CON T E N T S. XIIT 



ORBITS (On periodic) of the type Hestia. 47. 



ORE VEINS (On) in the province of Limburg. 76. 



OVULE (The development of the), embryo-sac and egg in Podostemaceae. S2i. 



OXYMETHYLDINITROBENZONITRILE (On the Constitution of van Geüns'). 509. 



Palaeontology. L. Kutten: "On fossil Trichechids from Zealand and Belgium". 2. 



— Clemend Eeid and Mrs. Eleanor M. Reid: "On Dulichium vespiforrae sp. 

 nov. from the brick-earth of Tegelen". 860. 



PARTIAL SECTION (On ascendiug degeneration after) of the spinal cord. .386. 

 PEKELHARING (c. A.). An investigation of Mr. J. W. A. Gevtin: "On the 



relation of pepsin to chymosin". 283. 

 PENTA-ERYTHRITOL TETBAFORMATE (The decomposition of) ou heating. 166. 

 PEPSIN (On the relation of) to chymosin. 283. 

 PEROT (Observations of the magnetic resolution of spectral lines by means of the 



method of Fabry and). 440. 

 PHAGOCYTOSIS (Ouantitative researches on). 144. 

 Physics. J. D. van der Waals: "Contribution to the theory of binary mixtures". 



IV. 56. V. 123. VI. 188. 



— H. Kamerltngh Onnes and J. Clay: "On the measurement of very low tem- 

 peratures. XV. Calibration of some platinum resistance thermometers". 200. 



^- H. Kamerlingh Onnes and C, Braak : "Isotherms of diatomic gases and their 



binary mixtures. VI. Isotherms of hydrogen between — 104° C. and 217° C. 



204. Continued. 413. Vtl. Isotherms of hydrogen between 0° C. and 100° C." 419, 



— H. Kamerlingh Onnes and J. Clay : "On the change of the resistance of the 

 metals at very low temperatures and the influence exerted on it by small 

 amounts of admixtures". 207. 



— H. Kamerlingh Onnes and G. H. Fabius: "Repetition of de Heen's and 

 Teichner's experiments on the critical state". 215, 



— H. Kamerlingh Onnes and W. H. Keesom: "f'ontributions to the knowledge 

 of the »l/-surface of Van der Waals. XV. The case that one component is a 

 gas without cohesion with molecules which have extension. Limited miscibility of 

 two gases". (2'>d Continuation). 231. XVI. On the gas phase sinking in the liquid 

 phase for binary mixtures in the case that the molecules of one component exert 

 only a feeble attraction". 274. 



— J. J. van Laar: "Some remarks on the last observations of Prof. H. Kamerlingh 

 Onnes and W. H. Keesom". 238. 



— P. Zeeman : "The intensities of the components of the spectral lines divided by 

 magnetism". 289. 



— H. Kamerlingh Onnes and J. Clay: "Some remarks on the expansion of 

 platinum at low temperatures". 342. 



— P. Zeeman: "Magnetic revolution of spectral lines and magnetic force". 2^^ part. 351. 



— 0. Postma: "Motion of molecule-systems on which no external forces act." 390. 



— H. Kamerlingh Onnes, C. Braak and J. Clay: ''On the measurement of 

 very low temperatures. XV IT. Determinations for testing purposes with the 

 hydrogen thermometer and the resistance thermometer". 422. 



