Baptised on 23 November 1616 in Bodicote near Banbury, John Kersey the elder established himself in London as a prominent mathematics teacher and textbook author. Throughout the seventeenth century, he operated within the Kingdom of England, navigating the academic and professional landscape of his era while contributing foundational texts to the field of algebra.
Professional Life in London
Upon arriving in London, Kersey built his reputation primarily as an instructor of mathematics. His residence changed over time, moving from a property opposite the White Lion in Charles Street near the Covent Garden piazza to a home on Chandos Street in St Martin's Lane. His instructional work extended to elite households, most notably as a tutor for the sons of Sir Alexander Denton at Hillesden House in Buckinghamshire. These students, Edmund and Alexander Denton, later became significant public figures, with both serving as Members of Parliament for Buckingham and Alexander further establishing a career as a judge.
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Kersey was a significant figure in mathematical communication, maintaining professional ties with contemporaries such as John Collins, who encouraged his authorship. His principal original work, The Elements of that Mathematical Art, commonly called Algebra, appeared in two folio volumes published in 1673 and 1674. Dedicated to his former pupils, the Denton brothers, the text achieved status as a standard authority in the subject. The work received recognition in the Philosophical Transactions and earned praise from Charles Hutton. Furthermore, Kersey’s algebraic methods were incorporated into the 1703 edition of Cocker's Arithmetick.
Historical Contributions
Among his specific analytical advancements, Kersey is credited with the earliest known reference to the aliquot formula in his 1673 publication. This formula identifies the number of divisors of a positive integer by calculating the product of the powers, each increased by one, from the prime decomposition of that integer. His career concluded before the turn of the century; he died in London in 1677 at the age of 61 and was buried at St Paul's Church, Covent Garden.
Fast facts
- Born: 1616, Bodicote
- Died: 1677, London
- Citizenship: Kingdom of England
- Occupation: Mathematician
- Primary Employer: Alexander Denton
- Burial Site: St Paul's Church, Covent Garden
Questions readers ask
What is John Kersey the elder’s most significant mathematical contribution?
He is noted for the earliest known reference to the aliquot formula, which determines the number of divisors of a positive integer.
Where did John Kersey the elder work as a tutor?
He served as a tutor for the sons of Sir Alexander Denton at Hillesden House in Buckinghamshire.
Achievements
- Held posts at Alexander Denton
- Fields: mathematics
