SCIENCE. 



131 



Fig. 2. 



Kig. 5. 



Fig. 10. 



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 selenious 

 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. 



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