The apparatus, probably part of the endowment of instruments purchased in 1864, is used in showing the Seebeck (or thermoelectric) effect and is composed of a copper reed bent at the ends at right angles and soldered to a bar of antimony (13.2 x 2 cm) so as to form a rectangle with the bar forming one of the longer sides and the reed the other three.
It is an astatic system composed of two magnetic needles joined together and parallel to each other but with the poles inverted, suspended at the centre one above and the other below the copper plate, which reveals the passage of current in the closed circuit represented by the plate and the bar. The apparatus is supported by a column on a circular lathed wooden base (overall height 16 cm).
A. M. Ampère, Ann. Chim. Phys., XVIII (1821), p. 320
Daguin (1867), T. III, p. 367
Ganot (1864), p. 672
Privat Deschanel (1869), p. 657
Turner (1983), p. 121