Dictionary of National Biography, 1885-1900/Murphy, Robert

MURPHY, ROBERT (1806–1843), mathematician, born in 1806, was the third of the seven children of a shoemaker, parish clerk of Mallow, co. Cork. When eleven years of age he was run over by a cart, and for twelve months he lay on his bed with a fractured thigh-bone. During this confinement he studied Euclid and algebra, and before attaining the age of thirteen was an extraordinarily efficient mathematician. Subsequently he continued his studies in a classical school kept by Mr. Hopley at Mallow. At the age of eighteen he published a remarkable ‘Refutation of a Pamphlet written by the Rev. John Mackey, R[oman] C[atholic] P[riest], entitled “A Method of making a Cube double of a Cube, founded on the principles of elementary geometry,” wherein his principles are proved erroneous, and the required solution not yet obtained,’ Mallow, 1824, 12mo.

His friends raised a subscription to send him to the university, and he began his residence in Gonville and Caius College, Cambridge, in October 1825. In 1829 he graduated B.A. and came out third wrangler. In May 1829 he was elected a fellow of his college, and shortly afterwards he was admitted to deacon's orders in the church of England. In May 1831 he was appointed dean of his college—an office which involved the regulation of chapel discipline. Unfortunately he fell into dissipated habits, and in December 1832 he left Cambridge, with his fellowship under sequestration for the benefit of his creditors. After living for some time among his friends in Ireland, he came to London in 1836 to begin life again as a teacher and writer; and in October 1838 he was appointed examiner in mathematics and natural philosophy in the university of London. He died on 12 March 1843.

His friend, Augustus De Morgan [q.v.] , remarks that ‘he had a true genius for mathematical invention;’ and that ‘his works on the theory of equations and on electricity, and his papers in the “Cambridge Transactions,” are all of high genius.’

To the ‘Cambridge Philosophical Transactions’ his contributions were: vol. iii. pt. iii., ‘General Properties of Definite Integrals;’ vol. iv. pt. i., ‘On the Resolution of Algebraic Equations;’ pt. iii. ‘On the Inverse Method of Definite Integrals, with Physical Applications,’ with two further memoirs on the same (v., ii. and iii.); vol. v. pt. i., ‘On Elimination between an Indefinite Number of Unknown Quantities;’ vol. vi. pt. i., ‘On the Resolution of Equations in Finite Differences.’

To the ‘Philosophical Transactions’ he contributed: 1837, pt. i., ‘Analysis of the Roots of Equations;’ pt. i., ‘First Memoir on the Theory of Analytical Operations.’ His separate works are: 1. ‘Elementary Principles of Electricity, Heat, and Molecular Actions, part i. On Electricity,’ Cambridge, 1833, 8vo. 2. ‘Theory of Algebraical Equations,’ in ‘Library of Useful Knowledge,’ London, 1839, 8vo; reprinted 1847.

[Athenæum, 6 Aug. 1864, p. 181; De Morgan's Budget of Paradoxes, p. 214; Gent. Mag. May 1843, p. 545; Penny Cycl. 1st Suppl. p. 337 (by Augustus De Morgan); Cat. of Library of Trin. Coll. Dublin.]

T. C.