Smithsonian Report, 1924. — Whitney 



Plate 4 



c> 



1 JL. I 



The Balloons Illustrated in Figure 2, 

 Plate 3, Are Here Shown in Their Normal 

 Positions as the Result of Their Charges 

 Having Been Dissipated by a Feeble Beam 

 of X-Rays 



2. Apparatus Devised to Demonstrate the 

 Characteristics of Electron Emission 



FROM A THORIATED TUNGSTEN FILAMENT 



