Peter Guthrie Tait (28 April 1831 – 4 July 1901) was a Scottish mathematical physicist, best known for the seminal energy physics textbook Treatise on Natural Philosophy, which he co-wrote with Kelvin, and his early investigations into knot theory, which contributed to the eventual formation of topology as a mathematical discipline.

in an address to the University of Edinburgh graduates, as quoted by Cargill Gilston Knott (1911). Life and scientific work of Peter Guthrie Tait. Cambridge University Press. p. 11.

Peter Guthrie Tait — in Note on a Quaternion Transformation , Communication read on Monday, 6th April, 1863, Proceedings of the Royal Society of Edinburgh (1866), p. 117.

Peter Guthrie Tait — when complimented about coaching his one pupil scoring higher than his rival's pupils at Peterhouse Tripos, as quoted by Cargill Gilston Knott (1911). Life and scientific work of Peter Guthrie Tait. Cambridge University Press. p. 11.