Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/220

 supported, at least for the former South Pole, by the cases of the tapering southern ends of South America, Africa and India. But in this case also there are only indications of a systematic arrangement; in detail there are many deviations.

The question as to what forces have caused these displacements, folds and rifts cannot yet be answered conclusively. Here information can only be given as to the present position of the investigations concerning it.

Eötvös was the first to claim that a force exists which endeavours to displace the continental blocks towards the equator. He especially drew attention to the fact “that the direction of the vertical is curved in the plane of the meridian, the concave side turned to the pole, and that the centre of gravity of the floating body lies higher than that of the displaced mass of liquid. As a result, the floating body is subjected to the action of two forces working in different directions, the resultant of which is directed from the pole towards the equator. A tendency would thus prevail in the case of the continents to move towards the equator, a movement which would produce a secular variation of the latitude, as has been suspected for the observatory at Pulkova.”

Without any knowledge of this small inconspicuous reference, W. Köppen recognized the nature of the force producing the drift from the poles and its importance to the question of the displacement of continents, and gave a description of it, although without any calculations: “… The flattening of the various levels thus diminishes with the depth; they are not parallel, but slightly inclined to one another, except at the equator and at the poles, where