The formula τ = 978.049 (1 + 0.0052884 sin²φ - 0.0000059 sin²2φ), in which φ is the geodetic latitude. This is a development of the formula for gravity, based on the representation of the Earth by a body shaped like a rotational ellipsoid having the dimensions of the International Ellipsoid of reference (Madrid, 1924) and rotating about its minor axis one in a sidereal day, and on the assumptions that (a) the surface of the ellipsoid is a level surface and that (b) the value of gravity acceleration at the equator is 978.049 gals. The International Gravity Formula was adopted by the International Association of Geodesy at its meeting in Stockholm in 1930. The purpose was not, primarily, to represent the gravity measurements then avail-able, although the value 978.049 was based on those measurements, but rather it was intended to put the determination of the figure of the Earth from gravity data on the same basis as the determination of the figure of the Earth from deflections of the vertical. The formula is based on the Potsdam value for gravity. It has been replaced, for general used, by Gravity Formula 1967 and by later formulae, but is still used for some purposes.