circumferentor

Cir*cum`fer*en"tor, n. Etym: [See Circumfer.] 1. A surveying instrument, for taking horizontal angles and bearings; a surveyor's compass. It consists of a compass whose needle plays over a circle graduated to 360º, and of a horizontal brass bar at the ends of which are standards with narrow slits for sighting, supported on a tripod by a ball and socket joint. 2. A graduated wheel for measuring tires; a tire circle.

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