Artificial magnets can be made either by rubbing a piece of steel or iron with the lode stone or by passing a heavy direct current through a coil wound over the piece of steel or iron. Magnets prepared by the later method are known as electro-magnets.

It has been noted that certain substances like steel retain their magnetism unaltered for long time after removal of magnetizing force. Such substances are said to have high retentively power an after being magnetized are termed as permanent magnets.

Other substances, like soft iron remain magnets so long as they are in the field of permanent magnet and loose most of the magnetism as soon as the magnetizing force is removed. Such substances are said to have low retentively poser and termed as temporary magnets.

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