THE GULF STREAM 



E. E. Watson 

 Queen's University, Kingston, Ontario 



Anyone who has sailed from the eastern coast of the United 

 States to Bermuda or the West Indies will recall the startling tran- 

 sition from the cold, dull coastal water to the deep blue waters 

 of the Gulf Stream. The air becomes warmer, and the breeze 

 freshens; the roll of the ship has increased, but, above all. one is 

 fascinated by the intense blue of the water. The white air-bubbles 

 along the ship's sides and in its wake enhance the depth and purity 

 of the color. Something yellow is floating on the surface, and 

 as we come closer it turns out to be a stray bit of Sargassum weed. 

 Soon we see more and more of this brightly colored weed, float- 

 ing in patches or in long streaks. Columbus thought this weed 

 grew on rocks or submarine ledges, and this idea persisted for a 

 long time, but we know now that it is a pelagic perennial which 

 grows fresh, greenish shoots at one end while withering to a 

 brown color at the other. It is kept afloat by berry-like bladders 

 which contain air. This Sargassum or gulf weed is found over 

 a large area of the North Atlantic, but does not reach the North 

 American coast. It is first noticed in any quantity as we approach 

 the Gulf Stream. The most marked characteristic of the Stream 

 is its blue color, flecked with the yellow of the weed, for there 

 are no "landmarks" at sea to tell the casual observer that he is 

 not only being driven through the water by the ship's engines or 

 sails but is carried by the water itself in a northeasterly direction 

 at a speed which may be as great as 4 knots. For a modern 

 liner making 20 to 30 knots such a current is of no great impor- 

 tance, even though it may be about 60 miles wide, but for a sailing 

 vessel it was, and is, a serious navigational influence. 



Owing to its eff'ect on the course of ships, considerable knowl- 

 edge of the surface characteristics of the Stream has been accu- 

 mulated, but it is only in recent years that we have learned much 

 about its sources, the mechanism of its propulsion, and the trans- 

 fer of moisture and heat to and from the atmosphere above it. 

 Popular conceptions of the Gulf Stream are somewhat vague 

 and often incorrect. Along the Atlantic seaboard any unusual 

 weather condition is sure to be blamed on the Gulf Stream, espe- 

 cially a long hot spell such as was experienced in the summer of 

 1949. Since on the eastern side of a continent the weather 

 moves from land to sea, the oceanic conditions are more likely to 

 be influenced by the weather coming from the land than the other 

 way round. 



HISTORY AND THE GULF STREAM 



Before describing the Gulf Stream and its problems according 

 to modern oceanography, one may approach the subject from 

 an historical point of view. On Columbus' first voyage in 1492, 

 when nearing the Bahamas, he was influenced by the flight of 

 birds (the fall migration by way of Bermuda to the West Indies) 

 to change his course from west to west-southwest. Had he not 

 done so his landfall would have been Eleuthera Island, and he 

 would have sailed through Providence Channel straight into the 

 Gulf Stream. He might then have made the coast of Florida or 

 have been swept along the coast of Georgia and the Carolinas, 

 if lucky enough to survive. There would have been no gold from 

 Hispaniola, and the history of the Spanish conquistadors in the 

 Caribbean might never have been written. It is a striking fact 

 that the eastern coast of the present United States was not dis- 

 covered by a direct voyage from Europe. In 1498 John Cabot 

 discovered Newfoundland and pushed southward around Cape 

 Breton. These explorations were continued by his son Sebastian, 

 but how far down the coast he penetrated is uncertain. Even 

 before the Cabots fishermen may have known the Nova Scotian 

 and New England shores, but they would have been interested in 

 the fishing banks rather than the shore, and hence disinclined to 

 publish their knowledge. Probably the first thorough exploration 

 of the coast was'carried out by Giovanni Verrazzani, a Florentine, 

 on behalf of Francis I of France. In considering the possible 

 effect of the Gulf Stream on the early explorations, it is worth 

 while to look at some of the details of Verrazzani's voyage. He 



left the isle of Madeira (which is almost at the same latitude as 

 Bermuda) in January 1.524, and sailed due west. By 20 February, 

 a month later, he had traveled about 1,600 miles when he was 

 "overtaken by a tempest." Unfortunately his account does not 

 state the direction in which he was blown nor the duration of 

 the tempest. After this he changed course to west by north, and 

 25 days and 1,300 miles later he discovered a new land. His land- 

 fall must have been near Charleston, S. C, or Savannah, Ga. This 

 means that he must have crossed the Gulf Stream where the 

 flow is rapid, so that he must have been carried north for "many 

 leagues." It is hard to understand how he reached the coast at 

 the same latitude as his starting point, Madeira, unless his mid- 

 Atlantic storm carried him southward, though not so far as to 

 land him on the Bahamas. Verrazzani sailed up the coast as far 

 as Cape Breton, landing at many points. In 1.562 Capt. John 

 Ribault, again on behalf of the French, sailed directly from the 

 Brittany coast to the west "to prove a new course which hath 

 not been yet attempted." It was thought that this could not be 

 done, for lack of favorable winds, but Ribault wished to avoid the 

 more southerly route because of possible unpleasantness with the 

 Spaniards. He succeeded in reaching the coast of northern 

 Florida directly, but gives no details of his voyage. It is note- 

 worthy that none of these explorers knew that he had crossed the 

 Gulf Stream. No wonder the early maps of North America were 

 distorted ! 



Not until two centuries later do we find what is probably the first 

 scientific reference to the Gulf Stream. This occurs in a letter 

 sent by Benjamin Franklin to the secretary of the British Post 

 office,' much of which is quoted below: 



Craven Street, October 29, 1769 

 Sir: Discoursing with Captain Folger ... I received from him the 

 following information, viz.: . . , that the whales are found generally 

 near the edges of the Gulph Stream, a strong current so called, which 

 comes out of the Gulph of Florida, passing north-easterly along the 

 coast of America, and then turning off most easterly, running at the 

 rate of 4, 3H, 3 and 2V2 miles an hour; that (people concerned in the 

 whale fishery) . . . cruise along the edges of the stream in quest of 

 whales . . . ; that they have opportunities of discovering the strength 

 of it when their boats are out in pursuit of this fish, and happen to get 

 into the stream while the ship is out of it. or out of the stream while 

 the ship is in it. for then they are separated very fast, and would soon 

 lose sight of each other if care were not taken; that . . . they fre- 

 quently . . . speak with ships bound from England to New York, 



Virginia, etc and it is supposed that their fear of Cape Sable 



shoals, George's Banks, or Nantucket shoals, hath induced them to keep 

 so far to the southward as unavoidably to engage them in the same 

 Gulph Stream, which occasions the length of their voyages, since . . . 

 the current being 60 or 70 miles a day, is so much subtracted from the 

 way they make through the water. 



At my request Captain Folger hath been so obliging as to mark for 

 me on a chart the dimensions, course, and swiftness of the stream from 

 its first coming out of the Gulph . . .; and to give me withal some 

 written directions whereby ships bound from the Banks of Newfound- 

 land to New York may avoid the said stream, and yet be free of danger 

 from the banks and shoals above mentioned . . . With much 

 esteem, I am, etc. 



In a later paper, written in 1785, Franklin said that he had 

 been pi-ompted to write this letter by the observation that the mail 

 packets from Falmouth to New York were generally a fortnight 

 longer in their passages than merchant ships from London to 

 Rhode Island. The chart referred to in his letter was "engraved 

 and copies were sent down to Falmouth for the captains of the 

 packets, who slighted it however." It is amusing to note that 

 then, as now, sea captains were suspicious of any new scientific 

 procedure or information, particularly when coming from a 

 landsman, despite the fact that their navigation is entirely de- 

 pendent on accurate scientific instruments and calculations. 



' Carl Van Doren, ed., Benjamin Franklin's Autobiograhical Writings 

 (New York: The Viking Press, 1945), pp. 191-2. 



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