1037 
Summarizing we may state: 
1. That we have given an experimental method to determine 
plaitpoints, and other phenomena which must be made directly 
visible, at high pressures to an amount of more than 3000 atm. 
2. That we have demonstrated that the course of the theoretically 
predicted plaitpoint lines is in concordance with reality in the systems 
under investigation, albeit that the more intricate case of the 
splitting-up of a plait occurs more frequently, the less intricate case 
of simple retreat more rarely than was supposed. 
Meteorology. — “On the interdiurnal change of the air-teimperature.” 
By Dr. J. P. van DER STOK. 5 
(This communication will not be published in these Proceedings). 
(April 24, 1913). 
