Report of the Committee of the House of Commons, on ventilation, warming and transmission of sound / abbreviated, with notes, by W.S. Inman.

  • Great Britain. Parliament. House of Commons. Committee on Ventilation, Sound, etc.
Date:
1836
Catalogue details

Licence: Public Domain Mark

Credit: Report of the Committee of the House of Commons, on ventilation, warming and transmission of sound / abbreviated, with notes, by W.S. Inman. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    velocity of sound varies about ^^th part. The velocity is diminished by cold fogs, and increased by warm vapours; and in steam would be fths greater than in air. The sound of a bell, transmitted through water, was heard by professor Robison at 1200 feet distance. Calculated by the comparative elasticity of air to water, the velocity of sound in water would be 4900 feet per second ; and of an impulse conveyed in direct or parallel lines, through fir- wood, would be 17,400 feet per second. Dr. Young states that all minute impulses are conveyed through any homogeneous elastic medium (solid or fluid) with a uniform velocity, always equal to that which a heavy body would acquire by falling through half the height of the modulus of elasticity ; i. e. in the case of air, half the height of the atmosphere supposed to be of equal density ; which, taken at 28,000, would give 946 feet per second : but if the direct velocity of sound, by experiment, be 1130 feet, it would give a height of 39,800 feet for the modulus of the air's effective elasticity. Laplace suggested that the theory and experiment may be reconciled by the difference attributed to the effect of the elevation of temperature always accom- panying the action of condensation, and to the depression produced by rarefaction. Direct Velocity of Sound in Atmospheric Air* Merscnnus, Balistica . . . 1474 Walker, philos. trans., 1638 . 1338 Roberts, do. do., 209 • • 1300 Boyle, on Motion . . 1200 « Feet per Cassini and others, Duhamel . . 1172 f second. Florentine Academicians . . J148 Flamstead, Halley, Derliam . . 1142] Parry, Philos. Trans., 1828 . . 1038 J • Its state as to temperature, moisture, electricity, &c, must always in- fluence the velocity.