Isaac Todhunter

TODHUNTER, ISAAC (182o-1884), English mathema tician, son of George Todhunter, a Nonconformist minister, was born at Rye on Nov. 23, 182o, and died at Cambridge on March r, 1884. He was educated at University college, London, and at St. John's college, Cambridge. He became a fellow of his college and college lecturer and private tutor. Todhunter held many academic honours, and was a member of council of the Royal society. He became an assistant master at a school at Peckham, attending at the same time evening classes at the University college, London. In 1842 he obtained a mathematical scholar ship and graduated as B.A. at London university. In 1844 he entered St. John's college, Cambridge, where he was senior wrangler in 1848, and gained the first Smith's prize and the Burney prize; and in 1849 he was elected to a fellowship, and began his life of college lecturer and private tutor. In 1862 he was made a fellow of the Royal Society, and in 1865 a member of the Mathematical Society of London. In 1871 he gained the Adams prize and was elected to the council of the Royal Society. He died at Cambridge on the Ist of March 1884.

WoRxs:—Treatise on the Differential Calculus and the Elements of the Integral Calculus (1852, 6th ed., 1873) ; Treatise on Analytical Statics 4th ed., 1874) ; Treatise on the Integral Calculus (1857, 4th ed., 1874) ; Treatise on Algebra (1858, 6th ed., 1871) ; Treatise on Plane Coordinate Geometry (1858, 3rd ed., 1860 ; Plane Trigonome try (1859, 4th ed., 1869) ; Spherical Trigonometry (1859) ; History of the Calculus of Variations (1861) ; Theory of Equations (186r, 2nd ed. 1875) ; Examples of Analytical Geometry of Three Dimensions (1858, 3rd ed., 1873) ; Mechanics (1867), History of the Mathematical Theory of Probability from the Time of Pascal to that of Lagrange (1865) ; Researches in the Calculus of Variations (1871) ; History of the Mathematical Theories of Attraction and Figure of the Earth from Newton to Laplace (1873) ; Elementary Treatise on Laplace's, Lame's and Bessel's Functions Natural Philosophy for Beginners w (1877). An unfinished The History of the Theory of Elasticity,

was edited and published posthumously in 1886 by Karl Pearson.

TODI

(anc. Tuder), a town and episcopal see of the province of Perugia, Italy, 26 m. S. of Perugia by rail, on a steep hill above the east bank of the Tiber, 1,348 ft. above sea-level, and 866 ft. above the river. Pop. (1931), 3,552 (town), 19,645 (commune). Some portions of the ancient town walls—of two enceintes, an inner and an outer, the former attributed to the original Umbrian inhabitants, the latter to the Romans—are preserved, while the mediaeval walls are still more extensive, and also remains of baths, amphitheatre, theatre, and a substruction wall of massive masonry, with four niches. Here was found the bronze statue of Mars, now in the Vatican; some fine bronze objects of the 5th cent. B.C. have been found in tombs. Beneath the cathedral square, at the highest point of the town, is a large Roman reservoir. The Romanesque cathedral has a simple facade (partly of the iith, partly of the 14th century), with a fine portal and rose window. In the same square are the massive Roman esque Gothic structures, Palazzo dei Priori (I 213), the Palazzo del Capitano del Popolo (c. I 29o) and the Palazzo del Podesta (1293– 1337). The Gothic church of S. Fortunato, with its nave and aisles of the same height, has a splendid portal.

Just outside the town on the west is the church of S. Maria della Consolazione, one of the finest buildings of the Renaissance, and often wrongly attributed to Bramante. Contemporary docu ments prove that the interior was begun in 1508 by Cola di Matteuccio da Caprarola, and the exterior completed in 1516 1524 by Ambrogio da Milano and Francesco di Vito Lombardo; the slender dome was not added till 1607.

See Pirro Priore Alvi, Todi (Iwo) ; G. Bellucci, La regione di Todi prima della storia, Perugia, 1915 ; Bendinelli in Monumenti dei Lincei, xxiii., 609-684; xxiv.,