XIV CONTENTS 



Palaeontology. O. Posthumus: "Contributions to our iinowledge of tiie 

 palaeontology of the Netherlands. I. Otoliths of teleostei from the 

 oligocene and the miocene of the Peel-district and of Winterswijk." 231. 



— O. Posthumus: "Contributions to our knowledge of the palaeontology 

 of the Netherlands. II. On the fauna of the phosphatic deposits in 

 Twente, (lower oligocene)." 235. 



— F. Meunier: "Sur quelques nouveaux insectes des lignites oligocènes 

 (Aquitanien) de Rott. Siebengebirge (Rhénanie)." 605. 



Paraffin (Hydrogenation of) by the Bergius' method. 226. 



Permeabilities (Measurements of magnetic) of chromium chloride and 

 gadolinium sulphate at the boiling point of liquid hydrogen in alter- 

 nating fields of frequency 369.000 per second. 840. 



Perquin (J. N. J.) and H. I. Waterman. Hydrogenation of parafifin by 

 the Bergius' method. 226. 



Petrography. W. F. Gisolf: "On the rocks of Doormantop in central 

 New Guinea." 191. 



Petromyzon fluviatilis (The presence of cardio-regulative nerves in). 438. 



Phosphatic deposits (On the fauna of the) in Twente (Lower oligocene). 235. 



Photo-catalytic influence (The) of some series of ketones on the light 

 oxidation of ethyl alcohol. 443. 



Physics. J. P. Kuenen, T. Verschoyle and A. Th. van Urk: "Isotherms 

 of di-atomic substances and their binary inixtures. XX. The critical 

 curve of oxygen-nitrogen mixtures, the critical phenomena and some 

 isotherms of two mixtures with 50 % and 75 "/o by volume of oxygen 

 in the neigbourhood of the critical point." 49. 



— W. H. Keesom and J. de Smedt: "On the diffraction of Röntgen-rays 

 in liquids II." 112. 



— W. H. Julius and M. Minnaert: "The relation between the widening 

 and the mutual influence of dispersion lines in the spectrum of the 

 sun's limb." 329. 



— H. W. J. DiK and P. Zeeman : "A relation between the spectra of 

 ionized potassium and argon." II. 498. 



— W. TuYN and H. Kamerlingh 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. " 504. 



— G. Breit: "Transients of magnetic field in supra-conductors." 529. 



— H. R. Woltjer: "Magnetic researches. XXII. On the determination of 

 the magnetisation at very low temperatures and on the susceptibility of 

 gadolinium sulphate in the region of temperatures obtainable with 

 liquid hydrogen." 613. 



