CONTENTS. XI 



Mathematics. Lucien Godeaux: "The theorem of Grassmann in a space of n dimen- 

 sions". 271. 



— W. Kapteyn : "On an infinite product, represented by a definite integral". 347. 



— P. H. Schoute: "The section of the measure-polytope Mn of space Spn with a 

 central space Sfn — 1 perpendicular to a diagonal". 485. 



— Mrs. A. Boole Stott and P. H. Schoute : "On five pairs of four-dimensional 

 cells derived from one and the same source". 499. 



— J. A. Barrau: "The analogon of the Cf. of Kummer in seven-dimensional 

 space". 503. 



— P. H. Schoute: "Fourdimensional nets and their sections by spaces". !«« part. 

 536. 2,!j part. 636. 



— Z. P. Bouman : "Contribution to the knowledge of the surfaces with constant 

 mean curvature". 545. 



— W. Kapteyn: "On the multiplication of trigonometrical series". 558. 



— J. Cardinaal: "Some constructions deduced from the motion of a plane 

 system". 648. 



— P. H. Schoute : "The sections of the net of measure polytopes Mn of space z^;?) 

 with a space Spn — 1 normal to a diagonal", 688. 



— J. C. Kluyver: "On the cyclic minimal surface". 750. 



— Jan de Vries : "On twisted curves of genus two". 832. 



— Jan de Vries : 'On algebraic twisted curves on scrolls of order u with (w — 1) 

 fold right line". 837. 



MEASURE-POLYTOPE Mn (The section of the) of space Spn with a central space ^S^;?» — I 

 perpendicular to a diagonal, 485. 



MEASURE-POLYTOPES Mn (The sections of the net of) of space Spn with a space ^S/^n — I 

 normal to a diagonal. 688. 



MEASUREMENT (On the) of very low temperatures. XV. Calibration ot some platinum- 

 resistance thermometers. 200. XVII. Determinations for testing purposes with the 

 hydrogen thermometer and the resistance thermometer. 422. XV [II. The determi- 

 nation of the absolute zero according to the hydrogen thermometer of constant 

 volume and the reduction of the readings on the normal hydrogen thermometer 

 to the absolute scale. 429. 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. 589. XX Influence of the devia- 

 tions from the law of Boyle-Charles on the temperature measured on the scale 

 of the gas-thermometer of constant volume according to observations with this 

 apparatus. 743. 



METALS (On the change of the resistance of the) at very low temperatures and the 

 influence exerted on it by small amounts of admixtures. 207. 



Meteorology. J. P, van der Stok : "The analysis of frequency-curves of the air-tem- 

 perature". 309, 



METHOD (a) of cold injection of organs for histological purposes. 687. 



method of Fabry and Perot (Ol)servations of the magnetic resolution of spectral 

 lines by means of the). 440, 



