XVI CONTENTS. 



ROM burg ii (p. van) and A. D. Mai henbrecher. On the action of bases, 



ammonia and amines on s. trinitrophenyl-metliylnitramine. 704. 

 röntgen kavs (On the polarisation of). 104. 



— (A hypothesis relating to the origin of). 714. 



ROOZEBOOM (II. W. B A K II U I S). V. B.VKHUI3 ROOZEBOOM (H. W.). 



rotations in Spt ^Equilibrium of systems of forces and). 820. 

 salicylic acid (The formation of) from sodium phenolate. 20. 

 s a n d e bakhuyzen (h. g. v a N i) e) presents a paper of Dr. J. Stein : 



"Observations of the total solar eclipse of August 30, 11)05 at Tortosa (Spain)". 45. 

 presents a paper of Dr. A. Pannekoek : "The luminosity of stars of different 



types of spectrum". 134. 



— presents a paper of Dr. A. Pannekoek : "The relation between the spectra and 

 the colours of the stars". 292. 



— presents a paper of Dr. H. J. Zwiehs : ""Researches on the orbit of the periode 

 comet Holmes and on the perturbations of its elliptic motion". IV. 414. 



On the astronomical refractions corresponding to a distribution of the tempe- 

 rature in the atmosphere derived from balloon ascents". 578. 

 satellites of Jupiter in 1908 (Mutual occultations and eclipses of the). 304. 2nd 



part. 444. 

 sciioute (p. H.) presents a paper of Dr. W. A. Versluys : " Second communica- 

 tion on the Pliicker equivalents of a cyclic point of a twisted curve." 364. 



presents a paper of Dr. F. Schuh : "On the locus of the pairs of common points 



and the envelope of the common chords of the curves of three pencils". 1st part. 424. 



— 2nd part. Application to pencils of conies. 548. 



presents a paper of Dr. VY. A. Wvtiiokf: "The rule of Neper in the four- 

 dimensional space." 529. 



— The locus of the cusps of a threefold infinite linear system of plane cubics 

 with six basepoints. 534. 



presents a paper of Dr. F. Scnuil : "The Incus of the pairs of common points 



of four pencils of surfaces". 555. 



— presents a paper of Dr. F. ircnuii : "The locus of the pairs of common points 

 f n _f- i pencils, of (« — 1) dimensional varieties in a space of n dimensions". 573. 



presents a paper of Dr. S. L. van Oss : "Equilibrium of systems of forces and 



rotations in #p 4 . v 820. 



s c U R E I ne m a K E R s (f. a. H.). On a tetracoinponent system with two liquid 

 phases. 607. 



schuh (fred.). On the locus of the pairs of common points and the envelope of 

 the common chords of the curves of three pencils. 1st part. 424. 2nd part. Ap- 

 plication to pencils of conies. 548. 



— The locus of the pairs of common points of four pencils of surfaces. 555. 



— The locus of the pairs of common points of n-\-\ pencils of(« — 1) dimen- 

 sional varieties in a space of n dimensions. 573. 



sciurus vulgaris (On the placentation of). 2S0. 



serum (On the amboceptors of an antistreptococcic). 336. 



