PHYSICS NINETEENTH CENT.-SOUND. 



545 



manner confirm the results of Helmholtz, and in the highest degree 

 combine popular and scientific interest. These are the Speaking Tele- 

 phone and the Phonograph. Before explaining the former it will be 

 desirable to describe an earlier form of telephone which reproduced 



musical notes at a distance. It was founded on a discovery made in 

 1837 by an American physicist named Page. This gentleman found 

 that at the instant when a bar of soft iron is magnetized, by passing a 

 current through a coil of wire surrounding it (see Chap. XX.), a sharp 

 click is emitted. CC in Fig. 259 represents such a coil traversed by a 

 slender rod of iron, which is mounted by the supports // on the 



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