VOLTAIC REACTION. 



Fig. i. 



Fig. 2. 



absorb) this reaction, so another method of effecting the same 

 object would be, to add the reacting to the initial force, which, 

 from the separable character of the former, did not appear 

 impracticable. After sundry devices the following experiments 

 realised my views on the subject 



Experiment I, fig. I. db is a single cell 

 of the nitric acid battery, exposing six square 

 inches of each metal ; v is an ordinary volta- 

 meter, each electrode exposing half a square 

 inch, charged with dilute sulphuric acid ; de- 

 composition was allowed to proceed with this 

 arrangement for six hours ; the battery, for 

 greater assurance of constancy, being in this 

 and the two following experiments re-charged every two 

 hours ; the level of the liquid in the voltameter was carefully 

 marked on the tube. 



Experiment 2, fig. 2, is the 

 same nitric acid battery, d b, the 

 same voltameter, v, but with an in- 

 terposed pair of large platinum 

 plates, a c, exposing each to each 

 forty-two square inches of surface, 

 and immersed in dilute sulphuric 

 acid ; this arrangement was also set 

 to work for six hours. A slight 

 evolution of gas had taken place 

 in the voltameter in this experi- 

 ment, and the water-level was also 

 marked. 



Experiment 3. The same ap- 

 paratus as fig. 2 ; but my assistant 

 was directed to change at a certain 



interval the wires dipping into the mercury cups,^^, so as to 

 reverse the plates, a c, with regard to the direction of the cur- 

 rent, making what was the anode the cathode, and vice versa, 

 as shown by the dotted lines ; and at the expiration of a 

 similar interval to restore them to their original positions, and 

 to continue thus alternating the position of these plates with 

 reference to the current during six hours. 



