

Forces of Attraction between Atoms and Molecules. 785 



approximately constant, as should be the case according to 

 equation (1), i£ %c a is proportional to 2 \^m 1 and %v* 



Table I. 



Name of liquid. 



Ether 



Methyl formate 



Carbon tetrachloride 



Benzene 



Chloro-benzene 



Ethyl acetate 



Propyl formate 



Methyl propionate . . 



Propyl acetate 



Ethyl propionate 



Methyl butyrate 



j Methyl isobutyrate .. 



. 1/2 



.1/2 



x X /2 



A m 



X m 



X m 



P 



pE V m x 



p2v 



404-2 



14-5 



13-5 



287-7 



15-2 



14-4 



437-5 



160 



137 



421-6 



15-7 



14-1 



493-7 



16-4 



13-7 



4351 



14-6 



13-6 



428 



14-3 



13-4 



428-8 



14-4 



13-4 



502-5 



14-2 



13-2 



500-8 



14-2 



13-2 



500 



14-2 



13-2 



4976 



14-1 



13-1 



E m 



E 1/2 m 



P 



psV^i 



752-6 



27 



530-1 



28-0 



813 



29-8 



778 



29-1 



905 



300 



p2y 



251 

 265 

 25-4 

 25-9' 

 251 



From equation (6) we have that the ratios 





and 





should each be constant for corresponding states. Table II. 

 gives the values of these ratios for a number of liquids. It 

 will be seen that the values in the upper part of the table 

 are approximately constant. A comparison of these results 

 with those obtained with %c a instead of X\Zm { or %v, 

 Table XIII. Phil. Mag. p. 507, Oct. 1909, shows that 

 equation (6) is better satisfied in the latter case. The reason 

 for this will appear later. 



The lower part of the table contains the liquids which are 

 known to be polymerized. They do not fit in with the other 

 liquids, as observed before. When a liquid is polymerized 

 we should, in accordance with the assumptions on which the 

 above equations are_ founded, use ii%c a , n% \Z?n u ri£v, nm, 

 instead of %c a , 2 i/m 1? 2v, ra, where n denotes the number of 

 normal molecules combined into a single molecule, which 

 would then make the liquid fit in with the normal liquids. 

 But n is usually not known. We may, however, assuming 

 the theory true, do the opposite thing, and determine n for a 

 polymerized liquid by means of one of these equations. In 

 Phil. Mag. S. 6. Vol. 19. No. 113. May 1910. 3 E 



