Vintage opisometer used for measuring distances on maps. Part of the Kevin John Herdman, No. 397661, Collection. See Catalogue No. 5942P for details of his service record..1) Circular chromed metal instrument with handle. Calibrated dial with black markings and hand on a white background. Reverse face has unit conversion details in black text on white background. Each face is covered with a convex glass lens. On the opposite end to the handle is a small wheel with milled edge. As it turns, the hand on the front dial turns to measure distance. .2) Rigid plastic rectangular storage case in two parts. Base is yellow, top is clear..1) Printed on front dial: 'INCHES, MADE IN FRANCE'. Printed on back dial: 'Unit conversion details'. Stamped on metal near wheel: 'DEPOSE, H(logo)B'. .2) Stamped on clear cover: 'CURVIMETRE, MAP MEASURER, H(logo)B, MADE IN FRANCE'.map, map measure, equipment, opisometer, kevin john herdman