Also by Dava Sobel
Longitude
Galileo’s Daughter
Letters to Father
The Planets
A More Perfect Heaven
And the Sun Stood Still (a play)
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Here: Angelo Secchi, Le soleil, 1875–1877.
Here: Courtesy of Carbon County Museum, Rawlins, Wyoming
Here: UAV 630.271 (E4116), Harvard University Archives
Here: Courtesy of Harvard College Observatory
Here: Schlesinger Library, Radcliffe Institute, Harvard University; here: Courtesy of Hastings Historical Society, New York
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Library of Congress Cataloging-in-Publication Data
Names: Sobel, Dava.
Title: The glass universe : how the ladies of the Harvard Observatory took the measure of the stars / Dava Sobel.
Identifiers: LCCN 2016029496 (print) | LCCN 2016030208 (e-book) | ISBN 9780670016952 (hardcover) | ISBN 9780698148697 (e-book)
Subjects: LCSH: Women in astronomy—Massachusetts—History. | Women mathematicians—Massachusetts—History. | Astronomy—History—19th
century. | Astronomy—History—20th century. | Harvard College Observatory.
Classification: LCC QB34.5 .S63 2016 (print) | LCC QB34.5 (ebook) | DDC
522/.19744409252—dc23
LC record available at https://lccn.loc.gov/2016029496
Printed in the United States of America
Version_1
To the ladies who sustain me:
Diane Ackerman, Jane Allen,
KC Cole, Mary Giaquinto, Sara James, Joanne Julian,
Zoë Klein, Celia Michaels, Lois Morris,
Chiara Peacock, Sarah Pillow,
Rita Reiswig, Lydia Salant, Amanda Sobel,
Margaret Thompson, and Wendy Zomparelli,
with love and thanks
CONTENTS
Also by Dava Sobel
Title Page
Copyright
Dedication
Preface
PART ONE
The Colors of Starlight
CHAPTER ONE
Mrs. Draper’s Intent
CHAPTER TWO
What Miss Maury Saw
CHAPTER THREE
Miss Bruce’s Largesse
CHAPTER FOUR
Stella Nova
CHAPTER FIVE
Bailey’s Pictures from Peru
PART TWO
Oh, Be A Fine Girl, Kiss Me!
CHAPTER SIX
Mrs. Fleming’s Title
CHAPTER SEVEN
Pickering’s “Harem”
CHAPTER EIGHT
Lingua Franca
CHAPTER NINE
Miss Leavitt’s Relationship
CHAPTER TEN
The Pickering Fellows
PART THREE
In the Depths Above
CHAPTER ELEVEN
Shapley’s “Kilo-Girl” Hours
CHAPTER TWELVE
Miss Payne’s Thesis
CHAPTER THIRTEEN
The Observatory Pinafore
CHAPTER FOURTEEN
Miss Cannon’s Prize
CHAPTER FIFTEEN
The Lifetimes of Stars
Photographs
Appreciation
Sources
Some Highlights in the History of the Harvard College Observatory
Glossary
A Catalogue of Harvard Astronomers, Assistants, and Associates
Remarks
Bibliography
Index
PREFACE
A LITTLE PIECE OF HEAVEN. That was one way to look at the sheet of glass propped up in front of her. It measured about the same dimensions as a picture frame, eight inches by ten, and no thicker than a windowpane. It was coated on one side with a fine layer of photographic emulsion, which now held several thousand stars fixed in place, like tiny insects trapped in amber. One of the men had stood outside all night, guiding the telescope to capture this image, along with another dozen in the pile of glass plates that awaited her when she reached the observatory at 9 a.m. Warm and dry indoors in her long woolen dress, she threaded her way among the stars. She ascertained their positions on the dome of the sky, gauged their relative brightness, studied their light for changes over time, extracted clues to their chemical content, and occasionally made a discovery that got touted in the press. Seated all around her, another twenty women did the same.
The unique employment opportunity that the Harvard Observatory afforded ladies, beginning in the late nineteenth century, was unusual for a scientific institution, and perhaps even more so in the male bastion of Harvard University. However, the director’s farsighted hiring practices, coupled with his commitment to systematically photographing the night sky over a period of decades, created a field for women’s work in a glass universe. The funding for these projects came primarily from two heiresses with abiding interests in astronomy, Anna Palmer Draper and Catherine Wolfe Bruce.
The large female staff, sometimes derisively referred to as a harem, consisted of women young and old. They were good at math, or devoted stargazers, or both. Some were alumnae of the newly founded women’s colleges, though others brought only a high school education and their own native ability. Even before they won the right to vote, several of them made contributions of such significance that their names gained honored places in the history of astronomy: Williamina Fleming, Antonia Maury, Henrietta Swan Leavitt, Annie Jump Cannon, and Cecilia Payne. This book is their story.
PART ONE
The Colors of Starlight
I swept around for comets
about an hour, and then I amused myself with noticing the varieties of color. I wonder that I have so long been insensible to this charm in the skies, the tints of the different stars are so delicate in their variety. . . . What a pity that some of our manufacturers shouldn’t be able to steal the secret of dyestuffs from the stars.
—Maria Mitchell (1818–1889)
Professor of Astronomy, Vassar College
The white mares of the moon rush along the sky
Beating their golden hoofs upon the glass heavens
—Amy Lowell (1874–1925)
Winner of the Pulitzer Prize for Poetry
CHAPTER ONE
Mrs. Draper’s Intent
THE DRAPER MANSION, uptown on Madison Avenue at Fortieth Street, exuded the new glow of electric light on the festive night of November 15, 1882. The National Academy of Sciences was meeting that week in New York City, and Dr. and Mrs. Henry Draper had invited some forty of its members to dinner. While the usual gaslight illuminated the home’s exterior, novel Edison incandescent lamps burned within—some afloat in bowls of water—for the amusement of the guests at table.
Thomas Edison himself sat among them. He had met the Drapers years ago, on a camping trip in the Wyoming Territory to witness the total solar eclipse of July 29, 1878. During that memorable interlude of midday darkness, as Mr. Edison and Dr. Draper executed their planned observations, Mrs. Draper had dutifully called out the seconds of totality (165 in all) for the benefit of the entire expedition party, from inside a tent, where she remained secluded, blind to the spectacle, lest the sight of it unnerve her and cause her to lose count.
The red-haired Mrs. Draper, an heiress and a renowned hostess, surveyed her electrified salon with satisfaction. Not even Chester Arthur in the White House lighted his dinner parties with electricity. Nor could the president attract a more impressive assembly of science’s luminaries. Here she welcomed the well-known zoologists Alexander Agassiz, down from Cambridge, Massachusetts, and Spencer Baird, up from the Smithsonian Institution in Washington. She introduced her family friend Whitelaw Reid of the New York Tribune to Asaph Hall, world famous for his discovery of Mars’s two moons, and to solar expert Samuel Langley, as well as to the directors of every prominent observatory on the Eastern Seaboard. No astronomer in the country could refuse an invitation to the home of Henry Draper.
It was her home, in fact—her childhood home, built by her late father, the railroad and real estate magnate Cortlandt Palmer, long before the neighborhood became fashionable. Now she made certain the house suited Henry as perfectly as she did, with its entire third floor converted into his machine workshop, and the loft over the stable repurposed as his chemical laboratory, which he reached via a covered walkway connected to the dwelling.
She had barely heeded the stars before meeting Henry, any more than she regarded grains of sand at the shore. He was the one who pointed out to her their subtle colors and differences in brightness, even as he whispered his dream of abjuring medicine for astronomy. If she feigned interest at first to please him, she had long since found her own passion, and proved a willing partner in observation as in marriage. How many nights had she knelt by his side in the cold and dark, spreading foul-smelling emulsion on the glass photographic plates he used with his handcrafted telescopes?
A glance at Henry’s plate confirmed he had not touched the banquet fare. He was fighting a cold, or perhaps it was pneumonia. A few weeks earlier, while he and his old Union Army pals were hunting in the Rocky Mountains, a blizzard had struck and stranded them above the timberline, far from shelter. The chill and exhaustion of that exposure still plagued Henry. He looked terrible, as though suddenly an old man at forty-five. Yet he continued chatting amiably with the company, explaining anew, each time anyone asked, how he had generated steady current for the Edison lamps from his own gas-powered dynamo.
Soon she and Henry would be leaving the city for their private observatory upriver at Hastings-on-Hudson. Now that he had finally resigned his professorship on the faculty at New York University, they could devote themselves to his most important mission. In their fifteen shared years, she had seen his landmark achievements in stellar photography win him all manner of acclaim—his 1874 gold medal from Congress, his election to the National Academy of Sciences, his status as a fellow of the American Association for the Advancement of Science. What would the world say when her Henry resolved the seemingly intractable age-old mystery of the chemical composition of the stars?
After bidding the guests good-night at the close of that glittering evening, Henry Draper took a hot bath, then took to his bed, and stayed there. Five days later he was dead.
• • •
IN THE OUTFLOW OF CONDOLENCES following her husband’s funeral, Anna Palmer Draper drew some comfort from a correspondence with Professor Edward Pickering of the Harvard College Observatory, one of the guests at the Academy gathering the night of Henry’s collapse.
“My dear Mrs. Draper,” Pickering wrote on January 13, 1883, “Mr. Clark [of Alvan Clark & Sons, the preeminent telescope makers] tells me that you are preparing to complete the work in which Dr. Draper was engaged, and my interest in this matter must be my excuse for addressing you regarding it. I need not state my satisfaction that you are taking this step, since it must be obvious that in no other way could you erect so lasting a monument to his memory.”
This was indeed Mrs. Draper’s intention. She and Henry had no children to carry on his legacy, and she had resolved to do so on her own.
“I fully appreciate the difficulty of your task,” Pickering continued. “There is no astronomer in this country whose work would be so hard to complete as Dr. Draper’s. He had that extraordinary perseverance and skill which enabled him to secure results after trials and failures which would have discouraged anyone else.”
Pickering referred specifically to the doctor’s most recent photographs of the brightest stars. These hundred-some pictures had been taken through a prism that split starlight into its spectrum of component colors. Although the photographic process reduced the rainbow hues to black and white, the images preserved telltale patterns of lines within each spectrum—lines that hinted at the stars’ constituent elements. In after-dinner conversation at the November gala, Pickering had offered to help decipher the spectral patterns by measuring them with specialized equipment at Harvard. The doctor had declined, confident that his new freedom from teaching at NYU would allow him time to build his own measuring apparatus. But now all that had changed, and so Pickering repeated the offer to Mrs. Draper. “I should be greatly pleased if I might do something in memory of a friend whose talents I always admired,” he wrote.
“Whatever may be your final arrangements regarding the great work you have undertaken,” Pickering said in closing, “pray recollect that if I can in any way advise or aid you, I shall be doing but little to repay Dr. Draper for a friendship which I shall always value, but which can never be replaced.”
Mrs. Draper rushed to reply just a few days later, January 17, 1883, on notepaper edged in black.
“My dear Prof. Pickering:
“Thanks so very much for your kind and encouraging letter. The only interest I can now take in life will be in having Henry’s work continued, yet I feel so very incompetent for the task that my courage sometimes completely fails me— I understand Henry’s plans and his manner of working, perhaps better than anyone else, but I could not get along without an assistant and my main difficulty is to find a person sufficiently acquainted with physics, chemistry, and astronomy to carry on the various researches. I will probably find it necessary to have two assistants, one for the Observatory and one for the laboratory work, for it is not likely that I will find any one person with the varied scientific knowledge that was peculiar to Henry.”
She was prepared to pay good salaries in order to draw the most qualified men as assistants. She and her two brothers had inherited their father�
��s vast real estate holdings, and Henry had managed her share of the fortune to excellent effect.
“It is so hard that he should be taken away just as he had arranged all his affairs to have time to do the work he really enjoyed, and in which he could have accomplished so much. I cannot be reconciled to it in any way.” Nevertheless she hoped to get the work running as soon as possible under her own direction, and “then, when I can buy the place at Hastings where the Observatory is, to do so.”
Henry had built the facility on the grounds of a country retreat owned by his father, Dr. John William Draper. The elder Dr. Draper, the first physician in the family to mix medicine with active research in chemistry and astronomy, had died a widower the previous January. His will bequeathed his entire estate to his beloved spinster sister, Dorothy Catherine Draper, who had founded and run a girls’ school in her youth to finance his education. It was not yet clear whether Henry’s widow would win control of the Hastings property as she wished, and move Henry’s Madison Avenue laboratory there, and endow the site as an institution for original research, to be named the Henry Draper Astronomical and Physical Observatory.
“As long as I could I should keep the direction of the institution myself,” she told Pickering. “It seems the only suitable memorial I can erect to Henry, and the only way to perpetuate his name and his work.”
At the end she entreated Pickering’s counsel. “I am so unusually alone in the world, that without feeling that those friends who were interested in Henry’s work would advise me, I could not do anything.”
Pickering encouraged her to publish her husband’s findings to date, since it might take her a long time to add to them. Once again he extended his offer to examine the glass photographic plates on the measuring machine at Harvard, if she would be so good as to send him some.
Mrs. Draper agreed but thought it best to deliver the plates in person. They were small objects, only about an inch square each.
“I may be obliged to go to Boston in the course of the next ten days to attend to some business matters with one of my brothers,” she wrote on January 25. “If so I could take the negatives with me and by going to Cambridge for part of a day, if it was convenient for you, could look over the pictures with you, and see what you think of them.”