C o N T F, N T S. XXI 



VRIES (jan de) presents a paper of Z. P. Bouman: "An article on the know- 

 ledge of the tetrabedriil complex." 358. 



— A group of complexes of rays whose singular surface consists of a scroll and a 

 number of planes. 662. 



— Some properties of pencils of algebraic curves. 817. 



WAALS (van der) »J,-surface (Contributions to the knowledge of). X. On the 

 possibility of predicting the properties of mixtures from those of the components. 743. 



WAALS (j. D. VAN der). The shape of the sections of the surface of saturation 

 normal to the x axis, in case of a three phase pressure between two temperatures. 184. 



— The /■,.?• equilibria of solid and fluid phases for variable values of the pressure. 193. 



— presents a paper of Dr. A. Smits : ''On the hidden equilibria in the/J,a!-diagrani 

 of a binary system in consequence of the appearance of solid substances." 196. 



— presents a paper of Dr. A. Smits: "Contribution to the knowledge of the /«- 

 and the /^J-lines for the case that two substances enter into a combination which 

 is dissociated in the liquid and the gasphase." 200. 



— Properties of the critical line (plaitpoint line) on the side of the components. 271. 



— The properties of the sections of the surface of saturation of a binary mixture 

 on the side of the components. 280. 



— The exact numerical values for the properties of the plaitpoint line on the side 

 of the components. 289. 



— presents a paper of Prof. J. D. van deb Waai.s Jr.: "Kemarks concerning the 

 dynamics of the electron." 477. 



WAALS JR. (j. D V A N d E ii). Remarks concerning the dynamics of the electron. 477. 

 WEBER (max) presents a paper of Prof. Svdney J. Hickson: "On a new species 



of Corallium from Timor." 268. 

 WEEDER (J.). Approximate formulae of a high degree of accuracy for the ratio of the 



triangles in the determination of an elliptic orbit from three observations. II. 104. 

 WENT (f. a. r. c). Some remarks on the work of Mr. A. A. Pulle, entitled: "An 



enumeration of the vascular plants known from Surinam, together with their 



distribution and synonymy." 639. 



— and A. H. Blaauw. On a case of apogamy observed with Dasylirion acrotrichum 

 Zucc. Ü84. 



w I c H M a N N (c. E. A.). On fragments of rocks from the Ardennes found in the 



diluvium of the Netherlands North of the Ühine. 518. 

 wilterdink (j. h.). Report on the operations with the tvvo slit-spectrographs for 



the solar eclipse of August 30, 1905. 606. 

 WIND (c. H.) presents a paper of C. Easton : "Oscillations of the solar activity and 



the climate". 2^^ communication. 155. 

 WINKLER (c.) presents a paper of D. J. Hülshoff Pol : "Bolk's centra in the 



cerebellum of the mammalia". 298. 



— presents a paper of Dr. G. van Eunberk : "The designs on the skin of the 

 vertebrates, considered in their connection with the theory of segmentation". 307. 



— presents a paper of Dr. L. J. J. Muskens : "Anatomical research about cerebellar 

 connections." 563. 



