CONTENTS. SV 



SPACES Sn (On the connection of tlie planes of position of the angles formed by 

 two) passing through u point and incident spacial systems. 53. 



SPECTRAL LINES (Ou maxima and minima of intensity sometimes observed williin the 

 shading ot' strongly widened). 662. 



e , 

 SPECTRUM (Tlie cahiulation - from the magnetic rotation of the plane of polarisation 



for substances without an absorptionbaud in tlie visible). il8. 

 SPHERES of Monge (On the) belonging to ordinary and tangential pencils of quadratic 



surfaces. 4S4'. 

 SPONGES (On the shape of some siliceous spicules of). lOt. 

 SÏANDARDCLOCK (On the yearly periodicity of the rates of the) of tlie Observatory at 



Leyden, Hohwii no. 17. (I). 68. (II). 193. 



— (Preliminary investigation of the rate of the) of the Observatory at Leyden, 

 Hohwii no. 17, after it was mounted in the niche of the great pier. 267. 



STATISTICAL electro-mechanics. (I). 22. (11). 114. 



STELlU-TIlEORIE (Die). 497. 



STIMULUS and Ell'ect (A new law concerning the relation between). 392. 441. 



STHENGERS (TU.) and E. (JouEX. Ou the atomic weight of antimony. 513. 



STRUCTURE (The geological) of the lioiidsrug in Drenthe and the origin of that ridge. 

 (I). 93. (11). 101. 



SUGARS and Glucosides i^ Formaldehyde (methylene)-derivatives of). 175. 



SULPHUR (On the action of) on toluene and xylene. 288. 



iJ,-suRi'ACE (Contributions to the knowledge of van der Waals'). VII. The equation 

 of state and the 4»-surface in the immediate neighbourhood of the critical state 

 for binary mixtures with a small proportion of one of the components. 321. 836. 



— (Plaitpoints and corresponding plaits in the neighbourhood of the sides of the) 



of VAN DER WAALS. 445. 



SURFACE OF CONTACT (On the potential-ditference, which occurs at the) of tw'o dilferent 

 non-miscible liquids, in which a dissolved electrolyte has distributed itself. 431. 



SURFACES (On the spheres of Monge belonging to ordinary and tangential pencils of 

 (juadratic). 484. 



SYSTEM (On the conditions for the occurrence of a minimum critical temperature tor 

 a ternary). 225. 



— Acetaldehyde -{- Paraldehyde (Equilibria of phases in the) with and witlmiit 

 molecular transformation. 283. 



— Hydrazine -j- Water (The boilingpoint-curve of the). 171. 



SYSTEMS (On the connection of the planes of position of the angles formed Ijy two 

 spaces S/i passing through a point and incident spacial). 53. 



— (On the geometrical representation of the motion of variable). 386. 



— (Ternary). (IV). 1. (V). 121. 



TEMPERATURE (Bath of very uniform and constant low) in the cryostat. 502. 628. 



— (On the conditions for the occurrence of a minimum critical) for a ternary system. 225. 

 TEMPERATURES (Arrangement of a IjURCKH.xrdt- "Weiss vacnumpump for use in the 



circulations for low). 633. 



