KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 

 TE AMSTERDAM. 



PROCEEDINGS OF ÏHE MEETING 

 of Saturday December 24tb 1898. 



(Tiniislatud l'roiu: Veisljig vmi de gewone vergadering der Wis- en Natuurkundige 

 Afdeeling van Zaterdag 24 December 1898 Dl. VII). 



Context» : ,,Un mixed crystals of nitrate of kalium and nitrate of thallium." By Prof. H. W. 

 BakhtjIs Roozeboom, p. 229. — „Variation of volume and of pressure in mixing (II)." 

 By Prof J. D. tak der Waals, p. 232. — „Measurements on the course of the isotherms 

 in the proximity of the plaiipoint and particularly on the course of the retrograde 

 condensation in a mixture of carbonic acid and hydrogen." By Dr. J. Vekschaffislt. 

 (Communicated by Prof. H. Kajieklisou Osnes), p. 243. — „Measurements on the 

 magnetic rotatoiy dispersion of gases." By Dr. L, H. Siertsema. (Communicated by 

 Prof H. Kamerlingh Onxes), p. 243. 



The tbllowing papers were read : 



Chemistry. — „On mixed erijduls of nitrate of kalium and nitrate 

 of thallium". Dissertation written by Dr. C. van Eijk and 

 presented by Prof. H. W. Bakhuis Roozeboom who reads 

 on this subject as follows : 



Some time ago (vide Proceedings of the meeting of the Acuideniy 

 of 24 Sept. last, page 101) speaker has given a tlieoretical develo[)- 

 ment of the course of congealing of a molten mixture of two sub- 

 stances, from which mixed crystals are deposited when cooling and 

 of the course of transformation of such crystals, in case one of the 

 two components or both of them pass into another solid modification. 



Nitrate of kalium and nitrate of thallium now are the first 

 examples of a system of two substances, of which we have acquired 

 a general survey of the course of these two phenomena over the 

 entire field of concentration, and in which the observations agree 

 in all respects with the course deducted theoretically. 



1(5 



Procccdiugs lloyal Acad. Amsttrdiuu. Vol. I. 



