Dingeldey, 315.

Dini, 337; ref. to, 362.

Dinostratus, 32; ref. to, 25.

Diocles, 50.

Diodorus, 10, 40, 58.

Diogenes Laertius, 17, 32.

Dionysodorus, 54.

Diophantus, 74–77; ref. to, 55, 61, 86, 93, 95, 96, 105, 106, 107, 110, 111, 179, 372.

Directrix, 49, 60.

Dirichlet, 367–369; ref. to, XIII., 179, 291, 334, 338, 339, 348, 356, 357, 359, 362, 371, 396.

Dissipation of energy, 400.

Divergent parabolas, 217, 257.

Divergent series, 255, 337.

Division of the circle, 7, 271, 329, 365.

Diwani-numerals, 102.

Donkin, 379.

Dositheos, 40.

Dostor, 325.

Dové, 384.

D'Ovidio, 306.

Dronke, XII.

Duality, 290, 297, 308.

Duhamel, 333, 388.

Dühring, E., X.

Duillier, 230.

Duodecimals, 124, 126.

Dupin, 288, 289; ref. to, 300, 314.

Duplication of the cube, 23–25, 31, 32, 45, 50, 153.

Durège, 354; ref. to, 309, 315.

Dürer, A., 156.

Düsing, 340.

Dyck, 315. See Groups.

Dynamics, 318, 378–381.

Dziobek, XIII., 377.

Earnshaw, 383.

Earth, figure of, 257, 292; rigidity of, 391; size of, 214, 215.

Eddy, 300.

Edfu, 12, 53.

Edgeworth, 340.

Egyptians, 9–16, 19.

Eisenlohr, 333.

Eisenstein, 369; ref. to, 354, 357, 365, 370, 371.

Elastic curve, 237.

Elasticity, 278, 387–392.

Electricity, 394–398.

Electro-magnetic theory of light, 394.

Elements (Euclid's), 36–39, 104, 114, 125, 127, 128, 133, 135, 136, 138. See Euclid.

Elimination, 250, 308, 310, 330, 331. See Equations.

Elizabeth, Princess, 188.

Ellipsoid (attraction of), 215, 277, 280, 285, 298, 366, 378, 379; motion of, 383.

Elliptic co-ordinates, 379.

Elliptic functions, 241, 279, 280, 296, 329, 345, 346, 347–354, 363, 367, 370.

Elliptic geometry. See Non-Euclidean geometry.

Elliptic integrals, 247, 252, 328, 349, 350.

Ely, 372.

Encke, 366.

Energy, conservation of, 397, 398.

Eneström, XI.

Enneper, 353; ref. to, XIII.

Entropy, 400.

Enumerative geometry, 297.

Epicycles, 51.

Epping, IX., 9.

Equations, solution of, 15, 149, 153, 186, 250, 260, 263, 277, 348; theory of, 75, 166, 189, 193, 216, 240, 241, 250, 328–331; numerical, 147, 264, 282. See Cubic equations, Algebra, Theory of numbers.

Eratosthenes, 44; ref. to, 25, 35, 40, 71.

Errors, theory of. See Least squares.

Espy, 384.

Ether, luminiferous, 393.

Euclid, 35–40, 70, 71; ref. to, 17, 21, 22, 26, 30, 31, 33, 34, 42, 46, 50, 53, 57, 58, 61, 72, 73, 78, 81, 97, 104, 108, 114, 125, 127, 136, 138, 144, 162, 281, 303.

Euclidean space. See Non-Euclidean geometry.

Eudemian Summary, 17, 21, 30, 32, 33, 35.

Eudemus, 17, 22, 45, 46, 69.

Eudoxus, 32, 33; ref. to, 16, 28, 31, 32, 35, 36, 51.