Wireless Telegraphy and Telephony
Forfatter: Alfred P. Morgan
År: 1917
Forlag: The Norman W. Henley Publishing Company
Sted: New York
Udgave: Third Edition, Fully Illustrated
Sider: 33
UDK: 621.396.1 Mor
A practical Treatise on Wireless Telegraphy and Telephony, giving Complete and Detailed Explanations of the Theory and Practice of Modern Radio Apparatus and its Present Day Applications, together with a chapter on the possibilities of its Future Development
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WIRELESS TELEGRAPHY
107
cate their vibrations to the surrounding air and thus set it
into waves, just as a stick waved back and forth in a pool
of water creates ripples.
Sound implies vibration, and whenever a sound is heard
Fig. 122.—Bon jour (“good day” in French) as represented by a
wave picture. The picture was made by a mirror arranged to
move under the influence of the voice and to cast a beam of
light upon a strip of sensitized paper.
some substance, a solid, a liquid, or a gas is in vibration
and the surrounding air is in unison with it.
Sound has been likened to a picture painted not in the
space and color of substance but in time and motion. What
really passes out from the source is merely a rhythmical
motion of the air particles, manifesting themselves as
changes in pressure, spreading out in ever-widening
spheres through the atmosphere. The order of these com-
pressions is different for every sound. The musical sounds
of an orchestra embody a different set of vibrations for