What I have up there is just a power source and magnetic field.
The magnets are either sintered or directionally cast, and then annealed in a magnetic field.
In a refined form this method is often employed for measuring the intensity of a magnetic field at a given place, just as the intensity of gravity at different parts of the earth is deduced from observations of the rate at which a pendulum of known length vibrates.
Any space at every point of which there is a finite magnetic force is called a field of magnetic force, or a magnetic field.
The strength or intensity of a magnetic field at any point is measured by the force in dynes which a unit pole will experience when placed at that point, the direction of the field being the direction in which a positive pole is urged.
