Abstract
THE method employed in this research to measure the velocity of light resembled the method of M. Fizeau, subsequently employed by M. Cornu. A revolving toothed wheel is employed in the same way to alter the intensity of the light reflected from a distance. In the present method, however, there are two distant reflectors instead of only one. They are separated by a distance of a quarter of a mile. The observing telescope and the two reflectors are almost in the same line. The observer sees two stars of light, which go through their phases with different periods as the toothed wheel is revolved at increasing speeds. One star is increasing, while the other is diminishing, in intensity, with increase of speed of the toothed wheel. The speed required to produce equality of the light is determined by means of a chronograph.
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Abstract of a paper by Dr. J. Young, F.R.S., and Prof. G. Forbes, read before the Royal Society, March 19.
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Experimental Determination of the Velocity of White and Coloured Lights 1 . Nature 24, 303–304 (1881). https://doi.org/10.1038/024303a0
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DOI: https://doi.org/10.1038/024303a0