As an MP he lived at 33 Onslow Square, Kensington, and was a member of the Reform Club.Who's Who of British Parliamentary Members, 4 vols, London, vol.2, p.263. Mason supported many reformist bills and became a spokesman of the Women's Suffrage Association in 1881. He proposed motions for women's suffrage in 1881 and again in 1883 but was defeated on both occasions. He led the women's suffrage movement until 1883 when illness forced him to retreat from public life temporarily. His defeat in the 1885 General Elections was ascribed to his support of William Ewart Gladstone over the issue of Irish Home Rule and to his illness. He lost to the Conservative John Wentworth Addison by 3,152 votes to 3,104. Mason demanded a recount, but this increased the majority by one vote; he succumbed to illness and died before the result was announced.
