A manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity.

  • Davis, Daniel.
Date:
1847
Catalogue details

Licence: Public Domain Mark

Credit: A manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    the conducting wire, but tends to revolve around it without changing its distance. Hence the force must be considered as acting in the direction of a tangent to the circle in which the magnetic pole would move. It is true that, in many positions of the magnet with regard to the wire, apparent attrac- tions and repulsions occur ; but they are all referable to a force acting tangentially upon the magnetic poles, and in a plane perpendicular to the direction of the current. This peculiar action may be better understood by means of a figure. 153. Thus, let p n (Fig. 51) be a wire, placed in a vertical position, and conveying a current down- wards (p being connected with the positive pole of 2^jV 5i_ the battery.) Now, suppose the north pole of a magnet, N, to be brought near the wire, and to be perpendicular to any point C. If free to '^K move, the pole will revolve (IN _ ,.^/'M . around C as a centre, in the direction indicated by the ar- rows in the cut; that is, in the same direction as that of the hands of a watch, when its face is upwards. The plane of the circle which the pole describes is horizontal. On causing the current to ascend in the wire, the pole will rotate in the oppo- site direction. If the wire is placed in a horizontal position, the plane in which the pole revolves will, of course, be vertical. The actions of either a de- 7* V