An Account of Experiments to Determine the Figure of the Earth by Means of the Pendulum Vibrating Seconds in Different Latitudes
As Well As on Various Other Subjects of Philosophical Inquiry

Originally published in 1825, this account presents physicist Edward Sabine's findings on the true ellipticity of the Earth.

Edward Sabine (Author)

9781108062077, Cambridge University Press

Paperback / softback, published 6 February 2014

538 pages, 3 maps
25.4 x 17.8 x 2.8 cm, 0.92 kg

As early as the seventeenth century, scientists realised that a pendulum swings more slowly at the equator than it would at the North Pole. Newton predicted that gravity increased with latitude, and that the Earth could not be perfectly spherical. Although various experiments were undertaken to determine the exact degree of this ellipticity, none proved successful until physicist Edward Sabine (1788–1883) embarked on a series of expeditions across the world. Based on pendulum measurements from a wide range of latitudes, from Jamaica to Spitsbergen, his results were very different to mathematical predictions, and far more accurate; Charles Babbage would even complain that they were too good to be true. In this account, which first appeared in 1825, Sabine explains his methodology and presents his findings. His book opens a fascinating window into nineteenth-century geodesy for students in the history of science.

Preface
Experiments for determining the variation in the length of the seconds pendulum
I. With detached invariable pendulums
II. With attached invariable pendulums
Latitudes of the pendulum stations
Application of the observed variation in the length of the seconds pendulum to the determination of the figure of the earth
Geographical notices
Hydrographical notices
Experiments for determining the variation in the intensity of terrestrial magnetism
Atmospherical notices.

Subject Areas: History of science [PDX]