The Reason Why. Robert Kemp Philp

cut through a cabbage-stump do we find a tough coating enveloping a cellular substance, 1158

       Plants, why are their seeds formed within the corollas of flowers, 1168

       Plants, why does the flower of the poppy turn down during the early formation of seed, 1169

       Plants, why have those of the pea-tribe a folding blossom, 1170

       Plants, why are leaf-buds enclosed in scales which fall off as the leaves open, 1171

       Plants, what is meant by "species" of, 1209

       Plants, what is meant by "genus" of, 1210

       Plants, progressive discovery of new species, 1211

       Plants, what are the three great classes of, 1212

       LESSON LVIII.

       Plants, what are the characteristics of exogenous, 1213

       Plants, what are the characteristics of cryptogamus, 1216

       Plants, what are the effects of diverse climates upon, 1242

       Plants, what are the effects of altitude upon mountains, 1243

       Plants, what agencies influence their geographical distribution, 1250

       Plants, what are the chief facts connected with the distribution of by man, 1251

       Plants, why are herbaceous less solid than woody, 1265

       Plants, why are the stalks of herbaceous generally cylindrical, 1266

       Plants, what are the stomata of, 1267

       Plants, why are their stomata generally on the underside of their leaves, 1268

       Plants, why have they pith in their centres, 1269

       Porter, why does bottled produce large volumes of froth, 801

       Pulse, why do we feel it beat, 900

       Quadrupeds, geographical distribution of, 1331

       Quicksilver, why does it reflect light from mirrors, 513

       LESSON LIX.

       Radiation, why does scratching a bright metal surface increase its powers of, 199

       Radiation of heat, what benefits arise from it, 415

       Radiation of light, what is it, 503

       Radiation, do all bodies radiate light, 504

       Rain, what is it, 416

       Rain, does it ever occur without clouds, 417

       Rain-drops, why are they sometimes large, and at other times small, 418

       Rains, at what seasons are they most prevalent, 419

       Rainy days, in what months of the year are they most frequent, 420

       Rainy days, why are there more from September to March, 421

       Rain, in what part of the world does the greatest quantity fall, 422

       Rain, in what part of the world do the heaviest rains fall, 423

       Rain, in what part of the world does the least rain fall, 424

       Rainy days, how many are there in a year, 425

       Rain, in what part of England does the greatest quantity fall, 426

       Rains, why do the heaviest occur in hot countries, 427

       LESSON LX.

       Rain, why does the greatest quantity fall at the equator, 428

       Rain, why are some parts of the earth without it, 429

       Rain, why does it purify the air, 433

       Rainy localities, why are mountainous countries more rainy than flat ones, 434

       Rain, why does more fall by night than by day, 435

       Rain, why do bunches of dried sea-weed indicate its coming, 436

       Rain, why do weather-toys foretell its coming, 437

       Rain, the Capuchin toy; mysterious walk of a wooden horse, 438

       Rain, why does ladies' hair drop out of curl as rain approaches, 438

       Rain, why is it said to be coming, when the mountains are "putting on their night-caps", 439

       Rainbow, what causes a, 486

       Rainbow, why does it exhibit colours, 487

       Rainbows, why are there sometimes two, 488

       Rainbows, why are the columns of the secondary bow, arranged in the reverse order of those of the primary, 489

       LESSON LXI.

       Rainbow colours, why do glass lustres and chandeliers exhibit them, 498

       Rainbows, why are the colours of the secondary bow fainter than those of the primary, 491

       Rainbow, what is a lunar, 492

       Rainbow, why is a lunar bow fainter than the solar, 493

       Rainbow, why is one in the morning the shepherd's warning, 538

       Rainbow, why is one at night the shepherd's delight, 539

       Refraction of light, what is it, 472

       Refraction and reflection of light, what is the difference, 502

       Reflections, why are they reversed, 490

       Reflection, why do black bodies reflect any light, 505

       Reflection, why does a window-pane appear to reflect better by night than by day, 516

       Reflection, what is the line of, 520

       Reflection, what is the angle of, 522

       Repulsion, what is it, 792

       Respiration, why does the chest expand when we breathe, 889

       Respiration, how does blood communicate with the air in the lungs, 890

       Rest, why does it invigorate us, 1018

       Rice, where is it cultivated, 1219

       Rosewood, what is it, 1191

       LESSON LXII.

       Saliva, why does saliva enter the mouth while we are eating, 872

       Sea, why is it salt, 764

       Sea, what is the estimated amount of salt in the, 765

       Sea, what is the depth of the, 766

       Sea-gulls, why are they numerous in fine weather, 1119

       Sea-gulls, why do they fly over the land on the approach of stormy weather, 1120

       Sea-crow, why is its lower bill longer than the upper, 1135

       Sealing-wax, why does rubbing it attract to it small particles of matter, 565

       See, why do we, 963

       Seeds, why are they generally enveloped in hard cases, 1152

       Seeds, why do they throw out roots before they form leaves, 1153

       Seeds, why does the leaf-germ come up to the light and the root-germ penetrate the earth,