Free First Light: The Search for the Edge of the Universe by Richard Preston Page A

it, looking for hobos trying to ride under the disk, for this was the Depression. Huge crowds turned out. Ten thousand people in Indianapolis watched the telescope train pass. Afraid that someone might try to take a potshot at the disk, Hale and Anderson felt it necessary to armor the disk with steel plates. If a bullet had broken the glass, that certainly would have killed Hale. At night the train was parked on a siding, illuminated with floodlamps, and patrolled by guards carrying loaded rifles, who had orders to let nobody approach within shooting distance. The train passed through St. Louis, Kansas City, Clovis, Needles, and San Bernardino, and arrived in Pasadena on Good Friday, April 10, 1936, witnessed by crowds. The disk was unloaded and lifted into the Caltech optical shop. A Pasadena newspaper reported: “There has not been such excitement since Ambler’s Feed Mill burned.”
    The excitement was too much for George Ellery Hale. Too ill, physically and psychologically, to watch the triumphal entry of his glass into Pasadena, he had withdrawn from the world, broken on the wheel of whirligus. He spent his last years with his instruments in the underground chamber of his solar laboratory, looking into the sun. Day by day a heliostat mirror (a sun-tracker) turned slowly at the top of the building, throwing a shaft of sunlight into the basement, where Hale, staring through an eyepiece just two millimeters across, watched prominences heaving and lapsing around a ball of hydrogen as old as the world but never the same from one minute to the next. His grandchildren would visit him and listen to his stories, and perhaps the elf listened too. He maintained contact with the Palomar project through long letters to a few friends. In 1938, at the Las Encinas sanatorium in Pasadena, he said to his daughter, Margaret Hale, “It is a beautiful day. The sun is shining, and they are working on Palomar.” He died a few days later. Hale had not returned to Palomar Mountain since the day he chose the fern meadow. He never saw his greatest telescope.
    Marcus Brown, Caltech’s chief optician, directed the grinding of the mirror. Brown hired twenty-one unemployed men (mostly right off the street) to operate a polishing machine. Brown’s men wore white suits and white sneakers—clothing that never left the shop. The glass disk sat on a turntable. While the turntable rotated, an arm pressed a rotating circular polishing tool against the glass; the arm moved the tool in differing directions across the glass, thus tracing overlapping cycles of movement known as Lissajous figures.
    I drove up into the Verdugo Hills, near Pasadena, one afternoon in spring, along an unmarked dirt road, until I found a sunny house where lived Melvin Johnson, who as far as I could tell was the only master optician still alive who had worked on the two-hundred-inch mirror. We sat and drank coffee, and Johnson said that it had been so long since he had talked about that mirror that he might have a little trouble finding the right words, but then his words began to move in Lissajous figures around a giant disk of flame Pyrex with a hole in the middle. The opticians inserted a Pyrex plug into the hole before they started to polish the disk. The polishing tool was covered with a layer of black pitch, which rubbedand sleeked against the glass. The formula for the pitch changed now and then, Mel Johnson said, and the method of cooking the pitch in a pot was essentially a black art. “We tested all kinds of mixtures. I threw out a garbage can full of formulas,” he said. The pitch, he said, contained amber rosin from Alabama pines, pine-tar oil, and beeswax. Hoping to get a smoother polishing action on the glass, the opticians experimented with pitches adulterated with paraffin wax, automobile motor oil, and a powder made from ground walnut shells, “which was like flour,” Johnson said. Every few minutes the opticians poured across the glass a slurry of water and