AbstractAs a result of the importance of gravity in dynamic levelling and in studies of deviation, the measurement ofgplays an increasing part in the work of the field surveyor. An essential part of high order gravity-difference measurement is the calibration of the gravimeter used. Survey gravimeters fall broadly into one of two classes, those with a short range and a reset facility (exploration type) and those with a long range (geodetic type). The Worden Master is a well-known example of a gravimeter which straddles these classes by means of a dual-dial system and the principles of the field calibration of the dials of this meter, which are discussed here, typify the calibration of any gravimeter which the field surveyor is likely to encounter. The problem of inter-dial calibration, which is peculiar to a dual-dial system, is also discussed.