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tact to the lower level there depositing it in great piles 

 called moraines. They are of two or three classes ac- 

 cording to the locality and circumstances of the 

 deposit. They are sometimes one hundred feet or over 

 in height. Erosion of glaciers is their cutting tearing 

 or rubbing against the sides of the valley through 

 which they pass. In old and deserted ravines where 

 they had previously been, these evidences of this cut- 

 ting are plainly visible. The largest and best known 

 glacier region is in Europe near the central Alps, where 

 not less than eleven hundred occur many of which are 

 quite large. 



Ice bergs may be found in great abundance in the 

 arctic regions, and navigation could be extended much 

 farther north were it not for them. The adventures 

 of explorers on their voyages toward the poles are both 

 thrilling and interesting. Sometimes a number of ice 

 bergs become detached and float loosely around. These 

 are deadly foes of vessels. 



The dew which refreshes the earth in summer is 

 w^orthy of our notice and claims our attention and a 

 share of our regard as well as other natural agencies 

 which have already been described. Everyone has 

 noticed that when water is poured into a glass on a 

 hot day the outer surface becomes covered with mois- 

 ture. Dew is caused in the same manner. In the even- 

 ing when the plants and other objects become cool or 

 cooler than the surrounding air, their contact with 

 it brings its temperature below dew point, when the 

 moisture in the air is condensed and settles upon the 

 plants in little drops. Some collect more than others, 



