WILLIAM JONES

William Jones (1675 – 3 July 1749) was a Welsh mathematician, born in the village of Llanfihangel Tre'r Beirdd, on the Isle of Anglesey.

He owed his successful career partly to the patronage of the distinguished Bulkeley family of north Wales, and later to the Earl of Macclesfield.

Jones served at sea, teaching mathematics on board ship between 1695 and 1702. After his voyages were over he became a mathematics teacher in London. He also held a number of posts in government offices.

As a mathematician, his most noted contribution is his proposal for the use of the symbol π (the Greek letter pi) to represent the ratio of the circumference of a circle to its diameter. He became a close friend of Sir Isaac Newton and Sir Edmund Halley. In 1712, he became a Fellow of the Royal Society, and was later its Vice-President.

Jones published Synopsis Palmariorum Matheseos in 1706 , a work which was intended for beginners and which included theorem on differential calculus and infinite series. Navigation was also a topic which interested Jones; his first published work was A New Compendium of the Whole Art of Navigation. In 1731 he published Discourses of the Natural Philosophy of the Elements.
His son, also named William Jones, was a renowned philologist who discovered the Indo-European language group.