1064 Mr. C. F. Bickerdike on the 



cases by means of long, narrow glass capillary tubes bent in 

 the form of long loops ; this served the double purpose of 

 protecting the instruments from shocks and from air-currents 

 which would be engendered by rapid alterations of pressure 

 in the case. The air which is allowed to enter must be dried 

 by passage over suitable reagents, and subsequently filtered 

 through tightly-packed cotton-wool. It is not advisable to 

 introduce drying agents into the case itself. Gray and 

 Ramsay noted that when air was allowed to enter rapidly, 

 slight shifts in resting-point were observed, and they attri- 

 bute this to the lodgment of dust particles on the balance ; 

 the source of this dust was doubtless the solid barium oxide 

 which they put into the case for drying purposes. Phosphoric 

 anhydride is particularly liable to cause such trouble. 



My thanks are due to Mr. J. A. Smith for much useful 

 information on the design of balance beams. 



Chemical Laboratories, 



University of Melbourne , 

 October 1921. 



CXIV. The Interaction betiveen Radiation and Electrons. 



By C. F. BlCKERLUKE *. 



IN a "Report on Radiation and the Quantum Theory" 

 . to the Physical Society (1914) Jeans examines the 

 question of the equilibrium distribution of energy between 

 electrons and the aether. In a paper in the 'Philosophical 

 Magazine ' June 1914 he points out that the substantial 

 difficulty of reconciling the facts with dynamical theory 

 arises not in connexion with the mere propagation of 

 radiation in the aether conceived as a continuous medium, but 

 solely in the interchange of energy between radiation and 

 matter. He applies the equations appropriate to the motion 

 of a charged particle acted upon by radiation, and deduces 

 that the only final state of equilibrum would be one which is 

 not to be reconciled with the facts observed experimentally. 

 His inference is that " the departure from the classical 

 mechanics is to be looked for in the fundamental equations 

 of aether and electricity." 



The writer ventures to suggest that possibly the classical 

 conception of Faraday lines may afford a clue to the direction 

 in which to seek for the solution of the difficulty. 



* Communicated by the Author. 



