BIGELOW: COAST WATER EXPLORATION OF 1913. 257 



students and laity alike. It is true that the surface temperature falls 

 very low in winter near the coast, cooling to about 39° over the zone 

 between Marthas Vineyard and New York (Sumner, Osburn, and Cole, 

 1913), with even lower winter temperatures in enclosed sounds and 

 bays, for instance, 31.2° in February at the Woods Hole Station of the 

 Bureau of Fisheries (Sumner, Osburn, and Cole, 1913, p. 48, average 

 of three years) . But this only happens where surrounding islands give 

 the waters more or less the hydrographic character of lakes. And the 

 zone over which the surface temperature falls below 40° in the coldest 

 month (February) is nowhere more than thirty-five miles broad, south 

 and west of Cape Cod, with a steady rise of surface temperature from 

 the land seaward. The cold water is also correspondingly shallow, 

 bottom water colder than 40° being probably limited seaward by the 

 fifty fathom contour in this region. In short, the water is coldest 

 just where it might be expected to be influenced most by the icy north- 

 west winds of winter. And so far as the scanty winter data show, 

 this is true all along the coast as far as Chesapeake Bay. 



Air temperatures 10°-15° F. below freezing, such as are common 

 in winter in southern New England, are surely enough to account for 

 considerable cooling of the adjacent water. How closely the winter 

 temperature of our coast water depends on the influence of the land 

 is illustrated by the fact that Gloucester Harbor, which opens freely 

 to the deeps off Massachusetts Bay, is l°-2° warmer than the more 

 enclosed waters of Woods Hole in winter, although a degree of latitude 

 further north, and bordering a colder ocean area. Gloucester Harbor 

 in turn, is colder than Massachusetts Bay; for example, its surface 

 temperature fell to about 34° during the winter of 1912-1913, the 

 lowest reading a few miles outside being 37°. An^d Boothbay Harbor, 

 seventy-five miles north of Gloucester, which bears something the 

 same relation to the land as Woods Hole, being shut in by numerous 

 islands, is colder than eitlier Gloucester or Woods Hole (about 30° F. 

 in February), reflecting the very cold winter climate of northern New 

 England; and likewise colder than the water off shore. (The mean 

 temperature for December and March, at Mt. Desert Rock, is about 

 38° and 36°; at Boothbay, 37° and 32.2°). These comparisons of 

 surface readings apply just as well to the whole of the upper 30-40 

 fathoms, for our winter work (1914b) has shown that the tempera- 

 ture of the Gulf of Maine is practically uniform, vertically, to at least 

 that depth from December to March. The fact that in summer the 

 water is coldest at the bottom of such partially enclosed sinks as the 

 trough between Jeffrey's Ledge and the mainland, i. c, just where 



