( 200 ) 





or 



^_ j PJ^ j « / 



'^'o ~ Po 'o (l + «)(!- ^) (1 + «O KI 4 «) (1 - I') (1 + «O S 



^=1 ^? i ^ ^! . 



d'o po{l+a)(\-b){li-at)i[\+a){l-b){l+cci) ) 



If we tnke for p a ceitaiu fraction of tlie critica] pressure e.a'. 



(as Leduc tlocs „Aunales de chimic et de physique, Sept. 1898"), 

 then 



71 1 a Pq p la 



^^ ~ 7(3 "~ 70 27 b^ °^ f7 ~~ 7(3 27 b^ 

 and 



(f„ 1 1 a I a 



rf'o 76 27 b{[-{- a) {I— b) {I + at) (b {I + a) {I— b)i].+ at) 



By means of the critical temperature 



1 + «</. 



27 6(1 +ö)(l — i) 



we find 



^> ^ J _ _ J ?)^/27 71. _ ^ 



rf'o ~ 76 X 8 T \ 8 r 



or 



^=1- 0,001645 ^^:r^ "^^-iV 



d'o T\8 T J 



^ n s 



For = — the correction is and tlie density tuuiid is the 

 T 27 ^ 



normal density. At this temperature a gas follows the law oi 



Boyle, of course only under a slight pressure. 



Th 8 27 ^ . . 



For — <" ^ — or r^ — Ti the correction is negative, as is the 

 T 27 8 » ' 



case with hydrogen at 0". In this case f/„ > (</u)'. Then the value 



dn ' . ^27,, 



of has a maximum for 7 = — 7'/.. Imu' Indrnoeu at 0° the 



K)' 4 ■ ^" 



