Timing Light

Ranked in scientific achievement with Newton and Einstein, Dr. Albert Abraham Michelson, 78, last week began his final contribution to physics. Again and again delayed--by illness, the collapse of delicate machinery, minute improvements in apparatus--Dr. Michelson stepped up to his corrugated steel, mile-long test tube stretching along the valley near Santa Ana, Calif., pressed a button, started whirling the tiny 32-sided mirror that is to determine once and for all the exact velocity of light.

To the search for this "yardstick of space beyond the stars," to an unrelaxing effort to calibrate it ever more accurately, Dr. Michelson has devoted 52 years. In its pursuit he has literally turned the light on light, made it disclose new truths: about stars so huge that the earth and its whole orbit could be dropped in them and lost; about the ether; about the mysterious place in the universe toward which the sun, all the planets are hurrying at terrific speed.

To that unending pursuit Dr. Michelson has been stimulated by the same feeling for beauty that has made him also a violinist of exceptional skill, an artist whose sketches and water colors were exhibited last winter at his University (of Chicago).

Chance and his own rare abilities shaped his scientific destiny. Argued by his father, against his own will, into applying for Annapolis; arguing President Grant, against the laws of the land, into creating a special appointment for him; he was graduated, served four years as an ensign-instructor.* At Annapolis, at 26, with $10 worth of new apparatus, several years of physics experience, Ensign-instructor Michelson began measuring the speed of light with record-breaking precision, gained international fame, international fellowships. In 1907, for forever determining in terms of light the length of the standard-metre bar,/- he became the first American to get the Nobel prize for scientific achievement.

He invented the interferometre by which in the Michelson-Morley experiment of 1887 he split a ray of light in two and raced the fractions against each other. This single experiment disproved the theory of a drifting ether, broke down old scientific philosophy, triggered off Einstein's study of relativity, created a new conception of time, space, motion of reality itself.

Last week Dr. Michelson started his latest machinery. A ray of light shuttled through the tube for a course of 44 mi. It was a swift flash, less than 1-4,000th of a second in duration, was mechanically clocked with minute precision. Again Dr. Michelson made the light flit; and again. Repetitions, which must be averaged, will take weeks. Dr. Michelson waved goodbye to his assistants, motored to the comforts of his home in Pasadena.

*Dr. Michelson's favorite self-description: "A sailor degenerated into a college professor."

/-The international basis of scientific measurement is an iridio-platinum bar cut by two scratches one metre apart, preserved, guarded carefully at Paris, but subject some day to possible destruction. Dr. Michelson measured the bar against the wavelength of red cadmium light, forever unchangeable.

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