A determination of the differences in gravity between the National Physical Laboratory, Teddington, the Dominion Observatory, Ottawa, and the National Bureau of Standards, Washington

Abstract

Comparisons have been made with the Cambridge pendulum apparatus between the values of gravity at the National Physical Laboratory, Teddington, the Dominion Observatory, Ottawa, and the National Bureau of Standards, Washington. The three measured differences form a satisfactorily consistent set, and the connexion between Teddington and Washington is in good agreement with that determined in 1939 by Browne & Bullard (1940) with the same pendulums. Gravimeter observations have been used to relate the points occupied to the national reference station in Washington and to the site of the absolute determination in progress at the National Research Council, Ottawa. If the value on the Potsdam system for the British fundamental station at Teddington is taken as 981·1963 cm/s 2 , the following values are obtained for the national reference stations of the United States and Canada: Washington (Commerce) g = 980·1192 ± 0·00055 cm/s 2 Ottawa (pier) g = 980·6191 ± 0·00045 cm/s 2 .