Flame, viii, 57-61; colors as metal tests, 133, 134, 144, 289, 301; heat production by, iv, 138, 144 Flamingos, xii, 256 Flammarion, books on Mars, ii, 238; on curious showers, i, 355; on lightning pranks, 153-4 Flamsteed, astronomer, xvi, 124; star numbering, ii, 302-3 Flannel, heat conductivity, iv, 179 Flannelette, x, 308 Flashboards, vii, 40 Flash Boiler, v, 213 Flashes, electric, vi, 91; extinguished by electromagnets, 102 Flashing Arcs, i, 194, 372 Flatfish, eyes of, xii, 138 Flatulence, sleeplessness from, ix, 219 Flatworms, xii, 18, 44-5 Flavors, ix, 95, 97; chemistry of, viii, 251-2; food value, 366, ix, 98, 240, 242; in plants, viii, 349; perception of, ix, 97-8 Flax, retting of, xiii, 243; spinning of, in ancient Egypt, xv, 243, 244 (fig.) Flax Plant, products and origin, xiii, 235, 244, xiv, 382 Flesh-eating Animals, as food, ix, 24; bile color in, 275; intestine length in, 246; protein surplus in, 284-5 Flexner, medical work of, x, 200, 218, 302 Flexor Muscles, ix, 76-7; strength, xi, 41, 43; withdrawing reactions by, 54 Flies, xii, 120; appearance in Jurassic, 104; buzzing of, 103; claws of, 102-3; evolution and varieties, 104-6; plant fertilizers, xiii, 131-3; typhoid fever spread by, x, 287, 288; wings of, xii, 103 Flight, bodily preparations for, ix, 166; instinct of, xi, 55, 132, 136 Flint, iii, 13, 337; fire production by, iv, 48; flaking of, xv, 103, 104, 107 (fig.), 109 Flint and Steel, xv, 232 Flint Implements, ancient, xv, 79, 81, 82, 87, 104, 105, 109 Flintlock, viii, 145, xv, 217, 218 (fig.) Floating Bodies, v, 95, 195-6; laws of, iv, 103-4, 107 Flood Lighting, vi, 283 Flood Plains, iii, 379, xiv, 53; alluvial soils of, 70, 71; embankments and slopes, 161-2; illustration, iii, 80, (Pl. 4); in old and new areas, 33, 34; plant societies of, xiv, 372 Floods, power of, iii, 31; rainfall and, i, 110-11 Flood Warnings, i, 240 Floors, warm, importance of, ix, 320 Flora, defined, xiv, 363 Florida, alligators of, xii, 197; coal forming conditions, iii, 199; coasts of, xiv, 251; co-, xii, 40, 42; crocodiles of, 198; frosts in, xiv, 370; serpula quina rock, viii, 152; coral reefs, tubes, xii, 55; shad fishing in, 155; snakes of, 226, 236; tarpon of, 154; wolves of, 341; youthful topography and drainage system, xiv, 157-8, 199-200, 201 Florissant, Colorado, insect remains at, iii, 279-80 Flour, calories in, ix, 299; Graham, ix, 35; vitamines in various kinds of, x, 262, 267 Flourens, Dr., x, 126, xvi, 185