THE TELEPHONE 341 



from the hook, a second light glows before the operator, and 

 the two lights continue to glow as long as the telephones are 

 being used. When the receivers are hung up, the lights 

 go out ; this is a signal to the operator, who then pulls out 

 the plugs. 



The cords containing the connecting wires are weighted 

 and hung below, so that when a plug is taken out of a hole 

 the wires fall back into their places automatically, out of 

 the way and ready for the next call. Practice enables these 

 girls to work with astonishing rapidity. In the best ex- 

 changes they answer a call in an average time of 3^ seconds. 



For out-of-town calls, connection is made with " Long 

 Distance," who makes the connection in much the same way 

 as that already described. A record of the time occupied 

 by the conversations is kept by means of an automatic time 

 stamp. Charges are made according to the time that the 

 line is in use. 



FIELD EXERCISE 7 



Purpose. To visit the central telephone office. 



Directions. Arrangements can usually be made with the 

 superintendent of the telephone exchange to allow the class to 

 visit the central office. Here some one can explain the work of 

 the operators and the construction of the central telephone 

 outfit. At the next meeting of the class the points observed 

 should serve as a basis for discussion. 



Wireless telephone. Now, most wonderful of all, comes 

 the wireless telephone, by means of which people may talk 

 with each other at a distance without any wires between. 

 The more recent development of the wireless telephone has 

 been largely the work of Americans. In 1900 the wireless 

 was first successfully used for a distance of one mile, although 

 the sounds reproduced were not satisfactory. The mechan- 

 ism was gradually perfected so that it was used over longer 

 distances, and the sound was reproduced more exactly, until 



