INFLUENCE OF LIGHT ON ELECTRODES. 413 



August 25. Solution, water with sulphuric acid. 



o 



Deflection by polarisation ... .2 



Sunlight . 7 



Blue glass . . . . . 4'5 



Yellow glass 3 



Red glass 3 



Exposed platinum positive.* 



September 4. Very dilute muriatic acid. 



o 



Deflection by polarisation .... 6 



Sunlight 14 



Blue glass ....... 9 



Yellow glass ...... 7*5 



Red glass . 7'5 



Diffuse daylight 8 



Exposed platinum negative. 

 September 6. Very dilute nitric acid. 



Deflection by polarisation . i 



Sunlight 7 



Blue glass 3 



Yellow glass ...... 2 



Red glass i 



Exposed platinum negative. 

 September 8. Dilute nitric acid. 



o 



Deflection by polarisation .... 3 



Sunlight ....... 6 



Exposed platinum negative. 



* In a second cell with the same solution the exposed plate was negative, and 

 the deflection increased by sunlight in the same direction as the polarisation, from 

 2 to 10. 



