Few African-American women were involved in STEM subjects over the Twentieth Century, and there are still not as many as there should be. However one successful mathematician in that period was both black and female. She was Martha Euphemia Lofton Haynes.
Born in Washington, DC, to a dentist father and a mother who was very active in the Catholic church, Euphemia (she rarely used Martha) graduated from Smith College in 1914 with a major in mathematics and a minor in psychology. In 1917 she married Harold Appo Haynes, who eventually became a principle and deputy superintendent of the "colored" schools in Washington. She earned a master's from the University of Chicago in 1930 in education, and went on to obtain a doctorate in mathematics from The Catholic University in Washington in 1943. She was the first female African-American to get a Ph.D. in mathematics. Her dissertation was titled "The Determination of Sets of Independent Conditions Characterizing Certain Special Cases of Symmetric Correspondences." Rather than go into research she pursued a career in public school teaching, spending 47 years teaching high school mathematics, becoming the first woman to chair the D.C. school board. She played a major role in the integration of D.C. schools. She also taught mathematics at two teachers' colleges and occasionally lectured at Howard University.
On her death at 90 she bequeathed $700,000 to The Catholic University to create the Euphemia Lofton Haynes Chair in the Department of Education.
Haynes broke numerous barriers during her long life. She was proof that women and African-Americans could succeed in the abstract world of advanced mathematics and also teach this subject. This was long before affirmative action and she thus had to succeed despite prejudice against both females and African-Americans in academia. She was indeed a very remarkable individual!
Internet References:
Martha Euphemia Lofton Haynes http://www.math.buffalo.edu/...
Euphemia Lofton Haynes http://www.agnesscott.edu/...
Martha Euphemia Lofton Haynes, a leader in education, community and the church. http://www.aaregistry.org/...