Diamonds are expensive things, and so difficult to experiment upon, even if they were not expensive, that the doors of inquiry seem locked. To turn diamonds into charcoal, or into carbonic acid gas, is a very costly formula of experiment. Charcoal fires, thus sustained, would soon burn a man out of his house; and soda water, impregnated with carbonic acid gas, produced from diamonds, would be a very expensive beverage. If we could only turn charcoal into diamonds, and carbonic acid gas into brilliants, that would be quite another affair. A new Eldorado would be discovered, and there would be so many experimenters that, when they all succeeded, they would find that diamonds had lost their value. However, as a fact for the encouragement of those who would like to be early in the race, we may state that the atoms of charcoal which are repulsed from the charcoal points, during the electric agitation which produces the electric light, acquire a hardness and a sharpness almost equal to that of the diamond--only there is still the awkward obstacle in the way, that _they happen to be black_. [Verse: "He delivereth and rescueth, and he worketh signs and wonders in heaven and in earth."--DANIEL VII.] We must see, therefore, whether there is anything in nature that we can experiment upon, theoretically or practically, to give us a clearer conception of this difficult matter. There is a large _dew-drop_ resting upon a luxuriant cabbage leaf--one of those great leaves that have flourished in defiance of the snail, and now spreads out like the gigantic frond of the _Victoria Regina_. That dew-drop is one of the beautiful diamonds which Nature sprinkles about on cloudless nights, as if to show the stars, in answer to their twinkling, that we have something that will glisten and twinkle too.