KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM. 
PROCEEDINGS OF THE MEETING 
of Saturday March 22 and Friday April 25, 1913. 
DoS 
President: Prof. H. A. Lorentz. 
Secretary: Prof. P. ZrEMAN. 
Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundige 
Afdeeling van Zaterdag 22 Maart en Vrijdag 25 April 1913, Dl. XXI). 
Cre IF TEE NT, “ES: 
H. A. Brouwer: “Leucite-rocks of the Ringgit (East-Java) and their contact-metamorphosis.” 
(Communicated by Prof. G. A. F. MorENGRAAFF). p. 1238. 
W. Karreyn: “Expansion of a function in series of ABEL’s functions 9, (2), p. 1245. 
L. E. J. Brouwer: “Some remarks on the coherence type a’, p. 1256. 
JAN DE Vries: “An involution of associated points’, p. 1268. 
L. S. Ornstein: “The diffraction of electromagnetic waves by a crystal.” (Communicated by 
Prof. H. A. Lorentz), p. 1271. 
J. Borge: “Nerve regeneration after the joining of a motor nerve to a receptive nerve”, p. 1281. 
H. J. HAMBURGER and J. Dr Haan: “The effect of fatty acids and soaps on phagocytosis,” 
p. 1290. | 
W. pe Sitter: “A proof of the constancy of the velocity of light”. p. 1297. 
F A. H. SCHREINEMAKERS: “Equilibria in ternary systems”. Part VI, p. 1298, Part VII, p. 1318. 
F. A. H. SCHREINEMAKERS and D. J. van Proown: “The system sodium sulphate, manga- 
nous sulphate and water at 350”, p. 1326. 
C. van WisseriNGH : “On intravital precipitates”. (Communicated by Prof. J. W. Morr), p. 1329. 
H. R. Krurr: “The influence of surface-active substances on the stability of suspensoids.” 
(Communicated by Prof. P. van RompurGn), p. 1344. 
H. J. WATERMAN: “Potassium, sulfur and magnesium in the metabolism of Aspergillus niger.” 
(Communicated by Prof. M. W. BrrsErtck), p. 1349. (With two tables). 
J. D. vaN DER Waars Jr.: “On the law of partition of energy.” II. (Communicated by Prof. 
J. D. VAN DER WAaLs), p. 1355. : 
J. K. A. WeERrTHEIM SALOMONSON: “The electroeardiogram of the foetal heart”, p. 1360. 
W. A. Verstuys: “On a class of surfaces with algebraic asymptotic curves.” (Communicated 
by Prof. J. CARDINAAL), p. 1363. ‘ 
H. KAMERLING ONNES and Mrs. Anna BECKMAN: “On piezo-electric and pyro-electric pro- 
perties of quartz at low temperatures down to that of liquid hydrogen,” p. 1380. 
Benct BECKMAN: “Measurements on resistance of a pyrite at low temperatures, down to the 
melting point of hydrogen,” (Communicated by Prof. H. KAMERLINGH ONNES), p. 1384. 
H. KAMERLINGH ONNES, C. DoRSMAN, and Sornus WeBER: “Investigation of the viscosity of 
gases at low temperatures. I. Hydrogen”, p. 1386. 
H. KAMERLINGH ONNES and Sopmus Weser: “Investigation of the viscosity of gases at low 
temperatures IJ. Helium. p. 1396. III. Comparison of the results obtained with the 
law of corresponding states,” p. 1399. 
H. KAMERLINGH Onnes and E. Oosreruurs: “Magnetic researches VIIL On the susceptibility 
of gaseous oxygen at low temperatures”, p. 1404. 
H. KAMERLINGH ONNES: “Further experiments with liquid helium. H. On the electrical re- 
sistance of pure metals etc. VII. The potential difference necessary for the electric current 
through mercury below 49.19 K.”, p. 1406. 
Mad. P. Curie and H. KAMERLINGH Onnes: “The radiation of Radium at the temperature 
of liquid hydrogen,” p. 1430. 
H. G. VAN DE SANDE BAKHUYZEN: “The periodic change in the sea level at Helder, in 
connection with the periodic change in the latitude, p. 1441. 
W. H. Juus: “The total solar radiation during the annular eclipse on April 17th 1912”, 
p. 1451. 
Erratum, p. i464. 
81 
Proceedings Royal Acad. Amsterdam. Vol, XV. 
