File:Annual report of the Board of Regents of the Smithsonian Institution (1891) (14594142249).jpg

Identifier: annualreportofbo1891smit (find matches)
Title: Annual report of the Board of Regents of the Smithsonian Institution
Year: 1846 (1840s)
Authors: Smithsonian Institution. Board of Regents United States National Museum. Report of the U.S. National Museum Smithsonian Institution. Report of the Secretary
Subjects: Smithsonian Institution Smithsonian Institution. Archives Discoveries in science
Publisher: Washington : Smithsonian Institution
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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nited are banked against the cold Labrador current in its coursealong the American coast. Undcmbtedly, the early observations made upon the temperature ofthe ocean were defective, owing to the somewhat imperfect instrumentsat the disi)osal of the early ex))lorers; yet they determined the generalposition of the cold and warm currents of the ocean along our shores. *Th«> direction from which the currents come is plainly shown by the nature of thehotloiu specimens, miulo up in part of globijieriujB brought by the warmer southerlysurface currents, and in part of northern foraraiuifera and of volcanic sand derivedfrom Jan Mayen and Spitzbergen. The dividing lines between these deposits njay beconsidered as the boundaries of tbe arctic current where it passes under the GulfStream. f Tlie )):nallelism of temperature is also very marked in the S<nitli Tacitic, wherethere are no disturbing influences. (See J. J. Wild, Thalmm, (pi. xv.) and Chal-hiKjer Temperutuies.) 192 THE GULF STREAM.
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6lS 390 iVcvs. . SV Thomaa THE GULP STREAM. 193 The more systematie work of the officers of the Coast Survey firstproved the existence of vast bodies of water, of considerable thickness,and of very dilierent temperatures at corresponding- depths, movin^ jnopposite directions. It is to tlie Coast Survey that we owe the denion-stiation of the fact that the waters of the polar regions pour into thetropics along- the bottom, just as the warmer equatorial waters flowacross the temperate zones near the surface, and make their influencefelt in the polar regions. The submarine ridges interrupt the flow of these cold polar waters,and form the so-called closed basius, with a higher bottom temperaturethan that of the adjoining oceanic basin. The effect of such ridgesupon the bottom temperature was first traced by the soundings of theForvupine in the North Atlantic and in the Mediterranean. Subse-quently the Ghallenger discovereil several such inclosed seas whilesounding in the East Indian Archip

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