XVlII C o N T F. N T S. 



s c II O u T E (p. H.). A tortuous surface of' order six and of genus zero in space Sj)^ 

 of four dimensions. 489. 



— presents a paper of Dr. W. A. Veksluys : "Tlie Plvckeu equivalents of a cyclic 

 point of a twisted curve." 498. 



— A particular series of quadratic surfaces with eight common points and eight 

 common tangential planes. 754. 



SECTION of two algebraic surfaces (On the rank of the^. 52. 



SECTIONS (On the hidden equilibria in the p,x-) below the eutectic point. 568. 



SEGMENTATION (The designs on the skin of the vertebrates, considered in their con- 

 nection with the theory of). 307. 



siLAT in Western-Borneo (On brackish and fresh water deposits of the river). 742. 



sissiNGH (r.). On the theory of reflection of light by imperfectly transparent 

 bodies. 377. 



— Derivation of fundamental equations of metallic reflection from Cauchy's 

 theory. 486. 



SITTER (w. D e). On the orbital planes of Jupiter's satellites. 767. 



SKIN (The designs on the) of the vertebrates, considered in their connection with the 



theory of segmentation. 307. 

 SMITS (a.). On the hidden equilibria in tlie p,x-dia.gv:\m of a binary system in 



consequence of the' appearance of solid substances. 196. 



— Contribution to the knowledge of the px- and the ;)Z'-lines for the case that two 

 substances enter into a combination which is dissociated in the liquid and the 

 gajphase. 200. 



— On the hidden equilibria in the ^j.ar-sections below the eutectic point. 568. 



— On the phenomena which occur when the plaitpoint curve meets the three phase 

 line of a dissociating binary compound. 571. 



s Ö H N G E N (n. l.). Methan as carbon-food and source of energy for bacteria. 327. 

 SOLAR ACTIVITY (Oscillations of the) and the climate. 2nd communication. 155. 

 SOLAR DISK (Measurement of the heat produced by the integral radiation of the corona 

 and of the). 503. 



— (A new method for determining the rate of decrease of the radiating power 

 from the center toward the limb of the). 668. 



SOLAR ECLIPSE (Preliminary Report on the Dutch expedition to Burgos for the obser- 

 vation of the) of August 30, 1905. 501. 



— (Report on the operations with the two slit-spectrographs for the) of August 

 30, 1905. 506. 



SOLUBILITIES (The) of the isomeric chromic chlorides. 66. 



SOLUTIONS (The boiling points of saturated) in binary systems in which a compound 



occurs. 536. 

 SOUND (On the pressure of) in Corti's organ. 60. 

 SPACE Spt (A tortuous surface of order six and of genus zero in) of four dimensions. 489. 



— of LoBATSCHEFSKY (Central projection in the). Ist part. 389. 

 SPECTRAL LINKS (Magnetic resolution of) and magnetic force, lat part. 814. 



