John Pell

John Pell
John Pell (1611-1685).
Born	(1611-03-01)1 March 1611 Southwick, Sussex, England
Died	12 December 1685(1685-12-12) (aged 74) Westminster, London, England
Residence	England
Nationality	English
Fields	Mathematician and linguist
Institutions	University of Amsterdam
Alma mater	Trinity College, Cambridge
Doctoral students	William Brereton
Known for	Pell's equation Pell number
Influences	Henry Briggs

John Pell (1 March 1611 – 12 December 1685) was an English mathematician.

He was born at Southwick in Sussex. His father, also named John Pell, was from Southwick, and his mother was Mary Holland, from Halden in Kent. He was the second of two sons, and by the age of six he was an orphan, his father dying in 1616 and his mother the following year. John Pell senior had a fine library and this proved valuable to the young Pell as he grew up. He was educated at Steyning Grammar School, and entered Trinity College, Cambridge, at the age of thirteen. During his university career he became an accomplished linguist, and even before he took his B.A. degree (in 1629) corresponded with Henry Briggs and other mathematicians. He received his M.A. in 1630, and taught in the short-lived Chichester Academy, set up by Samuel Hartlib. On 3 July 1632 he married Ithamaria Reginald (also rendered variously as Ithamara or Ithumaria, with the surname Reginolles), sister of Bathsua Makin. They went on to have four sons and four daughters. Ithumaria died in 1661, and some time before 1669 he remarried.

Pell spent much of the 1630s working under Hartlib's influence, on a variety of topics in the area of pedagogy, encyclopedism and pansophy, combinatorics and the legacy of Trithemius. By 1638 he had formulated a proposal for a universal language. In mathematics, he concentrated on expanding the scope of algebra in the theory of equations, and on mathematical tables. As part of a joint lobbying effort with Hartlib to find himself support to continue as a researcher, he had his short Idea of Mathematics printed in October 1638. The campaign brought interested responses from Johann Moriaen and Marin Mersenne.