Historical Introduction 11 



Secondly, the parameters depending upon turbulence are very poorly 

 known. Thirdly, even today we do not have nearly as much accurate 

 synoptic information about the Gulf Stream as we desire. 



V. W. Ekman (1905) developed a wind-drift theory, taking into account 

 the effect of the earth's rotation, which for the first time made possible 

 computations of the effect of wind stress in transporting water. In Ekman's 

 treatment the ocean is regarded as homogeneous and of infinite extent 

 horizontally. A constant wind blows over this ocean. In deep water the 

 surface- current vector is 45° cum sole to the wind and changes direction 

 and diminishes with depth according to the Ekman spiral. 



Later, Ekman (1923, 1932, 1939) carried out further investigations of 

 ocean currents in which he discovered certain deflecting effects of the 

 inequalities in the depth of a homogeneous ocean. A quaHtative study of 

 the ejBfect of bottom topography upon currents in a heterogeneous ocean 

 has been advanced by Sverdrup, Johnson, and Fleming (1942). Certain of 

 these deflections have been apparently observed (Neumann, 1940) in the 

 northern parts of the Gulf Stream System associated with the Altair cone. 



The first intensive surveys of the Gulf Stream System by the research 

 ketch Atlantis began in the early 1930's, soon after the estabhshment of 

 the Woods Hole Oceanographic Institution. This program was carried out 

 under the leadership of C. O'D. Iselin. 



From this point on, I shall dispense with the historical narrative in 

 favor of a topical exploration of the present knowledge concerning the 

 Gulf Stream. It is not surprising that even now, after many years of effort, 

 our conception of the Gulf Stream is incomplete. I shall try to show in 

 what respects this knowledge is deficient, as well as those features which 

 we do understand, and also endeavor to explain some of the greatest 

 difficulties encountered in planning and executing surveys. 



