The Figure of the Earth

Abstract

Some of the more striking features of our planet are apt to escape attention if our studies are made upon charts without the assistance of a ‘globe.’ Thus the remarkable alignment of many volcanoes, volcanic islands, coast-lines, and even mountain-chains along circular arcs does not seem to have excited the interest which might otherwise have been expected. An arc-like form is not infrequently alluded to, but the almost precise correspondence of some great terrestrial features with a circular form seems to be generally overlooked. As an example, the chain of the Aleutian Islands may be cited: it is certainly one of the most perfect. If a circle be swept out on a terrestrial globe with its centre in lat. 6° N., long. 177° W., its circumference passing through one of the islands of the festoon will traverse nearly all the rest and extend through the length of the Alaskan peninsula. (See Al in fig. 2, p. 183.) The correspondence is so precise as to suggest that it must have some real physical meaning. The numerous mighty volcanoes which characterize the region point to the existence of an extensive subterranean reservoir of lava, and to discontinuity of the earth9s crust, in the form of a circular crack. It is difficult, as we look upon this part of the globe, to avoid the impression that we have before us the remains of a spherical dome or blister, which has broken down along circular and radial fractures, the islands standing over a circle, the coasts of the Kamchatkan