The Glass Universe

by Dava Sobel

  Newspapers nevertheless kept up their coverage of “Astronomers at War” through the summer months. Harvard president Charles Eliot defended the observatory throughout. On July 31 he cautioned Pickering, “As I have said to you before, the best way of meeting this and all other criticism is to issue more fresh good work, and this I doubt not that you are bent on doing. My chief anxiety in connection with this matter is that it should not disturb your peace of mind or impair your scientific activity. At first it had to a little; but I hope the temporary effect is wearing off. If it does not, I beg to repeat what I said to you at our last conversation—you ought to take a good vacation.”

  The Pickerings’ prescribed vacation in the White Mountains of New Hampshire restored some of the director’s equanimity. He felt even better that fall, when a new photometric catalogue from the Potsdam Observatory appeared. It showed near-perfect agreement with the myriad magnitude determinations made at Harvard.

  • • •

  WILLIAM PICKERING, HAVING RELUCTANTLY relinquished his house and position of authority in Arequipa, returned from Peru via Chile, where he observed the total solar eclipse of April 16, 1893. As soon as he resettled in Cambridge, he began plotting his next rendezvous with Mars. Favorable orbital alignments coming up in October 1894 offered William the irresistible opportunity to build on his observations of 1892. It had been his good fortune to find himself ideally situated south of the equator for the last close approach. This time the American Southwest offered the most desirable perspective. Luckily for William, the wherewithal for mounting a trip to the Arizona Territory came to him in the person of Percival Lowell. The wealthy Lowell had recently developed a passion for planetary astronomy, and required an expert’s guidance for his first serious endeavor in the field. A Boston Brahmin and Harvard alumnus, Lowell knew the Pickering brothers socially through the Appalachian Mountain Club.

  Edward Pickering granted William a year’s leave without pay to join Lowell’s “Arizona Astronomical Expedition.” He also allowed Lowell the yearlong lease of a 12-inch Clark telescope and mount for $175 (a sum equal to 5 percent of the equipment’s value). Lowell and William successfully negotiated with another telescope maker, John Brashear of Pittsburgh, for the loan of a second, larger instrument—an 18-inch refractor—to further their cause. On July 14, a euphoric William wrote Edward from Flagstaff to say the seeing in Arizona rivaled that at Arequipa.

  At Arequipa itself, Bailey tried to estimate the danger to the Harvard station posed by the opening salvos of civil war in Peru. The country was still rebuilding itself, settling its international debts and internal turmoil after years of fighting as Bolivia’s ally in conflicts with Chile. As early as July 1893, Bailey had half-jokingly proposed “to remove the lenses and use the telescope tubes for cannon” if the need arose. Two months later, after taking serious stock of his available defenses (“two or three revolvers”), he concluded that the wisest move in the event of an armed attack would be to surrender “and rely on the government for indemnity.” He laid in extra provisions as a precaution and built heavy wooden shutters for the windows and doors. These were not quite complete when rioting and shooting broke out in Arequipa, bringing government troops into the city. After the death of President Francisco Morales Bermúdez in Lima in April 1894, increasing violence prevented the vice president’s succession to office. Bailey added an adobe wall between the station and the road, and then another wall along the northern perimeter, facing in the direction of a village that was now rebel-occupied territory. Rebels also controlled the area surrounding the original observing site on Mount Harvard.

  Spring elections restored a former president, Andrés Avelino Cáceres, to office in summer, but the political situation remained unstable. The observatory carried on its normal activities to the extent possible. In early September, assistant George Waterbury set out, as he did every ten days or so, to check on the weather gauges installed atop El Misti. When he reached the 19,000-foot summit, he found the meteorology shelter had been vandalized and several of the instruments stolen.

  • • •

  “DEAR UNCLE DAN,” ANTONIA MAURY wrote to Daniel Draper, the Central Park meteorologist, on September 2, 1894, from North Sydney, Nova Scotia, “I have been having a good time here and have got well rested in the last three weeks. I am still however too lazy to be able to make any plans for the winter. I have to be in Cambridge for about two weeks to finish up some odds and ends. Then Mrs. Fleming is going to attend to the printing of the work, so I shall be free. I think a little of going with Carlotta [her sister] to study at Cornell, but may decide to study by myself in Boston where I can have excellent library advantages.”

  She had missed the agreed-upon deadline of December 1, 1893, for completing her work at the observatory, but felt close to finishing now. Unfortunately, the remaining “odds and ends” overwhelmed her, especially as she also resumed her teaching duties for the semester. Her father, the Reverend Mytton Maury, whose lack of a permanent posting no doubt added to his daughter’s stress, expressed his concerns to Pickering on November 12. “I wish you would try to give Miss Maury every assistance in finishing up the work in hand,” he wrote. “It is most important that she should go away. She is growing so nervous that she often wakes long before daybreak & can’t get to sleep again.” Along with the increase in her anxiety from September to November, her winter plans had taken the shape of a trip to Europe. “She and her brother are to sail on the 5th of Dec.,” Reverend Maury said with emphasis. “You will see therefore that a conclusion must be reached. As to the Orion lines please assume that labor yourself & so relieve her. That at least seems to be one point in which her responsibility can be lightened. I do not know that there is anything else that can be done by others—but if there is, please do me the favor to have it done.”

  The Orion lines, as the reverend must have known from his daughter’s description, were particularly conspicuous spectral lines in some stars of the constellation Orion, the Hunter. Orion lines were separate from the twenty known hydrogen lines, distinct also from the calcium lines, and not to be confused with the hundreds of “solar lines” typical of the Sun’s spectrum. In short, it was not yet clear what substance or condition the Orion lines represented, but they figured importantly in the first five stellar spectra categories of Miss Maury’s classification system.

  “It is very desirable to have the work done of course,” Reverend Maury continued, “but not at the expense of injured health.” In a postscript, he asked Pickering to provide a letter of introduction to foreign astronomers for Miss Maury’s use in Europe. Pickering did as he was asked.

  “Many thanks for the letter of introduction,” Reverend Maury wrote again on December 1. “It was just the thing. . . . Thanks too for your efforts to facilitate the work on those perplexing Orion lines. I hope now things will be left in such a shape that there will be no perturbations in the mind of ‘the Astronomer,’ as we call her.”

  Over the next several weeks, as the day of her departure was delayed and Miss Maury continued working at the observatory, she took offense at some remark of the director’s, so that Reverend Maury felt it necessary on December 19 to remind Pickering that his daughter “is a lady and has the feelings and rights of one.”

  In an effort to excuse her father’s intervention, Miss Maury sent her own agitated note to Pickering on December 21: “The fact is that my father was excited because I often came home tired and nervous and sometimes complained as people are apt to do about their work. It is true I have often said that your criticisms had from the beginning so shaken my faith in my own ability to work with accuracy that I had been struggling against a great weight of discouragement from the start. But although I several times before have taken offense at things you have said to me I have always decided in the end that the only trouble was that I, being naturally unsystematic, was not able to understand what you wanted and that you also, not having examined minutely with all the
details, did not see that the natural relations I was in search of could not easily be arrived at by any cast iron system.”

  She drafted one last letter while riding the train to New York on January 8. “I am very sorry I did not see you to say goodbye,” she began. The last week had passed in such a rush. Her steamer was leaving the next day. “I felt the more sorry as I wanted to tell you that I appreciate your kindness to me all along and understand entirely many things that I did not always [understand] in times past. And that I should have done differently had I seen more clearly. I am sorry I have been so long about the work, but partly on account of my inexperience and partly because the facts developed gradually, I am not sure that I could have done any better what I have done in the past year and six months, at any earlier time.” She hoped he would have no trouble reading her manuscript, and promised to send Mrs. Fleming an address in Europe where she could receive mail.

  “I sail tomorrow at 2 pm—at least I believe so though I am not sure whether or not I am dreaming, so confused is everything in my mind. I hope that although my work at the observatory is at an end I may still keep your friendly regard and confidence which I value very greatly.”

  • • •

  ASTRONOMERS WHO HAD DOUBTED William Pickering’s impressions of Mars were scandalized at what Percival Lowell saw there—not just watery surface features, but a fully developed network of irrigation canals engineered by intelligent Martians. William would not go so far. By November 1894 he had made up his mind to leave Lowell and return to the Harvard fold. The choice proved wise, as the weather in Flagstaff that winter destroyed the quality of the seeing.

  In Peru, where the seasons were reversed, Solon and Ruth Bailey spent a few overcast January days in 1895 tending to a problem at an auxiliary meteorology station in Mollendo. On their way back to Arequipa, a crowd of armed men surrounded their train and rushed aboard. “The car was at once filled with cries of ‘Jesus Maria’ and ‘Por Dios,’ by the ladies and children,” Bailey wrote Pickering on January 14. “I advised Mrs. Bailey and Irving to keep quiet and there would be no harm done and so it turned out. The revolutionists behaved with great moderation and offered us no indignity whatever. We were sent back to Mollendo however while the men followed us in another train which they had captured. When near the town they left us locked in the car and forming in line marched in and took the place in a few minutes. Mollendo is said to have a population of about 3000 but there were only 15 soldiers and they surrendered after about a hundred shots were fired.”

  The Baileys and scores of other temporarily displaced passengers found shelter for the night at the home of the steamship agent. The next day, when the rebels left and troops loyal to President Cáceres reclaimed Mollendo, the Baileys again boarded the train for Arequipa. At home they found that Hinman Bailey had removed the lenses from the several telescopes—not to use the tubes as cannon, as Solon had quipped, but to bury the glass for safekeeping. The Bruce photographic telescope, with its 24-inch lens, was still undergoing tests in Cambridge, and for once the delay in its delivery seemed providential.

  Within a fortnight of the train incident, Arequipa came under heavy attack. Rebels cut the telegraph line and Bailey reburied the recently retrieved telescope lenses. In the diary-like letter he composed during the siege, which lasted from January 27 to February 12, he recorded daily events, the din of nearby rifle fire, and his relief that the battle coincided with the cloudy season, “as otherwise it would sadly interfere with our night work.”

  By March the victorious rebels had ousted Cáceres and installed a provisional government. New elections planned for August seemed likely to elect the rebel leader, Arequipa native Nicolás de Piérola. The Baileys had reported hearing shouts of “Viva Piérola!” punctuating their January ride on the hijacked train. Now they invited the old warhorse to tour the observatory station, and treated his entourage to a reception with refreshments. “The expense was moderate,” Bailey assured Pickering on April 15, “about twenty dollars, and as Pierola is sure to be the next president, if he lives, I think it was a wise act.”

  With good weather and nightly observations restored, Bailey resumed his contemplation of the gorgeous globular clusters. Four of them contained such astonishing numbers of variable stars that he took to calling them “variable star clusters.” With Ruth’s help, he kept count of their contents as he searched for additional examples.

  Pickering promised to send more experienced, more reliable assistants to Peru. Soon he would send the Bruce telescope as well. He had taken more than a thousand photographs with it and worked out the various kinks inherent in its unusual design. For example, the huge tube (truly a piece of heavy artillery) had tended to flex slightly under its own weight, so that long exposures stretched some star images into oblong shapes. The Clarks helped Pickering add strengthening rods and otherwise ready the Bruce to meet its destiny at Arequipa.

  The telescopes in Cambridge, in contrast, faced a dim future as the growing city encroached on the observatory. Municipal plans to widen nearby Concord Avenue for streetcars concerned Pickering, for fear the traffic might rattle the Great Refractor atop its several-hundred-ton supporting pier of granite blocks set in gravel and cement. Already the unwanted glare of electric lights thwarted the instrument’s power. It could no longer register faint objects such as small comets and nebulae. Pickering had written to various city offices with his concept for screens that could be placed over outdoor light fixtures to prevent them from illuminating the atmosphere above, but the idea fell on deaf ears. Since he could neither eliminate nor shield the streetlights, he learned to make use of their intrusion. “The electric lights,” he told the observatory’s Visiting Committee of patrons and advisers, “prove an advantage in one way.” He and his telescope assistants needed to assess and reassess the clarity of the sky many times per night, so that the quality of the photographs made during each hour could be graded accordingly. Photometry demanded still more rigorous attention to sky conditions, with updates made every few minutes while manning the meridian photometer, when even the faintest wisp of cloud might throw off a brightness reading by several tenths of a magnitude. The streetlights alerted the observers to virtually invisible clouds. “The effect is like that of the Moon,” Pickering explained, “but as the lights are below the clouds instead of above them, the latter become conspicuous even when too faint to be seen in moonlight.”

  • • •

  THE LETTER OF INTRODUCTION that Pickering had provided for Miss Maury won her a warm welcome at the observatories of Rome and Potsdam. As she traveled abroad with her brother in 1895, Scottish chemist William Ramsay released the results of his laboratory experiments with cleveite gas, which findings threw Miss Maury’s Orion lines into stark new relief.

  Ramsay, working at University College in London, collected the gas bubbles given off when the uranium compound called cleveite was dissolved in sulfuric acid. He described the properties of the gas and submitted a sample to spectrum analysis. One of its spectral lines shared the same wavelength as a line previously seen only in the Sun’s spectrum—a line that English astronomer Norman Lockyer attributed in 1868 to a solar substance, which he called helium after the Greek sun god, Helios. Ramsay’s new discovery proved that helium occurred on Earth as well. He went on to demonstrate its presence not only in uranium ores but also in the atmosphere.

  While Lockyer had named helium on the basis of a single spectral line, Ramsay revealed the element’s full spectrum. Its additional lines matched the “Orion lines” that Miss Maury had so often mentioned in the manuscript she left with Pickering upon her departure. She thought it imperative to incorporate the new revelation about helium into her classification, now in preparation for publication. On the other hand, the time for making major revisions had long since passed. “I do not know,” she wrote “in haste” in an undated letter to Mrs. Fleming, “whether Professor Pickering will care to insert the statement in regard to
Orion lines being due to helium.”

  • • •

  SOLON BAILEY TRAVELED ALONE to Cambridge to claim the Bruce telescope in the summer of 1895. Pickering wanted him to spend a few months at Harvard familiarizing himself with the operation of the instrument before superintending its removal to Peru.

  Ruth Bailey had asked her husband to carry two gifts to her friend Lizzie Pickering, but the bulky alpaca shawl and robe took up so much room in his luggage that she sent them on ahead, with a letter. “The only regret I have about the robe is that it needed cleaning, and as there are no establishments here for anything of the kind, I was obliged to send it just as it was.” She hoped it would reach Cambridge before the Pickerings left for Europe. She also wanted to plead, woman to woman, for Mrs. Pickering to look out for Solon. “I am very anxious for Mr. Bailey to leave Cambridge before December for fear of the cold,” she wrote. “I trust you will see that he starts for Arequipa before it is too cold. Men take no care of themselves, that is most men need looking after, they never think they must be careful of their health. I dread to have him go, still I think it is wiser for him to see the instrument there in running order.”

  Her concerns sounded like typical wifely worries, but the turn of events in the following months lent them eerie prescience. In July, while her husband was at Harvard, their son, Irving, fell seriously ill. Bailey rushed back to Arequipa as soon as he received her cable, though even “as the crow flew,” the distance to Peru exceeded four thousand miles, and the roundabout route by available transport widened that gap. Fortunately, the child recovered soon after his father’s return.

  On February 13, 1896, Bailey stood waiting at the dock to greet the Bruce telescope when its ship pulled into Mollendo. Willard Gerrish had dismantled the instrument in Cambridge and chaperoned the pieces as far as New York, where he took pains to delay loading them until the incoming tide raised the steamer to the level of the wharf. Then he convinced the captain to store the lenses in the vessel’s strong room for the long voyage down the eastern coasts of both Americas, through the Strait of Magellan, and up the Pacific to Peru.