Here, Mary Seton is explaining to the narrator how the paucity of the finance available to establish Fernham (only £30,000) meant that there was no money to spare for those luxuries (or 'amenities') that were available in the men's colleges.
The reference to the lack of 'amenities' (as noted in the footnote) is made by R. Strachey in The Cause.
The full title of the book referred to is The Cause: A Short History of the Women's Movement in Great Britain (Port Washington: Kennikat Press (1928), reprinted 1969).
Its author's full name was Rachel Conn Costelloe Strachey (1887-1940), usually known as Ray Strachey, a feminist writer of the early part of the 20th century who wrote widely on women's issues. She was also a writer of fiction and biography.