Cells (organic), basis of life, ix, 12, x, 119, xii, 10, 14, 25, xiii, 74, xv, 16, xvi, 142; dynamics of, xvi, 144-5; growth by division of, ix, 43-8, xiii, 166-7; living and nonliving, ix, 12-17; maintenance and growth, 34-6; metabolism of (see Cell Metabolism); motions of, ix, 73-4; of plants, viii, 337, 338, 352, ix, 26; reproduction from, 43, 324-5, 332-3, x, 228, 232, xiii, 166-7, xv, 54, xvi, 155-6, 157-8; size of, ix, 49; substance of, (protoplasm), 13 (see also Body Cell) Celluloid, composition of, viii, 255 Cellulose, viii, 223, 227-8, 229, 254-6, ix, 30; as food, 30; industrial uses, viii, 229, 241, 254-6, 261; in plants, iii, 344, viii, 49, 223, 335, 348, 349, ix, 30; in wood composition, iii, 345, viii, 44, xiv, 65 Celsius, thermometer of, iv, 136 Celsus, A. Cornelius, x, 27, 43; on sleeping sickness in Rome, 301; rediscovery of "De Re Medicina," 44 Celtic Languages, xv, 162 Celts, of Ireland, xvi, 49 Cement, chemistry of, viii, 280; manufacture, iii, 373-4 Cement Floors, in factories, xi, 361-2 Cement Gun, v, 136 Cementite, viii, 160, 273 Cement Plants, potash from dust, viii, 279; smoke precipitation, vii, 347-8 Cenozoic Era, iii, 20, 377; animals of, 284, 293, 295, 298-301; birds developed in, 297; divisions and surviving species, xv, 71; in North America, iii, 221-48; plants in, 256, 257-8 Centaurus, "coal sack," ii, 352; star cluster, 336-7 Center of Gravity, iv, 99-101; tendency of wheels to turn on, v, 150 Centers of Action, i, 218, 241-2, 368; Iceland area, 361 Centigrade Thermometer, i, 73, iv, 136, 137, viii, 27; comparison with other scales, iv, 137, 141, viii, 27, 384 Centimeter-gram-second System, iv, 46 (see Metric System) Centipedes, xii, 87-8 Central America, animals of, xii, 198, 208, 276, 289, 349; coasts, coral reefs on, 40; rainfall and rivers, xiv, 135, 195; volcanoes of, 315, 316, 325-6, 338 Central Asia, antelopes of, xii, 327; climatic changes, results of, iii, 75, xiv, 361, 362; cradle of human race, xvi, 46; desert basins, xiv, 215, 217, 355; flowers of, xiii, 202; horses of, xii, 306-7; manual of, 356; marriage custom of, xv, 282; migrations from, xiv, 362; oases of, 150-1; plains of, 215; rock weathering in deserts, 79; rodents of, xii, 294; salt lakes of, xiv, 199 Central Nervous System, ix, 129-32; at birth, 348-9; connections with glands and smooth muscles, 159-60, 162-3; in the chordata, xii, 128; preferred pathways of, ix, 134 Central Park Obelisk, iii, 23, xiv, 78-9 Central Sun Hypothesis, ii, 305 Centrifugal Force, iv, 71-5; of earth's rotation, ii, 69, iv, 74-5, 101 Centrifugal Pumps, vi, 363 Centrifugal Railroads, iv, 74 Centripetal Force, iv, 72-3