176 



Prof. W. Ramsay. The Complexity and the [June 14, 



and it was assumed, as a first approximation, that the second term, 



the variation of x* with temperature, was negligible. In such a 



case 



... /, At It. 



(4) X = S K T= TTTTT- f > 



I dy (M)l J 



and it was on this assumption that the results given in the papers 

 referred to for the alcohols, the acids, and water were calculated. 



The numbers obtained were, however, as will be shown, much in 

 excess of the truth. 



An attempt was made to approximate to the true value of x, by 

 calculating it by means of equation (4) approximately, and using the 

 results obtained to correct equation (3), by inserting the neglected 

 second term. This was found to be impossible, and to lead to absurd 

 results; hence it was inferred that the variation of x with tem- 

 perature was such as to make it imperative that attention should be 

 paid to the second term of equation (3). At the same time it was 

 noticed in mapping x that its alteration with temperature was 

 'approximately linear ; and this fact greatly simplified the problem. 



Mr. J. Rose-Innes, who has taken much interest in this work, and 

 lias on several occasions given valuable assistance, was kind enough 

 to endeavour to find an expression which would satisfy these condi - 

 tions. 



A formula of the form 



(5) 



agrees admirably with the experimental values of molecular surface- 

 energy for methyl and ethyl alcohols, water, and acetic acid between 

 low temperatures and some 30 below their critical points. Even at 

 89'8, it will be noticed, the agreement for methyl and ethyl alcohols 

 is reasonably good. 



The constants for these substances are : 



Jc. 

 Methyl alcohol ...... 1-489 



Ethyl alcohol ....... 2-170 



Water ............. 2'631 



Acetic acid ......... 1-910 



A comparison between the calculated and found values of 

 given in the following table : 



