8 GO Mr. Otto Stnhlmann on Difference in Photoelectric 



Iron. 



Bi/A. 



B.JA. 



B 1( /B, 



Log B /A proportional 

 to thickness of film. 



114 



1-18 



•967 



•072 



1-21 



123 



•983 



•089 



1-25 



1-28 



•976 



•107 



1-25 



1-30 



■961 



•113 



1-26 



1-31 



•962 



•117 



1-22 



145 



•841 



•161 



Fiir. 2. 



.050 



.OGO .090 .110 .|S0 .150 2.10 

 LOGARITHM ey A ^ THICKNESS." 



170 30 



J- 





Fig. 



3. 





a/2o 



U- 

 u- 



ZINC. 









ZZjoo 



LiJ 



Q 



_ o - — ° *S — o- 



COPPER. 



o 



^o 











^^>\. 



o 

 i— 











2 



§40 





















a: 











5 .OSO i2.o .i50 .180 ,2,10 Z4-0 



LOGARITHM By A tv TH\CKNLSS. 



Hence a grapli (see figs. 2, 3, 4) of the ratio o£ the emergent 



