Page:On the various forces of nature and their relations to each other.djvu/156

152 has scarcely any action; and here is a plate of platinum, which I will immerse in the same solution, and might leave it there for hours, days, months, or even years, and no action would take place. But by putting them both together, and allowing them to touch (fig. 44), 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