KONINXLIJXE AKADEMIE VAN WETENSCHAPPEN 

 TE AMSTEKDAM. 



PROCEEDINGS OF TPTE MEETING 

 of Saturday February 25tii 1899. 



fïranslatcd from: Verslag van de gewone vergadering der Wis- en Natuurkundige 

 Afdeeling vau Zaterdag 25 februari 1S99 Dl. VII). 



CojiTESTS: ,,0n the oithoptical circles belonging to Unear systems of conies." By Prof. Jan de 

 Vries, p. 30.5. — ,,0n solubility and meltinj; point as criteria for distinguishing racemic 

 combinations, psendoracemic mixed crystals and inactive conglomerates." By I'lof. 

 II. W. Bakhuis Koozeboom, p. 310. — „A geometrical interpretation of the invariant 

 n (ab)" of a binary form o " of even degree." By Prof. P. H. Schoüte, p 313. — 



„On tlie deflection of X-rays." By Prof. H. Haga and Dr. f'. H. Wind, p. 321. — 

 Prof. B. J. Stokvis presents the dissertation of Dr. G. Bellaar Sprutt: „On the 

 physiological action of methylnitramine in connection with its chemical constitution," 

 p. 321. — „On a simplified theory of the electrical and optical phenomena in moving 

 bodies." By Piof. H. A. Lorektz, p. 323. — „Stokes' aberration theory presupposing 

 an ether of inequal density." By Prof. II. A. Lorektz, p. 323. — „Measurements on 

 the system of isothermal lines near the plaitpoint, and especially on the process of the 

 retrograde condensation of a mixture of caibonic acid and hydrogen." (Continued). By 

 Dr. J. VKRScnAFF.-LT, ^Communicated by Prof H. Kamerlixgh Okxes), p. 323. (With 

 one plate). — „Measurements on the change of pressure by replacing one component 

 by the otlier in mi.xtures of carbonic acid and liydrogen." By Dr. J. Veksciiaffelt, 

 (Communicated by Prof. H. KAMERLixoa Okxes), p. 328. — „On the velocity of electrical 

 reaction." By Dr. Ernst Cohes, (Communicated by Prof. H. W. Bakhuis Roozebocm), 

 p. 334. — Prof. A. P. X. Fraschimont presents the dissertation of Mr. L. T. C. Schey: 

 „On synthetically prepared neutral glyceryl-ethereal salts — triacylins — of saturated 

 monobasic acids with an even number of C-atoms," p. 338. — „On the Vibrations of 

 Electrified systems, placed in a Magnetic Field." By Prof II. A. Lorektz, p. 340. 



The following papers were read : 



Mathematics. — „O/i the oytlioptical circles belongliKj to linear 

 systems of conies." By Prof. J. de Vries. 



1. The locus of the points through which we can draw ortho- 

 gonal tausents to the conic 



A ^ B 



21 



Proceedinss Roval Acad. Amsterdam. Vol. I. 



