250 bulletin: museum of comparative zoology. 



deep water oft" Piatt's Bank, where the stations were occupied within 

 six days of the same date. 



In the eastern basin, the water was considerably less salt in 1913 

 than in 1912, although the two sets of observations were taken within 

 a few days of the same dates. On its western side (Station 10027, 

 1912; Station 10092, 1913) the difference was greatest in the mid- 

 depths (.35%o at fifty fathoms), very slight at surface and bottom; 

 but further east (Station 10028, 1912; 10093, 1913), it was uniform 

 (.3%o-4%o) all the way from twenty fathoms down to the bottom. 

 And the 120 fathom salinity at Station 10028 in 1912 (34.54%o) is 

 almost .3% higher than any salinity in 1913. In the northern end 

 of the basin, on the coastal bank near Lurcher Shoal, and off the 

 northeastern coast of Maine the water was also slightly Salter at all 

 depths in 1912 (Station 10036) than in 1913 (Station 10097), though 

 the two sets of observations were taken at nearly the same season, and 

 the geographic locations were almost identical. But on German Bank 

 the reverse is true, the water being about .05%o-.l%o Salter at all 

 depths in 1913 than in 1912. The sahnity of the coast water between 

 Cape i\.nn and Cape Elizabeth was about the same in August, 1913, as 

 it was two to three wrecks later in 1912, correspondingly Salter than the 

 July salinities of that year (1914a). Off Monhegan, where the observa- 

 tions for the two years were taken at practically the same date, the 

 water was slightly fresher on the surface, slightly Salter at sixty fath- 

 oms, in 1913 (Station 10102) than in 1912 (Station 10021). 



Thus, in brief, the Gulf was colder and fresher in its eastern, warmer, 

 but of about the same salinity, in its western half, in 1913 than in 1912. 



In the preceding lines the differences between the two years have 

 been emphasized. But the most important general conclusion is that 

 these differences are really very slight; and that the general distribu- 

 tion of salinity, highest in the east, lowest in the west, was the same 

 in 1913 as in 1912 



Origin of the coast water. 



In few parts of the world is the coast water so sharply defined by 

 salinity, temperature, and color, from oceanic water, as it is over the 

 coastal shelf between Nova Scotia and Cape Hatteras. And not only 

 are the physical differences great, but the transition from one t.vpe to 

 the other is often surprisingly sudden. 



The general characteristics of the coast water, as they impress the 



