( 668 ) 



The critical quantities for the other mixtures were found by gra- 

 phical interpolation. Fig. 1 gives pkx, fig- 2 T kj as function of x; in 

 iig. 3 Vkx has been calculated from p kx and 7\ 2 , by the aid of X (see 

 formula (1)); the Vkx observed by Kuenen have been indicated there. 



By carrying out the construction for the connode by the aid of the 



d\b dip dif? 



p, — and tfr — m- v —- curves (see Comm. N°. 59a 1 )), which the 



1 OX OX OV 



models for those different temperatures yield, we may derive v^ — v p i. x , 

 pkx — Ppi.x in first approximation (see Comm. N°. 59a). Applying 

 these corrections we should then have to repeat the calculation from 

 the beginning, to obtain more accurate values for Vkx, pkx- We have 

 confined ourselves to a first approximation in all our constructions, 

 as also a further correction of the equation of state V.s. 1., which 

 can cancel the deviations mentioned in § 2, has not been applied 

 and we were the more justified in this, as these latter deviations 

 are larger than those we have now in view. 



§ 4. Construction of the ^-surfaces. 



From the equation of state V. s. 1 we find immediately the reduced 

 iprT curves, from which are then deduced the ordinary ip-curves accor- 

 ding to Suppl. N°. 8, § 4; or the ordinary virial coefficients, w hie hare 



then used for the calculation of if' according to Comm. N°. 59. 

 For the construction (cf. Comm. 59) use was made of: 

 at 5° i)\ =if + 0,10,r-f 25 v 



„ 2(T ip' 90 = *|> + 0,10* + 36,5 v 



., 26 3 ^ M = * + 0,24a + 57,3t>, 



while a suitable constant was subtracted from every \y. Here v is 

 expressed in the theoretical normal volume, just as in the diagrams. 

 From the ifv/ curves (cf. tig. 1, pi. II) the ty r curves (see fig. 2, 

 pi. II) and the />/ curves were graphically derived. The models for 

 i|j were construed on a scale 5 times larger than the diagrams on 

 pi. II, pi. Ill and pi. IV. 



§ 5. Determination of the coexisting phases. 



Applied was both the construction by rolling a glass plate on the 



!) In giving the figure 3 in Comm. X". 59a for this construction it was stated 

 that this figure was very imperfect. It appears now that the loop ought to contain 

 two cusps. We found out the error by the aid of the general propert : cs of the 

 substitution-curves treated by van der Waals (Coir.p. Proceedings of this meeting). 

 This error shows the more how necessary it is that graphical solutions are 

 controlled by such general properties as van der Waals is now publishing. 

 [Added in the English translation]. 



