May 8, 1896.] 



SCIENCE. 



695 



? 



the outside. This joint was found to hold 

 so well that the discharge frequently passed 

 through the air (about 5 cm.) outside the 

 tube. 



A photographic plate in its plateholder 

 was placed at P, about two centimeters 

 from the aluminum plate B. The experi- 

 ments were as follows : 



1. A was made the cathode and B the 

 anode. The resulting photograph is given 

 in Fig. 2. It shows that the X-rays radiate 

 in all directions from the thin portion of 

 theB. 



2. B was made the cathode and A the 

 anode. The resulting photograph is given 

 in Fig. 3. It shows that the X-rays radiate 



