France Portable diptych sundial with wire axis. Square ivory case (pre-Convention), featuring a horizontal compass, with paper background printed with the latitudes of twenty-four European cities, and a brass rotating disc (lunar scroll) graduated from 1 to 93, on the reverse of the cover, at the centres of two annular dials with Arabic numeral indexes. The obverse of the cover engraved with a third dial with Arabic numerals. Denticulated friezes along the edge of the four sides of the shelves (typical of Dieppe). Hinges and clasps in brass wire. Dieppe, early 18th century. H. : 6 cm - Case size : 5,8 x 5 cm - Gross weight : 45 g. Some stains and crack.