Messrs. Gladstone and Tribe on an Air-battery. 65 



Proportion of surfaces. 



Deflection. 



Silver. 



Copper. 



Expt. I. 



Expt. II. 



Expt. III. 



1 



0-25 



24 



23 





1 



0-5 



28 



27 





1 



0-75 



31 



30 





1 



1-0 



33 



32 



28 



1 



1-33 







28 



1 



2-0 







32 



1 



4-0 







30 



The increase of the copper surface, therefore, has comparatively 

 little effect. 



Proportion 



of surfaces. 



Deflection. 



Copper. 



Silver. 



Expt. I. 



Expt. II. 



Expt. III. 



1 



0-25 







7-5 



1 



0-5 







16 



1 



0-75 







21 



1 



1-0 



33 



32 



28 



1 



1-33 



41 



40 





1 



2-0 



56 



54 





1 



4-0 



96 



92 





The increase, therefore, of the silver or negative metal causes 

 an almost proportionate increase in the chemical action. This, 

 doubtless, arises from the necessity of oxygen, and explains the 

 value of the large surface exposed by the silver crystals in the tray. 



The effect of heat on the action of this cell was examined ; it 

 increases the action greatly : thus an arrangement which gave a 

 deflection of 40 at 20° C. gave one of 250 at 50° C; and the aug- 

 mentation was observed to be much more rapid in the higher than 

 in the lower portions of this range of temperature. 



If the formula given above for the reaction be a true one, it 

 follows that every atom of copper deposited on the silver in the 

 state of suboxide must be compensated by an atom of copper dis- 

 solved from the copper plate. This was proved quantitatively. In 

 a cell that had been in action for a week the loss of the copper 

 plate was 0-391 grm., while the suboxide deposited on the silver 

 was found to be equivalent to 0'398 grm. of metallic copper. This 

 deposit of suboxide, though it soon forms apparently a complete 



Phil. Mag. S. 4. Vol. 47. No. 309. Jan. 1874. * F 



