KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM, 
PROCEEDINGS OF THE MEETING 
of Saturday December 24, 1904. 
IGC 
(Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundige 
Afdeeling van Zaterdag 24 December 1904, Dl. XIII). 
OENE eN ESE 
D. J. KorreweG and D. pe Lance: “Multiple umbilies as singularities of the first order of 
exception on point-general surfaces”, p. 386. 
A. F. Horteman: “On the preparation of pure o-toluidine and a method for ascertaining its 
purity”, p. 395. 
Miss T. Tames: “On the influence of natrition on the fluctuating variability of some plants”. 
(Communicated by Prof. J W. Mott), p. 398. (With one plate). 
J. W. Morr: “On the nuclear division cf Fritillaria imperialis L”. Results from Dr. B. 
SYPKENS’ thesis for the doctorate, p. 412. 
J. M. Janse: “An investigation on polarity and organ-formation with Caulerpa prolifera”. 
‘Communicated by Prof. HvGo pr Vries), p. 420. 
P. ZEEMAN and J. Geest: “Double refraction near the components of absorption lines mag- 
netieally split into several components”, p. 435. (With one plate). 
H. A. Lorentz: “The motion of electrons in metallic bodies” I, p. 438. 
S. Brok: “The connection betweea the primary triangulation of South Sumatra and that of 
the West Coast of Sumatra”. (Communicated by Prof. J. A. C. OUuDEMANS), p. 453. (With one 
plate). 
Cu. M. van Deventer: “On the melting of floating ice”. (Communicated by Prof. J. D. van 
DER WAALS), p. 459. 
J. J. BrANKSMA : “On trinitroveratrol”. (Communicated by Prof. H. W. Baxuvis RoozEBoom), 
p- 462. 
S. Try stra Bz.: “On W. Marcxwatp’s asymmetrie synthesis of optically active valeric acid”. 
(Communicated by Prof. H. W. Bakuvis Roozesoom), p. 465. 
A. H. W. Aten: “On the system pyridine and methyl iodide”. (Communicated by Prof. 
IL. W. Baxuvis Roozesoom), p. 468. 
J. BorsekeN: “The reaction of FrieperL and Crarrs”. (Communicated by Prof. A. Fe 
HorrEMAN), p. 470. 
J. E. Verscuarrert: “The influence of admixtures on the critical phenomena of simple sub- 
stances and the explanation of TEICHNER’s experiments”. (Communicated by Prof. H. Kamer- 
LINGH ONNEs), p. 474. (With one plate). 
J. A. C. OtpEMays: “Determinations of latitude and azimuth, made in 18%6—99 by Dr. 
A. PANNEKOEK and Mr. B. Postnumus Meyses at Oirschot, Utrecht, Sambeek, Wolberg, 
Harikerberg, Sleen, Schoorl, Zierikzee, Terschelling (the lighthouse Brandaris), Ameland, 
Leeuwarden, Urk and Groningen”, p. 482. 
Errata, p. 485. 
The following papers were read: 
i) 
“I 
Proceedings Royal Acad. Amsterdam. Vol. VII. 
