Colorado River, navigability, xiv, 195; Salton Sink and, iii, 156-7, xiv, 205; superimposed character, 173; water supply of, 182 (see also Grand Canyon of the Colorado) Color Blindness, ix, 116, xi, 93; inheritance of, ix, 340-1, x, 234; in men and women, ix, 340-1 Colored Hearing, xi, 222 Color-Index of Stars, ii, 297-8 Color Photography, iv, 368-9 Color Printing, iv, 370-1; in newspapers, v, 304 Color Vision, iv, 364-5; inheritance of, ix, 340; limits of, iv, 360-1; theory of, x, 96 (see also Colors) Colt Gun, v, 363-4 Columbia Plateau, iii, 105, 181, 227-8, xiv, 104, 164, 170, 172, 188 Columbia River, xiv, 174-5; canyon of, iii, 39, 226, 228, xiv, 165-6; navigability, 195; salmon of, xii, 157 Columbine, fertilization, xiii, 126-8; flowers, 196 Columbium, atomic weight and symbol, viii, 383 Columbus, compass troubles of, iv, 52-3, vi, 27; debt to early scientists, ii, 12, 13, 40; discovery of America, xiv, 309; Genoese birth, 310; in Sargasso Sea, xiii, 73; on rubber balls in Haiti, 245; potatoes found by, 218, 219; syphilis introduced by sailors of, x, 60; tobacco-using seen by, xiii, 256; trade winds on voyage, i, 128-9 Columnar Structure, iii, 111, 212 Combustion, iv, 138; chemistry of, viii, 11-13, 53-63, 100; heat of, 308; oxygen and, i, 10; oxygen and, viii, 35-6, 61; power developed by, ix, 15-16 Comets, ii, 273-82; asteroids and, 258; dangers to earth, 279-80; disintegration, 286-7, 288; families related to planets, 270-1; first scientific studies, 40, 41, 57; former ideas, 83-4, 85; habitability, ii, 250-1; in relation to solar system, 164; Newton's views, 85; orbits discovered, 85; orbits and meteor streams, 287; photographic study, 134; Seneca on, 85; solar corona and, 224; various particular, 280-1, 286 (see also Halley's Comet) Commensalism, xii, 32 Commerce, ocean, development of, xiv, 305-11 Commercial Meteorology, i, 261-70 Common Salt, composition and properties, iii, 332, vi, 109-10, 111, viii, 84; deposits, iii, 332, 374-5, viii, 139-40, 196, xiv, 141; deposits from atmosphere, i, 59-60; in body fluids, ix, 174, 175; in diet, x, 256; in ground water, xiv, 142; in protoplasm, ix, 32; in sea and inland waters, iii, 51-2, 152-3, 154-5, 332, 374, viii, 138-9, 195-6, xiv, 206, 295-7; mixture with ice, temperature resulting, iv, 175; physical and chemical divisions, 21; plants and, xiv, 364; production, iii, 374, 375, viii, 140, 275; refining of, for table, xiv, 296; size of molecules, vi, 112; taste of, xi, 70, 71, 72; uses, iii, 332, viii, 138, 140, 276-7 (see also Sodium Chloride) Commutators, electrical, iv, 308, vi, 159, 177-9, 344-5; use and construction, vii, 364-5 Como, Lake, iii, 146