Barlow's wheel, electric motor

Shares in a magnetic field of a magnet. The wheel of Barlow is a tool purely didactic, but is an example of an electric motor, in fact it transforms electrical energy into mechanical energy. The metal wheel with a horizontal axis has the edge outcropping in the mercury contained in a tank. An intense magnetic field is generated by a magnet. To the two clamps set on wooden board it connects a battery or a power supply of 12 volts DC. The circuit goes from the clamp at the center of the loop down along the wh