Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/143

Rh Koch would nevertheless have the prior claim to have made the first discovery of the alteration of co-ordinates.

As the table shows, a still greater amount of displacement is to be expected in the case of Cape Farewell. Also on Iceland the displacement in the course of five to ten years must be quite readily ascertainable.

The circumstances relating to the determination of the difference of longitudes of Europe-North America are less propitious. According to the table, an annual increase of distance of about 1 m. is to be expected, but this figure is an average one from the time of the break of Newfoundland from Ireland. But since then the direction of movement of North America seems to have been altered by the breaking away of Greenland, and now certainly appears to be directed more to the south. This is shown by the present relative positions of the corresponding points on the coasts of Labrador and South-west Greenland, and is confirmed by the direction of displacement (to be described in detail later) of the earthquake-fault of San Francisco, as well as the nascent compression of the Californian peninsula. It is therefore difficult to say how great the present-day increase of longitude might be. But in any case it must be less than 1 m. per annum. I at one time concluded, from the trans-Atlantic determinations of longitude obtained by the cable in 1866, 1870 and 1890, that there is an actual increase in distance of several metres a year. According to Galle, however, the measurements based on this method cannot be accurately combined. Shortly before the war a new determination of longitude with regard to our problem was in operation, which was also controlled by a wireless measurement.