Smithsonian Report, 1915. — Rutherford. 



Plate 2. 



- s; 



::t.';V,>,''' /•rr/"'^•••v^''>'•' 



■^ 





/■ ;... 'v>' ■«■•.:- 



1. Photographic Effect Due to Alpha Particles from a Central Point. 



■Vw\U.WyuAW\^^ 



2. Photographic Record on String Electrometer of Entrance of Alpha 

 Particles into the Detecting Vessel. 



%N^jyg^3j^^^ 



3. Record with String Electrometer; Upper Record 

 FOR Beta Particles, Lower for Alpha Particles. 



