Concluding Remarks 177 



SOME REMARKS OF A POLEMICAL NATURE 



By far the greatest part of physical oceanographic knowledge was accumu- 

 lated by the following process : 



First, a grand cruise, or expedition, brings back data obtained at many 

 hydrographic stations. 



Secondly, extensive plots, graphs, and tabulations of the data are made 

 and published for the benefit of future generations (e.g., in Bulletin 

 Hydrographique) . 



Thirdly, certain of the more striking features of the data plots are noted. 



Fourthly, some plausible hypotheses are advanced to explain them. 



At this stage the procedure had usually exhausted the energy of those in- 

 volved, and almost always the funds, and the study usually stopped. In a 

 few projects, such as the Discovery Antarctic studies, the Scripps Marine 

 Life Program, and the Woods Hole Gulf Stream studies, attempts were 

 made repeatedly (third step) to bring the striking features into better focus, 

 the first and second steps being repeated in various combinations and per- 

 mutations, with the goal of presenting the main features of the findings in 

 great detail. Thus, much of the effort in the Gulf Stream work has been 

 devoted to attempts to detect changes in the total transport of the Stream, 

 to surveys of the shapes of meanders, and to determinations of the 

 'width' of the Stream and of the transverse surface velocity profile. The 

 plausible hypotheses (fourth step) are modified as needed, to avoid conflict 

 with the observations. Sometimes the choice of h3rpothesis is easy and the 

 modification slight, because a variety of different plausible hj^otheses all 

 fit the observations. 



These first four steps are absolutely necessary, of course ; without them 

 we would know nothing at all about the ocean as it really is. But for the 

 full development of the science there must be one additional step : 



Fifthly, the plausible hypotheses must be tested by specially designed 

 observations; in this way theories can be rejected or accepted, or may be 

 modified to become acceptable. 



As an example of an untested hypothesis one may take any particular 

 choice of the ' depth of no motion ' for dynamic computations of the Gulf 

 Stream (see Chapter XI). A knowledge of the truth or falsity of this 

 hypothesis will become indispensable once the theoretical models begin to 

 approach reality. To make a satisfactory test will exercise our ingenuity. 

 The surface currents are too strong to permit the making of accurate direct 

 current measurements from an anchored ship. Oceanographers may have 

 to devise and employ some new observational technique in order to make 



