244 



reached a velocity of 10 miles per day. On the three sub- 

 sequent cruises, maximum velocities decreased although the 

 direction of flow was still toward the shore. The August 

 19-20 returns show a strong northerly drift, and suggest a 

 return to conditions encountered during the fall of 1955. 

 In the interest of clarity, data from all sludge and 

 effluent outfall stations are summarized in Table XII. The 

 date and station ntimbers are given, together with the princi- 

 pal location of recoveries. Isolated cards which drifted to 

 the north or south of the principal area are not described, 

 although they were not neglected in calculating times of 

 drift or velocities. Under the column headed "Time of Drift" 

 the minimum time from each station is given „ For want of a 

 better word, "average" times of drift are also tabulated, 

 but the figures do not represent arithmetic means; they were 

 estimated by inspection of tabulated data and by arriving 

 at a reasonable figure which would give the time of arrival 

 of the first significant group of cards. Wherever the 

 difference between minimum and "average" times of drift is 

 large, it indicates that one or, at most, a few cards arrived 

 well in advance of the first significant groups. Velocities 

 in statute miles per hour are calculated from the paths of 

 drift of individual cards. The last column in the table gives 

 the time that would have been required for the cards to have 

 reached the nearest shore, assuming that the velocities 

 previously determined would apply had the cards drifted 

 directly toward the beach, a distance of approximately 5^ 

 miles. By this method an estimate can be made of the worst 



