Harriet Brooks was the discoverer of atomic recoil, as well as one of the first people to observe nuclear transmutation. And a badass.

From the Linda Hall Library, which provides a good overview of her associations with other scientists and her biography: https://www.lindahall.org/about/news/scientist-of-the-day/harriet-brooks

Marie Curie had assumed directorship of the lab at the Sorbonne following her husband’s death in April 1906. She was pleased with Brooks, her first hire, and invited the talented young scientist to stay on for at least another year. Brooks chose instead to rejoin Rutherford, who had moved to the University of Manchester. Eager to welcome her again, Rutherford supported Brooks’s fellowship application with a sterling letter of recommendation, in which he insisted that “next to Mme. Curie she is the most prominent woman physicist in the department of radioactivity.”

From Regina Nguyen, who provides additional details about her discoveries as well as the discrimination she faced: http://large.stanford.edu/courses/2018/ph241/nguyen2/

At Barnard, when she announced she was engaged to be married, administration asked her to resign because "according to the mores at the time, [women in academia] had to be of good Christian character and not only single but in no danger of marrying." [2] In a response letter to the dean, Brooks wrote, "I think it is a duty I owe to my profession and to my sex to show that a woman has a right to the practice of her profession and cannot be condemned to abandon it merely because she marries. I cannot conceive how womens colleges, inviting and encouraging women to enter professions can be justly founded or maintained denying such a principle."

Just thought I'd share this based lady with a July birthday since July is almost over :)