Informatics Educational Institutions & Programs

No higher resolution available.

Galton_whistle.jpg ‎(502 × 429 pixels, file size: 35 KB, MIME type: image/jpeg)

Summary

DescriptionGalton whistle.jpg	English: 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.
Date	June 1920
Source	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

Public domain	This media file is in the public domain in the United States. This applies to U.S. works where the copyright has expired, often because its first publication occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See this page for further explanation.	United States
	This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the rule of the shorter term for US works, such as Canada, Mainland China (not Hong Kong or Macao), Germany, Mexico, and Switzerland. The creator and year of publication are essential information and must be provided. See Wikipedia:Public domain and Wikipedia:Copyrights for more details.

Click on a date/time to view the file as it appeared at that time.

	Date/Time	Thumbnail	Dimensions	User	Comment
current	10:36, 20 December 2014		502 × 429 (35 KB)	Chetvorno	User created page with UploadWizard

The following pages on the English Wikipedia use this file (pages on other projects are not listed):

The following other wikis use this file: