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Rh vehicles; finally to treat of the ailments and misfortunes to which electromobiles are subject, and the general prospects and position of electromobilism at the present day.

An electric motor is a machine which produces rotary movement owing to the magnetic action caused by an electric current.

Everyone is doubtless familiar with the ordinary magnet, a piece of steel either straight or, more often, shaped like a horseshoe, possessing the property of attracting certain metals which are termed magnetic, or more accurately para-magnetic. Nickel and iron are amongst those which are attracted, but iron is much more powerfully attracted than nickel.

Next to the faculty of attracting iron, the most characteristic property of the ordinary magnet is what is generally known as polarity. Its two opposite ends possess different properties. This is not apparent when a magnet is applied to soft iron, which is unmagnetised, but is obvious when one magnet is applied to another. The ends and poles of the magnets are usually distinguished by being called north and south poles, and designated by the letters N and S. By the north pole of a magnet is generally meant the end which, if the magnet be very freely pivoted or floated on water, will point towards the north. The south pole is the other end. Sticklers for accuracy call these different ends the northward-pointing pole and the southward-pointing pole. We will content ourselves with designating them simply by the letters N and S. If a bar magnet be broken in two, each broken portion also displays polarity. If two magnets be confronted with the N pole of one opposite the S pole of the other, they will attract one another. If the two N poles or the two S poles be brought together, repulsion will result.

The main property of electricity, or, to be more correct, of an electric current, which is of most importance in connection with the production of movement by its means, is its power to produce magnetism.

We do not know precisely what electricity is, and by