Smithsonian Repott. 1 902 — Becquerel 



Plate I. 



Fig. 1 .—Reproduction of a Thin Strip of Copper, in 

 Form of a Cross, by Rays of Uranium on a Photo- 

 graphic Plate Wrapped in Black Paper. 



Fig. 2. 



-Radiograph of Aluminum Medal Produced by 

 Rays of Uranium. 



