An 18th-century silver octagonal 'Butterfield'-type compass dial, signed on the underside MARTINOT A PARIS, the horizontal plate with scales for latitudes 40°, 45°, 50° and 55°, the folding bird-gnomon engraved for similar latitudes and with scroll decoration, the compass with finely modelled needle, the underside engraved with the latitudes of thirty-two continental cities and towns, with leather display base, 3 7/8in. (9.8cm.) long