KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM. 
PROCEEDINGS OF THE MEETING 
of Saturday October 26, 1912. 
IG 
President: Prof. H. A. Lorentz. 
Secretary: Prof. P. Zeeman. 
(Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundige 
: Afdeeling van Zaterdag 26 October 1912, Dl. XXI. 
G7 @ isk; EEN NEE SS: 
.R. Karz: “The antagonism between citrates and calciumsalts in milkeurdling by rennet. 
A contribution to the knowledge of the relation between structure and biological action”. 
(Ist Communication). (Communicated by Prof. A. F. Ho_teman), p. 434. 
. R. Karz: “The law of surface-adsorption and the potential of molecular attraction”. (Com- 
municated by Prof. J. D. van DER Waars), p. 445. j 
C. Braak: “The correlation between atmospheric pressure and rainfall in the East-Indian 
Archipelago in connection with the 3,5 yearly barometric period”. (Communieated by Dr. 
J. P. vAN DER SToK), p. 454. a 
L. Rurren: “On orbitoids of Sumba”. (Communicated by Prof. C. E. A. WICHMANN), p. 461. 
F. A. H. SCHREINEMAKERS and Miss W.C. pr Baar: “On the quaternary system KCI —CuCl,— 
BaC],—H,.0”, p. 467. 
F. A. H. Scmrememakers and J. C. Tuoxus: “The system HgCl,—CuCl,—H,0” p. 472. 
W. Remprers and S. pr Lancer: “The system Tin —Iodine” (Communicated by Prof. F. A. 
H. SCHREINEMAKERS,, p. 474. . 
W. Rewpers and D. Lery Jr: “The distribution of dyestuffs between two solvents. Con- 
tribution to the theory of dyeing”. (Communicated by Prof. F. A, H. SCHREINEMAKERS), 
rp. 482. 
Hk. pe Vries: “On loci, congruences and focal systems deduced from a twisted cubic and 
a twisted biquadratic curve” I, p. 495. 
C. van Wisserinan: “On the demonstration of carotino'ds in plants. First communication: 
Separation of carotinoids in erystallice form”. (Communicated by Prot. J. W. Morr), Probie 
N. Scnerrema: “Determination of the geographical latitude and longitude of Mecca and 
Jidda, accomplished in 1910-1911”. (Communicated by Prof. B. F. van DE SANDE BAKHUYZEN), 
Part I, p 527. (With 1 plate), Part IH, p. 540, Part III, p. 556. (With 2 plates). 
A.H. W. Arrx: “On a new modification of sulphur’. (Communicated by Prof. A. F. Hor- 
LEMAN), p. 572. 
H. L. pr Lervuw: “On the relation between the sulphur modifications”. (Communicated by Prof. 
A. F. HOLLEMAN), p. 584. < 
A. F. Horreman and J. P. Winavr: “On the nitration of the chlorotoluenes”, p. 594. 
P. ZEEMAN: “On the polarisation impressed upon light by traversing the slit of a spectroscope 
and some ezrors resulting therefrom’’, p. 599. 
J. D. vaN DER Waars: “Contributioa to the theory of binary systems. XXI. The condition 
for the existence of minimum critical temperature”, p. 602. 
J. J. van LAAR: “The calculation of the thermodynamic potential of mixtures, when a com- 
bination can take place between the components”. (Communicated by Prof. H. A. LORENTZ), 
p. 614. 
J. W. Morr and H. H. Janssonivs : “The Linnean method of describing anatomical structures 
Some remarks concerning the paper of Mrs. Dr. Marie C. Srorrs, entitled: Petrifactions 
of the earliest European Angiosperms’, p. 620 
©. Exakman: “On the reaction velocity of micro-organisms”, p. 629. 
W. H. Kersom: “On the second virial coefficient for monatomic gases, and for hydrogen 
below the Borre-point”. (Communicated by Prof. H. Kamerurncn ONNES), p. €43. 
Benet BECKMAN: “On the Harr effect, and the change in resistance in a magnetic field at 
low temperatures. I!T. Measurements at temperatures between + 17° C. and — 2009 C 
Cl 
au 
of the Harr effect, and of the change in the resistance of metals and alloys in a magnetic 
- field”, (Communicated by Prof. H. Kamerrixem ONNes), p. 649. IV. Continuation}, p. 659, 
H. KAMERLINGH Onnes and Benet BECKMAN: “On the Harr-effect and the change in 
resistance in a magnetic field at low temperatures. V. Measurements on the Haut effect 
for alloys at the boiling point of hydrogen and at lower temperatures”, p. 664, 
C. A. CROMMELIN: “On the triple point of methane’, (Communicated by Prof. H. KAMERLINGit 
ONNES), p 666. 
E. Marrras, H. KaMERLINGH Onnes and C. A, CROMMELIN: “On the rectilinear diameter for 
argon”, p. 667. 
Erratum, p. 673, 
29 
Proceedings Royal Acad. Amsterdam. Vol. XV, 
