( 99) 



So if we represent the temperature function {c'T')-^ by «' ^), we get : 



e ^' — ^ 



1— ii = «' . 



Hence for bz=:h^-\-,iLlj — or as Ab=—b,-\-nO.„ b=nb.,—{-\—^)Lb — 

 we find : 



b = n6„ — «'Z-6 



{v—bf-^ 



Lb Lb 



As is about = — at the critical point, and will therefore be 



V — b b 



7}Ab 



comparatively small, we may put e "~* independent of y as a further 

 approximation, and write simply : 



Lb 



b =z nb., — a — - , 



(v~è)''-l' 



when a' e '•— ^ is represented by «. The apparent contradiction in 

 the dimensions of the fraction aLb : (v — b)'^—'^ with that of ?ib^ 

 vanishes when we consider that c' = c : E'^-\ and that therefore a' 

 and ft still contain the factor i?"-' . 



As for V = Qo at any rate b = nb, , we may write for nb.^ also 

 b(,, and so we get by approximation in the neighbourhood of the 

 critical temperature : 



b = bc) 



h \n~\' 

 1 — (f 



^V—b 



in which, therefore, y = . 



b " 



From (33) the approximate expression : 



db . r b 



(33) 



6' = _ = (.-l)^^-^J, (33.) 



d(v—b) 



now follows easily for 2^c , when — = 1 — b' = ^ is put as first 



dv 



approximation {b'c is about = 0,07). 



Finally we find, also at Tc : 



vb"=- « '^ = 



Vc { bn \"+l 



^) If we do not put qo — O, the factor e ^^ is added to c'T\ 



7* 



