— — ) for associating- substances has been calculated by me. 

 P dl Jj, 



When the heat of dissociation q of the double molecules may be 



pnt -- 0, we find for ƒ (see formula (28) loc. cit.) : 



n 



J ^^ /o X -; ~ 1 

 An — om 



01' when Ab = - 



. . (1 - ^){i-\3-}- y, ^-Q 



in which the factor of /„ both for p* := and for [3 = 1 again 

 assumes the value 1. For ,? =: Va ^^^^ value is, however, '16 : 19 = 0,84, 

 which would make the normal value 7 descend to about 5,9. As 

 ƒ for methylacohol is found ^ 7, namely = about 8,6 (cf. Kuenen, 

 Die Zustandsgleichung, p. 142, where the value 3,75 >< 2,30 is given), 

 the factor of ƒ„ would have to be about J ,2 instead of 0,84; i.e. 

 Lb not = 0, and again negative — or also the value of q (see the 

 full formula in Teyler, p. 42) would moreover have to be different 

 from 0, and that positive. 



Fontanivent sur Clarens, May 1, 1914. 



Physics. — "On apparent thernwdt/nfunic discontinuities, in connection 

 frith the value of the quantity b for infiniteh/ la lye vo/ti/ne." By 

 Dr. J. J. VAN Laar. (Communicated by Prof, H. A. Lorentz). 



(Communicated in the meeting of June 27, 1914). 



1. One of the principal results of the foregoing series of commu- 

 nications ^) has been this (cf. particularly II p. 926 and IV p. 464), 

 that the quantity b,, , i. e. the value of b for infinitely large volume 

 (hence in the ideal gas state) cannot possibly be =4»i as the classical 

 kinetic theory gives for it. With decreasing temperature b,/ approaches 

 namely more and more to ^^ . If in the ideal gas state b,, were 

 = 4:in, bg would have to be ::= 4»i also at very low temperature 

 (this kinetic result holds namely independent of the temperature), 

 while in the condensed liquid state with cubic arrangement e. g. of 

 the molecules, supposed to be spherical, b^ would be about = %n' , 

 in which m' is either equal to oi' smaller than m, so that then b,, 

 cannot possibly become = b^ . 



1) These Proc. of March 26, April 23, May 29 and Sept. 26, 1914 (to be cited 

 as 1-lV). 



