John Pell | Biography

John Pell wrote or contributed to several useful books on algebra and the study of mathematics itself. He was particularly known for his work on the algebraic equation, first studied by Brahmagupta, y²=ax² + 1, where "a" is a non-square integer.

Pell was born on March 1, 1611 (some sources say 1610) in Southwick, Sussex, England, the son of a vicar. He was only a small boy when both of his parents died, but it is not clear who raised him or where. He received his early education at the Steyning School in Sussex, leaving when he was 13 to begin studying at Trinity College in Cambridge, England. Pell received a bachelor's degree from the school in 1629, having published his "Description and Use of the Quadrant" in 1628, and a master's degree the following year.

In 1630, Pell worked as the assistant master at Collyer's School in Horsham and then for another year at the Chichester Academy. He married in 1632 and in 1638 moved to London with funding arranged by the Academy's headmaster. In this more cosmopolitan environment, Pell's talents in mathematics and languages soon made him a popular figure in the academic world. Also in 1638, he published his major work, Idea of Mathematics, which secured his reputation both in England and abroad as a mathematician of note. In it, Pell emphasized the importance of mathematics and proposed "the establishment of a public library of all mathematical books."

Due to political upheaval in London, Pell was soon compelled to move away from England in order to find an academic post in mathematics. Finally he settled in Amsterdam in 1643, becoming mathematics professor at the university there. While in Amsterdam, Pell wrote an inflammatory treatise called Controversiae de vera circuli mensura (The Controversy over the True Way to Measure a Circle) in 1647. His work, written to document his stance on the value of pi, met with reproofs from such stellar figures in the mathematics world as René Descartes and Gilles Personne de Roberval.

In 1646 Pell moved to a new university in the Dutch city of Breda and then moved back to England in 1652 to teach mathematics in London. From 1654 to 1658 he worked as a diplomat in Zurich, Switzerland, also tutoring students in mathematics. Although some sources disagree, others say that Pell should be credited for several accomplishments and advances in the years following this period. For instance, there is some dispute as to whether An Introduction to Algebra (1659) is actually Pell's work or that of one of his students in Zurich. In addition, Pell may have invented the symbol for division still in use today (a horizontal line with a dot above and below) and the method of writing out equations in three columns--one for explanation and two for identification.

In 1658 Pell left Zurich for England, where he became a vicar (a deputy cleric). Apparently, he spent the next 20 years in similar religious posts and suffered from extreme poverty toward the end of his life. However, he maintained his interest in mathematics, writing down a table of factors of all integers up to 100,000 in 1668. One source describes him as living with a former student for a period before dying in London on December 12, 1685.