19,890. Wieder, H. G. A. I., and Hupfeld, J. Oct. 5. Phonographs.-Diaphragms for reproducing and transmitting sounds, especially of the kind employed in phonographs &c. Three glass discs b, decreasing in size outwards, are separated by thin wires or tubes c of aluminium or magnalium. The wires are arranged radially, and are cemented to the discs. The outer disc carries a light metal cone a, surmounted by a sapphire tool. The largest disc b is held between washers d in proximity to a perforated vulcanite plate e, by a screw ring g. The back of the sound box is formed of a thin metal plate f, having a central opening leading to the sound tube h.