John Farrar (1779–1853), mathematician and educator, was a native of Lincoln, Massachusetts. He graduated from Harvard University in 1803 and studied at Andover Theological Seminary for two years before returning to Harvard, first as a tutor of Greek and, in 1807, as the Hollis professor of mathematics and natural philosophy. He held this position for the remainder of his career, retiring for health reasons in 1836. Farrar translated many important French scholarly works and introduced the latest European methods of teaching mathematics and science to Harvard. He was elected to the American Academy of Arts and Sciences in 1808 and served as its recording secretary, 1811–23, and vice president, 1829–31. Farrar occasionally sent TJ books and pamphlets he had authored or translated. When TJ’s granddaughter Ellen W. Randolph Coolidge and her husband, Joseph Coolidge, lived in Boston, they became friendly with Farrar, and through them in 1827 he offered advice on candidates to fill the vacant chair in mathematics at the University of Virginia. Farrar died in Cambridge (DAB; DSB description begins Charles C. Gillispie, ed., Dictionary of Scientific Biography, 1970–80, 16 vols. description ends ; Harvard Catalogue description begins Harvard University Quinquennial Catalogue of the Officers and Graduates, 1636–1925, 1925 description ends , 22, 63, 184; Joseph Coolidge to Nicholas P. Trist, 18 Apr., 1, [2], 28 June, 18 July, 16 Oct. 1827 [DLC: NPT]; Boston Daily Atlas, 11 May 1853; John G. Palfrey, Notice of Professor Farrar [1853]; gravestone inscription in Mount Auburn Cemetery, Cambridge, Mass.).

The Swiss mathematician Leonhard Euler was the author on whom Farrar drew for his work, An Introduction to the Elements of Algebra, designed for the use of those who are acquainted only with the first principles of Arithmetic. Selected from the Algebra of Euler (Cambridge, 1818; Poor, Jefferson’s Library description begins Nathaniel P. Poor, Catalogue. President Jefferson’s Library, 1829 description ends , 8 [no. 395]). For John Napier’s (nepier’s) theorem, see TJ to Louis H. Girardin, 18 Mar. 1814, and TJ’s Notes on Napier’s Theorem, printed above at that date.