dition of water. 



In fig. 3 is shown on the 

 X-axis the composition of the 

 binary mixture; on the F-axis 

 the critical mixing-tempera- 

 ture of this binary mixture 

 with water. We then get the 

 line de in which c? indicates 

 the critical mixing-tempera- 

 ture of jthenol with water, 

 and e that of aniline with 

 water. The line de may be 

 drawn according to the table 

 given below. 



Critical mixingtemperature 

 after the addition of 

 water. 



.... 68° 

 .... 95° 



Molec. anilin on 100 Moleo. phenol 



Composition of the biuaiT mixture 

 in Molec. aniline on 

 100 Molec. 

 Plicnol 4- Auiliuo. 



. . . . 



11.58 . . . . 



25.4 1U°— 115° 



37.3 127° 



50 139°— 140° 



62.8 148° 



76.07 155°5 



87.66 163° 



100 167° 



For each of the binary mixtures of phenol and aniline, given iu the 

 above table the mixing-temperature is determined by the addition of dif- 

 ferent quantities of water and the critical temperature deducted from it. 



We see therefore that the eiitical mixing-temperature of the binary 

 mixtures increases in proportion as they contain more aniline — 



