KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 

 TE AMSTEKDAM. 



PROCEEDINGS OF THE MEETINGS 

 of Saturday September 26, 1908. 



(Translated from : Verslag van de gewone vergaderingen der Wis- en Natuurkundig 

 Afdeeling van Zaterdag 26 September 1908, Dl. XVII). 



COFTEITTS. 



J. D. van der Waals: "Contribution to the theory of binary mixtures". VIII, p. 187, IX, p. 201. 



W. H. Julius: "Anomalous refraction phenomena investigated with the spectroheliograph", 

 p. 213. (With one plate). 



Mrs. H. B. van Bilderbeek— van Meurs : "The ZEEMAN-effect of the strong lines of the violet 

 spark spectrum of iron in the region ) 2380— i 4416". (Communicated by Prof. P. Zeeman), p. 222. 



C. Winkler : "The nervous system of a white cat, deaf from its birth. A contribution to the 

 knowledge of the secondary systems of the auditory nerve-fibres", p. 225. 



F. A. F. C. Went: "On the investigations of Mr. A. H. Blaauw on the relation between 

 the intensity of light and the length of illumination in the phototropic curvatures in seedlings 

 of Avena Sativa", p. 230. 



Erratum, p. 234. 



Physics. — "Contribution to the theory of binary mixtures." VIII. 

 By Prof. J. D. van der Waals. 



rn d*p dp 



The intersection of the curve — — = with — = 0. 



dv dx dv 



By the aid of the approximate equation of state the course of the 



d*p 



curve - — — =r is given by the equation : 

 dv dx 



, r ^^db da 



MRT — — 



dx dx 



(v—b) s v* 



As has been observed before, it has a course which is analogous 



dp 



to that of the curve — = 0. At given value of T it has an nsvmn- 

 das • l 



13 



Proceedings Royal Acad. Amsterdam. Vol. XI. 



