Jump to content

File:Mendenhall gravimeter pendulums.jpg

Page contents not supported in other languages.
This is a file from the Wikimedia Commons
From Wikipedia, the free encyclopedia

Original file (712 × 679 pixels, file size: 142 KB, MIME type: image/jpeg)

Summary

Description
English: Pendulums used in Mendenhall gravimeter apparatus, from 1897 scientific journal. The portable Mendenhall apparatus, developed in 1890 by Thomas C. Mendenhall, provided the most accurate relative measurements of the local gravitational field of the Earth. The gravimeters were used at 340 "stations" in the US, and also in Germany, Holland, Java, the Philippine Islands, Cuba, Haiti, the Bahamas, the Dominican Republic, Panama, Canada, and Mexico. The swing of the pendulum was more regular than the most accurate clocks of the era, and as the "world's best clock" it was used in the 1920s by A. A. Michaelson to time his measurements of the speed of light at Mt. Wilson, CA. The pendulums are made of a copper-aluminum alloy, weighing 1200 g, 24.8 cm long from the agate suspension surface to center of bob. In use they were suspended from an agate knife edge in a vacuum tank. The period was picked off by reflecting a light beam from a small mirror at the top of the pendulum. The lines in the image are aliasing artifacts from scanning the original halftone image. Captions:

18.Dummy temperature pendulum with integral thermometer,
19.Pendulum and knife-edge plate, showing mode of suspension,
20.Leveling pendulum,
21.Half-second pendulum, front view,

22.Half-second pendulum, side view.
Date
Source Downloaded 2009-01-19 from Putnam, G.R. (1897) Magnetic and pendulum observations in connection with the Greenland expedition of 1896 in The Technology Quarterly, Vol.10 (Oct 1896 - May 1897) , MIT, Boston, fig. 18-22, facing p. 90 on Google Books
Author G. R. Putnam
Permission
(Reusing this file)
Public domain in US - first published in US before 1923

Licensing

Public domain
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
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.

Captions

Add a one-line explanation of what this file represents

Items portrayed in this file

depicts

File history

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

Date/TimeThumbnailDimensionsUserComment
current17:38, 12 December 2012Thumbnail for version as of 17:38, 12 December 2012712 × 679 (142 KB)QuibikRemoved the moire.
18:22, 10 May 2009Thumbnail for version as of 18:22, 10 May 2009712 × 679 (197 KB)Chetvorno{{Information |Description={{en|Pendulums used in Mendenhall gravimeter apparatus, from 1897 scientific journal. The Mendenhall gravimeter, developed in 1890 by Thomas C. Mendenhall, was the most accurate The pendulums are made of a copper-aluminum all

Global file usage

The following other wikis use this file: