CONTENTS. XF 
NITRO-COMPOUNDS (Reduction of aromatic) by sodium disulphide. 42. 
NITROGEN (Fixation of free atmospheric) by Azotobacter in pure culture. 67. 
NOYONS (A. K. M.). About the determination of hardness in muscles, 43, 
— About the independence of the electro-cardiogram with regard to the form- 
cardiogram. 273. 
— About observations on the electroemyogram and form-myogram under the in- 
fluence of fatigue. 723. 
NUCLEI (About the function of the ventral group of) in the thalamus opticus of man. 295.. 
OENOTHERA LAMARCKIANA (Contribution to the knowledge of the cytological develop- 
ment of). 267. 
ONNES (4. KAMERLINGH). v. KAMERLINGH ONNEs (H.). 
ORNSTEIN (L. S.). Calculation of the pressure of a mixture of two gases by means 
of GrBBs’s statistical mechanics. 116. 
— Statistical theory of capillarity. 526. 
OXYGEN (The determination of the vapour pressure of) at three temperatures. 333, 
PAINLEVE (On a theorem of). 459. 
PARTITION of energy (On the law of the) in electrical systems. 580. 
PENNATULID (On Ptilocodium repens a new gymnoblastie hydroid epizoic on a). 635. 
Petrography. J. Scumurzer: “The mineralogic and chemical composition of some 
rocks from Central Borneo.” 398, 
PHFNOL (On plaitpoint temperatures of the system water-). 394. 
PHOTO-CHEMISTRY (A contribution to the) of silver (sub-) haloids. 730. 
Physics. A. P. H. Trivetit: “A contribution to the knowledge of the solarization 
phenomenon and of some other properties of the iatent image.” 2. 
— H. KAMERLINGH Onnes and C. Braak: “Isotherms of diatomic gases and their 
binary mixtures. VIII. The breaking stress of glass and the use of glass tubes 
in measurements under high pressure at ordinary and low temperatures.” 30. 
— L. S, Ornstein: ‘Calculation of the pressure of a mixture of two gases by 
means of GrBBs’s statistical mechanics,” 116. 
— J, D. van DER Waars Jr.: “On the law of molecular attraction for electrical 
double points.” 132. 515. 
— J. D. van DER Waars: “Contribution to the theory of binary mixtures.” VII, 
146. VIII. 187. IX. 201. X. 317. XI, 426. XII. 477. XIII 698, XIV. 816, 
XV. 890, 
— A. Smits: “The P-7-X-spacial-figure for a system of two components which are- 
miscible in the solid or liquid crystalline state in all proportions.” 165, 
— H. KAMERLINGH Onnzs: “The liquefaction of helium.” 168, 
— W. H. Jutius: “Anomalous refraction phenomena investigated with the spectro- 
heliograph.” 213, 
— Mrs. H. B. van BILDERBEEK-VAN Meurs: “The ZEEMAN-eftect of the strong 
lines of the violet spark spectrum of iron in the region A 2380—A 4416.” 222. 
— O. Postma: “On the kinetic derivation ef the second law of Thermodyna- 
mics.” 303, 
