KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM, 
PROCEEDINGS OF THE MEETING 
of Saturday April 21, 1900. 
OSG 
(Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundige 
Afdeeling van Zaterdag 21 April 1900 Dl. VIII). 
CONTENTS: „Solar Phenomena, considered in connection with Anomalous Dispersion of Light.” 
By Prof. W. H. Juris, p. 575. — „On the critical Isothermal Line and the densities 
of Saturated vapour and Liquid in Isopentane and Carbon dioxide,” By Dr. J. E. Ver- 
SCHAFFELT (Communicaied by Prof. H. KAMEeRLINGH ONNES), p. 588 (With one plate). 
— „Ihe theorem of JOACHIMSTHAL of the Normal curves.” By Prof. P. H. ScHovre, 
p. 593. — ,,Approximation formulae concerning the prime numbers not exceeding a 
given limit.” By Prof. J. C. Kiuyver, p. 599. — „Thermodynamics of Standard Cells 
(ist Part)” By Dr. Ernst Conen (Communicated by Prof. H.W. Baxuuis RoozrBoom), 
p. 610. — „Studies on Inversion (Ist Part)’. By Dr. Ernst COHEN (Communicated by 
Prof. H. W. Baxuuis RoozeBoom), p. 618. — ,,Determinations of the diminution of 
Vapour-pressure and of the elevation of the Boiling-point of dilute Solutions.” By 
Dr. A. Smits (Communicated by Prof. H. W. Bakutis RoozeBoom), p. 635. — .,Some 
reflexes on the Respiration in connection with LABORDE’s method to restore, by rhyth- 
mical traction of the Tongue, the respiration suppressed in Narcosis.” By M. A. van 
MELLE (Communicated by Prof. C. Winxier). (With one plate), p. 640. — ,,Echinopsine, 
a new crystalline vegetable base.” By Dr. M. Gresuorr (Communicated by Prof, A. 
P. N. FRANCHIMONT), p. 645. — „The constitution of the vapourphase in the system: 
Water-Phenol, with one or two liquidphases.” By Dr. F. A. H. SCHREINEMAKERS 
(Communicated by Prof. J. M. van BEMMELEN), p. 645. 
The following papers were read: 
Physics. — “Solar Phenomena, considered in connection with Ano- 
malous Dispersion of Light’. By Prof. W. H. Junius. 
(Read February 24, 1900.) 
The rule that the propagation of light is, in all directions, recti- 
linear, holds only for quite homogeneous media. If various consid- 
erations lead us to assume that the solar rays on their course 
penetrate media of unequal density, or of different composition, the 
rays must be curved, and the supposition that the observed light is 
emitted by objects situated in the direction of vision becomes untenable. 
Now, though no one doubts the unequal distribution of matter 
42 
Proceedings Royal Acad. Amsterdam, Vol. LI. 
