May 22, 1874 - April 13, 1945
Cowley taught at Vassar College from 1902 to 1926. In 1913 she was promoted to assistant professor, in 1916 to associate professor. In 1926 she took a three-year leave of absence to go to Pittsburgh to be with her mother. From 1908 until 1926 she served as an associate editor for the Dutch review journal Revue Semestrielle des Publications Mathématiques, in addition to her responsibilities at Vassar. Cowley officially resigned from Vassar in 1929 to stay in Pittsburgh. From 1926 to 1937 Cowley taught plane and solid geometry at the Allegheny Senior High School in Pittsburgh. She served as the vice-president and president of the mathematics section of the Pennsylvania State Education Association. She also served for a number of years as a reader in mathematics for the College Entrance Examination Board.
Cowley wrote a number of articles that were published in journals such as the Journal of Educational Research, the Bulletin of the American Mathematical Society, the American Mathematical Monthly, The Mathematics Teacher, and the Journal of the American Association of University Women. In 1907 Cowley and Ida Whiteside submitted a prize-winning paper on "Definitive Orbit of Comet 1826II," published by the Astronomische Nachrichten, for which they received a prize of 100 marks from the German Astronomical Society. A 1926 paper in the American Mathematical Monthly discussed a "Note on a Linear Diophantine Equation." This note concerned a generalized version of the classic arithmetic measuring problem where it is required to divide into two equal parts the contents of an 8-ounce vase if the only empty vases hold 5 ounces and 3 ounces respectively. Nearly the same problem appeared in the 1995 movie "Die Hard 3" in which a bomb will explode if the hero (played by Bruce Willis) cannot solve that problem within a couple of minutes.
Cowley also wrote a book on plane geometry (1932) and another book on solid geometry (1934). Both of these books were written primarily for use in the high schools. Cowley wrote a 1928 article for the MAA Monthly in which she addressed the controversy about teaching solid geometry in the high schools. She noted that the former requirement of solid geometry in the freshman year of college had been abolished by practically every college, and that critics wanted to replace solid geometry in the first year by an introduction to the calculus, placing more stress upon solid geometry in the high school. Cowley defended the teaching of solid geometry in the schools, saying that "students who have studied this subject in a good high school compete successfully with those who have had the college course when they take uniform examinations in the subject or when they pursue college courses in analytic geometry and in the calculus."