CONTENTS. xVït 



UATto of the triangles (Approximate formulae of a high degree of accuracy for the) 

 in the determination of an elliptic orbit from three observations. II. 104. 



RAYS (A group of complexes of) whose singular surface consists of a scroll and a 

 number of planes. 662. 



KEFLECTioN (Derivation of the fundamental equations of metallic) from Cacchy's 

 theory. 486. 



— of light (On the theory of) by imperfectly transparent bodies. 377. 

 UEFLE.v-sTiMULi (On the strength of the) as weak as possible. 821. 



ROCKS (On fragments of) from the Ardennes found in the diluvium of the Netherlands 



North of the Rhine. 5 IS. 

 ROMBÜRGH (p. van) presents a paper of Dr. F. M. Jaeger : "On some derivatives 



of Phenylcarbamic acid." 127. 



— On the presence of lupeol in some kinds of gutta-percha. 137. 



— On the action of ammonia and amines on allyl formate. 138. 



— presents a paper of Dr. A. J. Ultee : "On the action of hydrocyanic acid on 

 ketones". 141. 



— presents a paper of Dr. L. van Itallie : "Thalictrum aquilegifoliura, a hydrogen 

 cyanide-yielding plant". 837. 



— On the action of ammonia and amines on formic esters of glycols and glycerol. 339. 



— presents a paper of Dr. C. J. Enklaar : "On Ocimene and Myrcene, a contribution 

 to the knowledge of the aliphatic terpenes." 714. 



— presents a paper of Dr. C. J. Enklaar : "On some aliphatic terpene alcohols." 723. 



— and N. H. Cohen : "The occurrence of /?-amyrine acetate in some varieties of 

 gutta perclia". 544. 



•— and W. VAN Dokssen : "The reduction of acraldehyde and some derivatives of 

 s. divinylglycol (3.4 dihydroxy l.B hexadiene). 541. 



— On the simplest hydrocarbon with two conjugated systems of double bonds, 

 1.3.5 hexatriene. 565. 



r o o z E B o o M (h. w. b A k h u I s). V. Bakhuis Roozeboom (H. VV.). 



R ij N B E R K (g. van). The designs on the skin of the vertebrates, considered in 

 their connection with the theory of segmentation. 307. 



3ANDE bakhuyzen (H. g. VAN de) presents a paper of J. Weedeb : "Ap- 

 proximate formulae of a high degree of accuracy for the ratio of the triangles 

 in the determination of an elliptic orbit from three observations". II. 104. 



— Preliminary Report on the Dutch expedition to Burgos for the observation of 

 the total solar eclipse of August 30, 1905. 501. 



^- presents a paper of Dr. H. J. Zwiers : "Researches on the orbit of the periodic 

 comet Holmes and on the perturbations of its elliptic motion". 642. 



satellites (On the orbital planes of Jupiter's). 767. 



SCALPELLUM SIEARN3I (On the polyandry of). 659. 



SCHOUTE (c). Determination of the Thomson-efl'ect in mercury. 331. 



schout E (p. H.) presents a communication Dr. W. A. Vebsldys: "On the rank of 

 the section of two algebraic surfaces". 52. 



