KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 



TE AMSTERDAM. 



PROCEEDINGS 



VOLUME XXV 

 NOS. 9 and 10. 



President: Prof. F. A. F. C. WENT. 

 Secretary : Prof. L. BOLK. 



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

 Natuurkundige Afdeeling," Vol. XXXI). 



CONTENTS. 



J. P. KUENEN f: "The Magneto-Thertnic Effect according to Thermodynamics", p. 384. 



Shinkichi HORIBA: "Determination of the Vapour Pressure of Metallic Arsenic". (Communicated 

 by Prof. P. Zeeman), p. 387. 



B. SjOLLEMA: "On the Influence of the Composition of the Food on the Calcium output". (Commu- 

 nicated by Prof. H. ZWAARDEMAKER), p. 395. 



J. J. VAN Laar: "On Heats of Mixing of Normal and Associating Liquids". (Communicated by Prof. 

 H. A. LORENTZ), p. 399. 



H. A LORENTZ: "On Whittaker's Quantum mechanism in the atom", p. 414. 



E. D. WiERSMA: „Concordance of the Laws of some Psychological and Physiological Phenomena", 



p. 423. 

 G. HERTZ: "On the Separation of Gas Mixtures by Diffusion in a Flowing Gas". (Communicated by 



Prof. P. Ehrenfest), p. 434. 

 G. HERTZ: "On the Excitation and Ionization Potentials of Neon and Argon". (Appendix). (Commu- 

 nicated by Prof. P. Ehrenfest), p. 442. 

 H. KAMERLINOH Onnes and W. TUYN: "Further experiments with liquid helium. Q. On the electric 



resistance of pure metals etc. X. Measurements concerning the electric resistance of thallium 



in the temperature field of liquid helium", p. 443. 

 H. KAMERLINOH Onnes and W. TUYN: "Further experiments with liquid helium. R. On the electric 



resistance of pure metals etc. XI. Measurements concerning the electric resistance of ordinary 



lead and of uranium lead below 14° K.", p. 451. 

 J. P. WiBAUT and Elisabeth Dingemanse: "The Action of Sodiumamide on Pyridine, and some 



Properties of a-aminopyridine". (Communicated by Prof. A. F. Holleman), p. 458. 

 L. HAMBURGER: "On Centres of Luminescence and Variations of the Gas Pressure in Spectrum 



Tubes at Electrical Discharges". II (Communicated by Prof. H. A. LORENTZ), p. 463. 



F. A. F. C. WENT : "On a new clinostat after DE BOUTER", p. 475. 



B. SJOLLEMA and J. E. VAN DER Zande: "Concerning the Synthetic Action of Bacteria in the 

 Paunch of the Cow". (Communicated by Prof. H. Zwaardemaker), p. 482. 



25 



Proceedings Royal Acad. Amsterdam. Vol. XXV. 



