Stages of Ionization by Collision. 

 Table I. 



973 



1 



p=2 



min. 



P = S 



mm. 



p=4 



mm. 



p — 5 mm. 



z 



Z 



a 



z 



a 



Z 



a 



1 z 



a 



; p 



40 



k 



P 



k 



P 



k 

 177 



P 



! k 



P 





... 





— 



021 





45 







142 



•041 



1-89 



•044 



2-36 



•047 



50 



•98 



•065 



147 



•069 



1-96 



•07 



2-45 



•076 



55 



1-01 



•101 



1-515 



•105 



2-02 



•105 



2-525 



•11 



60 



104 



•142 



1-56 



•145 



2-08 



•149 



2-6 



•17 



70 



1-09 



•25 



1-64 



•28 



2188 



•39 







y 



It is observed that for a given value of ~ the values of - 



p p 



increase with the pressure, especially for the larger values 



of a. This is not unexpected, since the relation expressed in 



(5) must cease to hold when a is large. It is interesting to 



see how large a may become before this relation ceases to be 



true (theoretically it is true as long as — i- + - t~ + ... 



may be neglected in comparison with 1 4- 2a in the expansion 

 of e 2<t ). Now if a is known and substituted in (3) the value 



of /jl ( = ■ — — — ) can be evaluated by a method similar 



to that explained above. In the case of the pressure of 



2 mm. the values of - were taken from Table I. for three 



Z P 



values of — . a for each case was substituted in (3) as a 



first approximation. Values of — were thus 



ni + n 2 + n 3 N 



obtained and were compared with the values of ^ ^ — ^v- 



Z Ni + Ns + No 



for the corresponding values of j- ' 



k 



Table II. 



z 



Z 



k 



N 2 



n 2 



a 



P (1) 



a /ON 



p 



N t +N 2 +N, 



f'^+fto + ^a 



P ^ 



50 



■98 



•605 



•602 



065 



•065 



60 



1-04 



•615 



•598 



•14 



134 



70 



109 



•62 



•593 



•25 



•226 



