Smithsonian Report, 1902. — Becquerel 



Plate VII. 



Fig. 14.— Second PicTuriE Odtaincd dy the Arrangement 

 Shown in Fig. 12. 



Fig. 1 5.— Effcct of Radiations from Sides of Leaden Box 

 After Traversing 5 to 1 2 mm. of the Metal. 



