i86 



SCIENTIFIC RECREATIONS. 



We have a variation of this instrument which has been introduced 

 employing a diaphragm held in a telephone mouthpiece, and free to vibrate 

 under the influence of sounds. This is connected by a string to a bit of 

 wood that may be held in the teeth. In use the hearer places the wood 

 between his teeth, the string is drawn tight, and the speaker speaks through 

 the telephone mouthpiece, the vibrations of the diaphragm being then con- 

 veyed to the teeth through the stretched string. This apparatus works 



Fig. 1 8 8. The Telephone. 



very successfully, and ladies use it, but it is not so convenient for general use 

 as the Audiphone. 



The Telephone is now in daily use in London, and is by no means 

 strange to the majority of our countrymen, still some description of it will 

 probably be acceptable, and a glance at its history may prove interesting. 



In speaking of the Telephone, we must not lose sight of the facts before 

 mentioned, as regards our sense of hearing, and the manner in which the ear 



Fig. 189. The "receiving" apparatus. 



acts by the series of bones termed the hammer, the anvil, and stirrup. In 

 the process of reproduction of tone in the magnetic instruments, the 

 mechanism of the human ear was, to a certain extent, imitated, and a 

 diaphragm, by vibrations, generates and controls an electric current. 



Professor Wheatstone was the first person to employ the electric wire for 

 the transmission of sounds, but Professor Philip Reiss, of Friedrichsdorf, was the 

 first to make the experiment of producing musical sounds at a distance. His 



