A blind mathematician and scientist, Nicholas Saunderson
had an unusual academic career. Denied admission to Cambridge University, he was nevertheless permitted to teach there by William Whiston, whom he then succeeded as Lucasian professor
. Ironically for a blind man, he lectured on optics. He invented a type of abacus on which he could perform complex calculations by touch alone. He avoided the Church, so that Edmund Halley was quoted as saying: "Whiston was dismissed for having too much religion, and Saunderson preferred for having none."
Elements of Algebra: the book that captivated Harrison.