Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/9



third edition is again completely revised and certainly differs nearly as much from the second as that did from the first.

The reason for this does not merely lie in that during the intervening two years an extensive literature has appeared which directly or indirectly concerns the displacement theory, but also particularly in that the entire substance of the book has been cast into a new and, as I hope, more convincing form, so that the essential may appear better separated from the non-essential portion of the work.

That the new edition has only the same size as the previous one has been mainly produced by a shortened treatment of palæoclimatology, which has now only been drawn upon in so far as it serves for the establishment of the displacement theory. My further studies on this subject I hope to deal with in collaboration with Professor Köppen in a special publication.

In other respects also the present edition, like the preceding ones, bears traces of this joint work. ALFRED WEGENER