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IX.—A Measurement of the Velocity of Light*

Published online by Cambridge University Press:  14 February 2012

R. A. Houstoun
Affiliation:
Natural Philosophy Department, University of Glasgow.

Synopsis

The author has already described a new method of measuring the velocity of light, which replaces Fizeau's toothed wheel by a piezo-quartz. This acts as an intermittent diffraction grating, and it interrupts the beam 200 times more rapidly than Fizeau's wheel did.

The present paper describes the application of the method to the measurement of the velocity of light in air. The total length of path was 78 metres. The frequency of interruption was measured by comparison with the Droitwich radio station. The result reduced to vacuum is 299,775 kilometres per second and is in agreement with other recent determinations, but, as a result of the experience gained, it will be possible to increase the accuracy at least ten times.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1950

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References

References to Literature

Bergstrand, Erik, 1943. “Measurement of Distances by High Frequency Light Signalling”, Ark. Mat. Astr. Fys., XXIX A, N: 0 30.Google Scholar
Birge, Raymond T., 1941. “The General Physical Constants”, Reports on Progress in Physics, VIII, 90.CrossRefGoogle Scholar
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Houstoun, R. A., 1941. “A New Way of Measuring the Velocity of Light”, Proc. Roy. Soc. Edin., A, LXI, 102.Google Scholar
Houstoun, R. A., 1944. “A Measurement of the Velocity of Light in Water”, Proc. Roy. Soc. Edin., A, LXII, 58.Google Scholar