by Dava Sobel
Miss Cannon wrote a lengthy obituary notice for Science, in which she compared Mrs. Draper to another woman of her acquaintance, Lady Margaret Huggins. “It is interesting to note that the wives of two of the men connected with the beginnings of this science played such important parts in the careers of their husbands. . . . For Mrs. Draper not only was her husband’s associate in his investigations during the fifteen years of their lives together, but after his early death in 1882, she was able to provide for carrying on his work in a most efficient manner.” Miss Cannon did not mention her own part in the continuation of that work, except to say, “In 1911, observations were commenced for a New Draper Catalogue, which will contain the spectra of at least 200,000 stars situated over the entire sky. In this work Mrs. Draper was greatly interested until the very last, and wrote encouragingly about its progress.”
When Lady Margaret Huggins died a few months later, in March 1915, Miss Cannon wrote her obituary, too. Eddington of the Royal Astronomical Society accepted the notice for publication in the Observatory. “It gives me quite a new appreciation of her personality,” he said in his thanks to Miss Cannon on July 3. In the same letter, Eddington, a Quaker and therefore a pacifist, lamented the violent turn of current events: “It is very sad, after the jolly days in Bonn, that this division should have come between us and our German colleagues.” The zeppelin that had so delighted the visiting astronomers in 1913 had become a force of destruction, dropping bombs on Great Britain. “If only there was mutual respect between the combatants, it would be a less depressing outlook,” Eddington wrote, “but I am afraid the contempt and hatred of Germans has increased over here very much in the last 3 months, though personally I have not yet got to the length of imagining, say, Max Wolf, as a ‘pirate and baby-killer.’ The knowledge that we have the sympathy of nearly all American astronomers is much appreciated, because you have so much more opportunity than we have of learning what is to be said in favour of the other side.”
Pickering, too, rued the war’s undoing of the friendly ties binding observatories around the world. Already the usual course of international communication regarding comets and asteroids had been disrupted. Copenhagen took the place of Kiel, Germany, as the designated European clearinghouse for such information, but most astronomers on the continent were cut off. Even the cables to Copenhagen became problematic, when military censors on both sides of the Atlantic refused to permit the use of ciphers—over the protests of astronomers, who had always coded their messages (by substituting words for digits) to avoid errors in transmitting long strings of numbers.
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PLEASED WITH MARGARET HARWOOD’S three productive summers on Nantucket, the Maria Mitchell Association granted her a quadrennial year, beginning June 15, 1915, to spend as she liked while still collecting her stipend of $1,000. She chose to go West, to assist at the Lick Observatory on Mount Hamilton while taking her master’s degree in astronomy at the University of California, Berkeley.
“Dear Miss Cannon,” she wrote June 23 on Lick stationery, “This letter is really to both you and Professor Pickering.” She had too much to say to try to say it all twice.
“The trip out was perfect in every way.” Miss Harwood had stayed with Edwin and Mary Frost at the Yerkes Observatory in Williams Bay, Wisconsin, and been entertained by Percival Lowell’s staff in Flagstaff. In the Pasadena office and workshop of the Mount Wilson Observatory, she had met Harlow Shapley.
“I was having a good time talking variables with Mr. Shapley that first afternoon,” Miss Harwood reported, “when his telephone rang and he answered by asking whoever wanted him to call up again in half an hour. I objected but he said it was nothing important and we went on. In about three quarters of an hour more the telephone rang again and I started to go. He called me back saying that Mrs. Shapley was just calling to find out if I was coming to dinner with him. She had called before, but he was too busy talking to ask such an everyday question! So I went and had a delightful time. Mrs. Shapley is very attractive and young, and, if possible, more of a ‘shark’ than her husband.” Shapley had married his college sweetheart, Martha Betz, in Kansas City in April 1914, then boarded the train with her for a honeymoon trip to their new home in Pasadena.
“She was working for her philology degree at Bryn Mawr when she married,” Miss Harwood continued. “She plays the piano finely, tends the three months old baby girl (who is also a wonder and most attractive) and is a wonderful cook. Mr. Shapley has taught her astronomy so that she measures plates, works out the light curve of variables and writes out the discussion by herself. She is very shy and retiring and I found out almost nothing about her until I questioned Mr. Shapley on the way home [to the boardinghouse where several Mount Wilson computers lived]. She did play to me, however.”
The following day saw Miss Harwood ascend the winding road to the Mount Wilson summit, where she overnighted. “I stayed up until 1:00 AM watching Mr. Shapley photograph certain clusters. And I took a plate on Messier 3 with the 60 inch! I have not seen the plate yet and so better not be bragging. At 12 o’clock Mr. Hoge, the night assistant, makes cocoa in the kitchen of the 60-inch dome and we had a regular feast of strawberries, cocoa, toast and pilot bread. As each observer works all night, the midnight meal is very necessary and must go to the right spot.”
Miss Harwood’s big news for her mentors at Harvard concerned a forwarded letter that she had found waiting for her in Berkeley. It came from Ellen Fitz Pendleton, the president of Wellesley College, offering her a position as an instructor at “a salary of not less than $1,200” beginning in the 1916–1917 academic year, with the strong possibility of promotion and a pay increase in 1917–1918. The timing would allow her to complete her master’s degree, but she needed to make the Wellesley decision now.
Miss Cannon might well have thrilled at the prospect of her protégée on the faculty of her alma mater, but she balked at the thought that teaching would take Miss Harwood away from her ongoing research regarding the light curve of the asteroid Eros. Lydia Hinchman at the Maria Mitchell Association, who had been a teacher herself, thought abandoning research a terrible idea.
“I do not want to see her exchange the life of an astronomer for that of a teacher,” Mrs. Hinchman insisted to Miss Cannon on September 7, 1915. “A teacher grows weary and old before her time, but if I may judge from you my dear Miss Cannon, an astronomer is always young.”
Acting quickly, Mrs. Hinchman proposed that the association’s board designate Miss Harwood as the permanent fellow as well as director of the Maria Mitchell Observatory, with a salary to match the Wellesley offer. Her plan drew strong resistance from board member Anne Sewell Young of Mount Holyoke College. “While I value highly the very excellent work which Miss Harwood has done at Harvard as well as at Nantucket,” Dr. Young argued, “and appreciate the tact and good judgment which have so endeared her to the residents of Nantucket, I cannot approve of appointing a permanent Fellow as Director of the Nantucket Observatory. I strongly believe that the Cause of Astronomy as well as that of woman’s education will gain far more by continuing to offer one or more fellowships, giving opportunities for study and research to various women of ability or promise. . . . Those of us who are teaching know how few, even now, are the opportunities offered to women, and have been proud of this fellowship in astronomy. Miss Mitchell’s interest in ‘her girls’ was so great that it seems to me she would herself choose this for her memorial. I am very certain that my opinion is that of Prof. [Caroline] Furness of Vassar who did so much toward raising the fund, also of Prof. [Harriet] Bigelow of Smith, and Prof. [Sarah] Whiting of Wellesley College.”
Mrs. Hinchman bristled. As a blood relative of Miss Mitchell, she did not appreciate outsiders’ interpretations of the deceased astronomer’s wishes. Moreover Mrs. Hinchman and her husband, Charles, had contributed by far the largest sum and greatest effort toward the establishment of the fellowship. She steeled herself to sway the
board toward her opinion. “Meeting set for October 6 at the College Club,” she informed Miss Cannon, head of the fellowship committee. “I think they should know about Miss Harwood’s work, and experiences in the west. . . . I shall too make it as plain as I courteously can, that our observatory was meant for research— It was in no sense intended as a training school for teachers and the height of efficiency seems to me to have been reached, when its advantages provide the opportunity for a Fellow to complete undertaken work.” The other members voted along with her, and thereby made Miss Harwood, who happily accepted the directorship, the only woman in the world in charge of an independent observatory. She was thirty years old, the same age as Pickering when he took over at Harvard.
No sooner had Mrs. Hinchman won her way on Miss Harwood’s account than she saw the virtue of creating a second astronomical fellowship at Nantucket. She put together a committee that spent a year soliciting funds from Nantucketers, Harvard friends, and former students of Maria Mitchell. On November 16, 1916, in the Harvard Observatory, distinguished Vassar alumna Florence Cushing handed Pickering a check for $12,000 as an added surprise at the big surprise party celebrating his fortieth year as director. “It is our wish,” Miss Cushing told him, “that you will accept it with full power as to its use, and that in the future it will be managed with the same broad-minded fairness to women which has characterized your administration.”
The committee had thought of calling the second stipend the Harvard Fellowship, but President Lowell pointed out that the university’s name could not be attached to a fund controlled by an individual. At that, the Maria Mitchell Association moved to rename its new annual award the Edward C. Pickering Astronomical Fellowship for Women.
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“PRESIDENT WILSON HAS SEVERED diplomatic relations with Germany,” Miss Cannon wrote in her diary on Sunday, February 4, 1917. “The terrible submarine warfare is on again.” Pickering had discussed the submarine threat with the chairman of the U.S. Navy’s Consulting Board, Thomas Edison, at the start of the hostilities, suggesting strategies and offering all the resources of the Committee of 100 on Research. After the United States declared war on Germany in April 1917, Pickering bent his inventive mind more urgently to military needs. Together with Willard Gerrish, the observatory’s resident mechanical genius, he devised a means for heavy artillery operators to orient their equipment. The new device, like Pickering’s early photometers, relied on sighting the North Star. The War Department welcomed his model of the “Harvard Polaris Attachment,” and informed him of its plans to produce the instrument.
At Mount Wilson, Harlow Shapley announced his plans to enlist in the coast artillery, but Director George Ellery Hale advised him not to, on the grounds that he would likely be needed to help with crucial optical projects for the National Research Council. Shapley agreed to stay in Pasadena for the time being, keeping up his observations of clusters and Cepheids.
“Very much of my work on clusters,” Shapley wrote to Bailey on January 30, 1917, “has been the direct result of my conversation with you in Cambridge three years ago when you suggested the advantages of the Mount Wilson instruments and weather and when you expressed the hope that I would join in the study.” Since then Shapley had determined the distances to all the clusters that contained Cepheid-type variable stars, thanks to the period-luminosity relation. In so doing, he had assumed that Miss Leavitt’s law was not limited to the Magellanic Clouds, but could govern conditions anywhere.
To place the clusters not containing Cepheids, Shapley combined a variety of means and assumptions to leapfrog his way across space. Often he relied on other cluster variables that were faster-paced than Cepheids, but which seemed also to obey Miss Leavitt’s law. In August he wanted to pursue this line of thought with her, but she was away on vacation in Nantucket, visiting Miss Harwood.
In clusters too distant to reveal any variables, Shapley averaged the magnitudes of the thirty brightest stars he could espy. He then compared these averages with the average luminosity of the Cepheid-containing clusters, and deduced the greater distances accordingly. For clusters too far removed to be resolved into any stars at all, Shapley measured the one thing he could see—their apparent overall diameters, which he compared with the diameters of clusters whose distances he had already determined.
Shapley gauged the average cluster diameter to be about one hundred fifty light-years, or nine hundred trillion miles across. The range of cluster distances from the Sun reached the still more staggering numbers of fifteen thousand to two hundred thousand light-years. No other astronomer had stretched the bounds of the known universe to those extreme dimensions.
A chance encounter with ants on Mount Wilson briefly turned Shapley’s attention from the very big and distant to the small and close at hand. While watching patrols of trail-runner ants traverse the back of a concrete building, he noticed that they slowed from a run to a walk as they passed through the shade of the manzanita bushes. At first he presumed the ants were enjoying a cool respite, just as he was doing at that moment. “I began to wonder about this, however,” he recalled in his autobiography, “and soon I got a thermometer and a barometer and a hydrometer and all those ‘ometers,’ and a stop watch. I set up a sort of observing station while resting and getting ready for another night’s tussle with the globular clusters.” Shapley found that the ants set their pace by the ambient temperature. The higher the mercury, the faster they ran, even when carrying loads. No other factors, such as air pressure or humidity, affected their rate of travel. “I found it great fun to watch them.” Recording his ant observations as carefully as he treated any other scientific phenomenon, Shapley arrived at a temperature-speed ratio. He clocked ants in 35-degree cold (Liometopum apiculatum on the edge of a snow bank) and 103-degree heat (Tapinoma sessile in the den of Shapley’s Pasadena home, where he stripped off his clothes and turned up the thermostat to test the limit of the ants’ tolerance). He claimed he could tell the air temperature to within one degree by watching half a dozen ants pass through his “speed trap,” and he published his data on ant thermokinetics in the Proceedings of the National Academy of Sciences.
In time Shapley came to see the globular clusters as the scaffolding of the cosmos. Just as the planets orbited the Sun in a broad, flat plane, all the clusters appeared to occupy the same plane as the Milky Way. Together the clusters described an enormous ring around the perimeter of the galaxy. Shapley could tell by the distribution of the clusters that his own vantage point—atop Mount Wilson, riding planet Earth around the Sun—stood nowhere near the center of this great circle. Were he situated at the galactic center, he reasoned, he would see the clusters evenly spaced around him. As it was, when he looked in one direction he saw a sparse string of clusters, and in the opposite direction the “cluster of clusters” in Sagittarius. He concluded the center must lie in that direction. The Sun, though the center of the solar system, was not the hub of the universe. “Some of my series of papers on globular clusters published in 1917 and 1918 were rather revolutionary because the findings opened up a part of the universe that had not been known before,” he wrote of his bold speculation. In Shapley’s new cosmic picture, “the solar system is off center and consequently man is too, which is a rather nice idea because it means that man is not such a big chicken. He is incidental—my favorite term is ‘peripheral.’”
There was no telling how far into space astronomers might penetrate by the light of Miss Leavitt’s stars. Having limned the extent of the Milky Way on a foundation of Cepheids, Shapley recognized the need to refine Miss Leavitt’s magnitude measurements, to make sure they were strong enough to support his conclusions. In a letter to Pickering on July 20, 1918, Shapley stated, “I believe the most important photometric work that can be done on Cepheid variables at the present time is a study of the Harvard plates of the Magellanic clouds. Probably Miss Leavitt’s many other problems have interrupted and delayed her work on the variables o
f the clouds for the interval of six or seven years since her preliminary work was published.” No doubt her illness, which had been diagnosed as cancer, figured chief among Miss Leavitt’s problems, though her many other scientific assignments had effectively barred her from further pursuit of her Cepheid discoveries. Shapley closed his letter with a prediction: “The theory of stellar variation, the laws of stellar luminosities, the arrangement of objects throughout the whole galactic system, the structure of the clouds—all these problems will benefit directly or indirectly from a further knowledge of the Cepheid variables.”
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THE MEMBERS OF THE AAVSO, those devoted observers of the long-period variables, met in November 1918 at the Harvard College Observatory. They had been accustomed to getting together in Connecticut or New Jersey at the homes of the association’s officers, but now that Leon Campbell had returned from Peru and resumed close communication with the volunteers, the observatory served as the new unofficial headquarters. To further cement the Harvard connection, the organization inducted Solon Bailey, Annie Cannon, Henrietta Leavitt, and Edward Pickering as honorary members, with a special tribute for the director: “He has assisted us in everything that we have undertaken, and has carefully watched our progress along every step of the way.” Founder William Tyler Olcott compared Pickering’s manner to that of a benevolent older brother.
