594 



TATE AND FOOTE I ANODE FILMS 



magnitude as the ratio of the cathode and anode falls of poten- 

 tial. The anode fall is usually about 20 volts and the cathode 

 fall around 150 to 200 volts. 



Further measurements were made upon anode resistance films 

 in order to determine whether the resistance is inversely propor- 



50 anode 

 j.l cathode 



Fig. 1. Relation between surface resistance and current for probe acting 

 as anode and as cathode. 



tional to the area, a relation which would follow if the films 

 acted as ordinary resistances. Two probe wires of the same 

 diameter and having exposed areas in the ratio 1 : 2.28 were used 

 in the place of R p (fig. 1, p. 483). These could be operated as 

 secondary anodes, either separately or shunted together. The 

 resistances, Ri of probe 1, Ro of probe 2, and jBi + 2 of probes 

 1 and 2 connected, were measured in the manner previously 

 described. The results of these measurements made with vari- 

 ous current densities are given in table 1. 



