38 



Dr. Foote and Dr. Mohler on Ionization and 









Table II. 





Ionization and Resonance Potentials for Magnesium. 







Referring to fig. 2. 











Applied 



Resonance Potential. 











Potential 



_^_ 



Initial 



lurve. a. 



b. 



c. 



for 

 Ionization. 



b-a. c-b. 



Potentials 



1 17 



4-6 



7-6 





2-9 



09 



2 







7-i 







2a 







71 







3 2-2 



4 ; 6 







2-4 



0-4 



4 2-0 



4-5 







2-5 



06 



5 1-8 



4'2 







24 



0-8 



6 1-8 



4'2 



6-6 





2-4 2'4 



0-8 



7 2-0 



4-6 







2-6 



06 



8 1-8 



46 





.. . 



2-8 , ... 



0-8 



9 







7-0 







10 







6-9 







11 







69 









Means... 



... 70 



2-60 volts. 



07 



Mean Initial Potential 



... 0-7 







Ionization Potential... 



•7 volts. 



Final Mean Ionization Potential = 7'75 volts. 

 Final Mean Resonance Potential = 2-65 volts. 



The curves obtained for thallium vapour are shown by 

 fig. 3. The total current curve 4 clearly indicates ionization 

 at an applied potential of 6'6 volts. The other curves 

 represent partial current between the net and cylinder 

 against a retarding field of about 0*2 volt. Analysis o£ 

 these curves is given by Table III. It will be noted that 



Table III. 



Ionization and Resonance Potentials for Thallium. 

 Referring to fig. 3. 



Applied Resonance Potential. 



~. 77^ Potential . » . 



Curve, a. b. c. d. e. f. t „ 



J . for c _ 6j ^ c# e _ dm f_ 6i 



Ionization. 



6 ... 1-5 2-7 3-8 1-2 M 



7 ... 1-5 25 3:45 46 56 ... 1-0 0-95 M5 10 



8 ... 1-4 2-5 3-6 4-7 1*1 1-1 l'l ... 



9 0-25? 1-5 2-5 1-0 



10 ... 1-7 28 3-8 11 1-1 



11 ... 1-7 2-8 1-1 



4 ... 66 



Means 6*6 1*07 volts. 



Mean Initial Potential 0'7 



Mean Ionization Potential 7 '3 volts. 



Initial 

 Potential 



0-6 + 

 0-64- 

 0-74- 

 064- 



0-7 



