On the Experimental Proof of Ampère’s Molecular Currents

(E. Beck. Zum experimentellen Nachweis der Ampèreschen Molekularströme. Ann. d. Phys. 60, p. 109—1919).

In 1915 Einstein and de Haas gave proof of the existence of Ampère’s molecular currents, having discovered the rotation of an iron rod about its axis when it was magnetized or demagnetized, due to the fact that molecular currents are caused by the motion of the electron and the molecule is thus a gyroscope oriented in a definite direction. Since, upon remagnetization, the direction of motion of the electrons must change, a magnetic body consisting of a system of gyroscopes must acquire a rotational motion about an axis, the magnitude of which is readily calculated theoretically.

The experiments of Einstein and de Haas gave a very satisfactory result for the effect of rotation.

Beck undertook, with more precise experimental means, to verify Einstein’s experiments.

The result of his experiments is as follows.

Qualitatively, Beck succeeded in detecting Einstein’s effect in two kinds of iron and in one kind of nickel. Quantitatively, however, a considerable discrepancy with theory was obtained, amounting to 47% for iron and 43% for nickel.

P. Lazarev.