210 THYSICAL GEOGRArHY OK TUE SEA, AND ITS METEOROLOGY. 



surface, there is, it is supposed, a basin in wliicli the waters, as 

 they rise to the surface, are at 30°, or whatever be the tempera- 

 ture of the under current, which we know must be above the 

 freezing-point, for the current is of water in a fluid, not in a soHd 

 state. An arrangement in nature, by which a basin of consider- 

 able area in the frozen ocean couhl be supplied by water coming 

 in at the bottom and rising up at the top, with a temperature 

 not below 30°, or even 27°.2 — the freezing-point of sea water- 

 would go far to mitigate the climate in the regions round about. 



425. Indications of a milder climate. — And that there is a 

 warmer climate somewhere in that inhospitable sea, the observa- 

 tions of many of the explorers who have visited it indicate. Its 

 existence may be inferred also from the well-known fact that the 

 birds and animals are found at certain seasons migrating to the 

 north, evidently in search of milder climates. The instincts of 

 these dumb creatures are unerring, and we can imagine no miti- 

 gation of the climate in that direction, unless it arise from the 

 proximity, or the presence there of a large body of open water. 

 It is another furnace (§ 151) in the beautiful economy of Kature 

 for tempering climates there. 



426. How the littoral waters, hy being diluted from the rivers and the 

 rains, serve as a mantle for the Salter and warmer sea water below. — 

 The hydrographic basin of the Arctic Ocean is large, and it 

 delivers into that sea annually a ver}- copious drainage. Such" an 

 immense volume of fresh water discharged into so small a sea as 

 the Arctic Ocean is, must go far towards diluting its brine. 

 Fig. 2, Plate X. (§ 433), shows the extent to which the brine of 

 our littoral seas is diluted by the drainage from the Atlantic 

 slopes of the United States. It will be observed by that figure 

 that suddenly after crossing the parallel of 34^ N. the water 

 begins to grow cooler and lighter. The observations for the two 

 curves are a part of the celebrated series made by Captain Eodgers 

 in the U.S. ship "Vincennes" all the way from Behi-ing's 

 Straits by the way of Cape Horn to New York. He cleared the 

 inner edge of the Gulf Stream in 34°, where the waters began to 

 grow cooler and lighter, and so continued to do as he approached 

 the shore. The remarkable and sudden approach of the thermal 

 and specific gravity curves after crossing 34'' N. can be explained 

 by no other hypothesis than this, viz. : the surface water of the 

 sea was so diluted with the fresh water from the Chesapeake, the 

 Delaware, and New York Bays, that, notwithstanding the tern 



