JResonance Potentials for Electrons in Lead and Calcium. 11 



collisions of type 1. b is due to one collision of type 2. 

 Two collisions of type 2 will fall very near the point e. d is 

 due to one collision of type 1 followed by one of type 2 or 



Fig. 2. 



O 12 3 4 5 6 7 



Acc&terating Potential Volts 



Electron currents in calcium vapour. Curves 8, 18, and 22 " total 

 current " ; curves 1, 8, 9, 14, and 15 u partial current." 



vice versa, and /is due to two collisions of type 1 and one of 

 type 2 in any of the three possible orders. The positions 

 of e and /are above the ionization point, and for this reason 

 somewhat variable. The point b is too faint for accurate 



