Gulf Stream

The Gulf Stream is a warm ocean current in the Atlantic Ocean.  It begins in the Gulf of Mexico and heads north along the coast of the United States.  It then "makes a sharp right turn toward Europe as it passes Cape Cod."  This quirky description of its path is from the book "The Invention of Air" by Steven Johnson.

The Gulf Stream was first described by Ponce de León in the early 16th century.  The first precise measurement came because of a complaint about the postal system.

In 1769, the Customs Board in Boston made a formal complaint to the British Treasury about the speed of letters arriving from England.  People had noticed that letters going from America to Europe would arrive quicker than the letters going in the opposite direction, and were unhappy about it.  Benjamin Franklin, who was the deputy postmaster general for North America, happened to be in London at the time.  The British authorities brought the complaint to his attention. 

It was a lucky day.  Franklin would turn that postal mystery into one of the great scientific breakthroughs of his career. 

When he was twenty years old, he was traveling back from London, and recorded notes in his journal about the "strange prevalence of gulph weed in the waters of the North Atlantic."  Over the years, he had noticed that passage westward across the Atlantic was slower.  Then, in a letter in 1762 he wrote of the way "the waters mov'd away from the North American Coast towards the coasts of Spain."  He called that flow the "gulph stream."

So when the British Treasury came to him with the complaint of the slow mail delivery, Franklin was quick to suspect the "gulph stream."  He consulted with a seasoned New England mariner, Timothy Folger, and together they prepared a map of the Gulf Stream.  The Folger/Franklin map was the first known chart of the trajectory of the Gulf Stream across the Atlantic, but it was based only on the experience of New England whalers.  In 1775, Franklin took measurements of the temperature of the water along the way as he journeyed from England to America.  He found a wide but shallow river of warm water, often with the weeds from tropical regions. 

Who would have thought that slow mail and science would have anything to do with each other?

Now you have heard something interesting.