810 



without any special cause, in consequence of collisions, and of the 

 temporarily acting strengthened attractive forces, or bj other accidental 

 circumstances — so that this state of quasi-association ') for every 

 substance is quite determined by the value of the (reduced) tempe- 

 rature and of the volume — we are naturally led to combine all 

 the influences mentioned into one equation h^f{v,T), of which at 

 present we only know the general form, without being able to define 

 it more closely. It seems to me that the tinal decision — as regards 

 the derivation of the equation in question — will be given again 

 by the radiation theory and the theory of quanta. 



2. Before giving the new relation between the critical quantities, 

 found by me some time ago, we may briefly state the results of 

 the foregoing paper, as far as the relations existing between the 

 critical quantities are concerned. 



When b=/{v) is assumed, and f— j and (t~A is indicated by 



b'k and b"k, putting Vk:bh = r, it follows from the equation of state 



RT a 

 P = 



V — b v' 



(a) 



in the first place, by putting T^j and f^j =0 (loc. cit. p. 45 

 et seq.) : 



-1 2 \-Vk 



(1) 



(2) 



3 1-V,A 

 when ^"k = vkb"ic'.{l-b'i). 

 Further 



8 a , ^. , ^ 27(r--ir 2 



^^' =^ 27 ^^ 6", ' ^" '"^^^'^^ ^'^ = T ~"^ T^-TY- 



1 a 27 p-l 2 . 



In this ;, and A, are never far from 1; for substances that deviate 

 most from those which would correspond to the ideal van der 

 Waals 's equation of state — the latter will henceforth be called 

 "ideal substances" for shortness — )^^ and A, are both =0,98. 



For the so-called critical coefficient s=RTk:pkOk is found: 



.^'i-, (3) 



Aj r 



in which A^ : A, may always be put = 1. 



1) Which according to this view lias therefore nothing to do with real associa- 

 tion, as for NOo and H.O, which is of enlirely chemical nature. 



