544 



BELL SYSTEM TECHNICAL JOURNAL 



itate the localization of an accidental short circuit. If a short circuit 

 should occur in any part of the system this section can thus be dis- 

 connected and the balance used independentK". 



C 



IS 

 FEEDER 

 RECEIVERS 

 \_felJA CK BLOCKS 



SHOWIfiG DISTRlBUTIOn 

 OF RECELIVERS-SIX 

 SUPPLIED FROM OME 

 JACK BLOCK 



mm 



fe-JACK BLOCKS 



STETHOPHONE 



iJBM 



TELEPHONE CORD 

 WITH PLUGS 



-Wiring iiisl.ill.itioii in an aiiipliillu'atrc for U'aihinj; purposi'S 



In class room lectures, tiie iiisiiucior cm make amioimcements 

 to the students and point out features of particular interest in a 

 convenient and somewhat no\-el manner \vithf)Ut reciuirinjj; the removal 

 of the stethoscope tubes from their ears. The liiunan body acts as 

 a sounding board lur sounds in air thai is, wlicn \vor<ls are s])oki'n 



