CONTENT S. XVII 



WAALS (j. D. VAN D K r) presents ;i paper oC J'r. .1. (). VAN DER Waals Jr.: 

 "The variability witli the density of the (piantity /j of the eqnation of state." 487. 



— presents a paper of Mr. .T. J. van Laar: "On the course of the values of f/ 

 for hydroo-en, in oonnection with a recent formula of Prof, van der Waals". 573. 



WAALS .T R. (j. D. VAN D E r). Statistical electromechanics. (I). 22. (II). 114. 



— The variability with the density of the quantity h of the equation of state. 487. 

 WATER (The boilingpoint-curve of the system: Hydrazine -f-)- 171. 



w E E D E R (j.). On interpolation based on a supposed condition of minimum. 3G1. 



WEEVERS (t h.). Investigations of glucosides in connection with the internal muta- 

 tion of plants. 295. 



WENCKEBACH (k. f.). On the duration of the compensatory pause after stimula- 

 tion of the auricle of the mammalian heart. 378. 



WERTHEIM SALOMONSON (j. K. A.). The influence of variation of the con- 

 stant current on the pitch of the singing arc. 311. 



— A new law concerning the relation between stimulus and effect. 392. 441. 

 WIND (c. H.) and TI. Haga. Diflraction of RiJntgen-rays. 247. 



WINKLER (c.) presents a paper of Prof. J. K. A. Wertueim Salomoxson : "A new 

 law concerning the relation between stimulus and efrect". 392. 441. 



WOLFF (l. k.) and A. Smits. The velocity of transformation of carbon monoxide. 417. 



w Y H E (J. w. V A N). A new method for demonstrating cartilaginous mikroskeletons. 47. 



xylene (On the action of sulphur on toluene and). 288. 



zeeman (p.). Observations on the magnetic rotation of the plane of polarisation in 

 the interior of an absorption band. 41. 



— presents a paper of Prof. I. K. A. Wertheim Salomonson: 'The iufliience of 

 variation of the constant current on the pitch of the singing arc". 311. 



— presents a paper of Dr. .T. .). Hallo: "The value of some magneto-optic con- 

 stants". 438. 



Zoology. Gr. 0. J. Vosmaer: "On the shape of some siliceous spicules of sponges". 104. 



