English: Drawing of the measurement of the acceleration of gravity with an invariable pendulum at Madras, India by British astronomer John Goldingham in 1821. From his 1822 paper to the Royal Society. The pendulum swings on two knife edge pivots suspended from a bracket on the wall, in front of a precision pendulum clock set to correct time by the stars. The periods of the two pendulums are compared, using a sight to eliminate parallax error. The strength of gravity is calculated from the period of the pendulum. Alterations to image: Removed caption and frame. Image contains aliasing artifacts from scanning of original halftone image, partially removed with Gimp Fourier transform tool. Converted to 64 greyscale PNG.
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== Summary == {{Information |Description= {{en|Drawing of the measurement of the acceleration of gravity with a Kater's pendulum at Madras, India by British astronomer John Goldingham in 1821. Alterations to image: Removed
{{Information |Description= {{en|Drawing of the measurement of the acceleration of gravity with a Wikipedia:Kater's pendulum at Madras, India by British astronomer John Goldingham in 1821. Alterations to image: Removed caption and frame. Downloaded