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

Wood screw from green glass disc, 1725-1750.

1725-1750

Green glass disc, 1725-1750.

1725-1750

Ten blackwood and ivory discs

1843-1884

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

Two Pairs of Discs for Bottoming Machine

Green glass disc, 1725-1750.

1725-1750