THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIE^ 



[FIFTH SERIES.] 



DECEMBER 1896. 



XLYII. On some Experiments ivith Rontgeiis Radiation, 

 By Richard Threlfall, M.A., Professor of Physics, and 

 James Arthur Pollock, Demonstrator of Physics in the 

 University of Sydney, N.S. W.* 



THE experiments to be described were performed during 

 April and May of this year, and were made with the 

 object of elucidating the nature of the radiation. It was 

 thought that the following possible explanations should be 

 tested : — 



1.. The radiation consists of a swarm of material particles 

 projected through the glass of the generating tube. 

 Electrical changes taking place at the glass surface are 

 invoked to explain the differences between Rontgen's 

 and Lenard's rays. 



2. The radiation consists of an " sether wind." iEther is 



sucked through the glass towards the source of radia- 

 tion and then blown outwards. The question as to 

 whether the radiation observed by Rontgen is the 

 expression of the motion of asther to or from the source 

 remaining open. 



3. The radiation consists of asther vortices moving to or 



from the source. 



4. The radiation consists of aether waves : that is waves of 



regular or irregular sether motions. 



5. The radiation consists of electromagnetic waves of either 



* Communicated by the Physical Society : read November 13, 1896. 

 Phil. Mag. S. 5. Vol. 42. Nq. 259. Dec. 1896. 2 K 



