PREFACE 



Oceanography has surged forward as a subject for research during the past 

 twenty years, and great progress has been made in our understanding of the 

 structure of the water-masses, of the crust of the earth beneath the oceans, and 

 of the processes which are involved in creating these structures. This progress 

 has been particularly rapid in the recent past for two prime reasons. Firstly, 

 techniques of investigation have become available which have made many 

 hitherto intractable problems capable of solution. For example, it has only 

 recently become possible to measure the value of gravity in a surface ship, to 

 determine the deep currents of the oceans by direct methods, or to analyze wave 

 spectra with the detail which modern electronic computers allow. The second 

 reason for the present rapidity of progress lies in the increasing availability of 

 the resources for both theoretical and practical marine investigations; the 

 international character of oceanography and the growing world-wide interest 

 in fundamental research has resulted in the provision of opportunities hitherto 

 impossible. 



Some years ago Dr. Roger Revelle of the Sjcripps Institution of Oceanography 

 suggested to us that perhaps the production of treatises on the new develop- 

 ments in oceanography were not keeping pace with the progress in the subject. 

 It was true that papers were appearing in healthy numbers throughout the 

 journals of the world, but there were no recent comprehensive works such as 

 The Oceans, written by Sverdrup, Johnson and Fleming and published in 1942. 

 This work had been, and still is, of value to many, if not all, oceanographers ; 

 Revelle suggested that we produce another such volume containing ideas and 

 observations concerning the work accomplished during the twenty years since 

 this masterpiece. It was suggested that this new work should not attempt to be 

 a textbook but a balanced account of how oceanography, and the thoughts of 

 oceanographers, were moving. 



It was early apparent that a work of this nature would have to be from the 

 pens of many authors ; the subject had become too broad, the oceanographers 

 perhaps too specialized, to allow a small number of contributors to cover a vast 

 field of study. It was also apparent that we could do no more than include 

 biology in so far as it was directly related to physical, chemical and geological 

 processes in the ocean and on the ocean floor. Marine biology could alone fill 

 that space which we thought was the maximum we should allow for these 

 volumes. Biology is, therefore, somewhat scattered through this work; so it has 

 to be, since the contributions of biologists extend throughout the disciplines 

 embraced by the contents of these volumes. 



It has been said in the past that oceanography as a subject did not, or even 



