A 



B 



C 



D 



Figure 17. — Surface-current flow in Lake Huron determined from dynamic 

 heights (solid lines) and drift-bottle movements (broken lines). 

 Dynamic heights calculated and drift bottles released on June 22, 

 1956 (A), August 3, 1956 (B) , September 15, 1956 (C) , and Octo- 

 ber 27, 1956 (D). 



20 



