European discovery of the Gulf Stream dates to the 1512 expedition of Juan Ponce de León, after which it became widely used by Spanish ships sailing from the Caribbean to Spain. A summary of Ponce de León's voyage log, on April 22, 1513, noted, "A current such that, although they had great wind, they could not proceed forward, but backward and it seems that they were proceeding well; at the end it was known that the current was more powerful than the wind." Its existence was also known to Peter Martyr d'Anghiera.
Benjamin Franklin became interested in the North Atlantic Ocean circulation patterns. In 1768, while in England, Franklin heard a curious complaint from the Colonial Board of Customs: Why did it take British packets several weeks longer to reach New York from England than it took an average American merchant ship to reach Newport, Rhode Island, despite the merchant ships leaving from London and having to sail down the River Thames and then the length of the English Channel before they sailed across the Atlantic, while the packets left from Falmouth in Cornwall?
Franklin asked Timothy Folger, his cousin twice removed (Nantucket Historical Society), a Nantucket Island whaling captain, for an answer. Folger explained that merchant ships routinely crossed the then-unnamed Gulf Stream—identifying it by whale behavior, measurement of the water's temperature and the speed of bubbles on its surface, and changes in the water's color—while the mail packet captains ran against it. Franklin worked with Folger and other experienced ship captains, learning enough to chart the Gulf Stream and giving it the name by which it is still known today. He offered this information to Anthony Todd, secretary of the British Post Office, but it was ignored by British sea captains.
Franklin's Gulf Stream chart was published in 1770 in England, where it was mostly ignored. Subsequent versions were printed in France in 1778 and the U.S. in 1786.