Curie, Madame, radium discovery, xvi, 193 Curiosity, instinct of, xi, 55; of crowds, 328 Curlews, xii, 262 Currents (water) power of, iii, 30-1, xiv, 39, 52-3 Current Transformers, vii, 44 Current Wheels, v, 76 Curtis, on spiral nebulæ, ii, 362 Curtis Turbines, v, 151, 152, 382 Curved Motion, forces producing, iv, 72-3 Curves, pitching of, iv, 67-9 Cusa, Nicolas de, xvi, 102 Custom, Cicero on, x, 135; modesty and, xv, 254-5; morality and, 286; obedience to, how enforced, 374-5; crowd psychology in, xi, 333 Customs Examinations, by X-rays, vii, 256-7 Cut-off, of steam engine, v, 146-7, 208 Cutting of Metals, v, 46-7, 54-5, 383; by oxygen jet, i, 33 Cuttings, (plants) propagation by, ix, 337, xiii, 166, 167 Cutting Tools, of ancient Egypt, xvi, 66-7 Cuttlebone, xii, 79 Cuttlefish, iii, 260, 275-6, xii, 58, 78-9 Cuvier, biological works, xvi, 139, 148; work on paleontology, 168 Cyanamide Process, i, 36, viii, 74, 153 Cyanide Solution, vii, 317 Cyanogen, xvi, 160 Cycads, iii, 251, 255, xiii, 309, 316, 317 Cycles, chemical, viii, 334-5, 349-50 (see also Carbon, Hydrogen, nitrogen Cycles) Cycles, geographical and geological, xiv, 29 (see also Cycles of Erosion) Cycles, of alternating currents, vi, 153, 154-5; degrees of, 204 Cycles of Erosion, in land surfaces, iii, 33-6, xiv, 30, 34-5, 47-9, 155-64; in mountains, iii, 135-6; in shore lines, 56-7, xiv, 254-5 Cyclones, i, 135-8, 370, xiv, 349-50; electrification by, vii, 212-13; handling of ships in, i, 277-8 Cyclonic Thunderstorms, i, 138, 151 Cyclonopathy, i, 330, 370 Cyclonoscopes, i, 279, 370 Cyclops, (crustacean), xii, 84 Cygni, 61, measurement of distance, ii, 16, 315; parallax, 311-12 Cygnus, nebulæ in, ii, 360; new star in, 332 Cylinders, boring of, v, 44-5; cooling, 159-61, 166-7; in internal combustion engines, 157-61, 166-7; of steam engine, 147; pressure in, iv, 119 Cyme, flower form, xiii, 50 Cynodictis, xii, 346-7 Cypress Trees, in landscaping, xiii, 270; in southern forest, xiv, 372 Czecho-Slovakia, public health fellowships, x, 172; stone age remains in, 108 (fig.) Daboia, xii, 231 Daddy Longlegs, xii, 90 Da Gama, Vasco, xiv, 309, 351 Daggers, development of, xv, 212 Daguerre, ii, 125 Daimler, Gottlieb, v, 213, 382 Dairies, electricity in, vii, 226-7 Dairy Products, drain on farm of, viii, 342-3 Daisies, flowers of, xiii, 49-50; introduction to America, 353-4; seed dispersal, 58-9; stems, 23 Daisy Family, xiii, 206; fertilization in, 144; flower forms, 44 (fig.); fossil species, 324; in New Zealand, 380; in pampas, 376; original home and spread, 350, 353; petal arrangement, 190; seed dispersal, 344, 345 Dakin, antiseptic solutions of, x, 181-3, 382