Habit, xi, 247-58; autosuggestion and, 306; in physical functions, ix, 81, 88, 251; slaves of, xi, 263; will and, 261 Habits of Thought, xi, 198, 203-4, 247 Habitual Images, xi, 222 Hackberry Tree, xiii, 194 Haeckel, Ernst, biological work, x, 136, xvi, 182; on phosphorescence of sea, xii, 18-19 Hail, i, 106-8, 373-4; formation, 120; storms and stones, 119-20 Hail clouds, i, 102 Hail Insurance, i, 269, 344 Hail Rods, i, 341, 342-3, 374 Hail Shooting, i, 341-2, 374 Hailstorms, devices to avert, i, 340-4 Hair, cells of, ix, 13; color and form in different races, xv, 37-8, xvi, 48, 49, 50; cutting of by electricity, iv, 10; dyeing of, x, 58; emotion effects on, xi, 142; erection of, ix, 161, 162, 166, xi, 113; of mammals, xii, 270-1; on face and body, xv, 38 Hairdressing, among savages and Chinese, xv, 260-1; ancient Egyptian, 255 (fig.) Hairsprings, v, 70, 71-2 Hairworms, xii, 45 Hags (fish), xii, 130, 131 Haiti, gouffre of, i, 196; rubber growing, xiii, 245; words derived from, xv, 161; yellow fever of, x, 160; zoölogy of, xiv, 274 Hakemite Tables, ii, 38, 39 Hale, Prof. George E., ii, 147, 148, 177, 178, 225, 241; spectroheliograph of, 129, 183 Hales, Stephen, x, 88, xvi, 112 Halite, iii, 332 Haller, Albrecht von, x, 77, 87-8, 97, 98; medical works, xvi, 178 Halley, Edmund, comet and other discoveries, ii, 83-9; discovery of moon's deviations, 73; discovery of star motions, 304; on Eta Argus, 324 Halley's Comet, ii, 84, 85-6, 273-4, 275, 281; tail of, 134 Hallucinations, definition and kinds, x, 358; of crowds, xi, 328-9; visual, 91 Hallucinatory Images, xi, 221 Halogenation, viii, 266, 377 Halogen Derivatives, viii, 210, 211-12, 236 Halogens, viii, 18, 84-7, 377; similarity of, 176 Halos, i, 177-183, 374; circumscribed, 181, 369; tangent arc, 383 Haly, "Royal Canon," of, x, 32, 37 Hamadryad, xii, 228-9 Hamburg, Deutsche Seewarte, i, 223, 276; harbor of, xiv, 270 Hamilton Mill, vi, 296, vii, 209 Hamilton, Mount, ii, 142 Hammers, measurement of blows of, iv, 67; pneumatic, i, 28 Hammurabic Code, xvi, 63; on medical practices, x, 15 Hands, ape's and human compared, xv, 57, 58-60; bones of, ix, 67-8; cold or warmth felt in, 320; color in different lights, iv, 364-5; deftness of human, v, 248; evolution of, xii, 167-8; grasping reflex of, ix, 349, xi, 40-5; importance in child's education, 43; origin of flexed position, 42-3; reciprocal innervation, 86; tools resembling, 44-5; temperature of, ix, 93; X-ray pictures of, iv, 55 Hangars, i, 43 Hanging Glaciers, iii, 60-1 Hanging Valleys, iii, 65, xiv, 57 Hanks, of yarn, v, 272 Hanseatic League, xiv, 28, 308