405 



Uniformly absorbed b}- tlie snrroniiding' medium (see p. 809 of t, 

 already cited above). 



7. Hence at bottom the whole thermic behaviour of a substance 

 does not depend onhj on the two quantities a and h, which deter- 

 mine the critical quantities, whicii in their turn govern the law of 

 the corres|)onding states — in such a way that all the substances 

 behave correspondingly when they are only considered in equal 

 multiples or sub-divisions of their critical temperature and critical 

 pressure, but also (and the deviations from the said law are governed 

 by this) on the absolute height of the temperature, at whicli the 

 substance is considered. According to (36) every substance passes 

 namely through the different types — characterised by the \ariable 

 ratio hfj -. />„, from the type of the "ordinary" substances, where 

 l),j = /;,, is about 1,8 (y = 0,9) to the type of the "ideal" substances, 

 where hfj is = b„ (y = Ya) — when we descend from the ordinary 

 temperatures to the absolute zero point (see the tables in I, p. 819 

 and III p. J 052). 



The individual it 1/ of the different substances, which they continue 

 to preserve within the region of the Law of the CoiTcsponding States, 

 is therefore entirely determined by the real height of the (absolute) 

 temperatui-e. 



Hydrogen at 323° absolute (7^= J07/,) will e.g. on the whole 

 (Law of Corresponding States) exhibit the same behaviour as Helium 

 at 52° absolute {T also = 107\.) — but //, w^ill show a value of 

 about 1,7 for the ratio h^, : />„ at that higher temperature, while He 

 at the same ''corresponding" temperature shows a value of about 

 'J. 2 for that ratio. 



For vk : Ilk we shall find about 2,7 for Hydrogen and Helium at 

 their critical temperature, while vk : h/. = 2,1 is found for an ordinary 

 substance at its critical temperature. Etc. Etc. 



And this may suffice for the present. I hope to come back to 

 some separate problems later on, whicli are still awaiting solution. 

 I may mention : the temperature dependence of ƒ (see I, p. 811), 

 the change of direction of the '"straight" diameter from 7\ to xory 

 low temperatures (III p. 1051), the foi-m of the vapour-pressure 

 equation p=f{T), the dependence of the densities of liquid and 

 va|)()ur on the temperature (in connection with the problem of the 

 (lireclion of the sti'aight diameter); and finally the course of the 

 characteristic function in its dependence on T. 



But the very first point that will be elucidated in a following 

 Paper is the circumstance mentioned under of the conclusions, 

 that I),, cannot possibly be = 4:ui. 



Fontanivent sur Clarens, April 1914. 



(September 26, 1914.) 



