252 EXPERIMENTAL INVESTIGATIONS. 



The interval was to be dependent upon the following ob- 

 servation : When first the circuit was completed a marked 

 evolution of gas was perceptible in the voltameter ; this gra- 

 dually subsided, and when it had become nearly imperceptible 

 the change was to be made, when a fresh burst of gas took 

 place ; as this again subsided the wires were to be again 

 changed, and so on. At the expiration of six hours the water- 

 level was marked, as in the previous experiments. . 



The following is the quantity of gas evolved in the volta- 

 meter, deduced from a mean of several experiments : 



Cubic inch. 



Experiment i. = OT5 

 Experiment 2. =0*10 

 Experiment 3. = 0*23 



In neither of the last two experiments was a bubble of gas 

 perceptible on the large plates, a c. 



It appears from these experiments that the nitric acid 

 battery will decompose water across two pairs of interposed 

 inoxidable electrodes, provided one be of considerable size 

 with reference to the other parts of the circuit, so as to lessen 

 resistance. 



Whether this diminished resistance be occasioned by the 

 mere increase of the sectional area of the electrolyte ; whether 

 by the increased facility for solution of the oxygen and hydro- 

 gen ; whether the oxygen and hydrogen be not eliminated, 

 but merely thrown into a state of polar tension, or made to 

 adhere in a liquid or gaseous form to the plates ; or whether 

 any of these effects take place conjointly, I will not stop to 

 enquire, but proceed to the more remarkable fact, viz. that the 

 quantity of gas evolved in Experiment 3 is greater for a given 

 time, not only than that evolved in Experiment 2, but even 

 than that evolved in Experiment I ; thus we get the seeming 

 paradox, that a battery performs more work with an interposed 

 resistance than without it. 



While the battery is decomposing water in the voltameter 

 v, it is polarising the plates a c, or accumulating by its own 

 force an antagonist force ; when the wires are changed this 

 reacting force is united in direction with the initial force ; in 



