KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 

 TE AMSTEPxDAM. 



PROCEEDINGS OF THE MEETING 

 of Saturday February 29, 1908. 



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

 Afdeeling van Zaterdag 29 Februari 1908, Dl. XVI). 



OOlsTTEIsTTS. 



P. H. Schoutk: "Fourdimensional nets and their sections by spaces", 1st Part, p. 536. 



Z. P. BouMAN: "Contribution to the knowledge of the surfaces with constant mean curvature". 

 (Communicated by Prof. Jan de Vries), p. .545. 



W. Kaptetn : "On the multiplication of trigonometrical series", p. 558. 



D. H. Brauns : "On a crystallised d. fructose tetracetate". (Communicated by Prof. A. P. N. 

 Franchimont), p 563. 



P. Zeeman : "New observations concerning asymmetrical triplets", p. 566. (With one plate). 



P. Zeeman: "Change of wavelength of the middle line of triplets", p. 574. 



H. E. J. G. DU Bois and G. J. Elias : "The influence of temperature and magnetisation on 

 selective absorption spectra", p. 578. (AVith one plate) 



H. Kamerlingh Onnes: "On the measurement of very low temperatures. XIX. Derivation of 

 the pressure coefficient of helium for the international helium thermometer and the reduction 

 of the readings on the helium thermometer to the absolute scale", p. 589. 



Jean Becquerel and H. Kamerlingh Onnes : "The absorption spectra of the compounds of 

 the rare earths at the temperatures obtainable with liquid hydrogen, and their change by the 

 magnetic field, p. 592. (With 5 plates). 



H. Kamerlingh Onnes and W. II. Keesom: "On the equation of state of a substance in the 

 ntighbourhood of the critical point liquid-gas. I. The disturbance function in the neighbourhood 

 of the critical state, p. 603. (With one plate) II. Spectrophotometrical investigation of the 

 opalescence of a substance in the neighbourhood of the critical state", p. 611. (With one plate). 



F. M Jaeger: "On the fo^m-analogy of Halogene-derivatives of Hydrocarbones with open 

 chains". (^Communicated by Prof. A. P. N. Franchimont), p. 623. 

 Errata, p. 623. 



37 



Proceedings Royal Acad. Amsterdam. Vol. X. 



