6. The Michelson-Morley Experiment

Underlying the earliest years of University Circle’s life as a cultural center was a deep commitment by Cleveland’s industrial leadership to scientific and technological research.^[1] Leonard Case Jr.’s creation of Case School of Applied Science embodied that commitment, and Western Reserve’s scientists and science departments often had wealthy patrons. The support that underlay the historically significant light-wave researches of professors Albert A. Michelson and Edward W. Morley in the 1880s is an example of how philanthropy, in a variety of forms, became interwoven into the lives of Circle institutions.^[2]

Professor Edward W. Morley of Western Reserve had begun a scientific career even before the college moved to Cleveland. Morley was the son of a minister; he received his schooling at home in the New England towns where his family lived when he was a child. In 1857, at age nineteen, he enrolled at Williams College in Massachusetts, graduating three years later at the top of his class. He then went to Andover Theological Seminary for three years, and was ordained a minister of the Congregational Church in 1864.^[3]

On his path to the ministry, Morley had demonstrated a strong interest in science, showing a marked interest in astronomy as an undergraduate. His first professional position was at a New England academy where he taught both theology and general science. In 1868 Morley accepted an appointment to the pulpit of Twinsburg (Ohio) Congregational Church, where he quickly came to the attention of the trustees of nearby Western Reserve College (then in Hudson), who asked him to begin teaching there. He left Twinsburg before 1880, and from that time onward, Morley’s professional focus was the sciences, particularly chemistry.^[4] He taught undergraduates and, from 1873 to 1888, the medical students in Cleveland (commuting by train while he lived in Hudson).

Morley also had a strong streak of the technologist in him. He was interested in telegraphy, and toyed with the idea of stringing wires from the Hudson train station to his home and thence to the college, so that he could keep his wife aware of his comings and goings.^[5] He also recognized the monetary rewards of technological skill.

In June 1876 the Cleveland Rolling Mill Company donated a spectroscope to Western Reserve College. Whether this was largely a philanthropic gesture is unclear, but it seems likely that a few months later when Morley undertook a consulting job analyzing iron ore he used the spectroscope and that his client was the iron rolling mill.^[6] After Morley moved to Cleveland with the College in 1883 his consulting activities were more frequent. He worked for the city gas works, Standard Oil, a linseed oil firm, and others.^[7] He showed a continuing interest in the leading industrial enterprises of Cleveland, especially as sources of experimental apparatus.^[8]

This mix of scientific and technical interests made Morley an ideal research partner for one of the early faculty members at Case School of Applied Science, Albert A. Michelson. A native of Poland whose family immigrated to the United States when he was about age three, Michelson attended the U.S. Naval Academy from 1869 to 1873. There he received what was probably the most rigorous scientific and engineering education available in the United States during the latter nineteenth century.

Michelson became a science instructor at the Naval Academy and in 1878 conducted an experiment to determine the speed of light. Well-received by men of science, the experiment launched Michelson into a career which eventually brought him a Nobel Prize and recognition as one of the pioneers of modern physics.^[9] Michelson’s collaboration with Edward Morley began two years after his appointment to the tiny faculty of the infant Case School in 1882.

The two men, whose backgrounds seem radically different (Michelson a Pole of Jewish heritage; Morley, a New Englander and an ordained Protestant clergyman), found that they spoke the universal language of science. In the summer and fall of 1884 they traveled to Baltimore together to hear a series of twenty lectures given by Sir William Thomson, a renowned British physicist. Meeting with nineteen others who represented the cream of American physical science, and attending Henry Rowland’s lectures at Johns Hopkins as well, Michelson and Morley had their scientific interests honed to a sharp edge. On the train ride back to Cleveland and in the weeks that followed, Michelson and Morley discovered in each other a similar love for detailed and demanding work, and some common personal tastes (such as music).^[10] Michelson invited Morley to join him in his series of light–wave experiments.

Michelson had been to Germany in 1880-82 to study at Berlin, where he devised an outstanding instrument for studying light waves, later called an interferometer. With it a researcher could actually observe whether the wave patterns of two overlapping beams of light were consonant, or whether they were out of phase and “interfered” with one another. Such interference could be evidence of the different periods of time in which the two beams had traveled a specified distance.

With this device Michelson hoped to be able to determine the rate at which light was slowed down by passing through the “ether,” a fluid which physicists believed permeated all space. The concept of the ether, around even before Isaac Newton’s day, was necessary for those who believed that waves of light energy needed a medium in which to travel, similar to waves traveling in water.

Though all evidence pointed to the ether as colorless, weightless, and unable to be sensed directly, physicists craved secondary evidence of its existence and its role in light transmission, which Michelson’s experiment might provide. His first efforts (in Germany) to measure the speed of two light beams traveling at right angles to one another proved that the ether could not be stationary, if the ether’s effect was as predicted; but he thought that perhaps the ether was dragged along by the earth to some degree (an “ether drift”). If so, an even more precise measurement of the effect was called for.

In Cleveland, Michelson sought Morley’s aid to design and perform a second experiment. Morley’s laboratory was better equipped than Michelson’s, and Morley was probably the only scientist within hundreds of miles who could understand and critique Michelson’s plans. Painstakingly they assembled the apparatus: lenses and mirrors were purchased from John Brashear, an instrument–maker in Pittsburgh; a large sandstone block for a rigid foundation probably came from the bluestone quarries in Berea, Ohio, or possibly from a Doan’s Corners quarry; and carefully machined metal parts came from Morley’s friends Ambrose Swasey and Worcester Warner, the machine-tool makers of Cleveland. Morley’s glassblowing equipment and skill (as well as his access to a glassblower at the Brush Electric Company shops in Cleveland through the courtesy of industrialist Charles Brush) were also important, because a variety of pipes and vessels were required to contain the different gases and liquids Michelson and Morley intended to beam light though.^[11]

Michelson and Morley worked under the handicap of limited financial resources, and severe demands on their time. Neither professor had ample funds for constructing an expensive instrument, although Michelson had a grant from the Bache Fund of the American Association for the Advancement of Science. Their respective institutions provided them with research money, far more than any other faculty member, but Michelson and Morley strained against or exceeded the limits of whatever special funds were allocated. The crusty treasurer of Case (Eckstein Case, a nephew of the founder) recalled years later that “[Michelson] was a trifle liberal with other people’s money. He would simply go ahead and buy whatever he wanted.”^[12] Luckily, they obtained a considerable portion of their equipment at or below cost from Warner and Swasey, leaders of Cleveland’s industrial community who later became trustees of or donors to several of the Circle institutions.^[13]

Both professors also carried full teaching loads, and had families to attend to. The strain on Michelson began to show in the spring of 1885, when his serious miscalculations required an overhaul of the interferometer before experiments could begin. Morley thought the incident “curious.”^[14] Then, just as the fall session of classes began, Michelson applied for a year’s leave of absence to recover his health. He displayed symptoms of nervous exhaustion; Morley called it “softening of the brain.” Michelson’s wife committed him to the care of a nerve specialist in New York City whose cure seems to have consisted largely of leisure and relaxing massages. Michelson recovered quickly, showing no permanent damage, and in three weeks he wrote to Morley to ask “Have you had time yet to experiment . . . Let me know how everything is going on and how the two institutions agree; in short anything and everything that may interest us both.”^[15] On December 1, 1885 Michelson was back in Cleveland, now at Case’s new campus and new building at University Circle.

For the next two years Michelson and Morley performed a series of experiments which soon were regarded as classics. In the summer of 1886 they measured the speed of light as it passed through moving water and air, finding that the results confirmed the earlier measurements of the French physicist A.H.L. Fizeau. The next summer they carried out the test of the effect of the ether on light waves, and beginning in the fall of 1887 and continuing for some months they measured the length of light waves emanating from burning sodium.^[16]

They began their studies in the basement of the new Case Main building, but its disastrous fire in the night of October 26-27, 1886 caused a move. Saved from the fire by the brave action of some of the students of Western Reserve, Michelson and Morley’s equipment was moved to the adjoining campus and reinstalled in the basement of the Western Reserve dormitory, Adelbert Hall. This utilitarian building (about a hundred yards south of the current Adelbert Hall, which was then known as Adelbert College because it contained all of the institution’s classrooms and offices) has been torn down, and by the 1970s a parking lot stood in its place. In that basement Michelson and Morley carefully set up a brick foundation for a circular iron trough which held a pool of mercury. On that they floated a wooden doughnut which supported a five-foot square sandstone block. To the block Michelson and Morley fixed their mirrors, lenses, and lamp. The instrument was set up so that a single light beam would be divided into two portions, each traveling thirty-six feet, but one at right angles to the other for most of the journey. At the end the two beams coincided in the viewer’s eyepiece.

To conduct the experiment Michelson and Morley first adjusted the mirrors so that the lengths of the two light paths were as close to the same length as possible. They focused the lenses of the viewer’s eyepiece for clarity of image, and finally moved an adjustable mirror on one light path until the interference bands showed in the eyepiece. Then, on July 8-9 and 11-12, the two scientists made a series of observations by slowly rotating the stone and looking through the eyepiece at the sixteen points of the compass.

Estimating the shift of the interference bands from the pre-established setting, Michelson and Morley compiled a table of readings which, if the ether had as great an effect on the transmission of light as some scientists thought, should have shown a clustering of similar shifts at certain compass points. There the light beams would be roughly aligned with the Earth’s motion through space, or perpendicular to that motion. One beam would be more affected by the relative speed of the ether than the other.

Michelson and Morley’s results (published in the American Journal of Science) showed shifts of the interference bands, but they were so small that they could not be regarded as validation of any theory of the ether effect suggested to that point. Yet no one was disposed to question the experiment itself, conducted as it was by two seasoned scientists, both known for accuracy, and one of whom had been engaged in optical experiments for a decade. Michelson and Morley dutifully published their result, or better, their “null result,” and moved on to their measurement of sodium light waves, for which they were assured an unambiguous answer. In the first few years after their classic experiment neither Michelson nor Morley took much pride in the ether-drift work, since it did not appear to answer any important question.^[17]

Only in historical hindsight can we appreciate what happened in July 1887 at University Circle. After the Michelson-Morley experiment physicists were forced to come to grips with the inadequacy of the existing theory which described one of the supposed phenomena of light, which itself was one of the central constants in the natural world. Within a few years the simplicity and unquestioned accuracy of the Michelson-Morley experiment made it a reference point for the next generation working on the frontiers of physics, among whom was the young Albert Einstein. Einstein himself was not inspired to begin his work on relativity theory by the Michelson-Morley experiment, and it is even possible that he did not know of it directly until after he had formulated and published the core of his theory, but many scientists later seized upon the experiment as a proof of the validity of Einstein’s mathematics and metaphysics.

Michelson’s subsequent stature as a Nobel prize winner, based on his development of instruments for research, and Morley’s eminence as a recipient of the Rumford Medal of the Royal Society (London), based on his subsequent research, have perhaps made historians too certain that a fine experiment conducted by two great scientists must have been central to the development of relativity theory. Nonetheless, more than a century after the Michelson-Morley experiment it still appears to have been a remarkable achievement, a classic combination of instrument design and theoretical challenge.^[18]