Page:On the various forces of nature and their relations to each other.djvu/137

Rh attracts the uncoloured end of the little magnet. You see it pulls it towards it with great power; and as I carry it round, the uncoloured end still follows. But now, if I gradually bring the middle of the bar magnet opposite the uncoloured end of the needle, it has no effect upon it, either of attraction or repulsion, until, as I come to the opposite extremity (N), you see that it is the coloured end of the needle which is pulled towards it. We are now therefore dealing with two kinds of power, attracting different ends of the magnet—a double power, already existing in these bodies, which takes up the form of attraction and repulsion. And now, when I put up this label with the word, you will understand that it is to express this double power.

Now, with this loadstone you may make magnets artificially. Here is an artificial magnet (fig. 39) in which both ends have been brought together in order to increase the attraction. This mass will lift that lump of iron; and, what is more, by placing this keeper, as it is called, on the top of the magnet, and taking hold of the handle, it will adhere sufficiently