CLOUDS, 127 cause of, 129 classes of, 134 colour of, 132 compound, 136 " simple, 134 differ from fog, 128, 227 dissipated, 304 distance from the earth, 129 edges most luminous, 399 electrical, 131 fall in rainy weather, 337 float, 128 height of, 4, 120 highest and lowest, 130 intermediate, 135 light, 120 motion of, 133 red, 132, 399 round mountain tops, 137 thickness of, 130 " how ascertained, 130 vary in shape, 129, 130 " in colour, 133 where most abundant, 129 where least, 129 use of, 137 velocity of, 314 wind affects them, 129, 131 Coal gas, 280 mines explode, 281 Coals black, 403 COLD WEATHER affects the barometer, 328 makes us love fat, 90 " activity, 91 out of doors, 312 promotes hunger, 91 Collapsing, 289 Colour of clouds, 132, 133 Colours vary, 400 some warm, some cold, 187 Combining not mixing, 25 COMBUSTION, _see fire_, 33, 85 cause of, 36 elements of, 36 heat of, 37 increased by wind, 58 in the veins, 84 COMMUNICATION of HEAT, 164 Compound clouds, 136 Compression, 102 CONDENSATION, 98, 102 Condensed air, 289 CONDUCTION, 164 not absorption, 184 CONDUCTORS, best, 165 worst, 166 not absorbers, 185 of lightning, 22 dangerous, 24 CONVECTION, 219, 231 Convective currents, 245 cool broth, 247 cool iron, 247 Cooking vessels with wooden handles, 166 Cooper applies hot hoops, 122 Copper sonorous, 410 tarnishes, 259 COPPER-HOLE, 60 roars, 60 " not when the door is open, 60 Cornea, 388 Corns ache in wet weather, 256 Corpse cold, 95 Corrosive sublimates, 426 Cotton bales catch fire spontaneously, 57 handkerchiefs hot, 184 Countrymen ruddy, 243 Cowls, 67, 111 Crowds produce drowsiness, 251 head-ache, 249 vitiate air, 249 unhealthy, 250 Culinary vessels have wooden handles, 166 should be sooty, 71, 201 Cultivation promotes dew, 210 warmth, 160 Cumulo-stratus clouds, 136, 137 Cumulus clouds, 134, 135 Cup in a pie, 120 why full of juice, 124 Damp banisters, 217 beds, 158 house, 217 DANGER IN A STORM, 12 in attics and cellars, 16 a crowd, 18 theatre, &c., 19 before a fire, 15 near a tree, 12 river, 14 flocks and herds are exposed to, 19 those who bar shutters, 18 lean against a wall, 17 or carriage, 20 who ring bells, 15, 17 run, 15 Dark colours warm, 186 radiate heat, 197 Davy, Sir H., 281 Day-light produces hunger, 88 Dead bodies cold, 95 taller than living, 423 Deal snaps in fire, 107