PREFACE 



At the beginning of practically every hour that has passed during 

 the last 30 years, measurements of the direction and velocity of the 

 current have been made at one or more of the lightship stations along 

 our Atlantic coast. The Lighthouse Service for many years coop- 

 erated with the Coast and Geodetic Survey in securing the current 

 observations, and the Coast Guard, which now operates the lightships, 

 is helping to add to our knowledge of the complex movements of 

 coastal waters. 



The purpose of this volume is to make available in convenient 

 form for the use of the mariner, the scientist and the general public 

 the data derived from analyses of the current observations. 



In addition to the data derived from the relatively long series of 

 lightship observations, results from numerous short series secured 

 in the vicinity of Georges Bank are incorporated in the current charts 

 for that area, which are included in this volume. 



The section on the general characteristics of tidal currents, which 

 in this volume precedes the discussion of the observational material, 

 was taken from Tides and Currents in New York Harbor, United 

 States Coast and Geodetic Survey Special Publication No. Ill, 

 Revised (1935) Edition. 



In connection with this publication attention is invited to Coast 

 and Geodetic Survey Special Publication No. 121, Coastal Currents 

 Along the Pacific Coast of the United States, which discusses current 

 observations taken at lightships along that coast ; and to the following 

 publications which give observational current data for waterways 

 along our Atlantic coast: 



Tides and Currents in New York Harbor (1935); Tides and Cur- 

 rents in Delaware Bay and River (1926); Tides and Currents in 

 Boston Harbor (1928); Tides and Currents in Portsmouth Harbor 

 (1929); Tides and Currents in Chesapeake Bay (1930); Tides and 

 Currents in Long Island and Block Island Sounds (1932); Tides and 

 Currents in Hudson River (1934); Currents in Narragansett Bay, 

 Buzzards Bay, Nantucket and Vineyard Sounds (1938); Currents in 

 St. Johns River, Savannah River, and Intervening Waterways (1938). 



Attention is invited also to the annual Current Tables, Atlantic 

 Coast, North America. These tables contain data from which daily 

 predictions of the current may be readily obtained for numerous 

 locations. 



