764 



dimension at the greatest deformation reached in the collision. Hence 

 we find finallj : 



^ pv = RT + n (6,)o X iV ^Co* (1 - 5.^^ + 4.t-') . 

 Now according to (1 1) : 



RT 



so that we get : 



pv 



= RT 





I -f ^ X A (1 -f 2.t; 4- 3.f' + 4.r») 1, 



10 

 as A^ : ?i is evidently = ij. When we now put 



then as before we get (for intinitely large volume, and not taking 

 the attraction into account): 



pv = RT I 1 + 



RT 



Now we mav write 1 — «^^7' for j,* = (;„ : o^, as (1 — .vy = —-—== 



= a^T accoi-ding to (11), in which « is a coefficient, depending on 



the size of the quasi elastic atom force constant e in (10), viz. 



R: N 

 E z^ re^ : )\\ so that «" = — - — . In this way we find finally (or 



r — e' 



(b,)T= (M, X [1 - 2» t/r + V, {a \/Ty - V, {a [/Jy] , . (12) 

 where the form between [] can also be written = (1 — a['^Ty-\- 



+ v,(«rr)'(i-Vs«v^n 



Hence {b,,)T becomes =(è,/)„ = 4m for T=0, but at all other 

 temperatures bg<^'im, in consequence of the diminution of the 

 molecule which temporarily takes place during the collision. The 

 extreme limit of this diminution is determined by the ratio Qa ■ (>o' ==•«% 

 hence by the expression (1 —it\/Ty. 



At low temperatures the expression between [ ] may be represented 

 by (i — aVTy in approximation. 



VIII. Calculation of the values of a, h, and B. 



When from the values of b,, at the two fixed points 20° C. and 

 Ti,, i.e. (^,, — 967.10-6 ^nd 6., = 1 236 . 1 0-e (see above), we now 



