First edition of the Folger/Franklin map of the Gulf Stream.
The Gulf Stream is one of the most important natural phenomenon affecting navigators in the Atlantic Ocean. First named by Benjamin Franklin, The Gulf Stream is a high speed river within the ocean, flowing from the Gulf of Mexico, around the southern tip of Florida and along the East Coast of North America to Cape Hatteras, before turning eastward across the Atlantic Ocean, where it continues to Iceland, the British Isles and Norway. In the Straits of Florida, the Gulf Stream is about 40 miles wide and flows at about 5 miles per hour. In the Atlantic, it is over 100 miles wide and flows at about 3 miles per hour.
The strength of the flow of the current was first observed by Ponce de Leon on his return trip from St. Augustine, Florida in 1513. His pilot, Anton de Alaminos, utilized his observations to chart a course for Cortes' treasure ships returning from Mexico which significantly shortened the transatlantic voyage home. While the Spanish sailed the Gulf Stream waters for centuries, they managed to keep the existence of the Gulf Stream a secret from other nations.
The western portion of the "Northeast Current," as it was known before Franklin named it the Gulf Stream in 1762, was first described by Walter Haxton, a captain engaged in shipping tobacco from his Maryland farms to London merchants. In 1735 Haxton drew the first large-scale mariner's chart of Chesapeake Bay, giving detailed soundings and sailing directions. He included, as an addendum to the chart, latitude and longitude points locating the "Northeast Current" along with estimates of the current's velocity. While Haxton advocated use of the current for future crossings, he was largely ignored.
Benjamin Franklin began his study of the Gulf Stream in 1768, while serving as the postmaster of the British Colonies in North America. Franklin had observed that the westward crossings were taking 2 weeks longer than the return journey and observed that this was a result of the current. Franklin discussed the matter with his cousin Timothy Folger, a Nantucket Sea Captain who had worked his way up the ranks on New England fishing and merchant ships, who informed him of the current and his experiences. Franklin in turn asked Folger to compose a chart showing the location of the Gulf Stream.
Franklin transmitted the finished chart to the British Postal Service and suggested that it be published for use by British Sea Captains charged with transmitting mail across the Atlantic. Instead of publishing a new map, the Post Office utilized an old chart of the Atlantic published by Mount & Page and had Folger's information engraved on what amounted to an obsolete chart in 1768. The charts were distributed to Packet Captains for a brief period of time, but were largely ignored.
In 1775 and 1776, Franklin made two Atlantic crossings, during which time he tested the water temperatures in and out of the Gulf Stream and determined that the waters in the stream were warmer. This revived his interest in the Folger chart. On his arrival in Paris, he had it copied and printed by Le Rouge. Franklin intended to provide copies to all French ship captains carrying arms and supplies to the American colonies.
The original Folger charts - as printed for and distributed by Franklin - disappeared and were assumed lost for almost two centuries until September 1978, when Philip L. Richardson of the Woods Hole Oceanographic Institution found two copies in the Bibliotheque Nationale in Paris. They were most likely obtained and saved by the French during the years from 1776 to 1785 when Franklin was envoy to France for the American colonies.
The Mount & Page example of the map is extremely rare, so much so that it was not known to have survived until an example was discovered in 1978. The Le Rouge edition is also extremely rare, with this being only the second example to appear on the market in the past 25 years.
In 1786, after the Revolutionary War, Benjamin Franklin published Folger's sketch of the Gulf Stream as part of an article in the Proceedings of the American Philosophical Society of Philadelphia. In the article, Franklin wrote: The Nantucket whalemen, being extremely well acquainted with the Gulf Stream, its course, strength and extent, by their constant practice of whaling on the edges of it, from their Island quite down to the Bahamas, this draft of that stream was obtained from one of them, Captain Folger, and caused to be engraved on the old chart in London for the benefit of navigators by B. Franklin.
The chart appears to survive in 3 forms. Franklin seems to have distributed examples to family members upon his return to America, many of which were inscribed. Several examples of these inscribed copies can be found in American institutional collections. The chart was also bound into the very rare Pilote Neptune Septenrtionale . . . published by Le Rouge. Lastly, it appears that a group of about 15-20 examples of the map were left unbound and never issued. These apparently located by a French or British bookseller sometime in the first half of the 20th Century and sold to the Old Print Shop in New York City, where they were slowly sold off over the next several decades.
George-Louis Le Rouge (1712-1790), though known for his work in Paris, was originally born Georg Ludwig of Hanover, Germany. He grew up and was educated in Hanover, after which he became a surveyor and military engineer. Around 1740, however, Le Rouge moved to Paris and set up shop as an engraver and publisher on the Rue des Grands Augustins. It was at this time that he changed his name, adopting a French pseudonym that would later become quite famous.
Le Rouge spent much of his forty-year career translating various works from English to French, and his cartographic influence often came from English maps. His experience as a surveyor and engineer in Germany made him a skilled and prolific cartographer, and he produced thousands of charts, maps, atlases, and plans. His work spans from garden views and small-town plans to huge, multiple-continent maps. Le Rouge eventually accepted the position of Geographical Engineer for Louid XV, the King of France.
Later in life, Le Rouge became well-known for publishing North American maps, such as in his Atlas ameriquain septentrional of 1778. One of Le Rouge’s other more famous works is the Franklin/Folger chart of the Gulf Stream, which he worked on with Benjamin Franklin. Franklin and Le Rouge corresponded around 1780 and collaborated to create this map, a French version of Franklin’s famous chart which was originally printed in 1769.