Saturation Currents in Ionization. 657 
The quantity @ is constant for the purpose of integrating 
the equations, but the supply of ions by the plates may be 
aN a 
O02 
00+v7 
009 
$1704 
"6 “Sty 
008 
000! 
. 002! 
OOt! 
| such that @ depends on the other constants of integration. 
In particular, it may depend on the value of X, at the plates. 
For instance, if the ions are supplied at a constant rate, then 
