INDEX 



9 



References are to pages 



Formaldehyde (disinfectant) . 445 

 Formalin (disinfectant) . . . 445 

 Fossils (of animals and plants) 



522-523 

 Franklin, Benjamin (inventor of 



lightning-rod) 483 



Freeze (southern " cold wave ") 228 



Friction .... 63,72,462,480 



generator of electricity . . 480 



generator of heat ... 63, 72 



methods of lessening . . . 462 



Frost 104 



Fruits 427-431 



vitamin in 431 



Fuel-saving 74-77,94 



Fulcrum (of lever) . . . . . 464 



Fungi .... 398-399,438-439 



a cause of ptomaines . . . 439 



mushrooms and toadstools 398-399 



Gala'pagos Islands (home of 



great tortoise) ..... 541 

 Galile'o (inventor of lift pump) 118 



Gases 2,17,42,58,97, 



110,115,315,472,504 

 equality of pressure of . . . 115 

 formation of, in soil . . . 315 

 formation of, in volcanic 



eruptions . , . . . . 504 

 incandescent, of the sun . . 2, 16 



inert 97 



transformers of energy . . 472 



Gasoline 105, 140, 520 



Gastric juice 420, 433 



Geometry (developed by Egyp- 

 tians) 21 



Germination of seeds . . . 393-396 

 Germs (harmful bacteria) ; see 



Bacteria 

 Geysers (hot springs) . .511-513 



causes of 511 



effects of 513 



times of spouting . . . . 512 

 Gibraltar (a spit) .... 161-162 



Glaciers 285-301, 



304-305, 525-528 

 Alpine or valley . .... 288-289 



crevasse' 289 



glacial flour 291 



Glaciers Continued 



glacial formations . . . 279-300 



glacial lakes 300-301 



Glacial Period . . 285, 292-298, 

 525-528 

 effects upon animals and 



plants 525-528 



effects upon surface 285, 292-298 



glacial scratches 291 



icebergs 294-295 



ice fields (of Antarctic regions 



and Greenland) . . . 293-294 

 moraines .... 290,297-300 

 waterfalls (Niagara and Yo- 



semite) 526-528 



Glass (reflector of light) . . 348-349 



Globigeri'na 532 



Gneiss (metamorphic rock) . 255 



Gold (mineral) 516 



Graded rivers 185 



Grafting (method of plant-prop- 

 agation) 377 



Grains and cereals . . . 427-431 

 composition of .... 428-431 

 Granite (igneous rock) . . . 253 

 Grape sugar (developed in 



plant-leaves) 382 



Graphite (conductor of elec- 

 tricity) 490 



Graphs 213-214 



Gravel 310, 345 



Gravitation (attraction) . . 47, 49, 

 58, 93, 326 



laws of 47, 58 



Newton's discoveries . . 47 

 Gravity (earth-attraction) 47-48, 326 



vs. soil-water 326 



weight 47 



influences upon direction . 48 



Ground-water 170 



Gulf Stream 162-164 



influence upon climates . 162-164 



Haemoglobin (of blood) ... 411 



Hail 234 



Halley's Comet 18 



Halos .* 360,365 



Hammerfest's climate (Gulf 

 Stream) 164 



