Black, why should parts of kettles and saucepans be allowed to remain, 204
Blood, in what proportions are the gases found in it, 39
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 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, 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 those of the arms and legs formed into long shafts, 935
Bones, why are those of the feet and hands numerous and small, 936
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 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
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, why is it called a repulsive agent, 75
Caloric, how may it be excited to develope heat, 79
Caloric, is there any in ice, snow, water, marble, &c., 89
Caloric, how do we measure the quantity of in any substance, 329
Caloric, how do we know that it is caloric which fuses metals, 334
Calves and lambs, why have they no horns, 1069