Mark Dentinger, age 11, of Rochester' N.Y.,, for his question,
Where does the Gulf Stream start?
The first chart of the Gulf Stream was made to satisfy the curiosity of a postal official, way back in 1769. The English mail vessels were arriving two weeks late ‑ or at any rate, two weeks later than the New England ships crossing from Europe, This Deputy Post Master General thought that a New England seaman could explain the delay of the British packets. He was right, for this postal official was none other than our wise Benjamin Franklin.
Franklin talked with Timothy Folger, a Nantucket sea captain. Timothy said that the American sailors know how to dodge a strong ocean current flowing eastward across the North Atlantic. The British ships lost time trying to sail against it. Franklin had Folger and his friends make a chart from what they knew about this current from their sailing experience. This was the first map of the Gulf Stream.
The Gulf Stream is part of a vast circle of eddying ocean currents in the North Atlantic. It is an off shoot of the Equatorial current that sweeps westward from the coast of Africa to South America. There the Gulf Stream splits from the mother current, hoops up and over to, cross the Atlantic to Northern Europe. Here it bends south to become the Canary Current and ,join the mother Equatorial Current again off Africa.
This vast, eddying cycle of waters is started by the sun and wind. Its course is set by the shape of the continents and by the spinning earth. The tropical sun warms the equator causing a belt of light rising air above it. The trade winds blow into this area of low pressure from northeast and southeast. And the steady trade winds drive the waters in a current towards the west.
The spinning earth deflects all moving objects in the Northern Hemisphere to the right. Hence, off the coast of South America where the current is forced to bend, the Gulf Stream turns right and veers north. It parallels the continent a few miles from shore as far as Cape Hatteras. Here it veers right again. It meets the cold Labrador Current coming down from the north and sweeps eastward in a U‑turn.
Like a mighty river in the ocean, it flows duo east towards Scandanavia and the British Isles. Off southern Europe it makes another right turn. Flowing due south now, the stream is called the Canary Current.
In the North Atlantic, the Gulf Stream is a wide river of warm water flowing through cooler water. It was warmed by the tropical sun over the equator. The fringes of the stream mix and mingle with cooler waters on the. way. But the heart of the stream is warm from start to finish, It warns the air above it. This warm air clashes with cool air off Canada and makes the fogs of Newfoundland. It carries balmy breezes to Northern Europe, and causes the warns, misty climate of the British Isles.
The strong eddy of flowing water circles an area in the center of the North Atlantic. This is the calm, weedy Sargasso Sea, cut off from the mingling waters of the Atlantic.