254 



INDEX. 



Water, solvent power of, influence 

 of, in disintegration of rocks, 

 54, 55. 



vapor, screening influence of, 

 on sun's heat, 94. 



Wide distribution of plant germs, 



30 to 38. 

 Wind, influence of, in destruction 



of forests, 66. 

 Winged seeds, 32. 



THE END. 



