TENTH LECTURE. 



-ooJV<oo- 



THE STUDY OF OCEAN TEMPERATURES 



AND CURRENTS. 



By WILLIAM LIBBEY, Jr., Sc.D., 



PROFESSOR OF PHYSICAL GEOGRAPHY, COLLEGE OF NEW JERSEY, PRINCETON. 



Professor Whitman has been kind enough to ask 

 me to speak to you this evening upon the physical work 

 of the U. S. Fish Commission. As this work is so 

 intimately connected with the study of the Gulf Stream, 

 a few statements concerning ocean currents in general 

 and their causes will not be out of place. 



I do not know whether it is generally known that the 

 word ''ocean," as applied to the waters of the globe by the 

 ancients, seems to have been intended to convey some 

 idea of currents. It is derived from two Greek words 

 w/cew? and vdeiv which mean "fast flowing." This has 

 sometimes been thouQ-ht to refer to the onward motion 

 of the waves toward the shore. This may be its mean- 

 ing, but when we remember the great number of refer- 

 ences to the ''river ocean" in the classics, and the 

 inscriptions upon the older maps givino^ the direction of 

 the currents, as for example the " Periplus maris ery- 

 thraei " flowing along the Somali coast, we cannot help 



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