KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM. 
PROCEEDINGS 
VOLUME XIX 
N52. 
President: Prof. H. A. LORENTZ. 
Secretary: Prof. P. ZEEMAN. 
(Translated from: “Verslag van de gewone vergaderingen der Wis- en 
Natuurkundige Afdeeling,” Vol. XXIV and XXV). 
CONTENTS. 
H. A. BROUWER: “On the tectonics of the eastern Moluccas.” (Communicated by Prof. G. A. F. 
MOLENGRAAFF), p. 242. 
W. J. DE HAAS and Mrs. G. L. DE HAAS-LORENTZ: “An experiment of MAXWELL and AMPERE’S 
molecular currents.” (Communicated by Prof. H. A. LORENTZ), p. 248. 
HENDRIK DE VRIES: “The circles that cut a plane curve perpendicularly.” II. p. 255. 
JAN DE VRIES: “A simply infinite system of hyperelliptical twisted curves of order five”, p. 271. 
J. C. KLUYVER: “On some numerical series considered by EULER”, p. 275. 
J. TRESLING: “On the use of Third Degree Terms in the Energy of a Deformed Elastic Body.” 
(Communicated by Prof. H. A. LORENTZ), p. 281. 
J. J. VAN LAAR: “On the Fundamental Values of the Quantities 6 and p a for Different Elements, 
in Connection with the Periodic System III. Discussion of the Different Groups of Elements 
Separately.” (Communicated by Prof. H. A. LORENTZ), p. 287. 
J. J. VAN LAAR: “On the Fundamental Values of the Quantities b and p/a for Different Elements, 
in Connection with the Periodic System. IV. The Elements of the Halogen-Oxygen- and Nitrogen 
Groups.” (Communicated by Prof. H. A. LORENTZ), p. 295 
S. DE BOER: “The Structure and Overlap of the dermatomes of the hindleg with the cat.” (Commu- 
nicated by Prof. G. VAN RIJNBERK), p. 321. 
H. ZWAARDEMAKER: “Specific smell intensity and the electrical phenomenon of cloudlike conden- 
sed water vapours in chemical series”, p. 334. 
T. P. FEENSTRA: “A new group of antagonizing atoms. II. (Communicated by Prof. H. ZWAARDE- 
MAKER), p. 341. 
E. F. VAN DE SANDE BAKHUYZEN and J. E. DE VOS VAN STEENWIJK: “On a peculiar anomaly occur- 
ring in the transit observations with the Leiden meridiancircle during the years 1864—1868”, p 345. 
J. D. VAN DER WAALS: “The Increase of the Quantity a of the Equation of State for Densities 
Greater than the Critical Density”, p. 359. 
W. DE SITTER: “Planetary motion and the motion of the moon according to EINSTEIN's theory”. p. 367. 
F. M. JAEGER and JUL. KAHN: “Investigations on the Temperature-Coefficients of the Free Molecular 
Surface-Energy of Liquids between _g0? and 1650° C.” XV. The Determination of the Specific 
Gravity of molten Salts, and of the Temperature-Coefficient of their Molecular Surface- 
Energy, p. 381. 
F. M. JAEGER and JUL. KAHN: “Investigations on the Temperature-Coefficients of the Free Molecular 
Surface-Energy of Liquids between _g0° and 1650° C.” XVI. The surface-tension of some Halo- 
genides of Sulphur, Phosphorus, Arsenic, Antimony and Bismuthum, p. 397. 
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Proceedings Royal Acad. Amsterdam. Vol. XIX. 
