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bulletin: museum of comparative zoology. 



the former, which was decidedly lighter, owing to solar warming, with 

 no corresponding increase in salinity. And even this slight difference 

 does not extend to the eastern part of the Gulf, surface density being 

 nearly the same there as on Georges Bank, or at Station 10218. Thus, 

 on the profile across the western end of Georges Bank, there was no 

 great general difference in density, down to the level of the Bank, 

 between the waters over it, and north and south of it, though below 

 that level the latter were considerably the densest. But, and this 



Fig. 39. — Density at 100 meters, July-August, 1915. Density above 1.027 b shaded. 



is one of the most significant hydrographic discoveries made by the 

 Grampus, the mixed water along the slope further east (Stations 

 10220, 10233, 10295), was considerably denser, from 50 down to about 

 180 meters, than the Gulf of Maine on the one hand, or Gulf Stream 

 water on the other (Fig. 38), i. e., at just the level where, owing to 

 the topography of the bottom, ocean water can enter the Gulf only via 

 the Eastern Channel. Below the latter the difference in density be- 



