( 243 ) 



On the other hand t^ is the highest of these four temperatures, 

 if there should exist mixtures, the critical temperature of which is 

 higher than that of the components. In general the following rela- 

 tion exists between these four temperatures: 



bi ia + ^2 «i = 2 bi. t, + (6i + ^2 — 2 ?.j2) td . 



If wo call t,n the temperature that fulfils the condition that 



(6l + b^) t,n = i] «a + ^2 h , 



tm lies always between t^ and ij, while the distance between <« 

 and tc is smaller than that between <„, and t^ . 



Physics. — „Measurements on the course of the isotherms in the 

 proximity of the plaitpoint and particiilarhj on the course of 

 the retrograde condensation in a mixture of carbonic acid and 

 hydrogen." By Dr. J. Verschaffelt (Communication N°. 45 

 fro7n the Physical Laboratory at Leiden, by Prof. II. Kamek- 

 LINGH Onnes.^ 



(Will be published iu the Proceedings of the next meeting.) 



Physics. — „Measurements on the magnetic rotatory dispersion of 

 gases." By Dr. L. II. Sieutsema (Communication A'". 46 

 from- the Physical Laboratory at Leiden^ by Prof. Kamer- 

 LiNGH Onnes.) 



(Will be published in the Proceedings of the next mectingV 



(January Kjtli 1899.) 



