46 X. VI. Novák: Elektrické měření účinku světla na desku fotografickou. 



In table 3. T signifies the time (in minutes) after the exposure, 

 e the potenciál différence (in 10 -4 volt), and t the température of 

 the plate. 



The plates exposed 1 and 5 sec were underexposed 

 „ „ „ 15 and 30 sec were exposed normály 



„ „ „ 120 sec and more were overexposed. 



The upper limit of the normal exposure is very distinctly 

 marked by the curve constructed for the plate exposed 60 seconds. 

 The underexposed or the normal exposed plates are positiv on the 

 exposed half, the overexposed plate are negativ on the samé half. 

 The potenciál différence changes with the time like the electromotive 

 force of a polarised voltaic cell. These changes seem to be a sign 

 of the photographie induction. 



