BIGELOW: COAST WATER EXPLORATION OF 1913. 241 



influences on the part of the Gulf Stream. Nevertheless the Alba- 

 tross temperatures are instructive because they show that in 1884 

 the cool water which bathes the shelf was once more separated from the 

 cold water of the depths by a warm belt; i. c, that the normal dis- 

 tribution of temperature was reestablished. 



We know nothing about the subsurface temperatures of the next 

 four years. But in 1889 Libbey took no less than 1600 temperatures 

 on the surface and at depths, over the region south of Marthas Vine- 

 yard and Block Island. These records are so arranged as to show the 

 distribution of temperature in great detail for the region studied ; and 

 they are so extensive that I can only summarize them here. Full 

 tables, with charts and profiles, have been published by the U. S. 

 Bureau of Fisheries (Libbey, 1891). Libbey's profiles show a cold 

 tongue projecting southward into the warm off shore layers, in the 

 mid-layers, such as we found south of Marthas Vineyard (p. 165, 

 figs. 9, 10). The course of the curve of 50° in most of his profiles 

 suggests that the cold bottom water of the shelf was directly con- 

 tinuous with the cold water of the depths under the Gulf Stream, 

 instead of being separated from it by a zone of warm bottom water. 

 But his own tables show that the few bottom readings which he took 

 in the zone bounded by the seventy and ninety fathom contours were 

 warmer than the bottom water either in shallower or in greater depths. 

 And although his profiles off Nantucket, (Longitude 70°-71°) even 

 more strongly suggest a continuity between the cold bottom water of 

 the shelf and of the deeper part of the slope, this is chiefly because a 10° 

 interval between the curves is too great to illustrate the actual condi- 

 tions, the temperatures on which his profile D (Longitude 70° to 

 70° 20') was constructed showing that the coldest water on the shelf 

 (42°, 50 fathoms) was underlaid by warmer water (45.3° to 47.4°). 

 And the bottom temperature was even higher at ninety fathoms. 

 In short, the cold coast water was separated from the cold water of the 

 abyss by a warmer zone, in 1889, with a temperature of about 47°-51° 

 at 70-100 fathoms. And the same was also true in 1890 (Libbey, 

 1895). 



In 1889 the absolute temperature of the cold tongue was 46°-47° 

 off Block Island, falling to about 42°^3° south of Nantucket, which 

 agrees fairly closely with our observations at Stations 10065 and 

 10061, in July, 1913. But the facts that Libbey's temperatures were 

 taken late in August, by which time the water was much warmer in 

 1913 (Station 10112), and that the cold tongue projected much further 

 seaward in 1889 than in 1913, are good evidence that the water as a 

 whole over the continental shelf was colder in that year. Judging 



