Description:
A telephone receiver design without a diaphragm, by French inventor Clement Ader. Device consists of a frame made of four brass bars which supports a dish-shaped rubber earpiece and brass tapered cylinder at one end and a pair of flat brass disks with a tapered cylinder at the other end. A brown jacket of material surrounding the tapered cylinder furthest from the earpiece is cracked and chipped.
Connecting the two ends is an iron rod supporting small spool wound with wire, which attaches, with two coils of wire, to two brass binding posts. The binding posts, each with a knurled-edge thumb adjustment screw, are mounted on one of the brass bars, and protrude out of the frame.