( 232 ) 



the critical pressure of the least volatile component. It' the sup- 

 positions mentioned in § 2 might be applied for this, and the 

 values of am and bu for He might be borrowed from Comra. N°. 96 c , 

 Febr. '07, p. 660 footnote 2, so that a M He = 7 m aMH a = 0.0000024 

 and &MHe = 7s ÖmHj = 0.00044, this case would be realized for 

 mixtures of He and water 1 ). Then we should find Tu m = 1.056 Tk v 

 so that the gas-gasplait would occur over a range of temperature 

 of 36° above 365° C, and at pressures above 195 a 200 atnis. 



In the case that the molecules of the least volatile component act 

 on each other feebly, but still exert such an attraction that a double 

 plaitpoint 3 ) occurs in the net of the spinodal curves, the pressure 

 in this plaitpoint and its temperature in connection with the critical 

 temperature of complete miscibility give important indications as to 

 the pressures and temperatures of the gas-gasplait. 



In table II these data, calculated for the case that the suppositions 



TABLE II. 



J ) The flji and bn for water have been borrowed from Landolt-Börnstein- 

 Meyerhoffek's Physik. Ghem. Tabellen. 



s ) The appearance of a double plaitpoint near Km was already observed by 

 van Laar (These Proc. May 1905 p. 42). The conditions for its appearance, 

 however, were not correctly defined by him (cf. § 9 II). In view of this latter fact 

 we thought that we drew sufficient attention to this result of van Laar by 

 referring the reader to van Laar's papers, (see p. 797 footnote 1). The detaching 

 of a longitudinal plait at high temperatures, which leaves the J--surface with its 

 open side turned to v = ö, follows immediately (see These Proc. April '07 p. 848 

 footnote) from the general considerations and calculations of van der Waals Gont. II 

 § 19 sqq. and van der Waals' diagram in Zittingsverslag Kon. Akad. Nov. 

 1894 p. 133, when the case a) cf. § 9. I, a case which van Laar has not 

 included in his considerations, does not occur. 



