( 623 ) 



at a constant temperature near the critical temperature of separation, 

 desirable, and also such an investigation for a single substance in 

 the neighbourhood of the crilical point gas-liquid ^). 



This investigation in connection with what follows (see § 4) from 

 measurements as mentioned in § 3 on the size of the light-scattering 

 particles might give us an idea of the velocity of motion of the 

 light-scattering particles or of the mean time of existence of definite 

 aggregations governed by the statistic equilibrium. 



Chemistry. — "On the form-analogy of Halogene-derivatives of 

 Hydro-carbones ivitli open' chains''. By Dr. F. M. Jaeger. 

 (Communicated by Prof. A. P. N. Franchimont). 



(This paper will not be published in these Proceedings). 



ERRATA. 



In the Proceedings of the meeting of March 30, 1907 : 



Plate II belonging to the Communication of Prof. H. Kamerlingh 

 Onnes and Dr. W. H. Keesom: for r = 1.18 read t=:1.08; for 

 r = 1.05 read t=: 1.035. 



p. 798 I. 4 from the bottom: for 0.966 read 0.996. 



In the Proceedings of the meeting of September. 28, 1907: 

 p. 211 1. 12 from the bottom: for 0.16822 read 0.25234. 



In the Proceedings of the meeting of December 28, 1907 : 

 p. 414 1. 7 from the bottom: for 28.955 read 29.030. 



1) The possibility is namely not excluded that then the light-scattering particles 

 have larger dimensions and a greater mutual distance than at the critical point 

 of separation of two liquids. To form an opinion on this point a spectrophotometric 

 investigation for a liquid mixture, in the same way as we have made for a single 

 substance (§ 3) would be useful. 



(March 27, 1908). 



