KONINKLIJKE AKADEMIE VAN WETENSCHArrEN 

 TE AMSTERDAM. 



PROCEEDINGS OF THE MEETING 

 of Saturday February 24, 1906. 



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

 Afdeeling van Zaterdag 24 Februari 1906, Dl. XIV). 



coasTTEisr'rs. 



W. H. JüLirs: "A new method for deteimining the i-ate of decrease of tlie radiating power 

 from the center toward the limb of the solar disk", p. G68. (With one plate). 



A. F. HoLLEMAS: "On the nitration of ortho- and nietadibromobenzene", p. 678. 



J. J. Blasks.ma: "The introduction of halogen atoms into the benzene core in the reduction 

 of aromatic nitro-compounds". (Communicated by Prof. A. F. Holleman), p. G80. 



F. A. F. C. West and A. H. Blaavw : "On a case of apogamy observed .with Dasylirion 

 acrotrichura Zucc", p. 684. 



J. C. Kaptets: "On the parallax of the nebulae", p. 691. 



J. J. VAN Laar : "On the course of melting-point curves for compounds which are partially 

 dissociated in the liquid phase, the proportion of the products of dissociation being arbitrary". 

 (Communicated by Prof. H. W. Bakiiiis Roozeboom), p. 699. 



C. J. Enklaar: "On ocimene and myrcene, a contribution to the knowledge of the aliphatic 

 terpenes". (Communicated by Prof. P. van Romburgii), p. 714. 



C. J. Enklaar : "On some aliphatic terpene alcohols". (Communicated by Prof. P. van 



KOMBURGII;, p. 723. 



H. B. A. BoCKWiNKEL: "On the propagation of light in a biaxial crystal around a centre of 

 vibration". (Communicated by Prof. H. A. Lorentz), p. 728. 



K. Martin; "On brackish and freshwater deposits of the river Silat in Western-Borneo", p. 742. 



Physics. — "A neio metliod for deter minimj the rate of decrease 

 of the radiating poioer from the center toward the limb of 

 the solar disk". By Prof. W. H. Julius. 



(Communicated in the Meeting of January 27, 1906) 



The brightness of the .solar disk is known to diminish considerably 

 from the center toward the limb. Although this prominent feature 

 of the solar phenomenon should be among the first accounted for in 

 every theorj' of the Sun, it leads to problems presenting so many 

 difliculties, that a satisfactoi'y explanation is, until now, altogether 

 wanting. And even the empirical study of the law according to 

 which the radiating power varies across the disk, is not very advanced. 



What we know about the tjuestion is founded on researches in 



47 



Proceedings Royal Acad. Amsterdam. Vol. VIIL 



