The papers of the Fortnightly Ignorance Club consist of two manuscript volumes containing minutes of the group's meetings, correspondence, newspaper clippings, and club budgets. The correspondence, between recording secretary Jenny Marsh Parker and notable women reformers (including Marie E. Zakrzewska and Susan B. Anthony), is interleaved in the volumes and indexed. The two volumes cover the periods 1881 to 1883 (volume 1) and 1886 to 1891 (volume 3) with a gap during the intervening years.

The papers consist of four large scrapbooks containing original letters (including some from his friend George Eastman), photographs, newspaper clippings, programs, etc. relating to Hubbell and his life, family and career. Also with the papers are eighteen letters and telegrams not with the scrapbooks from such people as Theodore Roosevelt (10 items), William C. Bryant (1 item), Booker T. Washington (1 item) and Susan B. Anthony (1 item). These eighteen letters are indexed in the Department's card catalog index to individual manuscripts.