THE GULF STREAM OFF OUR SHORES 



505 



sees the edge of the GuU' Stream clear 

 cut in deep bhie against the dull gray- 

 green of the shore drift, and myriads of 

 little swirls and eddies mark the border 

 line between the two opposing currents. 

 At one stroke of the oars, one leaves the 

 barren shore drift and enters the tropi- 

 cal ocean with hundreds of heat-lov- 

 ing creatures swimming hither and to 

 through the genial limpid element that 

 is bearing them remorselessly northward 

 to perish in the "roaring furies" of the 

 Atlantic. 



Off Key AVest, or Miami, the Gulf 

 Stream flows within a few hundred yards 

 of the outer edges of the coral reefs. At 

 Cape Hatteras it may be ten miles or 

 more off shore, and beyond this point it 

 wanders with many variations as a wide 

 surface eddy farther and farther from 

 our shores to lose itself in the midst of 

 the Atlantic. 



Often one finds temporary whirls or 

 counter currents in its meandering un- 

 certain course, and none can predict its 

 movements except in the most general 

 way; so that some sea captains who 

 constantly sail over it, to and from the 

 West Indies, have actually lost faith in 

 the existence of the Gulf Stream. The 

 popular conception of it as a "mighty 

 river" flowing over the ocean is quite 

 erroneous, for ocean currents are more of 

 the nature of eddies or swirls, those 

 affecting the surface being counter- 

 balanced by others in the depths. Thus 

 the Gulf Stream is a surface eddy due 

 to the pressure and friction of the pre- 

 vailing tropical winds as they pass over 

 the ocean from colder regions toward the 

 heat equator. These tropical trade 

 winds blow as young gales with pro- 

 verbial constancy toward the southwest 

 in the northern, and toward the north- 

 west in the southern hemisphere. Thus 

 their westerly trend imparts a similar 

 movement to the surface waters of the 



equatorial region. Were the Isthmus 

 of Panama now widely open, as it prob- 

 ably was long ago in the age of the 

 reptiles, the equatorial current would 

 surely rush through the gap to continue 

 its course across the vast expanse of the 

 Pacific. In our day, however, the great, 

 deep, shut-in basin of the Gulf of Mexico 

 acts as a trap into which the waters are 

 forced through the wide Straits of 

 Yucatan, and out of which they must 

 rush through the narrow channel of the 

 Straits of Florida, to travel along our 

 coast toward Cape Hatteras, and thence 

 outward into the Atlantic. 



Just why it should desert our shores 

 beyond Hatteras and swerve ever more 

 and more toward the eastward may not 

 be so clear until we consider that any 

 body moving either north or south tends 

 to maintain its direction in space inde- 

 pendent of the rotation of the earth. 

 Thus the trade wind of the northern 

 hemisphere tends to go straight south- 

 ward toward the equator, but the earth 

 rotating from west to east passes under 

 it as the wind blows down from the 

 slowly moving northern latitudes to the 

 more rapidly moving equator. Hence 

 the wind is forced into a more and more 

 westerly direction. 



In fact, every body moving north or 

 south in the northern hemisphere is 

 forced by the earth's rotation toward 

 the right, and in the southern hemi- 

 sphere toward the left; and this applies 

 to the course of storms or air currents as 

 well as to water currents. Thus we 

 see why the cold northerly current must 

 cling constantly to our eastern coast, 

 while the Gulf Stream in its northerly 

 trend must go far out into the Atlantic — 

 both currents tending always toward the 

 right. 



Moreover, we know from recent re- 

 searches such as those of Harris upon 

 the tides, or of the Norwegian steamer 



