In 1901, the Royal Free Hospital appointed Florence into a new part-time position of medical electrician. The following April, the two sisters opened a new x-ray service in the electrical department. During their time at the Royal Free Hospital, the two sisters actively supported the women's suffrage movement, though opposed the direct violent action with which it was later associated. During her time at the school, she also played a central role in the British Federation of University Women (BFUW). She was elected treasurer, in her absence, at the first executive meeting on 9 October 1909, a position that she held until the end of May 1915. She became increasingly engaged with the political lobbying of the Federation. At the executive meeting on 19 October 1912, she proposed the names of two members for a subcommittee to secure the passing into law of a bill to enable women to become barristers, solicitors or parliamentary agents. The legislation was eventually enacted after the war within the Sex Disqualification (Removal) Act 1919. Edith Stoney resigned her post at the school in March 1915 and it was recorded that ‘with due regret and most unwillingly a change is desirable in the physics lectureship’. Edith Stoney was offered £300 on tendering her resignation.