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