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electrical and chemical changes. 
agents which, in proportion to their surface and their number, 
occasioned the constant circulation of a certain quantity of 
electricity through the fluids, or the connecting wires in the 
pile; and the chemical changes occurring in these fluids 
were considered as mere results, and not necessarily con- 
nected with the circulation. The inactivity of combinations 
where no chemical changes occur, is sufficiently hostile to this 
view ; but an examination of some of the circumstances of 
the construction of compound electrical combinations, will 
bring this hypothesis, and that which I have ventured to 
adopt, more distinctly into comparison. 
Let a piece of zinc and a piece of platinum, both in glasses 
filled with a solution of nitrate of potassa, be connected 
through the multiplier, and let the glasses be joined by 
asbestus moistened with the same fluid ; the needle will 
mark electrical action : let the two glasses now be joined by 
an arc composed of zinc and platinum, in such a manner that 
the order is Voltaic, i. e. that the zinc is opposite to the plati- 
num, in the original combination — the effect wdll be increased. 
Now let an arc of pure zinc be introduced ; the effect will 
be less than with the double arc, but superior to that with 
the asbestus, and the pole of the zinc opposite the platinum 
will oxidate, and that opposite the zinc will give off hydro- 
gen. Let arcs of other metals be substituted for the zinc ; 
for instance, of tin, of iron, of copper, of silver, of tellurium : 
the electrical effects will diminish with the oxidability of the 
metal; and with tellurium, which does not oxidate at the 
positive pole of a Voltaic battery, they will be destroyed ; 
and the case is the same with rhodium, palladium and pla- 
