654: POLAR SEAS pole have been made N. of Spitzbergen by Parry, through Smith sound by Kane, Hayes, and Hall, and to the east of Spitzbergen by the Austrian expedition under Payer and Wey- precht. The distances from the pole reached through these three routes do not differ ma- | terially, being all between 400 and 500 nauti- ; cal miles. In these parts the ice breaks up in summer and moves S., thus opening irregular j channels through which it is possible to pene- ; trate more or less easily, according to the sea- j son. The question of an open polar sea has received much attention of late years ; it was first advocated by the Russian explorers, Wran- gell, Middendorff, and others, who had observed a band of open water N. of the New Sibe- rian islands, to which they gave the name of Polynia. This is probably due to a current of warmer water passing from the Atlantic toward Behring strait. The American expe- ditions found open water at the N. end of Kennedy channel, and the tides have been sup- posed to indicate a free communication with the Pacific in the direction of Behring strait ; but this is very doubtful, as in all known in- stances the tide wave is promptly extinguished after passing through a narrow strait into a wide basin. Borgen, in discussing the results of the second German expedition, calculates that, supposing the whole polar sea to be fro- zen over in winter, about one third of the ice is carried off in summer by drifting and melt- ing ; but he thinks that the uncovered surface consists of irregular and constantly changing openings in the ice, not necessarily communi- cating with one another. The question will only be fully solved by actual exploration. The currents are very important, as determin- ing the limits of the drift ice. The different theories on the subject of the northern exten- sion of the Gulf stream are set forth in the article ATLANTIC OCEAN. Its observed effects are briefly these : The warm water, crossing the Atlantic diagonally, passes the North cape and strikes the western and northern parts of Nova Zembla, where it occasionally leaves proofs of its origin in the shape of bamboos and tropical seeds. Further E. observations are still wanting, but it is probable that the open water, the Polynia of the Russians, is still due to the same cause. A return current from E. to W. has been observed by the Aus- trians along the S. coast of Francis Joseph Land, which probably merges in the cold cur- rent descending along the E. coast of Spitz- bergen. On the W. of that island a warmer cur- rent sets N. The S. and E. coasts of Iceland also receive warm water from the south. Along the E. coast of Greenland a cold current sets S. and turns around Cape Farewell into Davis strait, which it follows up some distance, finally turning and merging in the Labrador current, which flows S. on the opposite side of the strait, and which after passing the banks of Newfoundland partly disappears under the Gulf stream and partly flows S. along the coast of the United States. A cold current | flows out of Behring strait into the sea of the j same name. In conformity with the tempera- ture of these currents, the Arctic ocean is found almost free of ice along the N. coast of j Europe as far as the northern part of Nova i Zembla and the Kara sea. On the E. coast of I Spitzbergen it is so thick as to be generally j impenetrable; on theW. coast it is very loose, I or even absent, in summer. Along the E. ! coast of Greenland the pack ' is so thick that I ships can rarely reach the land, though some
