809 



least I infer from an abstract in tlie Chern. Weekblad of Jan. 3, 

 1914, p. 29 of his most recent publication "Weiteres zur Zustands- 

 gleicliung" (summary of his latest Papers in these Proceedings of 

 Nov. and Dec 1912, .Ian. and P>br. 1913), that he has adopted 

 this opinion. 



Thus the quantity /; would control the whole thermic behaviour 

 of the ditferent substances, and the variability of this quantity in 

 dependence on v, and also on T would be the cause that this actual 

 behaviour deviates from that which would conform to van der Waals' 

 ideal equation of state with a and b constant. 



Further it seems to appear more and more that all the causes 

 devised up to now, which were to account for the variability of b, 

 yet jointly find their expression in one comparatively simple equation. 



When the former supposition of perfectly hard and elastic spheres 

 is abandoned for that of a (jradual exchange of the energy during 

 the collisions, in which at bottom the kinetic energy of the moving 

 and colliding molecules may be thought transferred to the interjacent 

 medium, which transition determines the external pressure — part 

 of the foundation of the before assumed correction on account of 

 apparent diminution is no longer valid, at least in its old form. 



When the molecules are considered as pretty stable systems, the 

 volume of which varies only slightly in consequence of the increase 

 of the internal and the external pressure, a great part of the correction 

 introduced later on account of the real diminution, must no longer 

 be applied. We are led to this view when we consider how exceed- 

 ingly slight the influence of the temperature is just at higher tem- 

 peratures (we shall come back to this presently), so that it seems 

 that the molecule systems are only slightly modified in volume even 

 by the influence of the thermal motion (which will certainly be 

 more intense than that of the pressure). The rise of temperature 

 seems chiefly to have this influence that some molecules (the number 

 of which is indicated by the wellknown thermodynamic relations) 

 suddenly break up into simpler ones or the reverse), when the strong- 

 chemical bond is broken for these molecules in consequence of the 

 too great intensity of the internal motions. Then in the "dissociating" 

 substance there are simply two kinds of molecules, e.g. for N^O^ the 

 molecules N^O^ and NO^, but — as long as they exist individually — 

 both seem to be pretty insensible to changes of volume by tempera- 

 ture or pressure. 



And finally — when the so-called quasi-association is considered 

 as a phenomenon inherent in the nature of things : 1 mean in this 

 sense that temporary molecule aggregations are naturally formed 



52* 



