Dictionary of National Biography, 1885-1900/Hayes, Charles
HAYES, CHARLES (1678–1760), mathematician, born in 1678, was a member of Gray's Inn. In 1704 appeared his ‘Treatise on Fluxions, or an Introduction to Mathematical Philosophy,’ London, fol., the first English work explaining Newton's method of infinitesimals. After an introduction setting forth most of the chief properties of the conic sections with concise proofs, Hayes applies Newton's method clearly and systematically, first to obtain the tangents of curves, then their areas, and lastly to problems of maxima and minima. His preface shows a good acquaintance with the existing literature of the higher mathematics. In 1710 he printed a pamphlet, ‘New and Easy Method to find out the Longitude,’ and in 1723 ‘The Moon, a Philosophical Dialogue,’ proving that she is not opaque, but has some light of her own. Having made a voyage to Africa and spent some time there, he had considerable repute as a geographer, and was chosen annually to be sub-governor or deputy-governor of the Royal African Company. After applying himself for some years to the study of Hebrew, Hayes in 1736 published his ‘Vindication of the History of the Septuagint,’ and in 1738 ‘Critical Examination of the Holy Gospels according to St. Matthew and St. Luke,’ with regard to the history of Christ's birth and infancy. His studies were afterwards mainly directed to chronology, excepting occasional tracts written to defend the policy of the Royal African Company. In 1747 appeared his ‘Series of Kings of Argos and of Emperors of China from Fohi to Jesus Christ,’ to prove that their dates and order of succession agreed with the Septuagint, and in 1751 a ‘Dissertation on the Chronology of the Septuagint,’ a defence of the Chaldean and Egyptian chronology and history.
When the Royal African Company was dissolved in 1752, Hayes settled at Down, Kent, and became absorbed in his great work, ‘Chronographia Asiatica & Ægyptiaca,’ which he did not live to complete. Two parts of it only were published, and that during the last two years of his life, when he had chambers in Gray's Inn: first, ‘Chronographiæ Asiaticæ & Ægyptiacæ Specimen,’ and the second, subdivided into (1) ‘Origo Chronologiæ LXX interpretum investigatur,’ and (2) ‘Conspectus totius Operis exhibetur.’ Part of his argument is that the Seventy and Josephus made use of writings preserved in the library of the Temple of Jerusalem which had been omitted in making up the Old Testament canon. Nichols remarks that Hayes spent much time in philosophical experiments. Hayes found favour with his contemporaries from his ‘sedate temper’ and clear method of exposition; and Hutton, who was twenty-three years old at Hayes's death, remarks that he had ‘great erudition concealed by modesty.’ Hayes died at his chambers in Gray's Inn on 18 Dec. 1760.
[Gent. Mag. 1761, pp. 543–6; Nichols's Lit. Anecdotes, ii. 322–6.]