Page:Motors and motor-driving (1902).djvu/312

280 (whether the pole of a permanent magnet or of an electromagnet does not matter) and if the current passes along the wire so as to produce a south pole near the top of  slightly below N, and if the coil and core be capable of upward movement only, there will be a tendency for  and  to rise.

If a casting of soft iron or mild steel, shaped like in fig. 2, have an insulated wire  wound round it in the manner shown, and a current passed round it in the direction of the

arrow, an electro-magnet will be produced with powerful poles, capable of strong attraction as at N and S. It will be understood that the windings are of course merely diagrammatic, many more turns of wire being used in actual practice.

If a soft iron ring,, fig. 3, have a wire continuously wound round it, and the current is supplied to this wire through the flexible brushes 1, from leads  and 1 coming from a battery of accumulators, the ring will become magnetic, and will resemble