Isostasie und Schweremessung: Bedeutung für geologische Vorgänge

Abstract

THE variation from place to place of the intensity and direction of the force of gravitation is one of the comparatively few phenomena from which we can obtain some knowledge of the nature of the earth's interior. We owe to Pratt and Airy the demonstration in 1855 that, broadly speaking, different regions of the earth's crust balance one another, or, as it is now expressed, are in a state of isostasy; that the weight of mountain masses above the sea-level is compensated by a defect of density below them, and that ocean deeps are underlain by material of high density. But, whereas Pratt believed that the high places of the earth were the result of expansion of the material beneath them, Airy compared a mountain range to a log of wood floating in water, which it displaced and by which it was buoyed up. After nearly seventy years the same difference of opinion as to the real meaning of isostasy continues to persist.

Isostasie und Schweremessung: ihre Bedeutung für geologische Vorgänge.

Von Prof. Dr. A. Born. Pp. iii + 160. (Berlin: Julius Springer, 1923.) 2.20 dollars.