He resigned this last appointment and his college lectureship of modern history (which he held for nearly forty years) in the summer of 1894, but he retained the place of librarian.
[1] On the formation of the Oxford Historical Society in 1884 Boase was one of the honorary secretaries, and he acted on the committee to 1 June 1892.
His library and manuscripts, including collections on Cornish genealogy, were dispersed at the time of his death.
He also wrote the preface to Thorold Rogers's Oxford City Documents, 1268-1665, which the society issued in 1891.
In with his two brothers he compiled an Account of the Families of Boase or Bowes, tracing ancestors back in West Cornwall to the end of the sixteenth century.
He contributed to the Literary Churchman, The Academy, and English Historical Review, wrote the article "Macedonian Empire" in the Encyclopædia Britannica, 9th edition, and the lives of the Cornish saints in William Smith's Dictionary of Christian Biography.