Every evening Miss Mitchell spent on the housetop "sweeping" the heavens. One memorable evening, October 1, 1847, she had put on her old clothes and taken her lantern to the roof as usual. After gazing through her telescope for a few minutes, she observed an object which she concluded must be a comet. Hurriedly she called her father, who also examined the unusual body in the heavens and agreed with her that it was a comet. He immediately announced the discovery to Professor Bond of Cambridge. It was learned afterward that the same comet had been seen in Rome by an astronomer on October 3, and in England by another on October 7, and still later in Germany. To Maria Mitchell was given the credit of the first discovery, and she received the gold medal which had been promised by the King of Denmark to the first discoverer of a telescopic comet. This brought her letters of congratulation from astronomers in all parts of the world. Miss Mitchell had always had a desire to travel abroad, and as her tastes were simple she soon saved enough from her small salary to enable her to do so. During her visits in foreign countries, she met many eminent scientists, among them Herschel, Airy, Mrs. Somerville, and Humboldt. The plain Nantucket lady was perfectly at home in the society of these distinguished people, whose tastes and occupations were similar to her own. They all opened their observatories for her inspection and their homes for social intercourse. The Greenwich Observatory especially interested Miss Mitchell. It stands in Greenwich Park, which comprises a group of hills with many beautiful oak trees which are said to date back to the time of Queen Elizabeth. The observatory was then in charge of Sir George Airy, who showed Miss Mitchell all the treasures of the place, among them the instruments used by the great astronomers Halley, Bradley, and Pond. The meridian of Greenwich is the zero point of longitude for the globe, and you can perhaps imagine the pleasure which Miss Mitchell experienced in being on the spot where time is set for the whole world. Miss Mitchell became Professor of Astronomy and Director of the Observatory at Vassar College, where her work gave the subject a prominence which it has never had in any other woman's college. She was not only a famous astronomer, but a noble, inspiring woman, much interested in the higher education of women and devoting much of her time to advancing this work. Many a young girl can trace the success of her life work to the impulse she received from Maria Mitchell. At the age of sixty-nine Miss Mitchell's health began to fail and she resigned her position in the College, going to live at her home in Lynn, Massachusetts, where she died June 28, 1889. [Illustration: LUCY STONE] LUCY STONE (1818-1893) "Woman is a creation between men and the angels." —_Honoré de Balzac_