SCIENCE IN THE INDUSTRIAL WORLD 



"calling-dial." This is a circular metal piece, near 

 the edge of which are ten finger-holes, numbered 

 from o to 9. When a subscriber wishes to call up any- 

 one he removes the receiver, and turns the dial so that 

 the finger-holes corresponding to the digits of the num- 

 ber he is seeking are brought in succession to a certain 

 point on the rim of the dial. For example, if he wishes 

 to call 973 he first turns the "9" finger-hole to the stop 

 on the indicator and allows it to return to its normal 

 position, doing the same thing successively with the 

 figures 7 and 3. He then pushes a button, which rings 

 the bell of the person wanted. If the 'phone he wishes 

 to call is busy at the time a peculiar buzzing sound 

 notifies him that such is the case. 



THE WIRELESS TELEPHONE 



The advantages of a system of telegraphy that does 

 away with wires are too obvious for discussion, yet any 

 system of communication whereby messages must be 

 spelled out slowly by means of dots and dashes is mani- 

 festly inferior to a system of enunciated words, such as 

 telephonic communications. 



When Marconi and his associates in experimental 

 wireless telegraphy set at rest forever all doubts as to 

 the possibility of electric communication through the 

 air by means of the Hertzian waves, they removed at 

 the same time all doubt as to the possibility of eventually 

 accomplishing spoken communications through space 

 in a similar manner. In theory, at least, it should be 

 possible to send wireless telephonic messages as well as 



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