Edward Williams Morley (January 29, 1838 – February 24, 1923) was an American scientist known for his precise and accurate measurement of the atomic weight of oxygen, and for the Michelson–Morley experiment.

In 1860–61 he mounted a transit instrument, constructed a chronograph, and made the first accurate determination of the latitude of the college observatory.

[1] During his residence in Cleveland, Morley assembled one of the best private collections of chemical periodicals in the United States.

In 1906, he moved to West Hartford, Connecticut, where he built a small house and a laboratory for his personal studies of rocks and minerals.

This involved making more and more accurate measurements of the speed of light in various directions, and at different times of the year, as the Earth revolved in its orbit around the Sun.

Michelson and Morley always found that the speed of light did not vary at all depending on the direction of measurement, or the position of the Earth in its orbit, deducing what we call a "null result" for their speed-of-light experiments.

[2] Neither he nor Michelson ever considered that these null results disproved the hypothesis of the existence of "luminiferous aether", in which electromagnetic waves were thought to be propagated.

Their null results led the Irish physicist George Francis FitzGerald to postulate what we now call the FitzGerald–Lorentz contraction of physical objects in the direction of their movement in inertial frames of reference.

The results of the Michelson–Morley experiments supported Albert Einstein's strong postulate in 1905 that the speed of light is a constant in all inertial frames of reference for his Special Theory of Relativity.

At Western Reserve College, Morley was required to teach, not only chemistry, but also geology and botany, leaving him little time for research.

[1] In chemistry, his original field, Morley had worked on determining accurate values for the composition of the atmosphere and the weights of its gases.

Much time was spent in the calibration of instruments and improving the measurement accuracy to the highest possible degree (ca.

He also won the Elliott Cresson Medal, awarded by the Franklin Institute of Pennsylvania, in 1912, for important contributions to the science of chemistry.