in publication called the North Atlantic Lane Routes, which is re- 

 vised whenever it is considered advisable. During the ice season 

 the tracks leading to Halifax, New York, and Boston are shifted 

 southward in accordance with a prearranged schedule, so as to be 

 as clear as possible of the worst ice as its works down the eastern 

 edge of the Banks. At the expiration of the patrol, usually about 

 July 1, the tracks are again moved up as far north as safety permits. 

 The principal trans-Atlantic steamship companies are signatories 

 to the track agreement. It is the duty of the patrol vessel to report 

 any vessel seen off the prescribed track. 



The above presentation of the work of the patrol is made for the 

 purpose of enabling the reader to fully comprehend the need for the 

 oceanographic data that was collected and its relation to the patrol. 



