Foreign Trade, meteorology in, i, 268-9 Forest Fires, aeroplane lookouts, i, 48-9; dust from, 56-7; losses by, xiii, 371-2; number and losses, i, 48-9; rain and, 333-4; records in tree rings, xiii, 25 Forests, ancient, iii, 252, 253-4, xiii, 10, 307-10, 312, 313; branching of trees in, 86; burial by sand dunes, iii, 74; climate affected by, xiv, 379; climax, xiii, 370; conservation of, xiv, 238-9, 382-3 (see also Conservation); earthquakes in, 333; European, 238-9; grasslands and, xiii, 348-9, 368 (illus), 374-5, xiv, 380-1; importance to industry, vi, 366; leaving of trees in, xiii, 86-7; migration of, xiv, 375-6; mountain, 239-9; northern limit, 375; park, 374; products, 382-3; rainfall and, xiii, 372, xiv, 377-8; soil protection by, 42, 379; squirrel planting of, xiii, 340; temperate, 366-73, 272 (illus), xiv, 370-1; trees in American and European, 363, 375-6; tropical, xiii, 358-66, xiv, 366-70; types of, xiii, 357-8; United States, xiv, 239, 372-4; United States national, xiii, 371-2; water supply and, 371-2, 9, xiv, 239 Forgetting, process of, xi, 209; rate of, 216 Forked Lightning, vii, 205, 206-11; sinuous character, i, 146 Form, athletic, ix, 159 Formaldehyde, viii, 219, 333, 335, 372 Formic Acid, viii, 220 Formosa, rice paper tree of, xiii, 214; continental island, xiv, 274 Form-wound Coils, vi, 202, 223, 245 Fortin's Barometer, iv, 119-20 Fossane, xii, 353 Fossil Botany, xvi, 167 Fossil Record, extent, iii, 13-14; imperfectness, xiii, 302-3, 306-7, 323-4, 325; of various geological strata, iii, 165, 174, 179, 180, 263-5, 268 Fossils, defined, iii, 13, 379; formation, 15-17; formation of plant, xiii, 301-2; former views of, iii, 14-15; geological strata determined by, 15, 18-19, xvi, 126, 169; of earliest animals, iii, 261-2, 263, 265-6; of earliest birds, xii, 239-43; of herbs and woody plants, xiii, 319, 324; of sharks' teeth, xii, 142; of water plants, xiii, 303; of worms, iii, 270; oldest known, 250; some remarkable, 286-8, 291, 292, 295, xiii, 306, 347 Four-Cycle Engines, v, 159, vii, 123-4 Fourdrinier Paper Machine, v, 291, 295-8, 377 Four o'Clock (flower), colors in crosses, ix, 334, 336 Foussa, xii, 353, 354 Fowls, white meat of, xii, 247 Foxes, xii, 342-4; excavators, xv, 206; storing of food by, xii, 292 Fox Fire, i, 346 Fractional Distillation, i, 32, iv, 168 Fracto-Cumulus, i, 102 Fracto-Nimbus Clouds, i, 101 Fracto-Stratus Clouds, i, 102 Fractures, Pott's, x, 92; X-ray locating of, vii, 254, 255, x, 185