days, months, or even years, and no action would take place. But by putting them both together and allowing them to touch (fig. 44),
Fig. 44.  |
Fig. 45.  |
you see what a coating of copper there is immediately thrown down on the platinum. Why is this? The platinum has no power of itself to reduce that metal from that fluid, but it has in some mysterious way received this power by its contact with the metal zinc. Here then you see a strange transfer of chemical force from one metal to another—the chemical force from the zinc is transferred, and made over to the platinum by the mere association of the two metals. I might take instead of the platinum, a piece of copper or of silver, and it would have no action of its own on this solution, but the moment the zinc was introduced and touched the
