CHARTING THE RIVER 97 



of the current and knows nothing but what experience tells 

 him; but to be anchored in its depths far out of the sight of 

 land, and to see the mighty torrent rushing past at a speed 

 of three to four miles per hour, day after day and day after 

 day, one begins to think that all the wonders of the earth com- 

 bined can not equal this one river in the ocean." 



Only in recent times, since the advent of steam, have 

 ocean travelers ceased to be at the mercy of the direction 

 and force of ocean currents; but even today the steady pace 

 of deep waters working on the hull of a steamer can set her 

 back fifty miles in a day's sailing along the axis of the Gulf 

 Stream. This, of course, has a direct effect both on time and 

 on fuel economy. It is obvious, therefore, that even though 

 we have largely graduated from the age of sail, a thorough 

 knowledge of ocean currents is still of considerable impor- 

 tance for all types of vessels. 



In the early days of sailing, especially with square-rigged 

 ships, the importance of currents as an aid or an obstacle to 

 navigation was paramount. Under conditions when wind and 

 stream were both unfavorable a ship might well be set back 

 in its course for many miles, or, at worst, might be lost on the 

 rocks of a lee shore. Though this is still true for all types of 

 sailing vessels it was particularly true of the square-rigged type 

 used in the early Atlantic crossings, because of their limited 

 powers of sailing against the wind. Largely because of this, 

 the existence of great currents and their position and strength 

 have shaped the course of early explorations and the pattern 

 of settlement of the Atlantic shores, first of all in the east 

 and later in the west. 



The influence of ocean currents on man, working in various 

 and devious ways, has inspired many scientists from many 

 lands to inquire into their movements and to speculate on 

 their cause. But progress in our knowledge of their position, 

 their strength, and their variations has been understandably 



