Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/223

 that the centrifugal forces of the rotation of the earth can produce a drift from the poles of the magnitude indicated by Wegener, and that it must produce it.” On the other hand, Epstein thinks the question as to whether the folded mountain chains of the equator could be traced back to this force must be answered in the negative, since this force only corresponds to a fall of surface of 10 to 20 m. between the pole and equator, whilst the raising up of mountains to altitudes of several kilometres and the corresponding submergence of sialic masses to great depths constitute a considerable amount of work against gravity, for which the force of the drift from the poles is not sufficient. Only hills of 10 to 20 m. in height could be produced by it.

W. D. Lambert, at practically the same time as Epstein, mathematically deduced the force of the drift from the poles with essentially the same results. He finds the force in the latitude of 45° to be one three-millionth part of the gravity. Since the force reaches its maximum in this latitude, it must thus have a rotatory effect on an elongated obliquely-lying continent, and will in fact tend, between the equator and latitude 45°, to bring its long axis into an east and west direction, and, between 45° and the pole, on the other hand, into a meridional direction. “All this is quite speculative of course; it is based on the hypothesis of floating continental masses and on the assumption of a sustaining magma that would, naturally, be a viscous liquid, but viscous in the sense of the classical theory of viscosity. According to the well-known theory, a liquid, no matter how viscous, will give way before a force, no matter how small, provided sufficient time