Heine, 339; ref. to, 362, 372.

Helen of geometers, 187.

Helicon, 32.

Heliotrope, 363.

Helmholtz, 397, 398; ref. to, 304, 305, 382, 385, 386, 393, 396, 400, 401.

Henrici, XIII.

Henry, 396.

Heraclides, 45.

Hermite, 353; ref. to. XIII., 328, 330, 343, 347, 350, 355, 362, 372.

Hermotimus, 33.

Herodianic signs, 63.

Heron the Elder, 52; ref. to, 50, 54, 65, 80, 98, 105, 131, 140.

Herschel, J. F. W.. 386; ref. to, X., 276, 283, 284, 356.

Hesse, 309–311; ref. to, 295, 309, 312, 325, 329, 330, 333, 342, 377.

Hessian, 295, 310, 327.

Heuraet, 190.

Hexagrammum mysticum, 178, 296.

Hicks, 382, 384.

Hilbert, 327.

Hill, 376.

Hindoos, 84–100; ref. to, 3.

Hipparchus, 51; ref. to, 54, 56.

Hippasus, 22.

Hippias of Elis, 25.

Hippocrates of Chios, 25, 28, 30.

Hippopede, 51.

Hirn, 400.

History of mathematics, its value, 1–4.

Hodgkinson, 389.

Hölder, O. See Groups.

Holmboe, 336, 347, 350.

Homogeneity, 293, 308.

Homological figures, 178.

Honein ben Ishak, 104.

Hooke, 213.

Hoppe, 306.

Horner, 147, 330.

Hospital, l', 239, 240.

Hoüel, 319.

Hovarezmi, 106; ref. to, 107, 110, 114, 125, 127.

Hudde, 189; ref. to, 203.

Hurwitz, 358.

Hussey, 377.

Huygens, 190–192; ref. to, 177, 182, 188, 213, 214, 219, 234, 257, 392.

Hyde, 321.

Hydrodynamics, 239, 255, 380, 381–384. See Mechanics.

Hydrostatics, 44, 255. See Mechanics.

Hypatia, 61; ref. to, 37.

Hyperbolic geometry. See Non-Euclidean geometry.

Hyperelliptic functions, 292, 328, 348, 354, 360.

Hyperelliptic integrals, 352.

Hypergeometric series, 335, 361.

Hyperspace, 304, 305.

Hypsicles, 51; ref. to, 7, 38, 71, 104.

Iamblichus, 72; ref. to, 10, 22, 69.

Ibbetson, 392.

Ideal numbers, 371.

Ideler, 32.

Iehuda ben Mose Cohen, 127.

Ignoration of co-ordinates, 380.

Images, theory of, 381.

Imaginary geometry, 301.

Imaginary points, lines, etc., 298.

Imaginary quantities, 146, 166, 241, 287, 349, 363, 372.

Imschenetzky, 342.

Incommensurables, 36, 38, 70. See Irrationals.

Indeterminate analysis, 95, 101, 111. See Theory of numbers.

Indeterminate coefficients, 186.

Indeterminate equations, 95, 101, 111. See Theory of numbers.

Indian mathematics. See Hindoos.

Indian numerals. See Arabic numerals.

Indices. See Exponents.

Indivisibles, 170–173, 176, 193.

Induction, 340.

Infinite products, 349, 354.

Infinite series, 197, 203, 208, 220, 247, 250, 255, 259, 269, 283, 334–339, 348, 349, 361, 363.

Infinitesimal calculus, See Differential calculus.

Infinitesimals, 135, 169, 207, 208, 211.

Infinity, 27, 135, 169, 178, 193, 269, 293, 304, 308; symbol for, 193.

Insurance, 239, 340.

Integral calculus, 171, 223, 348, 350, 368, 371; origin of term, 237.