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Magnetism is the peculiar property occassionally possessed by certain bodies (more especially by iron and steel) whereby they attract or repel one another.

If a piece of hard iron or steel be rubbed with a lodestone it will be found to have also acquired the properties of the stone. If hung up by a thread it will point north and south, will attract light bits of iron and if dipped into iron filings will cause the latter to cling in two small tufts near the ends with few, if any, near the middle.

FIG. 1. Lodestone which has been Dipped in Filings to show Poles

This indicates that the attractive power of the magnet is concentrated in two opposite parts. These parts are called the Poles. The line joining the poles is the Magnetic Axis.

Artificial Magnets are those made from steel by the aid of a lodestone or some other magnetising force. The principal forms of artificial magnets are the Bar and Horseshoe, so called from their shape.

FIG. 2. Bar and Horseshoe Magnet.

If a magnet (either artificial or natural) is suspended by a thread so that it may swing freely, and a second magnet held in the hand is presented successively to the two poles of the first, it will be observed that one pole is attracted and swings toward the magnet held in the hand, but that the other is repelled and swings away.