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 will remain unaltered or from the law of reflection ; viz., that the angle of reflection from the surface will be equal to the angle of incidence. Thus, sounds from the foci of an ellip- sis will be reflected from the circumference toward each other. In the whispering gallery of St. Paul's, the effect may be considered as produced by a continued repetition of reflections [and conduction.] In studying experiments and deductions, it should be borne in mind that the transmission is through an elastic medium, and that the voice gives a certain direction to the sound; so that parts of the space are differently affected. Probably the particles behind the speaker are moving towards the centre of the circle, and the particles before him retreat- ing from the centre, and wherever they intersect the motion would be neutralized; and there, most likely, the sound would be least audible. Rising seats enable the sound to proceed direct from speaker to hearer. In a theatre front seats are best for direct hearing, and those against the walls for reflected and conducted sound. Drury Lane theatre, though elegant in appearance, and constructed on acoustic principles by Ben- jamin Wyatt, architect, in 1812,* has since been altered and reduced to suit the stage business and public preference for small houses. The smaller the Houses of Parliament, compatible with the numbers to be accommodated, the more likely are they to be approved. DECADENCE OF SOUND.—The velocity appears to di minish as the distance from the centre increases; and the inten- sity or strength of sound varies as the square of the distance : thus, at 10 feet distant the velocity is ^th as great as at one foot distant; and the energy or intensity of sound ^0th as great; and for each degree of Fahrenheit's thermometer the * Original width 77 feet from back wall of boxes to opposite wall; 53 feet from front of stage to wall at back of boxes ; area of house on dress-circle 58 feet; height of auditory 48 feet; boxes 8 feet deep ; width of stage-opening 35 feet. In present House the distance from front boxes to curtain is 61 feet; transverse distance 50 feet.