CONTBNTS 



Physics, t^. Weber • "The tlierniiil conductivity of neon". '6\2. 



— .). K. Verschaffelt : "On the mensuremeiit of surface tensions by means of 

 small drops or bubbles". 36(5. 



— A. J. Byl and N. U. Kolkmeykr: "lnvestiü,ation by means of X-rays of the 

 crystal-structure of white and grey tin. I. 405. II. I'he structure of white tin, 494, 

 III. The structure of j^rey tin. 5tJl. 



— Th. de Donüer: "Le tenseur "ravitique". 437. 



— A. I). Fokker: "On the equivalent of parallel translation in non-Euclidean 

 space and on Kiemann's measure of curvature". 505. 



— W. H. IvEEsoM and Mrs. C. Nordstrom-van JjEEUwen : '-Deduction of the 

 third virial coefficient for material points (eventually for rigid spheres), which 

 exert central forces on each other". 593. 



— VV. II. Keesom and Mrs. CJ. Norüstuöm- van Leeuwen: "Development of the 

 third virial coefticient for material points (eventually rigid spheres), which exert 

 central attracting forces on each other proportional with / — 5 or r— 6". 602. 



— 0. Postma: "On friction in connexion with Brownian movement". til6. 



— J. J. VAN Laar: "On the Heat of Dissociation of Di-atoinic Gases in Connection 

 with the Increased Valency- Attractions \^A of the Free Atoms". 644. 



— P. G. Cath : "On the measurement of very low temperatures XXIX. Vapour- 

 pressures of oxygen and nitrogen for obtaining tixed points on the temperature- 

 scale below 0° C." 656. 



— J. J. Haak and R. b'lssiNGH : "Experimental Inquiry into the Nature of the 

 Surface- Layers in the Reflection by Mercury, and into the Ditt'erence in the Optical 

 Behaviour of Liquid and Solid Mercury". 678. 



— J. D. VAN DER Waals Jr.: "On the Theory of the Friction of Liquids. 743. 



— F. £. C. Schefi'er: "On the Occurrence of Solid Substance in Binary Mixtures 

 with Unmixing". I. 827. 



— J. E. Verschaffelt: "On the shape of large liquid drops and gas-bubbles and 

 the use made of them for the measurement of capillary constants". 836. 



— L S. Ornstein and ¥. Zernike: "Magnetic properties of cubic lattices". 911. 



— L. S. Ornstetn and H. C. Burger : "On the theory of the Brownian motion". 922. 



— G. HoLST and E. Oosterhuis: "The audion as an amplifier". 932. 



— J. D, van DER Waals Jr: ''On the Theory of the Brownian Movement, Appendix". 

 1067. 



— L. Hamburger: "Contribution to the knowledge of the removal of rest-gases 

 especially for the electric vacuum glow-lamp". 1062. 



— L. Hamburger, G. Holst and E, Oosterhuis: "On the influence of dilierent 

 substances on the absorption of light by thin tungsten layers". I<i78. 



— G. Holst and A. N. Koopmans: "The ionisation of argon''. 1089. 



— G. Krutkow: 'Contribution to the theory of adiabatic invariants". 11)2, 



— J. A. Schouten and D, J. STRuik : "On the connexion, between geometry and 

 mechanics in static problems". 1176. 



— J. J. van Laar: ''On the Equation of State for Arbitrary Temperatures and 

 Volumes, Analogy with Planck's Formula". 1184. 



