WORKS  .—Treatise on the

Differential Calculus and the Elements of the Integral Calculus (1852, 6th ed., 1873), Treatise on Analytical Statics (1853, 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., 1861); Plane Trigonometry (18J9, 4th ed., 1869) ; Spherical Trigonometry (1859) ; History of the Calculus of Variations (1861) ; Theory of Equations (1861, 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 (1875) ; Natural Philosophy for Beginners (1877) . An unfinished work, The History of the Theory of Elasticity, was edited and published posthumously in 1886 by Karl Pearson . Todhunter also published keys to the problems in his textbooks on algebra and trigonometry; and a biographical work, William Whewell, account of his writings and correspondence (1876), in addition to many original papers in scientific journals . See obituary notices in the Proc . Lond . Math . Soc . (1884), and Proc . Roy . Soc . (1884) .