Coins, chemical analysis of, viii, 286, 291; copper alloys in, 164, 171; gold and silver, making of, iv, 150 Coke, discovery, v, 315-16; manufacture and use, viii, 46-7, 252 Col (meteorology), i, 238, 369 Cold, body regulation to, x, 250; clothing as protection against, 306; comparative degree of, v, 345; physiological effects of, ix, 37, 78-9, 319-20, x, 239, 252-3, 271; "production" of, v, 345-7; sensation of, ix, 93-4, 319-21, xi, 109, 112-13, 114; skin defense against, 113 Cold Air Machines, v, 352-3 Cold Baths, ix, 313, 321-2, x, 240, 253, 312, 383 Cold-Blooded Animals, ix, 305; diseases of, x, 206; heart of, ix, 84; temperature changes and, 78-9, 306-7, x, 250 Colds, air during epidemics of, viii, 332; catching of, ix, 322-3, x, 239, 252-3, 306; diseases from, 253; ears affected by, ix, 103; from uncleanliness, x, 311; head, 341; infectiousness, i, 326; susceptibility of men and women to, x, 240; taste sensations in, xi, 73 Cold Storage, iv, 187-8, viii, 371; effect on vitamines, x, 263; electrical, vii, 229-30 (see also Refrigeration) Cold Sweat, xi, 131, 132 Cold Waves, i, 370; prediction of, 239 Coleus, xiii, 42, 79, 205 Collectors, electrical, i, 144, 370 Collection Stage, xv, 187, 188-91 College Students, study habits, xi, 212, 289 Collodion, making of, viii, 255 Colloids, viii, 314-16, 375; origin of life from, xii, 11-12; relation of water to, viii, 355-6 Colonnaded Spectrum, ii, 115 Color--Colors, chemistry of, viii, 85-6, 258, 259, 312; complementary, iv, 366-7, xi, 91-4; contrast, ix, 95; determined by vibration rate, 114, 115; distance effects, xi, 182; flame, viii, 301; heat absorption by, x, 309; hue, tint, and saturation, xi, 90; illusions of, in different lights, iv, 323, 324, 370, 379-80; induction of, xi, 94-5; in interior decoration, vi, 273, 274-5; memory, xi, 220-1; mineral identification by, viii, 201-2; mixtures, iv, 369, xi, 92-3; neutralization, 91-3; of glass, viii, 282; of objects, iv, 364, xvi, 119; of pigments, iv, 369-70; perception and sensation of, 360-1, 364-5, 366, vi, 282, ix, 114-17, xi, 89-90, 91-2, 95-6; physical effects, 63, 96; primary, iv, 366, xi, 90; psychological effects, vi, 273, 274-5; racial classification by, xv, 32-34, 36-7; rainbow, i, 175, ix, 115; spectrum, iv, 357-9; sunrise and sunset, i, 166, 167-8; temperatures for different, iv, 361; wave lengths of, 359, 360, 365, xi, 90; white light, (see White Light) Colorado, arid topography of, xiv, 42; glaciers of, 54; Jurassic strata of, xii, 165; mining products, iii, 362, 363, 364, 366 Colorado Plateau, iii, 140, 229-30