(G47) 
HP]ATINa AND COOLIJSTa APPARATUS FOR RONTGEN 
CRYSTALLOaRAPHIC WORK. 
By J. Steph. VAX der Lingen. 
(From tlie Applied Matliematics Laboratory, South African College.) 
(Read August 18, 1915.) 
One of the many problems of modern physics is the energy of atoms and 
its relation to temperature. Since the publication of De Bye's extension of 
1- 
von Lane's theory of Rontgen interference, several experiments were carried 
out with a view to determine, firstly, the validity of De Bye's theory, and, 
secondly, the variation of atomic energy due to " heat motion." * 
In order to facilitate the work of those who wish to carry on the research 
* See von Lane and Author : Phys. Zeit., January, 1914 ; Die Naturwissenchaften, 
March 27 and April 10, 1914. 
