The Atlantic Ocean by Governor Pownall F.R.S. published by Robert Sayer in London, Sept. 1787 in A Pilot for the West Indies
Pownall, Gov. Thomas (1722-1805)
1787

This large copper engraving shows the course of the lower gyre of the Gulf Stream as it arches from the north at the Grand Bank down to the coast of Africa, but shows no northern portion, mid-Atlantic gyre or connection with the North Equitorial Current. Arrows show some current in the Gulf of Mexico. The portion of the current along the coasts of Florida, Georgia, and Carolina is labeled "Gulf of Florida, Gulf Stream or Florida Stream." Dry Tortugas is labelled "Fortugas."

This depiction of the course of the Gulf Stream was based on Pownall’s communications with Franklin and shows the stream similar to the Franklin/Folger map of 1786 which was published in the Transactions of the American Philosophical Society.

Pownall was the Colonial Governor of Massachusetts and Lt. Governor of New Jersey. His most famous work was Topographical Descriptions of the Dominions of the United States of America, published in 1776. The only maps in that book are one of the British Colonies and a copy of the Bernard Romans Map of the southeastern U.S.

This map was copied by Benjamin Jones (1799) and John Thompson (1827) who gave Pownall credit in the image of the stream.