Dissolve a single grain of copper in about one dram of nitric acid,
and dilute the solution with about one ounce of water, when it will
be evident that a single drop of the mixture must contain an almost
immeasurably small portion of copper. Yet, if the blade of a knife
be dipped into it, it will become covered with a coat of copper;
thus showing that the copper can be infinitely divided without any
alteration in its properties.