
8
small flotsam bob up and down. Similarly, air waves when they
strike an object try to make it vibrate with the same characteristics as
their own. That is how we can hear sounds through a door or
partition; the door is made to vibrate, and its vibrations set up a new
lot of air waves on our side of it. When they reach our ears they strike
the ear-drums; these vibrate and stimulate a very remarkable piece of
receiving mechanism, which sorts out the sounds and conveys its
findings via a multiple nerve to the brain.
1.8 Electrical Communication by Wire
To extend the very limited range of sound-wave communication it
was necessary to find a carrier ...