412 Sir Humphry Davy on the relations of 
with each other in the fluids, it is evident that in cases in 
which arcs primarily inactive are connected with those pri- 
marily active, the chemical changes produced by the electri- 
cal attractions must tend to produce in the primarily inactive 
parts of the combination an arrangement which must give it 
a power in direct opposition to that of the primarily active 
circles ; so that when separated, their actions, if any, must 
be directly the reverse of the other. This result, which I 
anticipated, I have actually found to be correct ; six arcs of 
platinum in vessels filled with solution of nitre, were con- 
nected with a Voltaic battery of 50 pairs of plates ; of course 
each arc gave off oxygen, and collected acid round the pole 
in the place of the zinc, and afforded hydrogen and collected 
alkali round the pole in the place of the noble metal : on 
separating the six arcs from the battery, they were found to 
possess independent action, the poles which were negative 
being positive, and those positive being negative : in short, 
the combination acted as if an original one, consisting of acid, 
alkali, and platinum. 
With arcs of zinc, the results were of the same kind, but 
the electrical effects were much more distinct : as the tar- 
nished zinc in this case added its own negative power to that 
produced by the contact with the acid. 
In trying similar experiments with six arcs of tin, silver, 
copper, and other metals, and using different saline solutions, 
it was found that the reversed electrical effects were most 
powerful with the most oxidable metals, and the most con- 
centrated and most decomposable solutions ; and the weakest 
arrangement of this kind was with arcs of platinum and pure 
