THE GULF STREAM.* 
By ALEXANDER AGASSIZ. 
The Gulf Stream is the best known and at the same time the most re- 
markable example of the effect of oceanic circulation upon the distribu- 
tion of temperature in connection with the currents of the North Atlan- 
tic. It has long been known to geographers that a cold current coming 
from Greenland joins the Labrador current, and extends in a southerly 
direction along the eastern coast of the United States, while a warm cur- 
rent pouring through the Straits of Florida flows in the opposite direc- 
tion t along the coast of the southern Atlantic States, and is deflected 
from the banks of Newfoundland crossing the Aflantic diagonally. 
This body of warm water makes itself felt along the west coast of the 
British Islands, penetrating even as far as the coast of Spitzbergen, 
and perhaps beyond, to Nova Zembla. — It is impossible to discuss the 
results of the more recent investigations of the Gulf Stream carried on 
by the Blake, without ineluding the general questions of oceanic circu. 
lation, and of the thermal conditions of the Atlantic in particular. 1 
shall therefore briefly state such points, derived from the explorations 
of the Challenger and other expeditions, as will assist us in understand- 
ing the history and physies of this great oceanic current. 
Sir Charles Lyell has called attention to the fact that in the present 
epoch the most marked physical feature of the surface of the globe is 
its subdivision into a land and an oceanic hemisphere. Thomson, like 
him, looks upon the oceans as continuous, and has happily styled the 
Atlantic, the Pacific, and the Indian oceans as great gulfs of the South- 
ern Ocean. 
The striking hydrographic character of the North Atlantic is its com- 
parative isolation from the Arctic Ocean; the South Atlantic, on the 
contrary, is fully open to the circwation of cold water coming from the 
*From the Bulletin of the Museum of Comparative Zodlogy, at Harvard College, in 
Cambridge, Mass., vol. xtv: chap. ix, pp. 241-259. 
t Along the American coast the sudden transition from the green, cold, and more or 
less turbid water found along the coast and continental shelf, into the deep blue 
waters of the warm Gulf Stream, is one which has been noticed by all who have 
passed from the shore seaward. This cold green water, which has sueh a chilling 
influence on the climate of the New England States, follows the line of the Atlantic 
coast of the United States far towards the base of the peninsula of Florida. 
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