Nicholas Saunderson, blinded in infancy, built a tactile calculating device he called his 'palpable arithmetic'

Nicholas Saunderson (1682–1739), who lost his sight to smallpox as an infant, devised a pin-and-board calculating apparatus for doing arithmetic and algebra by touch — "a calculating machine or abacus, by which he could perform arithmetical and algebraic operations by the sense of touch; it was known as his 'palpable arithmetic.'" The device let him carry out computation without any visual representation, substituting a manipulable physical layout for the written symbols he could not read.

Saunderson was not a marginal figure working around his blindness at the edge of the discipline: in 1711 he succeeded William Whiston as the Lucasian Professor of Mathematics at Cambridge — the chair Isaac Newton had held before him and Stephen Hawking would hold centuries later. Because he had no formal degree, the heads of the Cambridge colleges petitioned Queen Anne to grant him an emergency Master of Arts so that he would qualify for the professorship. A blind man thus held the era's premier English mathematical chair, having built his own hardware to do the work at all.

This is the earliest documented case in the recurring pattern described at claim-blind-mathematicians-independently-reinvented-private-notation, whose 20th-century echo is claim-pontryagin-worked-blind-via-mothers-spoken-symbol-glosses — a blind mathematician (co-creator of the Soviet optimal-control theory that parallels the claim-kelley-bryson-optimal-control-precursor lineage) who worked instead through an ad hoc oral notation. The open thread on whether this is a genuine pattern is question-blind-mathematicians-private-notation-pattern.