Smithsonian Report, 1915. — Rutherford. 



Plate 2. 



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



f_i4_rf /f,::ii; %''*"**- 'in.' J' 1^ 



^N^N\«A\AAj&i^^ 



2. Photographic Record on String Electrometer of Entrance of Alpha 

 Particles into the Detecting Vessel. 



^.Udii^JWL^^.^^ 



k^M ^' Z-. 



3. Record with String Electrometer; Upper Record 

 for Beta Particles, Lower for Alpha Particles. 



