The Reason Why. Robert Kemp Philp

261

       Flame of a candle, why will a piece of paper twisted to form an extinguisher put it out, 263

       Flame of a candle, why does it become dim when the wick is loaded with carbon, 267

       Flames of a fire, why do some appear much whiter than others, 280

       Flames of a fire, why do some of them appear blue, 282

       Flesh, why does it heal when we cut it, 902

       Flesh-eaters, why do they satisfy themselves with a rapid meal, 1092

       Flesh, why do the marks of deep cuts remain, 905

       Flesh, why does that under the nails look red, 907

       Flies, how can they walk on the ceiling, 663

       Flies, why have they fine hairs growing on the extremities of their legs, 1102

       Flowers, what is the chief cause of the differences of their temperatures, 227

       Flowers, why may wet weather be expected when their perfume is strong, 1103

       LESSON XXXII.

       Flowers, why, if certain close, may rain be expected, 1116

       Flying-top, why does it rise on the air, 843

       Flying-top, why does it return to the earth, when its rotations are expended, 844

       Focus, what is a, 81

       Fogs, what are they, 365

       Fogs, why are certain coasts very liable to them, 366

       Fogs, what are dry, 367

       Fogs, why do they frequently rise in the morning and fall in the evening, 371

       Fogs, why do they sometimes rest upon a locality for days together, and then disappear, 372

       Food, why do we eat it, 869

       Food, why do we eat animal and vegetable, 172

       Food, why do we masticate it, 871

       Food, how does it descend into the stomach, 875

       Food, why do we not feel it being transmitted through the throat, 876

       Food, why do we feel uneasy after eating to excess, 877

       Food, why do we feel drowsy after eating heartily, 878

       Food, why do some portions nourish us, while other portions are useless, 883

       LESSON XXXIII.

       Fossil, vegetable, what is it, 272

       Friction, why does it produce heat, 321

       Friction, why does rubbing two surfaces together attract latent heat, 322

       Frost, why is the air warmer during, 163

       Frost, what is white, 412

       Frost, what is black, 413

       Frost, why are black frosts said to last, 414

       Fruit, why do gooseberries, plums, &c., taste acid, 1184

       Fruit, why do ripe taste sweet, and unripe sour, 1185

       Fruits, why are succulent most abundant in tropical climates, 1207

       Fruits and vegetables, why do they ripen in succession, 1284

       Furs, why are they worn in winter, 166

       Galvanism, what is it, 635

       Gas, what kind lights our streets, 56

       Gas, why does it expand in thin air, 833

       Geology, what has been its influence upon botanical geography, 1249

       Giraffes, why have they small heads, 1322

       Giraffes, why have they long necks, 1323

       Giraffes, why have they long and flexible tongues, 1324

       LESSON XXXIV.

       Giraffes, why are their nostrils narrow and small, and studded with hairs, 1325

       Glass upon a lamp, why does it increase the brilliancy of the light, 266

       Glass, why is it transparent, 506

       Glass, does transparent reflect any light, 507

       Glow-worms, why have they brushes attached to their tails, 1127

       Glow-worms, why do they emit light, 1128

       Gnats, why are their larvæ and pupæ found in water, 1314

       Gnats, why may fine weather be expected if they fly in large numbers, 1110

       Grasses, why are they so widely diffused throughout nature, 1166

       Grasshoppers, why are they comparatively active in their pupa stages, 1293

       Gravitation, what is the attraction of, 774

       Guano, why is it a good manure, 1262

       Gum resins, what are they, 1255

       Gums, vegetable, what are they, 1254

       Gunpowder, why does it explode, 808

       Gutta-percha, whence is it obtained, 1254

       LESSON XXXV.

       Hail, what is it, 448

       Hail, why is it supposed that the electrical state of the clouds affects the formation of hail, 449

       Hail-storms, why do they usually occur by day, 450

       Hairs, why do they grow across the passages of the nostrils, 993

       Halo, what is a, 494

       Halo, what is the cause of a, 495

       Haloes, why are they sometimes large, and at other times small, 496

       Haloes, why do they foretell wet weather, 497

       Hands, why when we hold them against the candle do we perceive a crimson colour, 906

       Hay-stacks, why do they sometimes take fire spontaneously, 316

       Head, why is it set upon the neck, 928

       Hearing, why do people engaged in battle frequently lose their, 991

       Hearing, death