The Glass Universe

by Dava Sobel

  “I shall always be glad that I have seen a total solar eclipse,” Mrs. Draper wrote Pickering on May 30, 1900. “Simply as a spectacle it is magnificent and as the Chief Justice remarked ‘it gave one a distinct thrill.’”

  William’s camera arrangement allowed him to make thirty-six plates of the eclipse. Unfortunately, none of the pictures yielded satisfaction, because someone inadvertently disturbed the instrument during the brief totality.

  The Eros campaign—the global effort to observe the newly discovered asteroid—proved more successful for Harvard. The privileged position of the Bruce telescope in the Southern Hemisphere enabled DeLisle Stewart at Arequipa to take some excellent photographs a month before the asteroid became visible anywhere else. Officially, Pickering cooperated with some fifty observatories worldwide to ascertain positions of Eros in the attempt to derive the Earth-Sun distance. Personally, however, he found the asteroid’s changing light even more intriguing. Viennese astronomer Egon von Oppolzer had shown Eros to be as variable in brightness as many a variable star, and Pickering hoped to construct its definitive light curve. He recalled that when Mrs. Fleming first retrieved the Eros plates, she had pointed out slight brightness variations in the asteroid’s trail. At the time, he attributed the irregularity to patches of haze in the intervening air; now he recognized other possibilities. Eros might prove to be a rotating body, with surface features of dramatic contrast, or perhaps a pair of two small bodies of differing complexion, tumbling around each other. Beginning in July 1900, Pickering directed the Cambridge chief of photography, Edward Skinner King, to make plates of Eros every clear evening through the 8-inch Draper telescope. Inside the dome of the Great Refractor, Pickering himself gauged Eros’s magnitude visually by comparing its varying brightness to the stars along its path.

  • • •

  PICKERING’S BID ON BEHALF OF MRS. FLEMING failed to win her the 1900 Bruce Medal from the Astronomical Society of the Pacific. In January 1901, however, he learned that he himself was to receive a medal—his second gold medal from the Royal Astronomical Society. The first one, in 1886, had recognized his exhaustive work on the Harvard Photometry, or “the comparative lustre of the stars,” as his English admirers described it. The 1901 medal extolled his studies of variable stars and also his advances in astronomical photography. The U.S. ambassador to the United Kingdom, Joseph Hodges Choate, agreed to accept the medal for Pickering at the February 8 ceremony in London.

  “I do not know when I have heard so much approval expressed about the award of a medal,” Mrs. Draper chortled. “Everyone I meet, who understands the subject at all, is delighted at the compliment paid to you, and what amuses me very much, I am brought in for a share in the congratulations, which I do not merit; but I shine a little from reflected glory.” In fact the RAS president, Edward B. Knobel, cited Mrs. Draper by name in his prize-presentation address. He saw her as the prime enabler of Pickering’s award-winning research, and commended “her beautiful idea” to hallow her husband’s memory by embracing, enlarging, and enriching the science in which Dr. Draper had labored.

  President Knobel also took the opportunity to praise Mrs. Fleming, “that most careful observer” among Pickering’s “lady assistants,” distinguished for her many discoveries regarding variable stars and stars with peculiar spectra. He mentioned her name not once but three times in the same speech.

  Mrs. Draper happened to be visiting London when Miss Cannon’s classification came off the press in late March 1901. Pickering immediately shipped a copy to her, along with a typewritten note expressing his satisfaction with it.

  Miss Cannon’s classification not only unified the earlier work of Mrs. Fleming and Miss Maury, but also clarified the interrelationships among the several stellar categories. The whole population of stars now seemed to be distributed along a continuum according to their spectra. While many stars belonged unmistakably to one class or another, there were just as many that blurred the boundaries by sharing some characteristics of two neighboring types. Miss Cannon represented these overlaps with new numerical subdivisions. For example, she introduced the designation B 2 A for spectra displaying B-type strong Orion lines as well as a few of the pronounced hydrogen lines typical of the A class. Stars labeled B 3 A tended a little more markedly that way, B 5 A still more so, and B 8 A much more. Her system allowed for as many as ten steps between letters.

  Miss Cannon thought her arrangement of the classification categories represented the stages of stellar development. Any given star would evolve from type O to type M in the course of its lifetime. Or perhaps progress moved the other way, from M to O. It was difficult to say.

  Miss Maury’s appreciation of the widths and borders of individual Fraunhofer lines had led her to institute subdivisions, which she labeled a, b, c, and ac, and which cut across her twenty-two categories. Miss Cannon missed none of these distinctions, but relegated her descriptions of the waviness or haziness of particular spectral lines to her “Remarks.”

  The publication of Miss Cannon’s lengthy treatise gave Mrs. Fleming no reprieve from the tedious supervision of manuscripts. The backlog of the observatory’s unpublished material, according to the director’s estimate, would likely fill twenty-eight volumes of Annals. He charged Mrs. Fleming to focus her attention on that wealth of data, and “put it in shape for publication, or at least in such a form that its final publication would not be a matter of great difficulty.” In consequence, the tally of her discoveries plummeted. Pickering commented on the fact in his annual report for 1901: “The number of objects with peculiar spectra found by Mrs. Fleming from an examination of the photographs is unusually small this year, as a large part of her time has been devoted to the preparation of the Annals.”

  In October Pickering repeated his endorsement of Mrs. Fleming for the Bruce Medal. But, once again, his entreaty failed to gain her that accolade.

  A particularly virulent form of “grippe” felled Mrs. Fleming in November, forcing her to miss several weeks of work. Other staff members were similarly stricken that winter season, including Pickering in December.

  “As you see,” the director wrote to Mrs. Draper on January 10, 1902, “I have at last got possession of my type-writer so that I am now in communication with the world this morning for the first time. I am gaining strength every day, so that, except for observing, I can now do a great portion of my daily work. I have still, however, a great respect for those persons who can climb stairs without difficulty.”

  After wheezing his way up the steps to his office on the second floor of the Brick Building, Pickering could send photographic plates or messages down again via the dumbwaiter near his desk. Everything in the office stood near some part of the great round revolving desk that all but filled the room. It had been custom-built, eight feet in diameter, to provide as much surface area as a table twenty-five feet long and two feet wide. From his seat at the desk’s perimeter, Pickering could easily reach the twelve-section rotatable bookcase at its center, or open any of the twelve drawers evenly spaced along the outer rim. Pickering’s paperwork, laid out around the desktop in piles, orbited the bookcase. With a spin he could bring the draft of a journal article to hand, or the sheaf of letters for his signature, or the latest reports from Arequipa.

  On the morning of February 1, 1902, Pickering arrived to find a present from Mrs. Draper awaiting him. It was a novelty clock for his office wall, along with a note congratulating him on his twenty-fifth anniversary as director of the observatory. A fête soon followed, organized by Mrs. Fleming. Toward 11 a.m. she and Mrs. Pickering summoned the director to the photographic library, where all the assistants gathered to offer their good wishes and gifts. The staff of the Henry Draper Memorial had chipped in on a comfortable desk chair; the other assistants gave him a silver loving cup a foot high. Pickering made a short speech, and then everyone shared a celebratory luncheon.

  “I enjoyed it very greatly,” he wrote later t
hat day to Mrs. Draper, “much to my surprise, for you know I do not like occasions. No one could help enjoying the kind feelings they all expressed, not the least acceptable being those in your letter. Altogether it seemed to me to be a great success, and I shall always carry with me most delightful memories of it. I want to make my 50th anniversary 25 years hence a more formal affair. Will you help us receive our guests then? Please do not say that you have a previous engagement!”

  In March, when Pickering found the quarterly expenses for the Henry Draper Memorial exceeding Mrs. Draper’s allowance, he informed her that he would balance the books by drawing on contingency funds. But Mrs. Draper refused his offer. Her proprietary feelings for the project prevented her from allowing any moneys other than her own to support it.

  “I have quite a sentiment about paying for it myself,” she told him on March 30, 1902, “but I do not feel that at present I can increase the amount I have set aside for the work.” She would rather see some part of the effort curtailed than relinquish her financial control. Pickering hastened to reassure her, both by letter and in person, that he wanted to manage the memorial exactly as she wished.

  Meanwhile the aging, decaying wood of the overcrowded original structures clashed with the observatory’s earned stature as one of the largest and most productive institutions of its kind. Pickering compared the mismatch to “that of a man with plenty of food who is dying of thirst, or who has no shelter in winter.” With a $20,000 gift earmarked by an anonymous donor for physical plant improvements, Pickering added a plain brick wing to the Brick Building, thirty feet square and three stories high—big enough to hold another ten or fifteen years’ accumulation of glass photographic plates. He also installed a hydrant on the observatory grounds, to augment the fire protection provided by chemical extinguishers and electric alarms. Still justifiably fearful of fire, Pickering mandated an observatory-wide fire drill every two months, in which all assistants and officers participated.

  Toward the end of September 1902, when another quarterly accounting revealed the ongoing discrepancy between Mrs. Draper’s payments of $10,000 per year and the cost of conducting the project at Harvard, she reiterated her concerns. “You will doubtless think it absurd that I should have any objection to being assisted from the funds of the Observatory, but I must confess to having a very strong feeling in regard to paying for this work myself. I hope, therefore, you will excuse my referring to the subject again, and not feel annoyed at my doing so.” After all, the endeavor constituted her own loving monument to Henry. Although she had long before conceded the impossibility of carrying out his mission by herself, she remained resolute in her determination to fund it with her inheritance. She wished her current circumstances allowed her more leeway, but one of her nephews was selling his interest in the Palmer family estate, and she felt duty bound to purchase it from him, rather than allow outsiders to buy in.

  Mrs. Draper knew she had every right to insist that the Draper Memorial budget be managed as she dictated, and yet, at the same time, she did not wish to appear unreasonable. On reconsideration, she agreed to let Pickering rely on supplementary support for the time being. “Whatever the indebtedness may amount to, I can return later,” she promised, as much to reassure herself as to inform him of her plans. She would need to “sail very close to the wind,” she said, through the coming winter, but, as soon as she settled the family business predicament, she expected “to feel quite easy again.”

  CHAPTER SEVEN

  Pickering’s “Harem”

  DEMAND FOR COMPUTER POSITIONS at the Harvard Observatory ran so high that some young ladies with college degrees offered to work there for free—for a time, at least, until they could prove themselves worthy of hiring. Mrs. Fleming usually deflected these overeager applicants. Even if tempted to avail herself of short-term volunteer assistance, she did not consider it good policy to place the observatory under obligation to anyone for services rendered gratis.

  Bona fide new job opportunities seldom opened, given the observatory’s tight economy and the loyal longevity of its employees. Anna Winlock, for one, had been at her post even longer than the director, and by 1902 her younger sister, Louisa, was nearing two decades in the computing room. No one had left to get married since Nettie Farrar’s departure at the start of the Draper project. As Mrs. Fleming could attest, the women now on staff were wedded to their work. No newcomers need apply. Then, all at once at the start of 1903, the director instructed her to hire ten new computers.

  Funding for the sudden expansion came from a $2,500 grant awarded by the new Carnegie Institution of Washington. Pickering had applied for the support through proper channels, but he conveyed his thanks directly to Andrew Carnegie. Aware of the millionaire’s commitment to building public libraries, Pickering described the plate collection in bookish terms. “We have this great library of glass photographs,” he wrote on February 3, 1903, “each unique, easily destroyed, and containing a vast number of facts relating to the entire sky, for some portions of which there have hitherto been no readers. This grant furnishes readers, who will extract from this storehouse of the history of worlds, facts heretofore unknown, and which, except for this collection, could never have been learned, since it contains the only record of them upon the Earth.”

  “Mr. Carnegie asks me to say that he is rejoicing at the receipt of your note,” the steel industrialist’s private secretary replied, “and he hopes the Carnegie Institution is to aid a hundred such things, and is to find, now and then, at long intervals, a man such as yourself to cooperate with.”

  The new “readers” at Harvard perused the chart plates (also called patrol plates) profiling each section of the sky. They traced the history of known objects and also of new objects as soon as any were discovered. They skimmed the nebulous regions for faint lights previously overlooked. They pored through star fields to recover “lost” asteroids that had gone missing for years.

  In March, Pickering wrote again to his new patron with two pieces of news. “A few days ago, the Potsdam Observatory announced a new variable star, having the shortest period known. They had observed it carefully during the last nine months—our plates extend the work back to 1887. Last night notice came from the Moscow Observatory, of another interesting variable. They have 13 photographs of it,— we have more than 200, which without your grant we could not examine. Our library, like the Sibylline books,* is the only storehouse of these facts open to human knowledge. You have given us the key by which new facts regarding unknown worlds are daily revealed to us.”

  Four months passed before a personal reply arrived from Skibo Castle, the Carnegies’ summer residence in Scotland. “My dear Professor, Go ahead; you are on the right lines. I hope to see you upon my return. I thought probably that I beat the record by selling 3 lbs. of steel for 2 cents, but the whole constellation of Orion for a cent knocks me out. Take the cake! Come and see us when you are abroad.”

  • • •

  MRS. DRAPER’S FINANCIAL SITUATION did not improve from 1902 to 1903. In fact, it worsened. For nearly twenty years, she had been channeling the income from one particular piece of her New York real estate into the Henry Draper Memorial fund, but in 1902 the city took over that property. “I have been seriously crippled in my income, by the loss,” she told Pickering. By juggling other holdings, she had “succeeded in making ends meet” through the spring of 1903, but still she felt pinched. “I have not forgotten that I owe to the general fund of the Observatory nearly a thousand dollars, and I hope another year to be able to repay it.”

  Her anxiety prompted her to question the way her money was spent. Did all of it go toward the photographic study of stellar spectra? Or were the lines blurring between the observatory’s several projects, possibly to her disadvantage? For example, she wondered to what extent her contribution funded the operation of the Bruce telescope at Arequipa, and how many of the photographs made with that instrument belonged to the Henry Drape
r Memorial, intended to examine stellar spectra. Moreover, she asked, was it wise to continue taking pictures “of the entire sky, night after night” in both hemispheres? She knew she had approved this pursuit, and even provided one of the instruments for it, but where would it all end? Had not the accumulated abundance of plates already grown unmanageable?

  “I should be obliged,” she wrote on June 15, “if you will give me a statement as to what the Observatory now possesses which you consider as belonging to the Memorial, including instruments, plates, printed matter, manuscript ETC.”

  Her questions staggered Pickering. Although his annual reports to the Visiting Committee discussed the progress of the observatory’s various projects under separate subheadings, the work formed a grand unified edifice. Parallel lines of research met and entwined. Photographs of spectra led inevitably to discoveries of variable stars, which necessitated tracing changes of brightness backward and forward in time on stored images, which process revealed other objects of interest and suggested other studies. In sum, the spectra that Henry Draper had been first to capture on glass plates were now yielding not only the composition of the stars, as the doctor had once dreamed, but many other insights as well. Spectral evidence for motion in the line of sight, for example, had disclosed the speeds of many stars toward or away from the Sun. Pickering and Miss Maury had found spectral-line clues to the presence of two stars where only one had been previously known. Stars’ relative temperatures could also be read in the spectrum, by the intensity of their radiation at different wavelengths. (Contrary to ordinary associations with the colors red and blue, the reddish stars were cool compared with those emitting mostly blue-white light.) The smooth continuum of spectral types—the way the Draper classification categories evolved gradually from one to the next—suggested that the stars themselves evolved, perhaps changing from type to type over the course of a stellar lifetime.