BIGELOW: COAST WATER EXPLORATION OF 1913. 259 



peake Bay. And the considerable difference in temperature between 

 thie surface and the water a few fathoms down is ahuost as conchisive 

 evidence in the same direction, because any constant accession of cold 

 water from below would have made the temperature more uniform, 

 vertically. 



The evidence of salinity supports that of temperature, for although 

 Schott (1912) believes that the low salinity of the coast water suggests 

 upwelling, a more rational explanation of this phenomenon is that it 

 results from the large amount of river water which enters the sea 

 between Chesapeake Bay and Newfoundland, as maintained by 

 Tizard (1897). I have already pointed out (1914a), that the river 

 water which enters the Gulf of IMaine would be sufficient to raise 

 the level of the latter half a fathom per year, were it an enclosed basin, 

 evaporation being more than offset by rainfall. And even larger 

 amounts of fresh water come from the rivers west and south of Cape 

 Cod; e. g., the Connecticut, Hudson, Delaware, and the watershed 

 draining into Chesapeake Bay. There is therefore no more need to 

 call upon upwelling to account for the low salinity of our coast water, 

 than for that of the Baltic, of the Gulf of St. Lawrence, or of the 

 waters off the mouths of the Niger and Amazon rivers. Furthermore, 

 while upwelling would lower the salinity of the surface water below that 

 of the Gulf Stream, it could not possibly reduce it to the comparatively 

 fresh state of the coast water (32%o to 33%o), because the deeper lay- 

 ers of the Atlantic, from which any updraught must come, are far Salter 

 than this (34.9%o, ^Murray and Hjort, 1912). In short, low surface 

 salinity does not indicate upwelling in this case, though it does not 

 necessarily preclude the possibility that such a process might be taking 

 place to a small extent. Unfortunately our salinity profiles across 

 the continental shelf do not establish the upper limits of the water of 

 the abyss as well as the temperature profiles, for they leave a bare 

 possibility that the fresh coast water may have been connected with 

 the abyssal water of 34.9%o by a continuous zone of bottom water 

 fresher than 3o%o (P- 344). But although the data are not absolutely 

 conclusive, for want of bottom salinities at the crucial depth (75-100 

 fathoms), it is very much more probable that the bottom water at this 

 depth was salter (above 35%o), just as it was warmer (p. 164), than the 

 water below it. And this w^as certainly the case south of Nantucket 

 in August, when the salinity of the bottom water, in sixty fathoms, was 

 So.17%0 (p. 193). If our salinity profiles are correct in this respect, 

 it is impossible to reconcile them with active upwelling. Density, 

 likewise, argues against the existence of an updraught of abyssal water 



