KONINKLIJKE AKADExMIE VAN WETENSCHAPPEN 

 TE AMSTERDAM. 



PROCEEDINGS OF THE MEETING 

 of Saturday September 26, 1914. 

 Vol. XVII. 



President: Prof. H. A. Lorentz. 

 Secretary: Prof. P. Zeeman. 



(Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundige 

 Afdeeling van Zaterdag 26 September 1914, Dl. XXIIl). 



GOIvTTElsTTS. 



H. DU Bois: "Modem electromagnets, especially for surgical and metallurgie practice", p. 468. 



A. Wichmann: "On the Tin of the island of Floros", p. 474. 



M. J. VAN UvEN : "The theory of the combination of observations and the determination of 



the precision, illustrated by means of vectors." (Communicated by Frof. W. Kapteynj, 



p. 490. 

 H. Kamerlingh Onkes and G. Holst; "On tlie measurement of ve.y low temperatures. XXlV. 



The hydrogen and helium thermometers of constant volume,, down to the freezing-point 



of hydrogen compared wiili each otlier, and with the platinum-resistance thermometer," 



p. 501. 

 H. Kamerlingh Onnes and G. Holst : "On the electrical resistance of pure metals etc. IX. 



The rtsistance of mercury, tin, cadmium, constantin and manganin down to temperatures, 



obtainable with liquid hydrogen and with liquid helium at its boiling point," p. 508. 

 H. Kamerlingh Ontjes: "Further experiments with liquid helium. L. The persistence of 



currents without electro-motive force in supra-conducting circuits", p. 514. 

 H. Kamerlingh Onnes and K. Hof: "Further experiments with liquid helium N. HALL-eifect 



and ihe change of resistance in a magnetic tidd. X. Measurements on cadmium, graphite, 



gold, silver, bismuth, lead, tin and nickel, at hydrogen- and helium-temperatures." p. 520. 

 H. Kamerlingh Onnes and H. A. Kuypers: "Measurements on the capillarity of li([uid 



hydrogen," p. 528. 

 F. A. H. Schreinemakers and Miss W. C. de Baat: "The system: Copjier sulphate, copper 



chlorid, potassium sulphate, potassium ehlorid and water at SO", p. 533. 

 J. BÖESEKEN: "The Catalyse." (Communicated by Prof. A- F. Hollemanj, p. 546. 



F. M. Jaeger: "Researches on the Temperature-coefficients of the free Surface-energy 

 of Liquids between —80» lo 1650" C. VII. The specilic surface-energy of the molten 

 Halogenides of the Aloali- metals", p. 555. "ibid VIII. The Specific Surface-energy of 

 some Salts of the Alcali-metals", (Communicated by Prof. H. Haga). p. 571. 



G. DE Bruin: "A crystallized compound of isoprene with sulphur dioxide." (Communicated 



by Pi-of. P. van Romburgh), p. 585. 



J. P. VAN DER Stok: "The treatment of frequencies of directed quantities, p. 586. 



J. J. van Laar: "Some remarks on the value.i of the critical ciuuntities in case of asso- 

 ciation." (Communicated by Prof. H. A. Lokentz), p. 598. 



J. J. VAN Laar: "On apparent thermodynamic discontinuitie.s, in connection with the value 

 of the quantity b for infinitely large volume." (Communicated by Prof. H. A. Lorentz) 

 p. 606. 



li. R. Kruyt: "Current Potentials of Electrolyte solutions." (Communicated by Prof. Ernst 

 Cohen), p. 615. 



H. R. Kruyt : "Electric charge and limit value of Colloids," (Communicated by Prof. Ernst 

 Cohen), p. 623. 



31 

 Proceedings Royal Acad. Amsterdam. Vol. XVll. 



