THE GRANDEST AND MOST MIGHTY TERRES- 

 TRIAL PHENOMENON: THE GULF STREAM 



B^ John Elliott Pillsbury, U. S. Navy 



THE subject of ocean currents is 

 one that has engaged the attention 

 of mariners and men of science 

 for centuries. In all oceans there are 

 movements of the water (other than that 

 caused by the tides) which may be said 

 to be due primarily to the prevalent wind. 



Many branches of scientific inquiry are 

 concerned in their examination, for they 

 bear directly upon the dissemination and 

 evolution of species and the deposit and 

 structure of geological formation, while 

 in the business world they enter as a 

 factor in the price of everything carried 

 afloat as well as in the safety of all those 

 who travel by sea. The currents of the 

 ocean too are the great transporters of the 

 sun's heat and moisture from the torrid 

 zone, to temper the climate of more polar 

 regions. 



In the two great oceans, the Atlantic 

 and the Pacific, there is to be found both 

 north and south of the equator, and 

 also in the Indian Ocean, a similar circu- 

 lation, that is, a general westerly move- 

 ment in the tropics, a flow toward the 

 poles along the eastern shores of the 

 continents, an easterly set in the temper- 

 ate zones, and a current toward the 

 equator along the western shores. It 

 thus becomes a grand circular movement, 

 some parts being quite slow, and other 

 parts very swift ; sometimes there may 

 be a temporary interruption in the slower 

 portions, or perhaps even a reversal, but 

 taken as a whole the movement is con- 

 tinuous (see map, page 768). 



In the North Atlantic Ocean the cur- 

 rents are probably more pronounced than 

 in either the Pacific or the Indian Oceans. 

 Without entering upon a discussion now 

 as to the causes of ocean flow, or of 

 any particular current, a brief description 

 of the main streams will not be out of 

 place, for they are all connected more or 

 less intimately with our Gulf Stream. 



The equatorial current is usually de- 

 scribed as being a broad band of water 

 moving across the Atlantic in the tropics. 



The portion of this current situated south 

 of the equator is divided into two parts 

 upon meeting the eastern salient of South 

 America, Cape St. Roque. One branch 

 turns south toward the Antarctic, while 

 the other is forced to the westward along 

 the shores of Northern Brazil and the 

 Guyanas, and is called the Guyana coast 

 current. The equatorial current north of 

 the equator has an almost uninterrupted 

 progress until it reaches the Windward 

 Islands, but a portion of it also impinges 

 against the Guyana Coast and thus aug- 

 ments the volume of that current. 



At the Windward Islands both are 

 united, and a portion of the flow enters 

 the Caribbean through the various pas- 

 sages, crosses it to the Yucatan and Hon- 

 duras coasts, and thence into the Gulf 

 of Mexico, from which it issues through 

 the Straits of Florida as the Gulf Stream. 

 Passing onward toward Europe it is aug- 

 mented in volume by a part of the north 

 equatorial current that sweeps along out- 

 side the West Indian Islands and the 

 Bahamas, and while this current is slow 

 in movement in comparison to the Gulf 

 Stream itself, it doubtless carries a much 

 greater number of heat units to help 

 warm up northern Europe. 



The GuU Stream, or rather the com- 

 bined flow mentioned above, divides as it 

 meets the resistance of the Eastern Con- 

 tinent, one branch flowing south along 

 the African coast, while the other pro- 

 ceeds northward into the Arctic toward 

 Spitzbergen and Franz Joseph Land. 



TiiJt imme;nsity of this ocean river 



The Gulf Stream is probably the grand- 

 est and most mighty of any terrestrial 

 phenomenon. Its waters are character- 

 ized by a deep indigo blue color of great 

 clearness and high temperature. It can 

 be penetrated by the eye to considerable 

 depths, and generally its meeting with the 

 less saline polar waters can be at once 

 distinguished. 



It is difficult for the mind to grasp the 



767 



