The Department of Terrestrial Magnetism of the Carnegie Institution of Washington bought this Kew pattern dip circle in 1919. The inscription reads "Dover, Charlton Kent, Circle 240." With four needles, tripod, case, Kew certificate of examination, and importation charges, it cost $184.70. The vertical circle is silvered, graduated to 30 minutes, and read by opposite verniers to single minutes. The horizontal circle is silvered, graduated to 30 minutes, and read by vernier to single minutes.