Demainbray's turquoise disc
1745-1755
Demainbray's yellow disc
1745-1755
Pair of coloured glass discs, 1750.
1745-1755
Disc, metal, obverse covered with concentric grooved circles
Ten blackwood and ivory discs
1843-1884
Green glass disc, 1725-1750.
1725-1750
Wood screw from green glass disc, 1725-1750.
1725-1750
Pair of Marble Adhesion Discs, with Band and Ring Handle
Eight ivory discs inlaid
1843-1884
Disc, metal, obverse covered with concentric grooved circles
Four ivory stage discs
Green glass disc, 1725-1750.
1725-1750