CHARTING THE RIVER 101 



Outside of this he imagined the Ocean River, as the Greeks 

 so aptly named it, to flow ceaselessly around the world, a 

 living moat of danger and destruction. 



The notion of a spherical earth came more than a thousand 

 years before the time of Columbus. Ptolemy had conceived 

 this idea long before, and by the fifth century a.d. his succes- 

 sors were aware that oceans lay to the west and to the south. 

 The map he prepared in 150 a.d. showed only the western 

 ocean between Africa and the Orient; the New World and 

 the Pacific Ocean were still undreamed of. But even this 

 limited knowledge was for all practical purposes lost when 

 superstition and ignorance again took hold during the fifth 

 and sixth centuries. And so, the maps of Bishop Isidore of 

 Seville in the seventh century were far cruder even than the 

 one Homer had made nearly 1,700 years earlier. Bishop Isi- 

 dore's concept was simple in the extreme. He drew a circle 

 for the earth; cut it into three portions, separated by the 

 Mediterranean Sea and by the two great rivers, the Nile and 

 the Don; and resurrected the Ocean River to form a circular 

 canal connecting the sea and the rivers and embracing the 

 whole. 



In the fifteenth century the spirit of exploration blossomed 

 under the encouragement of Prince Henry the Navigator, 

 and Ptolemy's map was brought out of hiding. So it came 

 about that, by the time Columbus was ready to set out across 

 the Ocean River, a great part of the coast of western Africa 

 had been added to the charts. Finally, when Bartholomew 

 Diaz rounded the Cape of Good Hope and found this con- 

 nection between the Indian and Atlantic Oceans, the extent 

 of the eastern shores was established. The stage was now set 

 for the gradual unfolding of the story of the River itself. 



The earlier navigators may not have known that there 

 were steady currents well out to sea, but they can hardly have 

 failed to notice the nearby currents where they ran parallel 



