Oceanography and hydrodynamics

Tuesday, November 11, 2025 09:06PM

As deputy postmaster, Franklin became interested in North Atlantic Ocean circulation patterns. While in England in 1768, he heard a complaint from the Colonial Board of Customs. British packet ships carrying mail had taken several weeks longer to reach New York than it took an average merchant ship to reach Newport, Rhode Island. The merchantmen had a longer and more complex voyage because they left from London, while the packets left from Falmouth in Cornwall.[194] Franklin put the question to his cousin Timothy Folger, a Nantucket whaler captain, who told him that merchant ships routinely avoided a strong eastbound mid-ocean current. The mail packet captains sailed dead into it, thus fighting an adverse current of 3 miles per hour (5 km/h). Franklin worked with Folger and other experienced ship captains, learning enough to chart the current and name it the Gulf Stream, by which it is still known today.[195]

Franklin published his Gulf Stream chart in 1770 in England, where it was ignored. Subsequent versions were printed in France in 1778 and the U.S. in 1786. The British original edition of the chart had been so thoroughly ignored that everyone assumed it was lost forever until Phil Richardson, a Woods Hole oceanographer and Gulf Stream expert, discovered it in the Bibliothèque Nationale in Paris in 1980.[196][197] This find received front-page coverage in The New York Times.[198] It took many years for British sea captains to adopt Franklin's advice on navigating the current; once they did, they were able to trim two weeks from their sailing time.[199][200] In 1853, the oceanographer and cartographer Matthew Fontaine Maury noted that while Franklin charted and codified the Gulf Stream, he did not discover it:

Though it was Dr. Franklin and Captain Tim Folger, who first turned the Gulf Stream to nautical account, the discovery that there was a Gulf Stream cannot be said to belong to either of them, for its existence was known to Peter Martyr d'Anghiera, and to Sir Humphrey Gilbert, in the 16th century.[201]

An aging Franklin accumulated all his oceanographic findings in Maritime Observations, published by the Philosophical Society's transactions in 1786.[202] It contained ideas for sea anchors, catamaran hulls, watertight compartments, shipboard lightning rods and a soup bowl designed to stay stable in stormy weather.

While traveling on a ship, Franklin had observed that the wake of a ship was diminished when the cooks scuttled their greasy water. He studied the effects on a large pond in Clapham Common, London. "I fetched out a cruet of oil and dropt a little of it on the water ... though not more than a teaspoon full, produced an instant calm over a space of several yards square." He later used the trick to "calm the waters" by carrying "a little oil in the hollow joint of [his] cane."[203]

Tuesday, November 11, 2025 09:07PM