MARCH H), 1921 THURAS: PROBLEM OF PHYSICAL OCEANOGRAPHY 133 



purpose of solving the general problems of oceanic circulation. This 

 article is written with the object of indicating the importance of this 

 subject, especially as regards a part of the North Atlantic ocean, from 

 the light of recent experience, and with the hope that in the near 

 future some systematic plan of work will be undertaken to solve the 

 important dynamical problems of the sea, thereby obtaining a more 

 accurate knowledge of ocean circulation. 



During recent years much work of an explorational nature has been 

 carried on in the coastal waters of the United States and Canada. 

 Dr. Henry B. Bigelow, in cooperation with the U.S. Bureau of Fisheries, 

 has made these investigations, and the results of his work are published 

 in the Bulletins of the Museum of Comparative Zoology, Har^-^ard 

 University. Several theories of the origin and circulation of our coastal 

 waters have been corrected, and sufficient data have been collected 

 to give a general working knowledge of the subject. Valuable ob- 

 ser^^ations have also been collected by observers in Canadian waters, 

 and from these observations some exceedingly interesting theories of 

 ocean circulation have been developed by J. W. Sandstrom. Most 

 of this work has also been of an explorational nature. 



Since the beginning of the International Ice Patrol an opportunity 

 has been given to extend this work further out into the North Atlantic 

 in the region of the Grand Banks of Newfoundland and in the Labra- 

 dor Current and Gulf Stream. The conflict of the Labrador Current 

 and Gulf Stream south of the Newfoundland Bank causes greater 

 changes in the physical properties of the sea water, only a few miles 

 apart, than occur in any other part of the world. The hydrographical 

 conditions which exist in this locality cause much ice and fog which 

 become a serious menace to navigation during the spring and summer 

 months. The vessels of the U. S. Coast Guard have collected many 

 observations while on patrol in this region. These observ^ations have 

 so far been chiefly of an explorational nature, as the primary purpose 

 of the Patrol has necessarily been to locate ice and convey this informa- 

 tion to other vessels. However, from the data obtained and the ad- 

 mirable current charts prepared by Captain C. E. Johnston of the 

 Coast Guard, a fairly accurate knowledge of the movements of ice 

 after passing Newfoundland is available. 



In the spring icebergs from the shores of Greenland and Labrador 

 are carried southward in the Labrador Current, their movement being 

 little affected by winds, on account of their small buoyance. Those 

 bergs which are sufficiently off shore to clear the bottom and keep in 



