Augustus De Morgan, an English mathematician, born on the island of Madura, East Indies, in 1806, died in London, March 18, 1871. His father was an officer in the British army, and he was educated at Trinity college, Cambridge, where he graduated in 1827. He had begun his studies for the bar when, in 1828, on the foundation of the university of London, he was appointed professor of mathematics in that institution. He resigned this post in 1831, but returned to it on the death of his successor in 1836, and retained it till 1866, when he again resigned. He was a frequent contributor to the "Penny Cyclopaedia," the "Athenaeum," and other periodicals, and to the transactions of various learned societies of which he was a member. He published "Elements of Arithmetic" (1830), "Elements of Algebra" (1835), "Connection of Number and Magnitude" (1836), "Elements of Trigonometry" (1837), "Essay on Probabilities" (1838), "Differential and Integral Calculus" (1842), "Formal Logic" (1847), "Arithmetical Books" (1847), "Trigonometry and Double Algebra" (1849), and "Book of Almanacs" (1851). The work on "Formal Logic" gave rise to a controversy with Sir William Hamilton, as to which of them was the discoverer of a new principle in the theory of syllogisms.

The "Arithmetical Books" gives the bibliography of the subject from the time of the invention of printing. The "Book of Almanacs" furnishes means by which the full almanac for any year down to A. D. 2000, either according to the old or new style, may be turned to at once. He wrote also on calculation of insurances and on decimal coinage. "A Budget of Paradoxes," written by him for the "Atheneeum," has been published since his death (London, 1872).