Tait, Peter Guthrie (1831–1901)
Peter Tait was a Scottish scientist and mathematician who carried out the world's first systematic investigation of knot theory. Early in his career he formed a friendship with William Hamilton and became fascinated in the application of Hamilton's quaternions to problems in physics. In 1857, he also took an interest in Hermann Helmholtz's theories on the behavior of vortex rings, and began experimenting with smoke rings and their interactions. These experiments greatly impressed William Thomson (Lord Kelvin) who saw in them a possible way (wrong, as we now know) to explain atomic structure and the buildup of different elements. This idea, in turn, led Tait, Thomson, and James Maxwell to do seminal work on knot theory, since the basic building blocks in Thomson's vortex atom model were rings knotted in three dimensions. Without any rigorous theory, which would have been well beyond 19th-century mathematics, Tait began to classify knots using his geometric intuition. By 1877 he had classified all knots with seven crossings. He then went on to consider the coloring of graphs and put forward a hypothesis (see Tait's conjecture) which, if true (which it wasn't), would have proved the four-color theorem. Among his many other accomplishments, Tait wrote a classic paper on the trajectory of golf balls (1896). This was a subject close to his heart because the third of his four sons was Frederick Gutherie Tait, the leading amateur golfer in 1893 and winner of the Open Golf Championship in 1896 and 1898.