KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM. 
PROCEEDINGS 
VOLUME XVIII 
N°, 10. 
President: Prof. H. A. LORENTZ. 
Secretary: Prof. P. ZEEMAN. 
(Translated from: Verslag van de gewone vergadering der Wis- en 
Natuurkundige Afdeeling, DI. XXIV). 
CONTENTS. 
S. DE BOER: “A study of the heartmuscle according to the pharmaco-physiological method.” (Com- 
municated by Prof. G. VAN RIJNBERK), p. 1588. 
H. G. VAN DE SANDE BAKHUYZEN: “Short account of some works by BENSAUDE upon the knowledge: 
of astronomy and navigation in Portugal at the time of the great discoveries in the 15th and 
16th centuries, presented to the Academy by the author”, p. 1600. 
DAN. DE LANGE: “Critical and theoretical considerations about the origin of the primary foetal 
membranes in Vertebrates.” (Communicated by Prof. J. F. VAN BEMMELEN), p. 1604. (With one plate). 
J. VERSLUYS: “Chemical actions in the subsoil of the dunes.” (Communicated by Prof. J. BOESEKEN) 
p- 1619. 
H. R. KRUYT: “The Doublerefractive Sol of Vanadium Pentoxide’’ (Communicated by Prof. P. VAN 
ROMBURGH), p. 1625. 
W. C. KLEIN: “On a Trilobite Fauna of presumably Devonian age in the Dutch East Indies near 
Kalooé (Tamiang district, S. E. Atjeh).” (Communicated by Prof. G. A. F. MOLENGRAAFF). p. 1632, 
K. W. RUTGERS: “On the nature of the limiting surface for multiple space transformations.” (Com- 
municated by Prof. JAN DE VRIES), p. 1636. 
J. BOESEKEN and W. D. COHEN: “The photo-oxidation of alcohol with the co-optration of ketones. 
Contribution to the knowledge of the photochemical phenomena’, IL p. 1640. 
J. BOESEKEN and A. H. KERSTJENS: “The hydrogen-ion-concentration of some complex polyhydroxy- 
borate solutions”, p. 1647. 
J. BÖESEKEN, A. H. KERSTJENS and C. E. KLAMER: “The configuration of z-galactose and z-fructose”, 
p. 1654. 
J. E. VERSCHAFFELT and CH. NICAISE: “The viscosity of liquefied gases. IV. Apparatus and method. 
V. Preliminary measurements on liquid mixtures of oxygen and nitrogen.” (Communicated by 
Prof. H. KAMERLINGH ONNES), p. 1659. 
F. A. H. SCHREINEMAKERS: “In-, mono- and divariant equilibria” IX, p. 1676. 
W. H. JuLius: “A Test of the Dispersion Theory of Solar Phenomena, derived from Measurements 
by ADAMS and ST. JOHN on the Displacements of FRAUNHOFER Lines in the Spectra of the 
Sun's Limb and of Sun-spots”, p. 1691. 
W. H. JULIUS: “Anomalous Dispersion and FRAUNHOFER Lines. Reply to Objections”. p. 1691. 
Errata, p. 1692. 
Proceedings Royal Acad. Amsterdam. Vol. XVIII. 
