The Reason Why. Robert Kemp Philp
why are valleys and low places chiefly subject to it, 353
Dew, what bodies receive little of it, 355
Dew, what bodies receive most of it, 354
Dew, at what period of the night is it chiefly formed, 356
Dew, why is it chiefly formed at that period, 357
Dew, in what parts of the world is the greatest quantity formed, 358
Dew, in what parts of the world is the least quantity formed, 359
Dew, why is it seldom formed at sea, 360
Dew, why is it, when heavy, regarded as a precursor of rain, 361
Dew, what is honey-dew, 364
Dew, why does it lie on the exposed sides of screens of plants, 401
Dew, why does it rest upon the upper surfaces of leaves, 402
Dews, why are cultivated lands more subject to them than those that are uncultivated, 403
LESSON XXII.
Dew, why does the gravel-walk receive less dew than the grass, 404
Dew, why does little of it form at the base of hedges, walls, and trees, 406
Dews, why do morning dews and mists usually come together, 407
Dew, what effect have winds upon its formation, 408
Dew, why does it form in round drops upon leaves, 794
Diamond, what causes the brilliant colours of the, 501
Digestion, why does food flow more freely to the stomach during, 879
Digestion, why does excess in eating impair, 880
Digestion, what changes occur to food in the stomach, 881
Digestion, what causes bilious attacks, 882
Digestion, how is the nutritious matter taken from that which is innutritious, 885
Digestion, what becomes of the nutrition when it enters into the circulation, 886
Dish-covers, why should they be plain in form, and have bright surfaces, 203
Dogs, geographical distribution of, 1333
Dream, why do we, 1020
Drowsiness, why is it felt in crowded rooms, 22
LESSON XXIII.
Ducks and geese, why do they dash water over their backs on the approach of rain, 1105
Ducks and geese, why have they square-pointed bills, 1044
Dyes, vegetable, what are they, 1259
Ear, why is it spread out externally, 984
Ears, why do hairs grow across them, 986
Ear-wig, why is it so called, 986
Ears, why is wax secreted in the, 987
Ears, why do singing noises occur in the, 988
Ears, why do people become deaf, 989
Ears, why do people accustomed to loud noises feel no inconvenience from them, 990
Ears of animals of prey, why do they bend forward, 1063
Ears of animals of flight, why do they bend backward, 1064
Earth, why is it warmer than air during sunshine, 398
Earth, why is it colder than air after sunset, 399
LESSON XXIV.
Earth, how can man weigh the, 784
Earth, what is the weight of the, 788
Earth-worms, why have they no feet, 1085
Echoes, why do some occur immediately after the sounds, 742
Echoes, why do some occur at a considerable interval after the sound, 743
Echoes, why do some change the tone and quantity of sounds, 744
Echoes, why are there sometimes several to one sound, 745
Echoes, are they caused only by distant objects, 746
Echoes, what are they, 741
Electricity, what is it, 561
Electricity, why is it so called, 562
Electric fluid, why is it so called, 566
Electrics, what substances are, 567
Electricity, what is positive, 568
Electricity, what is negative, 569
Electricity, what is vitreous, 570
Electricity, what is resinous, 570
Electrical phenomena, what produces them, 571
Electricity, how does its equilibrium become disturbed, 572
Electricity, how does it seek to regain its equilibrium, 573
Electricity, what substances are conductors, 574
Electricity, what substances are non-conductors, 575
Electricity, what substances are insulators, 576
LESSON XXV.
Electricity, what is the effect when a current of electricity meets with an insulator, 577
Electric sparks, what is the cause of, 578
Electricity, why does lightning attend it, 584
Electricity, why does it affect the shape of clouds, 613
Electric storms, why are they more frequent in hot than in cold weather, 624
Electric storms, why do they frequently occur after dry weather, 625
Electric storms, why do they purify the air, 629
Electricity, what is Voltaic, 636
Electrical attraction, what is it, 778
Elementary body, what is meant by, 19
Element, what is the most abundant in nature, 756
Elephant, why has it a short unbending neck, 1076
Elephant, why has it a trunk, 1077
Elephants' hind legs, why do they bend forward, 1078
Etna, what are the botanical regions of Mount, 1240
Endogenous stems, what are they, 1280
LESSON XXVI.
Endogenous stems, why do they abound in tropical climates, 1281
Endogenous stems, why have they no bark, 1282
Endogenous stems, why do they grow to a great height, 1283
Exogenous stems, what are they, 1279
Exercise, why does it promote health, 1016
Exercise, why does it make us feel warm, 839
Explosions of gas, what is the best method of preventing, 65