PHYSICAL OCEANOGBAPHY OF THE GULF OF MAINE 885 



about 3J^ miles during the flood, the westerly ebb about 4J^ miles. More recent 

 information, however, does not substantiate this, ebb and flood being given as 

 approximately equal along the axis of the Sounds in the current tables for 1924 

 (United States Coast and Geodetic Survey, 1923); and the fact that considerable 

 quantities of gulf weed so often drift into Vineyard Sound and through into Nantucket 

 Sound in the summer season points rather to a net movement inward into the former 

 from the westward. 



The returns from the line next to the east (Succonnesset Point to Cape Pogue; 

 fig. 175) are consistent with a dominant set from west to east along the southern 

 side of Nantucket Sound, because all but one of the recoveries were to the eastwai'd 

 of where the bottles were set out — 9 of them from points along its northern shores as 

 far as Chatham; 1 close to Rose and Crown Buoy outside the sound, about 11 miles 

 east of Nantucket Island; 1 from the southeast shore of Nantucket; and 1 from the 

 coast of Rhode Island. Bottles from all parts of the line stranded along the north 

 shore, and the drifts that went out of the sound were from both ends of the line (the 

 bottle picked up near Rose and Crown Shoal was thrown out closest to Succon- 

 nesset) . This suggests that all traveled eastward at first, as would naturally happen, 

 as they were put out one to two hours after low water; but this first flood, running 

 at an average rate of about 1 knot, can only have carried these bottles 4 or 5 miles 

 east. 



It is possible, of course, that the bottles that went fiom this line to the eastern 

 side of Nantucket and to Rose and Crown Shoal passed out of the sound via the 

 Tuckernuck Channel; but the more direct route eastward is the more probable when 

 these drifts are studied in connection with the line put out across the eastern end of 

 the sound. 



Fourteen bottles from this line were recovered, 6 of which (set out abreast the 

 channel between Nantucket and Monomoy) made long journeys to Long Island, 

 New York, and New Jersey, while 8 bottles set out behind Monomoy Island were 

 picked up along the coast near by, between Harwichport and Monomoy. This divi- 

 sion, and the fact that the only bottles from this line that were recovered within 

 the sound were those just mentioned, makes it fairly certain that the bottles that 

 made the long journeys did not go westward through the sound, but drifted east- 

 ward out of the latter at first and then veered clockwise to the southward and so 

 around Nantucket by the same general route followed by bottles set out off the 

 mouth of the sound in 1922 (line B, p. 880), and so continued westward, paralleling 

 the coast, to the points where they were finally picked up. 



This division between the drifts followed by the bottles from the southern and 

 northern parts of the line clearly reflect a tidal difference. All were put out two to three 

 hours before high water; but while the first group was carried eastward by the flood 

 and out of the sound, the second group was caught up in the current flooding north- 

 ward into Chatham Roads. The fact that so many then stranded there, instead of 

 coming out again with the ebb, and that so many bottles from the line next to the 

 west were found along the northern shore of the sound, shows that the bight inclosed 

 between Monomoy Point (with its submarine extension in Handkerchief Shoal) and 

 the south shore of Cape Cod is the site of a subsidiary anticlockwise eddy, as might 

 be expected from the trend of the coast and from the contour of the bottom. 



