2 Historical Introduction 



claimed, because the explorers of the Brazilian coast had never noticed 

 such a piling up of water. The second possibility was doubtful, because it 

 was the consensus among the Spanish navigators that the mainland was 

 not open, but presented a continuous barrier to the westward flow. Hence, 

 by elimination, only the third possibiHty was left; and as an example of 

 a deflection of the Equatorial Current by the mainland, the Gulf Stream, 

 said Peter Martjn-, was a case in point. 



The westward flow of the Equatorial Current itself was usually attri- 

 buted to the primum mobile — in some manner not clearly understood the 

 general westward motion of the celestial bodies across the sky drew the 

 water and air of the equatorial regions along with it. 



By 1519 the Gulf Stream was so well known that Spanish ships bound 

 for America came by way of the Equatorial Current but, on their return, 

 passed through the Florida Straits, followed the Gulf Stream to about the 

 latitude of Cape Hatteras, and then sailed eastward to Spain. In this way 

 they had favorable winds and avoided contrary currents over the whole 

 voyage. 



The sixteenth century marked the beginning of a period of intense 

 activity in the western North Atlantic Ocean, of exploration of the coasts, 

 and of the search for the Northwest Passage. Many of the early cruises in 

 and about the Gulf Stream, chronicled in Kohl (1868), need not concern 

 us here. Navigators of various nations investigated the geographic extent 

 of the Gulf Stream System. Among these we may number Sir Humphrey 

 Gilbert, who first suggested using a deep-sea anchor to determine surface 

 drift, Martin Frobisher, Ribault, and Laudonniere. Frobisher and John 

 Davis made numerous observations of the Labrador Current. 



Toward the end of the century Andre The vet (1575) attributed the Gulf 

 Stream to the great rivers that flow into the Gulf of Mexico. It was not 

 until many years later, when the transports of mass through the mouth 

 of the Mississippi and the Straits of Florida were measured and compared, 

 that the utter inadequacy of such an explanation was completely revealed. 

 The mass flux through the former is only one one-thousandth of that 

 through the latter. 



The sharp line of demarcation between the warm- and cold-water masses 

 was apparently flrst recorded by Lescarbot in 1609. His comment, as 

 quoted (from 2d ed., 1612, 2:531) by Kohl (1868, p. 68), reads: 



I have found something remarkable upon which a natural 

 philosopher should meditate. On the 18th of June, 1606, in 

 latitude 45° at a distance of six times twenty leagues east of the 

 Newfoundland Banks, we found ourselves in the midst of very warm 

 water despite the fact that the air was cold. But on the 21st of 



