KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 



TE AMSTERDAM. 



PROCEEDINGS 



VOLUME XXVI 

 N«. 7 and 8. 



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

 Secretary ; Prof. L. BOLK. 



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

 Natuurkundige Afdeeling," Vol. XXXII). 



CONTENTS. 



H. W. j. DIK and P. ZEEMAN: *A Relation between tlie Spectra of Ionized Potassium and Argon". 



(Second Communication), p. 498. 

 W. TUYN and H. KAMERLINQH OnneS: 'Further Experiments with liquid Helium. S. On the Electric 



Resistance of Pure Metals, etc. XII. Measurements concerning the Electric Resistance of Indium 



in the Temperature Field of Liquid Helium", p. 504 

 W. F. QlSOLF: "On the occurrence of diamond as an accessory mineral in olivine and anorthite 



bearing bombs, occurring in basaltic lava, ejected by the volcano Gunung Ruang (Sangir- 



Archipelago north of Celebes)". (Communicated by Prof. Eva. DUBOIS), p. 510. 

 G. SCHAAKE: "The Complex of the Conies which cut Five Given Straight Lines". (Communicated 



by Prof. Hendrik de Vries), p. 513. 

 G. SCHAAKE: "On the Plane Pencils Containing Three Straight Lines of a given Algebraical 



Congruence of Rays". (Communicated by Prof. HENDRIK DE VRIES), p. 322. 

 Q. BREIT: "Transients of Magnetic Field in Supra-conductors '. (Communicated by Prof. H A. 



LORENTZ), p. 529. 

 J. R. KatZ: "Further Researches on the Antagonism between Citrate and Calcium Salt in Biochemical 



Processes, Examined by the Aid of Substituted Citrates". (First communication). (Communicated 



by Prof. A. F. HOLLEMAN), p. 542. 

 J. R. KATZ: "Researches on the Nature of the So-Called Adsorptive Power of Finely-Divided Carbon. 



I. The Binding of Water by Animal Carbon". (Communicated by Prof. A. F. HOLLEMAN), p. 548. 

 J. LlFSCHiTZ: "Volta-Luminescence '. (Communicated by Prof. F. M. Jaeger), p. 561. 

 H. Zwaardemaker, W E. Ringer and E. Smits ; "Is Caesium Radio-active?", p. 575. 

 J. M. BURGERS: "On the resistance experienced by a fluid in turbulent motion". (Communicated hy 



Prof, P. EHRENFEST), p. 582. 

 FERNAND MEUNIER: "Sur quelques nouveaux insectes des lignites oligocenes (Aquitanien) de Rott, 



Siebengebirge (Rhénanie)", p. 605. 

 H. R. WoltjeR: "Magnetic Researches XXII. On the determination of the magnetisation at very 



low temjieratures and on the susceptibility of gadolinium sulphate in the region of temperatures 



obtainable with liquid hydrogen". (Communicated by Prof. H. KAMERLINGH ONNES), p. 613. 

 H. R. WOLTJER and H. KAMERLINQH OnneS: "Further experiments with liquid helium. T. Magnetic 



researches. XXIII. On the magnetisation of gadolinium sulphate at temperatures obtainable 



with liquid helium", p. 626. 

 W. F. EiNTHOVEN: "The string galvanometer in wireless telegraphy". (Communicated by Prof. W. 



Einthoven), p. 635. 

 L. BOLK: "The Menarche in Dutch Women and its precipitated appearance in the youngest 



generation", p. 650. 



33 



Proceedings Royal Acad. Amsterdam. Vol. XXVI. 



