KONINKLIJKE AKAUEMIE VAN WETENSCHAPPEN 

 ÏE AMSTERDAM. 



PROCEEDINGS OF THE MEETING 

 of Saturday January 28'^ 1899. 



(Traiislatutl from: Yei'slag van de gewone vergaacriiig der Wis- cii Naluiirkunclijjp 

 Afdecling van Zaterdag 28 Januari 1S99 Dl. VII). 



CoKTESTS: „Brackish water deposits of the Jlëlawi in the interior of Borneo". By Prof. K. Martin 

 p. 245. — „On Hydrogel of oxide of iron (ferric-oxide"). By Prof. J. 51. van Bem.melen 

 ]). 249. (With one plate.) — „The ei|uilibrium of systems of three substances, in wliidi 

 two liiiuids occur". By Mr. }i. de Brlyn. (f'oramunicated by Prof. J. M. van 

 Bkm.melen), p. 253. — „Tlie representation uf the screws of B.vll passing through a 

 point or lying in a plane, according to the method of CArOKAi.i". By Prof. J. Car- 

 DINAAL, p. 258. (With one plate.) — „On the vibrations of electrified systems, placed 

 in a magnetic field. A contribution to the theory of the ZEEMAN-effect". By Prof. 

 H. A. LoREXTZ, p. 2G3. — „On trinodal Quartics". By Prof. Jan de Vkies, p. 263. — 

 „Calcidution of the second correction to the nuautity b of the etniation of condition ur 

 TAN DER Waals". By Mr. J. J. van Laab. Communicated by Prof. J. D. van der 

 Waals), p. 273. — „Measurements on the system of isothermal lines near the plait- 

 |)uint, and especially on the process of the retrograde condensation of a mixture of 

 carbonic acid and hydrogen." By Dr. .1. Vi'.RSCiiAFi-.iLT. (Communicated by Prof. 

 II. Kamerlingh Onnes), p. 288. (With one plate.) — „Measurements on the magnetic 

 rotatory dispersion of gases". By Dr. L. II. Siertse.ma. (Communicated by Prof. 

 H. Kamerlingh Onnes), p. 296. (With one i)late.) 



The t'ollowing papers were read : 



Geology. — „On Brackish-watcr deposits of the Mduwl in lite 

 interior of Borneo". By Prof. K. Martin. 



It is more than forty years since the mining engineer R. Everwijn's 

 geognostical expeditions in the „Wcster-Afdeeling" of Borneo. Since 

 that time several explorers have been occupied with the geology of 

 that country and nevertheless all our present knowledge of the geolo- 

 gical formation of West-Borneo is still based on incoherent data only 

 of which we do not even possess a rough geognostical sketch map. 



During the last years the mining engineer N. Wikg Easton has 

 been intrusted to make a closer investigation o this country and 



IT ' 



Proceedings Royal Acad. Ainsterdaiii.^Vül 



