SOME COM F.Ml'OR.IKy . (/'/ '. /.V( /• s IX fllVSUs' II 11'' 



slal)le" statf, and the ciierny wliiili il lakes up. nRasurid in volts, 

 is called its resoname-potential. The electron is left with only the 

 difference between its initial energy and the I!).?") volts whii h it 

 surrendered. 



This loss of ciuTijx- iti .( so-called "inelaslii'" collision ciii lie diin- 



8tiChltunigtnde Spannung » 



Kig. 3 — Curve displaying resonance-potentials of mercury. 

 (Einsporn, Z5./. Physik) 



onstrated by inserting a third electrode into the path of the electrons, 

 charged negatively to just such a degree that an electron retaining 

 its full initial speed can overcome the repulsion of the electrode and 

 win through to it, while an electron which has lost a quantity of 

 its kinetic energy in an inelastic collision cannot quite "make the 

 grade." When the energy of the electrons streaming into the helium 



