1894.] Molecular Surface-energy of Mixtures of Liquids. 187 



The mean value of K, calculated over the whole range of tempera- 

 tare, is 2*115 ; the mean value found is 2*123 ; hence it may be con- 

 cluded that these liquids are without influence on one another. It 

 will also be noticed that the found and calculated values of <y and of 

 7(My) s are in very close correspondence. . 



To check these results the proportions were reversed, and a mix- 

 ture of 



(&) 5C 6 H 10 :NH to 1C 6 H 5 CH 3 was investigated. 



5C 5 H 10 :NH to 1C 6 H 5 CH 3 . 



The mean value of Jc, calculated over the whole range of tempera- 

 ture, is 2-087 ; the mean va.lue found is 2-067. Here again the found 

 values of surface-tension and of surface-energy agree very closely with 

 those calculated, 



It is possible, without assuming a molecular weight, to calculate 

 the mean molecular weights of such mixtures by means of the equa- 

 tion 



I fyt^ <y'i/^ 







[n doing this, the mean value of Jc for each mixture has been taken, 

 and the value of M has been calculated between extreme limits of 

 temperature. For the first mixture the mean molecular weight found 

 is 90'61 ; that calculated for a mixture of five molecules of toluene to 

 one of piperidine is 90'83 ; for the second mixture the mean molecular 

 weight found is 86" 12, and the calculated value for a mixture of five 

 molecules of piperidine to one of toluene is 86*17. This, of course, 

 constitutes only an arithmetical check on the other results, but if a 

 mean value for Jc had been chosen, e.g., 2*121, the results would have 

 been practically the same. 



It is obvious that in this case the liquids ai*e without influence on 

 each other. 



