ELECTROLYSIS ACROSS GLASS. 4*5 



This being covered, but kept in connection with the gal- 

 vanometer, the polarisation gradually diminished, passed the 

 zero-point, and took up an opposite deflection of 7'5 > the 

 outer platinum being now negative, the effect of sunlight was 

 now to reduce the 



Deflection to 3 



Red glass to ...... 6*5 



Yellow glass to 6*5 



Blue glass to 5'5 



On September 16, this same cell having been set aside in 

 the interim, with the plates metallically connected, the deflec- 

 tion by polarisation was increased by sunlight, the exposed 

 platinum being negative. 



September 1 5. Black and polished platinum plates in glass 

 cell without porous cell, the black platinum being towards the 

 light, and the plain platinum shaded by it ; the black platinum 

 was positive to the plain : 



o 



Deflection by polarisation . . . 10 



Sunlight 1 8 



Blue glass . . . . . . 1 2 



Yellow glass n 



After half an hour in connexion with a galvanometer : 



o 



Deflection by polarisation had sunk to . 4 



Sunlight . . . . . . 12 



Blue glass . . . - . . . 6 



Yellow glass ...... 4 



Red glass ...... 4 



ON THE TRANSMISSION OF ELECTROLYSIS ACROSS 



GLASS. 



Phil, Mag., Aug. 1 860. Read at the Chemical Section of the British 

 Association, June 28, 1860. 



IF glass or an equally non-conducting substance be interposed 

 between electrodes in an electrolyte, so that there be no liquid 



