A mahogany cased dip circle (dip needle) retailed by F. E. Becker and Co. London, with silvered azimuth circle split into 90 degree quadrants and with locking mechanism to the right hand side, raised on a short lacquered stem and vernier scale, circular plinth and three adjustable feet, 26cm high, 15cm wide, 16cm diameter plinth F. E. Becker and Co. traded at 33-37 Hatton Wall, Hatton Garden (1900-1910), also 17,19,21, 23, 25, 27, Hatton Wall (1912-1920s) and Nivoc House, 17-29 Hatton Wall (1930s) London, England. Founded in 1872 and taken over by W. J. George Ltd. in 1897 but continued to trade under the original name until the 1950s, when it was renamed W.& J. George and Becker Ltd. Dip circles are used to measure the angle between the horizon and the earth's magnetic field (the dip angle).