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Charting the Gulf Stream

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Benjamin Franklin (1706-1790) noticed something odd as Deputy Postmaster General for the American colonies in London: mail took much longer travelling west across the Atlantic than it did travelling east. Several weeks longer, in fact. In a 1746 letter, Franklin ascribes this anomaly to an effect of the Earth’s rotation, making an eastward journey faster than a westward one. By 1762, Franklin is using the term ‘Gulph Stream’ to describe the “Trade Wind blowing over the Atlantic Ocean constantly…in a strong current.” In 1768, Franklin approached his cousin, Timothy Folger, captain of a Nantucket merchant vessel who had extensive knowledge of the coastal Atlantic waters. According to Folger, Nantucket whalers had cruised their ships along the edge of the Stream while hunting for whales and were already familiar with its patterns.

[Franklin-Folger chart of the Gulf Stream]. 1768. Geography and Map Division, Library of Congress.
[Franklin-Folger chart of the Gulf Stream]. 1768. Geography and Map Division, Library of Congress.
Folger and Franklin jointly produced a chart of the Gulf Stream in 1768, first published in London by the English firm Mount and Page. The Geography and Map Division holds one of only three known copies of this first edition (see above), in addition to a copy of the ca.1785 second edition (see below). The second map, informally called the ‘Le Rouge edition’ is a French version of the Franklin-Folger chart, engraved by George-Louis le Rouge in Paris. The ‘Le Rouge edition’ was donated to The Library of Congress in 1935 by Franklin Bache, a direct descendant of Benjamin Franklin.

Remarques Sur la Navigation de Terre-Neuve à New-York afin d'éviter les Courrants et les bas-fonds au Sud de Nantuckett et du Banc de George. [1785]. Geography and Map Division, Library of Congress.
“Remarques Sur la Navigation de Terre-Neuve à New-York afin d’éviter les Courrants et les bas-fonds au Sud de Nantuckett et du Banc de George.” [1785]. Geography and Map Division, Library of Congress.
While Franklin was the first man to formally name and chart the Gulf Stream, he was not the first to write about it. In 1513, Ponce de Leon recorded what we now consider the first written description of the Gulf Stream. He and his chief pilot, Antón de Alaminos, encountered the current while sailing from Puerto Rico to the east coast of Florida and noted how their three ships were consistently pushed by the current. None of Ponce de Leon’s original logs or maps are extant. However, Antonio de Herrera used Ponce de Leon’s logs as the basis of an early 17th century book he wrote describing the voyage, Historia General de los Hechos de los Castellanos en las Islas y Tierra Firme del Mar Oceano, published in Madrid, 1601-1615.

So what exactly is this “Trade Wind blowing over the Atlantic Ocean constantly”? The Gulf Stream is a powerful, wind-driven ocean current that transports vast amounts of low altitude heat to high altitude, cooler areas. This kind of heat transport by ocean currents prevents extreme temperature differences between equatorial and polar regions. Wind exerts a frictional force on surface water, so ocean currents tend to flow in similar patterns as the wind. Without this kind of global heat transport, the Atlantic Ocean could be home to much more intense mid-latitude cyclones and hurricanes.

The Gulf Stream location in the Global Real Time Ocean Forecast System model (RTOFS).
The Gulf Stream location in the Global Real Time Ocean Forecast System model (RTOFS). Courtesy of NOAA.

If you’re interested in learning more about the history of the Gulf Stream, keep an eye out for a forthcoming Occasional Paper from our Division, “The History of the Gulf Stream’s Missing Chapter: John William Gerard De Brahm” by Louis De Vorsey.

Comments (3)

  1. I have long been aware of the 2 examples of the 1768 Folger-Franklin / Mount & Page charts at the BN in Paris. This is the first time I’ve seen any published reference to this third example at the LC. Thank you both for the information & the excellent scan.
    The juxtaposition of the NOAA infra-red Gulf Stream chart was both creative and illuminating.
    It has been suspected for some time that there was an earlier state of the c1785 Paris-Le Rouge plate, one intended for use at sea that pre-dated the more commercial one bearing Le Rouge’s advertisement in the lower right quadrant (pictured in your blog). An example of this (previously unrecorded?) first state was offered for sale last year and is now in my collection.
    I disagree with your use of the word “edition” to describe the two Folger-Franklin maps shown in your blog. Each was printed from a separate plate — the Paris-Le Rouge from a totally new plate. In my experience, “edition” refers to a later, essentially duplicate printing of a previously published book, map, graphic, etc.

  2. There are three different versions of the Franklin-Folger chart of the Gulf Stream. The first was printed by Mount and Page in London circa 1769-70, the second was printed by Le Rouge in Paris circa 1778, and the third was published by Franklin as part of his “Maritime Observations” in the Trans. Am. Philos. Soc. in 1786. There are three known copies of the 1769-70 London version. One is in the Bibliothèque Nationale in Paris, the second was obtained from the Bibliothèque Nationale and is in the Library of Congress, and the third is in the Naval Library in London. A more complete description of the charts is given by P. Richardson 1980, The Benjamin Franklin and Timothy Folger charts of the Gulf Stream, published in Oceanography: The Past, M. Sears and D. Merriman (Editors), Springer-Verlag, New York, pp 703-717.

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