Haynes' father attended the Philadelphia Centennial Exposition in 1876 where he learned of a school that would fit his son's interests. Using the money he had saved, Haynes decided to attend the college and enrolled in the Worcester Technical Institute in Worcester, Massachusetts, in September 1878. The school was revolutionary for its time, combining technical training with a classical liberal arts education. Although he easily passed the difficult entrance exam, he found that he was ill-prepared for some of his college courses, and he struggled with mathematics. To earn an income while away from home, he worked as a custodian and night guard at the local public library. He cleaned the building overnight and used his spare time to read books and study. During his final year at the school, boarding rates were increased beyond what Haynes could afford so with no other option, he lived in the library for several months. He could not afford to return home during his stay at the institute, so during the holidays he spent time with his family and friends in New England.