KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM. 
PROC Eee GS 
VOLUME XIX 
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. 
J. J. VAN LAAR: “On the Fundamental Values of the Quantities b and pa for Different Elements, 
in Connection with the Periodic System IL. Mercury and Antimonium. General Methods”, p. 2. 
A. SCHIERBEEK: “On the Setal Pattern of Caterpillars.” (Communicated by Prof. J. F. VAN 
BEMMELEN), p. 24. 
Mrs. C E. DROOGLEEVER FORTUYN—VAN LEIJDEN: “Some Observations on Periodic Nuclear Divi- 
sion in the Cat.” (Communicated by Prof. J. BOEKE), p. 38. 
H. ZWAARDEMAKER, H. R. KNOOPS and M. W VAN DER BIJL: “The electrical phenomenon in cloud- 
like condensed odorous water vapours”, p 44 
H. M. DE BURLET and J. J J. KOSTER: “On the determination of the position of the maculaplanes 
and the planes of the semicircular canals in the cranium”. (Communicated by Prof. H. ZWAARDE- 
MAKER), p. 49 
Miss E. TALMA: “The influence of temperature on the growth of the roots of Lepidium sativum.” 
(Communicated by Prof. F. A. F. C WENT), p. 61. 
C. DE JONG: “Determination of the constant of Precession and of the Systematic Proper motions of 
the stars, by the comparison of KiiSTNER’s catalogue of 10663 stars with some zone-catalogues 
of the “Astronomische Gesellschaft””’ (Communicated by Prof. E. F. VAN DE SANDE BAK- 
HUYZEN) p. 65. 
JAN DE VRIES: “Pencils of twisted cubics on a cubic surface”, p. 97. 
T. P. FEENSTRA: “A new group of antagonizing atoms”. I, (Communicated by Prof. H. ZWAARDE- 
MAKER), p. 99. 
D. J. HULSHOFF POL: “The relation of the plis de passage of GRATIOLET to the ape fissure.” 
(Communicated by Prof. C. WINKLER), p. 104. 
H. J. HAMBURGER: “Quantitative determination of slight quantities of SO4. Il. Contribution to mi- 
crovolumetrical analysis”, p. 115. 
P. ZEEMAN: “Direct optical measurement of the velocity at the axis in the apparatus for FIZEAU’s 
experiment”, p. 125. 
A. SMITS and A. H. W. ATEN: “The Application of the Theory of Allotropy to Electromotive 
Equilibria.” V. (Communicated by Prof J. D. VAN DER WAALS), p. 133. 
J D. R. SCHEFFER and F. E. C. SCHEFFER: “On Diffusion in Solutions.” I. (Communicated by Prof. 
A. F. HOLLEMAN), p. 148. 
V. WILLEM: “The movements of the heart and the pulmonary respiration with spiders.” (Commu- 
nicated by Prof. G. VAN RIJNBERK), p. 162. 
A. A. GRiNBAUM: “On the nature and progress of visual fatigue.” (Communicated by Prof. 
G. VAN RIJNBERK), p. 167. 
W. REINDERS: “The system Iron-Carbon-Oxygen.” (Communicated by Prof. J. BOESEKEN), p. 175. 
W. REINDERS: “Birefractive colloidal solutions.” (Communicated by Prof. J. BOESEKEN), p. 189. 
J. DROSTE: “The field of a single centre in EINSTEIN’s theory of gravitation, and the motion of a 
particle in that field.” (Communicated by Prof. H. A. LORENTZ), p. 197. 
H. J. WATERMAN: “The Metabolism of Aspergillus niger.” (Communicated by Prof, J. BOESEKEN), p. 215. 
D. J. HULSHOFF POL: “The ape fissure — sulcus lunatus — in man.” (Communicated by Prof. 
C. WINKLER), p. 219. 
BALTH. VAN DER POL Jr.: “The currents arising in n-coupled circuits when the primary current is 
suddenly broken or completed.’ (Communicated by Prof. W H. JULIUS), p. 225. 
Proceedings Royal Acad. Amsterdam. Vol. XIX. 
