John Machin

John Machin (baptised about 1686, died 1751) was a professor of astronomy at Gresham College, London, best known for developing a quickly converging series for pi in 1706 and using it to compute pi to 100 decimal places. His formula, a variation on the Gregory and Leibniz series using the inverse tangent, converged much faster and so made the calculation far more practical, and it remained the primary tool of pi-hunters for centuries, well into the computer era. He served as secretary of the Royal Society from 1718 to 1747, was a member of the commission that in 1712 decided the priority dispute between Leibniz and Newton over the calculus, and on 16 May 1713 succeeded Alexander Torriano as professor of astronomy at Gresham College, a post he held until his death in London. He enjoyed a high mathematical reputation, and his ingenious quadrature of the circle was later studied by Charles Hutton. The Royal Astronomical Society preserves a mass of his manuscripts.