Food converted to blood, 242 cooled by the breath, 312 Foot-prints frozen, 350 Foot-warmers, 173 Forked lightning, 5 dangerous, 5 Forests catch fire spontaneously, 102 France warmer than of yore, 162 FREEZING MIXTURES, 360 FRICTION (_see rubbing_), 98 excites electricity, 29 sets forests on fire, 102 Frogs cold, 94 FROST affects barometer, 329 sound, 414 braces, 147 breaks ewers, 349 tiles, stones, rocks, 350 pipes, 351 cracks earth, 357 expands water, 352 prevents fog, 227 warm, 356 Froth of beer, 269, 350 Frozen ruts and footprints, 350 Fruits cool the blood, 92 fall to the earth, 419 pleasant in summer, 92 Fuel for the body, 87 Fumigation for sick rooms, 421 FUR, bad conductor, 166 for clothing, 175 warm, 171 Furnaces of brick, 174 lined with clay, 174 Furr of kettles, 262 steam engines dangerous, 263 Gallery hot, 249, 316 Gas, 112 of candles, 281 Gauze wire of safety lamps, 282 prevents explosion, 282 German silver tarnishes, 260 German tinder, 102 Germany warmer than of yore, 162 Ghosts, 286 Gideon's miracle, 211 Ginger pop, 268 acid, 269 GLASSES broken by hot water, 125 covered with mist, 214 which soon subsides, 215 dulled by a hot hand, 215 by breath, &c., 215 _See spectacles._ Glass a reflector, 194 soon cools, 212 _See looking-glass._ Glauber salts, 426 Gloves, black kid, 188 Lisle thread, 188 Glow-worms glisten by night, 368 GOD'S WISDOM 182, 208, 210, 302, 308, 352, 357 Gold never tarnishes, 260 Goulard, 426 Grapes never ferment, 272 Grass promotes warmth, 161 collects dew, 209 Grate, _see stove_ Gravel collects no dew, 209 Gravity, 419 Gray morning, sign of a fine day, 140 GREASE liked in cold weather, 90 loathed in hot, 92 prevents rust, 258 used for wheels, 100 Green colour, 401 wood does not burn, 107 Grottoes famous for echoes, 416 Ground frost, 229 Growth promoted by moonlight, 220 Gulls fly to sea, 154 to land, 154 Gusty weather makes a smoky house, 71 HAIL, 331, 334 cause of, 335 accompanied with thunder, 335 falls in summer, 335 Hair, bad conductor, 166 covered with dew, 217 Halls famous for echoes, 417 Halo round the moon, 143 Hard work promotes hunger, 88 Hat covered with dew, 217 turned red at the seaside, 344 Hawks see near and far, 392 Hay-stacks catch fire spontaneously, 58 Haze round the sun, 143 moon, 143 affects sound, 414 Head aches in a crowd, 249 itches in wet weather, 150 Hearth-rug warm, 169 Hearth-stone cold, 169 hot, 170