Tyndall, John, 1820-1893 · New York : Appleton · leaf 91
e entirely, but left about one-third of it open. When this was repeated 720 times in asecond, the sound was uncommonly smooth and sweet.When reduced to 360, the sound was more mellow thanany mans voice of the same pitch. But the difficulty of obtaining the necessary speedrenders another form of the… … backing of tin, can be attached to a whirling table, andcaused to rotate rapidly. The individual holes then dis-appear, blending themselves into a continuous shadedcircle. Immediately over this circle is placed a bent tube,m, connected with a pair of acoustic bellows. The diskis now motionless, the…
Sound
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