Note 7 — Chapter I · GEOLOGY.

The compression deduced by M. Bessel from arcs of the meridian is 1⁄299; that deduced by Colonel Sabine from his experiment with the pendulum is 1⁄288·7. Other pendulum experiments have given a compression of 1⁄298·2 and 1⁄266·4. The protuberant matter at the earth’s equator produces inequalities in the moon’s motions, from whence the compression of the earth is found to be 1⁄305·05; and although the reciprocal action of the moon on the protuberant matter at the earth’s equator does not actually give the compression, it proves that it must be between 1⁄279 and 1⁄573. Coincidences so near and so remarkable, arising from such different methods, show how nearly the irregular figure of the earth has been determined. The inequalities in the motions of the moon and earth alluded to are explained in Sections 5 and 11 “Connection of the Physical Sciences.”