Abstract

The experiment consists of two parts: In part I the magnetic field produced by electric current flowing in a modified Helmholtz coil is balanced against the field of a permanent bar magnet. In part II this same magnet is swung at the center of the coil as a magnetic pendulum. From these observations, made in terms of length, mass, and time only, both the strength of the current and the magnetic moment of the magnet may be computed. Inaccuracy due to an unsteady local “earth’s field” is minimized, and a relatively high precision results.

© 1929 Optical Society of America

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