The history of the idea of variation of frequency with velocity is followed through Voigt, Larmor, Lorentz, and Einstein. The Michelson-Morley experiment is explainable by any contraction of dimensions in the ratio (1-ν2/c2)½: 1 along and transverse to the direction of motion. To each contraction corresponds a different value of frequency change. The theoretical speculations pointing to the relation νm = ν0(1 - ν2/c2)½ are discussed, together with the significance of the experimental test by means of canal rays.
HERBERT E. IVES, "Historical Note on the Rate of a Moving Atomic Clock," J. Opt. Soc. Am. 37, 810-813 (1947)