"After his graduation, he was kept at Hanover four years; the first, as the preceptor of Moor's Indian Charity School, and the following three as tutor in the college. During this period he joined the college church, and formed his purpose to prepare for the ministry, and spent nearly two years at the Theological Seminary, in Andover, Mass. He was appointed to a professorship of Latin and Greek, in 1833. In 1837 he was released from the Latin and became professor of Greek only, which office he held until 1849, when he resigned; but he remained Professor _Emeritus_ until his death.
"In 1834 he married Miss Abigail Grant Jones Cutler, only child of Joseph and Abigail Cheesboro Grant (Jones) Cutler, of Newburyport, Mass. Mrs. Crosby becoming an invalid, Professor Crosby took her to Europe and traveled with her through England, Germany, and France, until they reached Paris, where Mrs. Crosby died. On his return he resumed the duties of his professorship. After the death of his father-in-law, Mr. Cutler, he resigned his professorship, and removed to Newburyport to care for Mrs. Cutler, who was an invalid. His Greek Grammar, theological disquisitions, and the superintendency of schools in Newburyport occupied his attention until Mrs. Cutler's death in 1854, when he entered into the employment of the Board of Education in Massachusetts as its agent. In this capacity he rendered the State most valuable services by visiting the public schools in various parts of the State, and by his instructive and practical lectures on educational subjects. So efficient were his labors, that in 1857 he was appointed by the Board of Education to the principalship of the State Normal School in Salem; this important post he occupied eight years. To the interests of this school he zealously devoted his great knowledge and ability, raising it to a high standard of excellence and giving to it a most honorable reputation. He gave the school the largest part of its valuable library, and obtained for its use the most of its considerable cabinet. By his heartfelt kindness and his faithful instructions he secured the love and profound esteem of his pupils, who will ever hold him in affectionate remembrance. In the Normal School and elsewhere, as he had opportunity, Professor Crosby earnestly advocated the liberal education of women, believing that their educational advantages ought to equal those enjoyed by men.