Nature, actions of, former theories, iv, 18-19, 26; complexity and interdependence in, xv, 22; curative powers, of, x, 21, 73, 75-6, 84-5, 367, vii, 240; cycles in, viii, 349; efficiency of, vi, 96; life-renewing instinct, xiii, 116-17; Longfellow's lines, xvi, 43; man and, contrasted by language, xi, 224; personification of, xv, 357; prodigality (see Prodigality of Nature); savage attitude toward, xv, 321, 329, 331, 339; science and the forces of, vii, 235 Nature-Philosophy School, x, 113 Naunyn, Bernard, xvi, 184 Nausea, ix, 91; cause of, xi, 39; visceral sense, 63 Nautical Almanacs, ii, 13, 40, 216, 263; of Greenwich, xvi, 125 Nautilus, pearly, iii, 273-5, xii, 75-6 "Nautilus," submarine, v, 198 Navajo Indians, weaving of, xv, 247 (fig.) Naval Architecture, problems of, v, 194 Naval Warfare, projectiles in, v, 373 Navigation, chronometers in former, v, 66; historical development, 182, 188-9, xv, 261-5; meteorology in, i, 271-83; wireless applications, vii, 284-5 Neanderthal Cave, xv, 95 (fig.) Neanderthal Man, xv, 96-8; disappearance of, 99; implements of, 107, 108; period of, iii, 302, xv, 102; skull of, iii, 304 (fig.) Neap Tides, ii, 70, xiv, 292 Nearsightedness, ix, 112, xi, 85 Nebraska, potash supplies, viii, 279, xiv, 67; volcanic ash deposits, 327; water beneath, iii, 114 Nebulæ, ii, 357-60; distribution, 352; double, 377; Herschel's conception, 16, 368-9; in connection with new stars, 332, 333; in relation to Galaxy, 355, 364-5; in relation to stars, 308-9, 365, 381; motions, 364; photographic study, 135-7; spectra, 116; types, ring and spiral, iii, 160-1 (see also Spiral Nebulæ) Nebular Hypothesis, ii, 367-72, 374-5, 380, iii, 159-61; anticipated by Swedenborg, ii, 367; applied to asteroids, 258; in relation to earth's heat, iii, 108, 178, 184-5 Nebulium, ii, 359 Neck, arteries of, ix, 196-7; pulse in, 311 Necropsies, x, 98 Nectar, of flowers, xiii, 124, 125 Needles, primitive, xv, 81; threading of, ix, 118 Negative, electrical meaning, vi, 57, 124 Negative Electricity, i, 141, 142, iv, 258, 265, vi, 287, 288; electrons as, viii, 187-8; in atmosphere, i, 143 Negroes, color of skin, xv, 36; hair of, 38; in Tropics, xiv, 356; in U. S., 218-19; language of, xv, 159; nose index and nostril shape, 46; prepotency in crosses, x, 230; susceptibility to lung diseases, xv, 50; type characteristics, 35 (see also Black Race) Negroes (African), belief in Reincarnation, xv, 334; idea of soul, 330; ideas of sleep, 332; priests of, 350-1 Nematodes, xii, 45 Neodymium, atomic weight and symbol, viii, 383 Neolithic Period, domestic animals of, xii, 346; implements of, iii, 302, 306, v, 14, xv, 103, 109-10