214 bulletin: museum of comparative zoology. 



Bay of Fundy (Fig. 54), shows that the upper layers at Station 10096 

 are salter than the water at corresponding depths further off shore. 

 And this is true whether Station 10092 or Station 10093 be taken as 

 the outer end of the profile, though the difference is slightly greater 

 in the case of the latter. The uniform water between thirty and sixty 

 fathoms at Station 10096 is slightly Salter (33.4%o) than the mean 

 (33.27%o) of the corresponding column of water at Station 10093. 

 Station 10096 was likewise considerably salter as a whole than the 

 water over the slope of German Bank (Station 10094), especially in 

 the mid-depths; and though the latter was the salter of the two on 

 the surface this does not invalidate the general statement, because its 

 high surface salinity was due to local vertical mixing by tidal currents 

 (p. 204) . In short, the upper thirty fathoms of water was salter off the 

 mouth of the Bay of Fundy (Station 10096) than on the coast bank 

 to the south, the eastern basin, or for that matter, anywhere else in 

 the Gulf; probably due to an updraught from the mid-depths off shore. 

 And the profile is further interesting because the spreading of the 

 curves for 33.4%o and 33.5%o over the coast slope at 50-80 fathoms 

 suggests that vertical mixing, which in the Gulf is synonymous with 

 tidal currents, was active on the bottom at Station 10096, though 

 not on the surface. 



Density, at the temperature in situ. Cape Cod to Chesapeake 

 Bay. 



The chart of density on the surface south of Cape Cod (Fig. 55), 

 for the first half of July, is less significant in detail than the chart of 

 surface salinity, because surface density was constantly falling, with 

 the seasonal rise in surface temperature (p. 156). The off shore water 

 was as a whole heaviest, the coast water lightest. But on our voyage 

 south we encountered a secondary area of low density over the central ■ 

 part of the continental slope off New Jersey (Station 10070), as out- 

 lined by the curve for 1.0220, with heavier water (1.0227) between it 

 and the coast, a phenomenon caused by the rapid warming of compara- 

 tively fresh surface water (p. 187) by warm southerly winds from the 

 Gulf Stream, which prevailed at that time. And by the end of July 

 the rise of surface temperature (p. 156) caused even lower densities 

 next the coast (Station 10080, density 1.0215; Station 10081, density 

 1.02145). The density was lowest (1.0184) at the mouth of Chesa- 

 peake Bay, highest outside the continental shelf (Station 10071); 



