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Image: Galton whistle

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Description: A Galton whistle, the first ultrasonic whistle or "dog whistle".. It was invented in 1876 by Francis Galton and used to test the hearing range of various animals. It consists of a whistle blown by the rubber bulb, with a small sound chamber whose size can be accurately adjusted by a plunger attached to a micrometer. The micrometer can be calibrated to give the frequency in hertz.
Title: Galton whistle
Credit: Retrieved March 12, 2014 from H. Winfield Secor, "Oddities of Sound" in The Electrical Experimenter magazine, The Experimenter Publishing Co., New York, Vol. 8, No. 2, June 1920, p. 153, fig. 13 on http://www.americanradiohistory.com
Author: H. Winfield Secor
Usage Terms: Public domain
License: Public domain
Attribution Required?: No

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