( 578 ) 

 yields after some reductions^): 



, 1— .A' 



1 + 



3 1 V1+-'' 



l+(l-4l+:V M' 



Here is ,r ^ f - — —\ niid /< := " — . We iiuiv write for tlie 



second member : 



2(l + 3.f'') 



(i+.r)(2-.'-+.'-^r 



Therefore we n:et jUso : 



^' t/-'' 4 l + 3.^-*^ 



The vahie of./' may he (h'rivcd IVoiii lhis('(|iiatioii. As />,/:^l)17=l,l)8/>„, 



M irets the vahie — i=J,()'2, and we liiid in aiHU'o.xiination for ,i; 

 ^ ^ U,98 



the value OJOt). 

 Therefore 



-t-- = 1/ 0,709 = 0,842, 



from Avhich ^\ e may easily derive: 



A/, = 0.022 J>,i = 845. 



Ko^v Ave have : 



3 vh—hir 2(l + 3.r') 



from which we tind: 



ct = 2.b7bk\ /?,+/?, = 0,0837. 

 The critical \(>lume is therefore: 



ri^, = 2.57 hi- (= 2.37 h„ — 4.09 A„) = 2172. 



At 0° (\ this volume is (conip. the table) already reached at a 

 pressure of about 700 atm. The Aalnes of r at 0° range in the 

 experiments of Amagat to 1025; the verification of e(piation (1) of 

 VAN DER Waat-s may thei-efore be extended over volumes which have 

 the size of li(pnd volumes; this fact compensates the want of ex})eri- 

 ments below the critical temperature. 



We may also calculate the quantities /?; and j?^ separately. From'^) 



1) See V. D. Waals, 1. c. Ill, p. 652. 

 1) VAN DEu Waals, I.e. Ill, p. 651. 



