|Pierre Weiss electromagnetism|
Pierre Weiss derived a unit of magnetic field strength by comparing the magnetic properties of nickel and iron.
No theoretical argument
Theorists could not justify the Weiss magneton with their early quantum theory. Weiss’s idea of an elementary magnet originated with Walther Ritz, who said atoms might contain chains of tiny rods, some having no magnetization, and some acting as tiny bar magnets.
Units of the indefinite
I’ll explain everything in a moment. There’s no time for unnecessary uncertainty. Sufficient degrees of ineffable confidence will immediately set the matter to rest. If the shoe fits, then its size is right.
The Weiss magneton was based on a model of the atom that preceded the work of Ernest Rutherford and Niels Bohr. Weiss knew that something in some kinds of atoms was responsible for creating magnetic fields, but he didn’t know what it was. Theoretical physicists complained that it ought to be related to the Planck constant, which is the quantum unit of action, but the Weiss magneton could not be related to the Planck constant.
See also in The book of science:
Readings in wikipedia: