Show telephone kotce the poleu heard over tie the apo ei phone Is ie a mechanical atlon of the original voice and differs from froin that of a spooning spooking oking tubo tube or mega megaphone phong where the sound bound waves produced by the speaker at ono one end aro are tran transmitted i alit directly to the other end in the iho telephone the diaphragm of the transmitter mitter la Is caused to vibrato by tho the sound waves produced by some one ona talking into the transmitter mouthpiece this diaphragm la is connected with a small receptacle having a flexible front and partially filled with granular carbon this carbon offers resi resistance stanco to eloc electric electrio trio current in proportion to the mechanical pressure brought upon it the diaphragm therefore in vibrating pr produces odices a varying pros pressure sure against the carbon the tha carbon Is included in nn an electric circuit so that the variation in ita Its resistance will vary tho the current strength in the be circuit i |