Jeremiah Day, president of Yale college, born in New Preston, Conn., Aug. 3, 1773, died in New Haven, Aug. 22, 1867. He entered Yale college in 1789, but on account of infirm health was not able to go on with the class; but after an absence of several years he resumed his studies, and graduated with high honor in 1795. He succeeded Dr. Dwight in the charge of a school at Greenfield Hill, continued there a year, and was then elected tutor in Williams college, and in 1798 in Yale college. While acting as tutor he began to preach as a candidate for the ministry; but in 1801 he was elected professor of mathematics and natural philosophy in Yale college. His health being still feeble, he was not able to enter on his new duties till 1803, but after that continued in them till 1817, when, on the death of Dr. Dwight, he was elected his successor as president. In July of the same year he was formally inaugurated, and on the same day was ordained as a minister of the gospel. In 1817 he received the degree of LL. D. from Middlebury college, and in 1818 that of D. D. from Union college, and the latter also from Harvard college in 1831. He continued in the presidency of Yale college till 1846, when he resigned on account of feeble health.
His learning and talent, united with great kindness of heart, soundness of judgment, and urbanity of manner, secured alike the respect and love of his thousands of pupils. He was distinguished as a mathematician, and as a close and vigorous thinker. His mathematical works, which have passed through numerous editions, are "Algebra" (1814), "Mensuration of Superficies and Solids" (1814), "Plane Trigonometry" (1815), and "Navigation and Surveying "(1817). He also published "An Inquiry on Self-Determining Power of the Will, or Contingent Volition" (1838; 2d ed., 1849), "An Examination of President Edwards's Inquiry as to the Freedom of the Will" (1841), and a number of occasional sermons, and contributed papers to the "American Journal of Science and Arts," the "New Englander," etc. An address commemorative of his life and services was delivered by President Woolsey, and published (1867).