QUESTIONS FORMING A COMPLETE INDEX. 



LESSON XXXIII. 

 Fossil, vegetable, what is it ... 



272 



Friction, why does it produce heat 321 

 Friction, why does rubbu.'g two 



surfaces together attract latent 



heat 322 



Frost, why is the air warmer 



during 163 



Frost, what is white 412 



Frost, what is black 413 



Frost, why are black frosts said to 



last 414 



Fruit, \rhy do gooseberries, plums, 



&c., taste acid 1184 



Fruit, why do ripe taste sweet, 



and unripe sour 1185 



Fruits, why are succulent most 



abundant in tropical climates ... 1207 

 Fruits and vegetables, why do they 



ripen in succession ... ... 1284 



Furs, why are they worn in winter 166 



Galvanism, what is it 635 



Gas, what kind lights our streets ... 56 

 Gas, why does it expand in thin 



air ... , 833 



Geology, what has been its influ- 

 ence upon botanical geography 1249 

 Giraffes, why have they small 



heads 1322 



Giraffes, why have they long necks 1323 

 Giraffes, why have they long and 

 flexible tongues ... ... ... 1324 



LESSON XXXIV. 



Giraffes, why are their nostrils nar- 

 row and small, and studded with 

 hairs 1325 



Glass upon a lamp, why does it 

 increase the brilliancy of the 

 light 266 



Glass, why is it transparent ... 506 



Glass, does transparent reflect any 

 light 507 



Glow-worms, why have they 

 brushes attached to their tails ... 1127 



Glow-worms, why do they emit 

 light 1128 



Gnats, why are their larvae aud pu- 

 pae found in water 1314 



Gnats, why may fine weather be 

 expected if they fly in large num- 

 bers 1110 



Grasses, why are they so widely, 

 diffused throughout nature . ... 1166 



Grasshoppers, why are they com- 

 paratively active in their pupa 

 stages 1293 



Gravitation, what is the attraction 

 of 774 



Guano, why is it a good manure ... 1262 



Gum resins, what are they ... ... 1255 



Gums, vegetable, what are they ... 1254 



Gunpowder, why does it exp'.odo 808 



Gutta-percha, whotce is it ob- 

 tained 1254 



LESSON XXXV. 



Hail, what is it 443 



Hail, why is it supposed that the 

 electrical etate of the clouds af- 

 fects the formation of hail ... 449 



Hail-storms, why do they usually 

 occur by day 450 



Hairs, why do they grow across 

 the passages of the nostrils ... 993 



Hnlo, what is a ... 494 



Halo, what is the cause of a .. 495 



Haloes, why are they sometimes 

 large, and at other times small 496 



Haloes, why do they foretell wet 

 weather 497 



Hands, why when we hold them 

 against the candle do we per- 

 ceive a crimson colour 906 



Hay-stacks, why do they some- 

 times take fire spontaneously ... 316 



Head, why is it set upon the neck 928 



Hearing, why do people engaged 

 in battle frequently lose their ... 991 



Hearing, death of a dog through 

 noise 991 



Heart, why does it beat without 

 any effort of the will 948 



Heart, why is it placed in the chest 

 of the body 932 



Heart and lungs, why are they en- 

 closed by ribs 933 



Heart, why are its motions made 

 independent of the will 950 



LESSON XXXVI.! 



Heat, what is it 71 



Heat, what are the properties 



of 86 



Heat, what is animal 87 



Heat, what is latent 88 



Heat, what is a conductor of ... 108 

 Heat, what is a non-conductor of ... 109 

 Heat, how is it transmitted from 



one body to another 119 



Heat, what is the radiation of ... 114 

 Heat, what is the reflection of ... 115 

 Heat, what is the absorptfon of ... 116 

 Hear, what is the convection of ... 117 

 Heat, what is the cause of the sensa- 

 tion 134 



Heat, what becomes of that which 



the hearth-stone receives 136 



Heat, how long does a substance 



feel hot or cold to the touch ... 139 

 Hearth-rug, and hearth-stone, their 



relative states of heat 142 



Heat, which are the better conduc- 

 tors, fluids or solids 146 



HoHt, why are dense substances 

 the best conductors ... ... 147 



Heat, why are fluids bad conduc- 

 tors 148 



Heat, why are woollen fabrics bad 



conductors 149 



Heat, is air a good or bad conduc- 

 tor ... ... ... 150 



