INTRODUCTION xiii 



the microscopic tenants of a rock-pool as among the 

 larger animals of a more obvious world ; and so forth. 

 But we are unable to isolate mentally a single species, 

 and to describe how it reacts to the incessant changes 

 of its physical and organic environment. 



Between these extremes of scale — between the 

 gigantic and world-embracing movements of Air and 

 Water, and the brief life of the minutest organism — 

 lie, intricately interwoven, the problems with which the 

 student of oceanography must wrestle. But while his 

 proper work is the orderly marshalling of facts into 

 groups, as a basis for explanations — or at least for 

 hypotheses — the facts themselves can be gathered in 

 quantity by any traveller who chooses to take the 

 trouble of doing so. 



