THE SAFEGUARDING OF COASTS 307 



their heads by descending glaciers. They often have 

 hanging valleys which enter far up along their sides, the 

 streams of which descend by abrupt falls and adorn the 

 dark rock walls with bands of silver spray. 



It was such a coast as this which bred the ancient 

 Northmen, to whom the Sea of Darkness, as they called the 

 Atlantic, was terrorless. While less favored and hardy 

 sailors were dodging from bay to bay along the shore 

 always in sight of land, they were pushing boldly west, 

 guided only by the beacons of the sky, and discovering 

 Iceland, Greenland and the American continent. 



145. Harbors. The importance to mankind of good 

 harbors cannot be overestimated. No civilized country 

 by its own products can fill all the wants of its inhab- 

 itants. Since earliest times man has been a barterer of 

 goods. The sea offers him an unrestricted highway for 

 his traffic. Harbors he must have to load and unload his 

 wares safely. 



Although many of the best harbors of the world are 

 found along depressed coasts, such as the harbors of New 

 York, San Francisco, London, Liverpool and Bergen, yet 

 there are several other sorts of harbors. The delta of a 

 great river may afford a good harbor, as those of New 

 Orleans and Calcutta. Harbors may be formed by sand 

 reefs and spits, like those of Galveston, Provincetown 

 and San Diego. The atolls of the mid-Pacific and even 

 the submerged craters of volcanic islands afford safe rest- 

 ing places where ships may ride out the storms. 



146. The Safeguarding of Coasts. As nations advance 

 in civilization and their commerce develops, they realize 

 the necessity of safeguarding in every way possible the 

 ships bearing their citizens and their wealth. Thus a 

 great system of weather signals, of lighthouses and of life- 

 saving stations has been established. From these mariners 



