164 



THE WATERS OF THE EARTH 



four hours to melt a mass of iron as large as Mount Wash- 

 ington. Hammerfest at 71 north is a flourishing seaport, 

 but there are no important settlements above 50 on the 

 western side of the Atlantic. Alaska, the prevailing winds 

 of which are warmed by blowing over the warm ocean, 

 is a region which promises much for human habitation, 

 while the region on the opposite side of the Pacific must 

 remain almost destitute of human inhabitants. It should 



be noted that the 

 effect of the warm 

 ocean waters would 

 be slight, except 

 along the coast, were 

 it not for the air 

 movements. 



Tides. Prob- 

 ably the first thing 

 that impresses us 

 on visiting the sea- 

 shore is the regular 

 rising and falling of 

 the water each day. 

 These movements of the water are called tides. If we 

 observe the tides for a few days, we find that there are two 

 high and two low tides each day. As the tidal current 

 comes in from the open ocean and the water rises, it is 

 called flood tide, a"nd as it runs out or falls, ebb tide. When 

 the tides change from flood to ebb or ebb to flood, there is 

 a brief period of " slack water/' 



If we observe closely, we shall see that the corresponding 

 tides are nearly an hour later each day than they were 



HIGH TIDE IN NOVA SCOTIA 



