peech has yet been front, of about the size of the disk of an ordinary tele- | filled only the alternate spaces between disks, the interme-| transmitted by the selenium-cell-photophone is 213 meters, phone, and mounted in a frame, with a flexible India-rub- | diate spaces being occupied by mica… … when the mirror, B, is flat (that were heard without difficulty and without doubt as to the means is, when not vibrating) the beam In Fig. 8 the transmitter is shown as used in combi- against the disk, B, it isset into vibration, becomes alternately bulged out and in, and made slightly nation with…
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![An illustration from [Graphophone patents] (1878)](https://img.insideoutlibrary.com/img/200/ia-graphophonepaten10unit-397-270.webp)
