SMITHSONIAN PRESS MUSEUM OF HISTORY AND TECHNOLOGY Contributions From the Museum of History and Technology Papers 34-44 On Science and Technology SMITHSONIAN INSTITUTION · WASHINGTON, D.C. 1966 Publications of the United States National Museum The scholarly and scientific publications of the United States National Museum include two series, Proceedings of the United States National Museum and United States National Museum Bulletin . In these series, the Museum publishes original articles and mon

Figure 1.— A study of the figure of the earth was one of the earliest projects of the French Academy of Sciences. In order to test the effect of the earth’s rotation on its gravitational force, the Academy in 1672 sent Jean Richer to the equatorial island of Cayenne to compare the rate of a clock which was known to have kept accurate time in Paris. Richer found that the clock lost 2 minutes and 28 seconds at Cayenne, indicating a substantial decrease in the force of gravity on the pendulum. Subs