370 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
The apex of the triangle unites the Sea of Greenland with the polar 
basin. 
This region comprised between Greenland and Spitzbergen consti- 
tutes the outlet of the ice from the polar basin, and at the same 
time affords a passage toward the north of the farthermost branch 
of the Gulf Stream. This Atlantic current, which warms the western 
coast of Spitzbergen, passes around the northwest angle of this 
archipelago and loses itself in the Arctic basin, as Nansen has demon- 
strated. The oceanographic régime of the basin depends then, first 
of all, on the topographic conditions existing in the northern part 
of the Sea of Greenland. This region is in general blocked by ice, 
Fic. 1.—Bathymetric chart of Greenland Sea. 
and its depth is unknown to us except in the immediate vicinity of 
Spitzbergen. 
Nansen believes that this gate of communication is constricted by 
a submerged ridge extending between Greenland and Spitzbergen, 
and rising to within 800 meters of the surface. 
The origin of this hypothesis is curious; first of all, it has a hydro- 
graphic foundation. Nansen has shown that in the polar basin 
proper, the deeper lying water has a density of 1.02825, while the 
samples collected by Amundsen in the Sea of Greenland yielded, for 
the water from the depths of the basin, values a little less (about 
1.02811). Nansen concludes from this that if the waters have not the 
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