XII CONTENTS. 



Mathematics. F. Schuh: "The locus of the pair3 of common points of four pencils of 

 surfaces." 555. 



— F. Schuh : "The locus of the pairs of common points of » -f- 1 pencils of 

 (« — 1) dimensional varieties in a space of n dimensions." 573. 



— S. L. van Oss: "Equilibrium of systems of forces and rotations in £ƒ>.,." 820. 

 maurenbrecher (a. d.) and P. van Romburgh. On the action of bases, 



Ammonia and Amines on s. trinitrophenyl-methylnitraraine. 704. 

 maxwell's distribution of velocities (Some additional remarks on the quantity H 



and). 492. 

 meerburg (j. H.). On the motion of a metal wire through a piece of ice. 718. 

 metal wire (On the motion of a) through a piece of ice. 718. 

 Meteorology. W. van Bemmelen : "On magnetic disturbances as recorded at Batavia." 266. 



— J. P. van der Stok: "The treatment of wind-observatious." 684. 

 method (A few remarks concerning the) of the true and false cases. 222. 

 methods and apparatus used in the Cryogenic Laboratory at Leiden. X. How to obtain 



baths of constant and uniform temperature by means of liquid hydrogen. J 56. 



XL. The purification of hydrogen for the cycle. 171. XII. Cryostat especially for 



temperatures from — 252° to — 259°. 173. XIII. The preparation of liquid 



air by means of the cascade process. 177. XIV. Preparation of pure hydrogen 



through distillation of less pure hydrogen. 179. 

 miscibility (On a new case of form-analogy and) of position-isomeric benzene-deriva- 

 tives, and on the crystalforms of the six Nitrodibromobenzenes. 26. 

 mixtures of ethane and nitrous oxide (Graphical deduction of the results of Kuenen's 



experiments on). 664. 

 M o g E n d o r f f (e. e.). On a new empiric spectral formula. 434. 

 moll (j. w.) presents a paper of Mrs. M. Nieuwenhuis-von Uexküll-Güldenband: 



"On the harmful consequences of the secretion of sugar with some myrmecophilous 



plants." 15U. 

 moll (w. j h.). An investigation of some ultra-red metallic spectra. 544. 

 moll van c H a R a n T E (j.). The formation of salicylic acid from sodium 



phenolate. 20. 

 muller (f.). On the placentation of Sciurus vulgaris. 3S0. 

 M us kens (l. j. j.). Anatomical research about cerebellar connections. (3rd Commu 



nication). 819. 

 nectaries (On the influence of the) and other sugar-containing tissues in the flower 



on the opening of the anthers. 390. 

 neper (The rule of) in the four-dimensional space. 529. 

 new guinea (On the fresh-water fish-fauna of). 462. 

 nieuwenhuis-von uexküll-güldenband (m.). On the harmful 



consequences of the secretion of sugar with some myrmecophilous plants. 150. 

 nieuwe nhuyse (p.). On the origin of pulmonary anthracosis. 673. 

 nitration (On the) of phthalic acid and isophthalic acid. 286. 

 — of meta-substituted phenols. 278. 



