C^SIUM-OXYGEN-SILVER PHOTOELECTRIC CELL 



363 



to the amount of caesium deposited and the final sections approach 

 similarity with respect to the elapsed time. 



In cell G similar qualitative results are apparent. The cell was not 

 as active initially as cell F, and the rises in response are not so promi- 

 nent. For the slow position 1, Fig. 17, the maxima in the response 

 curves are lower and broader than for the slow position of cell F, 

 Fig. 15. But the maximum response for a wave-length of 7,500 A. 

 occurs again after the deposition of approximately one tenth of a 

 layer of caesium, though in Fig. 17 the maximum response at 8,000 A. 



LAYERS OF CAESIUM DEPOSITED 

 4 6 8 10"' 2 



I T 1 I I I I I 

 2 5 10 



HOURS OF DEPOSITION 



Fig. 17 — Spectral response changes in cell G, position 1. 



is greater than the maximum response at 7,500 A. In position 2, 

 Fig. 18, which had the fastest rate of deposition the maxima are 

 either entirely absent or else displaced to a position corresponding to 

 about 0.5 of an atomic layer where there are slight indications of 

 maxima for the wave-lengths 7,500 A. to 6,000 A. 



If we again refer to Fig. 14, which shows curves for the very rapid 

 deposition of caesium, it appears in this case that after the deposition 

 of one tenth of a layer the response has decreased markedly for light 

 of all wave-lengths. There appears to be a systematic variation of 

 behavior in that the maxima are very sharp for the slow rates of 



