INDEX, AND INDEX LESSONS. 



^^^ The numbers refer to the Questions. The Index Lessons do not cor* 

 respond with the Chapters, but are designed to bring together in their alpha* 

 betical connection, all the Questions and Answers upon each particular subject 

 included in the work. 



LESSON III. 



Air, which is heavier, dry or va- 

 porised 697 



Air-pistol (or pop-gun), why does 

 pressure applied to the handle 

 propel the cork 854 



Air-pistol, why must the handle be 

 drawn out before the cork is 

 placed iu 855 



Air, why does fresh impart a 

 healthy appearance 915 



Albumen, what is it 899 



Alkalies, what are they 36 



Amber, or electrum, what is it ... 564 



Animals, how is their greater 

 warmth in winter provided for 168 



Animal forms, why are there so 

 many 1029 



Animal furs, why do they become 

 thicker in the winter 1035 



Animals, why have carnivorous, 

 long pointed teeth 1038 



LESSON IV. 



Animals with long necks, why 

 have they large throats 1049 



Animals, why cannot flesh-eaters 

 live upon vegetables 1071 



Animals, why can ruminating 

 recover the food from their 

 paunches 1089 



Animals, why can ruminating 

 keep the chewed from the un- 

 chewed food in their stomachs 1090 



Animals, why do the smaller 

 animals breed more abundantly 

 than the larger ones 1094 



Animals, domestic, why may 

 change of weather be expected 

 when they are restless 1107 



Animals, plants, and minerals, 

 what are thv differences between 

 them 1140 



Animals that graze, why do they 

 crop the tender blades, but leave 

 the tall grass 1S87 



LESSON I. 



Acids, vegetable, whence are they 



obtained 1256 



Actinism, what is it 552 



Actinism, what effect has it upon 



vegetation 559 



Actinism, at what season of the 



year is it most abundant ... 560 

 Aerial spectra, what is the cause of 527 

 Affinity, what is the attraction of 777 

 Air, why do we breathe it ... ... 4 



Air, what is the composition of it 12 

 Air, what is its state after it has 



been breathed 13 



Air, is that sent from the lungs 



light or heavy 14 



Air, is it a good or bad conductor 



of heat 150 



Air, why is a still summer said to 



be sultry 171 



Air, why does it feel cooler when 



in motion, than when still ... 175 



LESSON II. 



Air, when is it hot enough to des- 

 troy life 179 



Air, why is it often excessively 

 hot in chalk districts 219 



Air, is it heated directly by the 

 sun's rays 221 



Air, why does it ascend the chim- 

 ney 240 



Air, why does it fly through the 

 doors and windows towards the 

 fire place 241 



Air, what does the motion of it 

 in our rooms illustrate 242 



Air, why does it become charged 

 with watery vapour 346 



Air, when is it said to be saturated 

 with vapour 430 



Air, what proportion of water is 

 air capable of holding in the 

 form of vapour 431 



Air, what is its weight relative to 

 that of water 647 





