TATE AND FOOTE : RESONANCE POTENTIALS 



519 



values obtained for V on this basis are 4.88 volts for mercury 

 and 3.79 volts for cadmium. 



The second type of inelastic impact has been observed at 

 10.3 s or 10.4 volts 9 for mercury and 8.92 volts 10 for cadmium. 

 Collisions taking place at these potentials are characterized 

 by the complete removal from the atom of one or more bound 

 electrons, i.e., by ionization of the atom," and by the emission of 

 the complete spectrum of the vapor. 1 - We may, following 





fc: 



2 6 8 



Accelerating Totential ( Vo/tsJ 



i+ 



Fig. 2. Variation with accelerating potential of current to outside cylinder. 



McLennan, calculate the ionizing potential on the basis of 

 Bohr's theory of atomic structure from the limiting frequency 

 v = (1.5, S) in the spectra of these metals and obtain for mer- 

 cury 10.41 volts and for cadmium 8.97 volts. The agreement 

 between observed and calculated values of both resonance and 



8 Tate. Loc. cit. 



9 Davis and Gaucher. Phys. Rev., 10: 101. 1917. 



10 Tate and Foote. Loc. cit. 



11 Tate. Loc. cit.; Tate and Foote. Loc. cit. 



12 McLennan and Henderson. Loc. cit. 



