Is there a 428‐day period in terrestrial magnetism?

That terrestrial latitudes vary with an average period of 428 days seems now to be an established fact. In other words, the pole of figure of the Earth is known to be moving continuously around its pole of rotation in the direction of decreasing west longitudes at a mean rate of one complete circuit in 428 days (ignoring for our present purpose the corresponding annual motion of the pole of figure). For each position of the pole of figure a set of stresses must be produced in the Earth representing its tendency to assume a new figure,—a new ellipsoid of revolution with its axis of figure coincident with the axis of revolution. These stresses are doubtless partially relieved, and only partially , by actual movements of matter to new positions in the oceans, in the envelope of atmosphere, and perhaps in the so‐called rigid Earth. Even with this partial relief each portion of the Earth is subjected to periodic stresses which repeat their various phases every 428 days. This suggests that there may possibly be corresponding periodic variations in the elements of terrestrial magnetism produced by these stresses.