William Jones (mathematician)

William Jones, FRS (1675  1 July 1749[1]) was a Welsh mathematician, most noted for his use of the symbol π (the Greek letter Pi) to represent the ratio of the circumference of a circle to its diameter. He was a close friend of Sir Isaac Newton and Sir Edmund Halley. In November 1711 he became a Fellow of the Royal Society, and was later its vice-president.[2]

William Jones
Portrait of William Jones by William Hogarth, 1740 National Portrait Gallery
Llanfihangel Tre'r Beirdd,
Isle of Anglesey
Died3 July 1749 (aged 73-74)
London, England