INDEX. 



249 



Guyot, Arnold, extract from 

 " Earth and Man," 28, 29, 48. 



H. 



Hail, 147 to 152. 



influence of destruction of 

 forest on occurrence of, 

 147. 



Volta's theory of, 149, 150. 

 Hail-rods, 150. 

 Hailstones, structural peculiarities 



of, 148. 



varying sizes of, 148, 149. 

 Hail-storms, damages caused by, 



151. 



electrical phenomena of, 148. 

 rate of the wind during, 



151. 



Hartt, Ch. Fred., extract from 

 " The Geology and Physical Ge- 

 ography of Brazil," 137, 138. 

 Heat and light, necessity of, for 



plant growth, 24. 

 energy, disappearance of, on 

 evaporation of water, 95. 

 liberation of, on conden- 

 sation of vapor, 95. 

 units, 95. 



Hough, Franklin B., extract from 

 " Report on For- 

 estry," 76, 77, 78. 

 extract from the " Re- 

 port of the United 

 States Commission- 

 ers for 1877," 159 

 to 16o. 



extract from " Report 

 of United States 

 Commissioners of 

 Forestry," 135, 136. 



Houston, Edwin J., extract from 

 "Elements of Physical Geogra- 

 phy," 29, 30, 86, 87. 



Humboldt, Alexander von, extract 

 from " Cosmos," 99, 104, 105. 



Humidity of air, influence of, on 

 evaporation, 92. 



Huxley, T. H., extract from 

 " Physiography," 106. 



Hydrogen, in plant tissues, source 

 of, 23. 



Hydroscopic properties of soils, 56. 



I. 



Inanimate enemies of the forest, 



61 to 67. 



Influence of mountains on drain- 

 age, 16. 

 Insects, destruction of forests by, 



73, 74. 

 larvae of, destruction of forests 



by, 74. 



Interests of lumbermen and for- 

 estry associations mutual, 18. 

 Inundations caused by destruction 



of forests, 81, 82, 83. 

 causes of, 81, 82, 83, 111, 



112. 

 influence of, on destruction of 



forests, 66. 



influence of the surface on the 

 number and severity of, 1 12. 

 Island of St. Helena, Lyell on the 

 destruction of its forests, 87. 



J. 



Jack Sprat, of nursery lore, 143. 

 " Journal of the Society of Arts," 

 extract from, 89. 



