# A Text-Book on Sound; the Substantial Theory of Acoustics Adapted to the Use of Schools, Colleges, Etc

Theclassics Us, 2013 - 34 páginas
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1887 edition. Excerpt: ... I absolute mechanical measurement, that a tuning-fork will sound audibly, held in the fingers, when its prongs, though alternating rapidly, have so nearly come to rest, and consequently when they are moving over such an infinitesimal space at each swing, that their actual velocity of travel, at the swiftest portion of the oscillation, is less than at the rate of one inch in two years, or about twentyfive thousand times slower than the hour hand of a family clock! Q. 25. By what mechanical process is it possible to measure such slow motion? A. It is done by a method discovered and first announced by A. Wilford Hall, founder of the Substantial Philosophy, as set forth in the Microcosm, Vol. III., page 90, and carried out mathematically by Capt. It. Kelso Carter, Professor of Higher Mathematics in Pennsylvania Military Institute, as set forth in the same volume, page 154. This method, though very simple, requires too much space for these answers; so the reader is referred to the volume containing it.* * We have demonstrated, in the mathematical sense of the term (and we will not keep the modus operandi a secret), that a tuning-fork will sound audibly, held in the fingers, when its prongs are not traveling to and fro a distance of the one sixteenmillionth of an inch! Doubling this distance, for the swing both ways, and we have the one eight-millionth of an inch as the entire travel of the prong through one complete vibration. Let us then use a fork having 256 vibrations in a second and we have the entire distance traveled by such prong but the one thirtythousandth of an inch in a second! Counting the swiftest velocity of the prong's travel at its centre of swing as three times this aggregate distance passed over, which is more than the facts...

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