The Reason Why. Robert Kemp Philp

of natural philosophy are illustrated in the play, 867

       Bats, why have they hooked claws in their wings, 1079

       Bats, why do they fly by night, 1080

       LESSON VIII.

       Bats, why do they sleep during winter, 1081

       Beds, why should they be raised two feet from the ground, 15

       Bed-room windows, why are they sometimes covered with ice crystals, 344

       Beer, why will it not run out of a cask until a hole is made at the top, 660

       Beer, why does it get flat, 805

       Bees, why have they stings, 1101

       Bees, why may we expect fine weather when bees wander far from their hives, 1114

       Beetles, why are they called "coleoptera", 1319

       Beetles, why have they hard horny wing-cases, 1320

       Beetles, why have many of them hard horns, 1321

       Bile, why does it separate nutritious from innutritious matter, 884

       Birds, why have water-fowls feathers of a close and smooth texture, 1033

       Birds, why are they covered with feathers, 1030

       Birds, why does black down grow under their feathers on the approach of winter, 1036

       Birds, why have they hard beaks, 1040

       Birds, why are their beaks generally long and sharp, 1041

       Birds, why are their bones hollow, 1050

       Birds, why do they lay eggs, 1051

       LESSON IX.

       Birds, why have those with long legs short tails, 1052

       Birds, why have aquatic web-feet, 1059

       Birds, why have those that swim and dive short legs, 1060

       Birds, why have some deep rough notches on the under surfaces of their feet, 1061

       Birds, why have they gizzards, 1072

       Birds of prey, why have they no gizzards, 1084

       Birds, why may wet and thunder be expected when they cease to sing, 1121

       Birds of passage, why, if they arrive early, may severe weather be expected, 1121

       Birds, geological distribution of, 1326

       Birds, tameness of in unfrequented countries, 1327

       Birds, why are birds of song not also remarkable as birds of plumage, 1328

       Birds, what are the velocities of their flights, 1329

       Birds, what is the cause of their migrations, 1330

       Black, why should parts of kettles and saucepans be allowed to remain, 204

       Blood, in what proportions are the gases found in it, 39

       LESSON X.

       Blood, what is venous, 41

       Blood, what is arterial, 42

       Blood, what is the constitution of the, 899

       Blood, what quantity does the human body contain, 920

       Blood, how frequently does the whole quantity pass through the system, 922

       Blowing upon tea, why does it cool it, 174

       Bow, why does it propel the arrow, 847

       Bow and arrow, what line does the arrow describe, 848

       Bow and arrow, what forces tend to arrest the arrow, 849

       Bow and arrow, why are there feathers at the ends of arrows, 850

       Bones, how many are there in the human body, 923

       Bones, of what substances are they composed, 924

       Bones, what are the uses of the, 925

       Bones, why are those of the back hollowed out, 927

       Bones, why are those of the skull arched, 930

       Bones, why are those of the skull divided by small sutures, 931

       Bones, why are they hollow, 934

       LESSON XII.

       Bones, why are those of the arms and legs formed into long shafts, 935

       Bones, why are those of the feet and hands numerous and small, 936

       Botanical geography, 1208

       Brain, why is it placed within the skull, 926

       Bread-fruit trees, where are they natives of, 1223

       Breathing, is it a kind of combustion, 17

       Breaths, have people ever been poisoned by their own, 24

       Breezes, why are summer said to be cool, 170

       Breezes, what is the cause of sea and land, 235

       Bubbles, why do they ascend in the air, 236

       Bubbles, why do they fall, after having ascended, 237

       Bubbles, why do they display rainbow colours, 499

       Bubbles, why are they round, 825

       Bubbles, why are they elongated when being blown, 826

       Bubbles, why do they close, and become perfect spheres when shaken from the pipe, 827

       Bubbles, why do they change their colours in the sunshine, 828

       Bubbles, why do they burst, 829

       LESSON XI.

       Burning or supporting combustion, what is the difference, 45

       Burning-glasses, why do they appear to set fire to substances, 80

       Butterflies, why do they lay their eggs upon cabbage-leaves, 1099

       Butterflies' eggs, why do they lie dormant in the winter, 1288

       Butterflies, why do they fly by day, 1296

       Calms, why do they prevail at the equator, 671

       Caloric, what is it, 72

       Caloric, what is