The lode stone's attraction for iron was well known to the Greeks as early as 500 B.C., and is mentioned by Homer, Plato and Aristotle in their writings. It was the original magnet, and was followed, in course of time, by a suspending needle, which has been touched by a lode stone, in order to give it magnetic properties. This was the elementary compass, and was used by Chinese mariners about 1000 A.D. At that time people considered these two magnets as bewitched, and it was not until William Gilbert. a scientist, in the year 1600 A.D., announced that the earth itself was an enormous magnet, that people began to realize the possibilities of magnetism. Today there are two kinds of magnets in common use, the electro-magnet and the steel magnet. The steel magnet is a bar of steel that appears to hold its charge of magnetic force indefinitely, although the force actually is diminishing, but never seems to arrive at a zero quantity. This magnet is used for light work, where electricity is ...
Moving Picture World synopsis