204 OUTLINES OF FORESTRY. 



the fields in order to protect them from the ravages 

 of the hail. 



The peculiar structure of the hailstone has also 

 been ascribed to a whirling motion of the air be- 

 tween snow- and rain-clouds around a horizontal 

 axis, whereby particles of snow are carried alter- 

 nately into the rain- and snow-clouds, and thus 

 receive their alternate coatings. 



Another theory accounts for the alternate coat- 

 ings of ice and snow by the exposure of moisture 

 to the different temperatures occurring in denser 

 and rarer portions of space around which the wind 

 is whirling. 



By reforestation is meant the replanting of trees 

 in any locality from which they have been removed 

 either accidentally or purposely. 



Provided the removal of the forest has not been 

 attended by too great a loss of soil, the same kind 

 of trees may be successfully replanted. 



There are two methods by means of which 

 reforestation may be effected. 



1. Sowing or Seeding. 



2. Tree Planting. 



Seeding can be profitably followed in the tem- 

 perate latitudes where the growth of the tree is 

 comparatively certain. In higher latitudes the 



