Experimental Determination of the Velocity of Light

Experimental Determination of the Velocity of Light is by Albert A. Michelson, and the opening lines say it was made at the U.S. Naval Academy, Annapolis. A note says the researches described were made at the United States Naval Academy, though at private expense. Experiments made with very crude apparatus and under great difficulties are said to give a table of results for the velocity of light in miles per second, with a mean of 186500 ± 300 miles per second, or 300140 kilometers per second.

A first-person account says the sum of $2,000 was placed at the speaker's disposal by a private gentleman for carrying out these experiments on a large scale. The text says that in order to obtain this deflection it was sufficient to make the mirror revolve 250 times per second and to use a radius of about 30 feet. A section headed Periodic Variations in Friction considers the case where the speed of rotation varied in the same manner in each revolution of the mirror.