English mathematician who wrote about sundials, cartography, accounting, navigational trigonometry, and the quadrant. An apprentice bookseller in Oxford, Collins became a clerk at Court and studied mathematics. To avoid the English Civil War he went to sea, where he continued his studies. Collins had a number of jobs, from mathematics teacher to accountant. He corresponded with many mathematicians, including Isaac Newton and Gottfried Leibniz, and helped publish important mathematical texts. Collins also became a member and librarian of the Royal Society.