SCIENCE. 
131 
ILLUSTRATING PAPER ON PHOTOPHONE. 
By Alexander Graham Bell. 
1 — The Interposition of Hard Rubber Plate. 2 — The Light passed through openings in rapidly revolving diaphagm and reflected in selcnious 
recesses. 3 — Application of figure four. 4 — Action of Voice on thin Plate of Silvered Mica. 5 — Application of Morse system of Telegraphy to 
Photophone. 6 — Listening directly to Receiving Plate, 7 — Another form of Receiver. 8— One of the first forms, Voice passed through 
Slits. 9 — Direct Action of Voice on Gas Flame. Action of Candle Light on selenius received. 
