Laivs of Molecular Force. 275 



as the first, consisting of a mere approximation of the first 

 pairs without any change in the values of A or of /. 



According to this assumption we should expect the beha- 

 viour of the liquid alcohols to be represented by a form similar 

 to our infracritical equation, and we will assume 



pv 





where R" is about 2R. 



It was on the infracritical equation that our second method 

 of finding M 2 Z was founded, giving the relation 



. 4/ a 25^\ m 



which can be applied to Amagat's data {Ann. de Chim. et de 

 Phys. ser. 5, t. xi.), and Pagliani and Palazzo's (Wied. Beild. 

 ix.) for the alcohols. 



Again, our assumption enables us to apply the fifth or 

 capillarity method of finding M 2 / to the alcohols, if only we 

 remember that the molecular domain becomes twice as large 



and its radius 2^ as large as it would be with only one pair- 

 ing; hence the equation for the fifth method becomes for 

 the alcohols 



I = ca#/(2m)i 



SchifFs data are available. 



As the latent heat and critical temperature are largely 

 dependent on the supraoptical equation, we ought not to 

 expect the formulae for M 2 / furnished by the third or latent- 

 heat method and by the fourth or critical-temperature method 

 to apply to the alcohols. But as the relation 



or, empirically, 



MX = 19'4T 6 , 



MX = 21 T 6 , 



which was deduced in the discussion of the third method, 

 does apply approximately to the alcohols, the constant being 

 26, we may as well, for purposes of comparison, see what the 

 formulae of the third and fourth methods give in the case of 

 the alcohols. 



