Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/224

 be allowed for the latter to act in. The peculiarities of the field of force of gravity will give us minute forces, as we have seen, and the geologists will doubtless allow us æons of time for the action of the forces, but the viscosity of the liquid may be of a different nature from that postulated by the classical theory, so that the force acting might have to exceed a certain limiting amount before the liquid would give way before it, no matter how long the small force in question might act. The question of viscosity is a troublesome one, for the classical theory does not adequately explain observed facts, and our present knowledge does not allow us to be very dogmatic. The equatorward force is present, but whether it has had in geological history an appreciable influence on the position and configuration of our continents is a question for geologists to determine. At any rate, it may be considered as one of the mechanical curiosities with which this paper deals.”

Finally Schweydar has calculated the force of the drift from the poles. He obtains for the latitude of 45° the value of about 1/2000 cm./sec., that is, the force amounts to about a two-millionth part of the weight of the block. “Whether this force suffices for displacement is not easy to decide. In any case, it would not explain a westward drift, since the velocity is too small to produce an appreciable westerly deflection by the rotation of the earth.”

Schweydar declares that in Epstein’s calculation the assumed velocity of displacement of 33 m. per annum is too great, and that the viscosity of the sima hence obtained is considerably too small. If a smaller velocity is taken, the required greater