KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM. 
PFROCE BRIGGS 
VOLUME XXIV 
Nes, 6 and 7. 
President: Prof. F. A. F. C. WENT. 
Secretary: Prof. L. BOLK. 
(Transiated from: “Verslag van de gewone vergaderingen der Wis- en 
Natuurkundige Afdeeling,” Vol. XXX). 
CONTENTS. 
G. C. DIBBETZ Jr. and P. ZEEMAN: “An Interference Phenomenon Due to the Introduction of 
Sodium Vapour into one of the Paths of the FIZEAU-MICHELSON Interferometer-Arrangement”, 
p. 206. (With one plate). 
V. J. KONINGSBERGER: “A method of recording growth under various external influences”. (Communi- 
cated by Prof. F. A. F. C. WENT), p. 209. 
CHR. VAN GELDEREN: “On the development of the sternum in reptiles”. (Communicated by Prof. 
L. BOLK), p. 221. 
K. LANDSTEINER: “On the formation of heterogenetic antigen by combination of hapten and 
protein”. (Communicated by Prof. C. H. H. SPRONCK), p. 237. 
F. ZERNIKE: “A moving coil galvanometer of high sensitivity”. (Communicated by Prof. H. HAGA), p. 239. 
H. ZWAARDEMAKER: “On Superficial and Internal Processes”, p. 246. 
W. E. DE MOL: “On Hypotriploid Dwarf-hyacinths derived from Triploid Dutch Varieties through 
Somatic Variation”. (Communicated by Prof. J. C. SCHOUTE), p. 251. 
H. BOSCHMA: “On Budding and coalescence of Buds in Fungia fungites and Pune actiniformis”. 
(Communicated by Prof. C. PH. SLUITER, p. 257. 
C. A. PEKELHARING: “On the. Movement of Pepsin in a protein-containing or protein-free Gel of 
Agar-agar”, p. 269. 
L. J. J. MUSKENS: “The Myoclonic Reflexes”. (Communicated by Prof. H. ZWAARDEMAKER), p. 280. 
B. G. ESCHER: “On the hot “Lahar” (mud flow) of the Valley of Ten Thousand Smokes (Alaska)”. 
(Communicated by Prof. G. A. F. MOLENGRAAFF), p. 282. 
J. J. VAN LAAR: “On the Equation of State for Arbitrary Temperatures and Volumes. III. On 
the Law of Force between the Molecules of Mon-atomic Substances”. (Communicated by Prof. 
H. A. LORENTZ), p. 294. 
EuG. DuBoIs: “On the Cranial Form of Homo Neandertalensis and of Pithecanthropus Erectus, 
Determined*by Mechanical Factors”, p. 313. (With one plate). 
H. A., LORENTZ:“Double refraction by regular crystals”, p. 333. 
14 
Proceedings Royal Acad. Amsterdam. Vol. XXIV. 
