Atlantic or Western Ocean

A chart of the Atlantic Ocean with the suspected course of the Gulf Stream marked according to Thomas Pownall, along with the usual sailing routes from England to North America.

This map is derived from a very similar 1787 map drawn by Thomas Pownall, former governor of the Massachusetts Bay Province prior to the American Revolution. Pownall's map was published by Robert Sayer as a sea chart and features rhumb lines, compass roses, and coastal profiles along the coast of West Africa.

Thomson's updated version of the Pownall map is much clearer with all of the unnecessary decorative elements removed and with clean, outline colour. Thomson has also added two specific sailing routes: Admiral Horatio Nelson's pursuit of the French fleet across the Atlantic in 1805, and the course of the USS Insurgent, a French frigate captured by the US Navy during the Quasi War in 1799. As Thomson's 'New General Atlas' was first issued in 1817, both of these events would have been quite old news by the time of publication, suggesting that this copperplate may have been in production for many years awaiting the completion of the other maps in the atlas.

Original hand colour. [AMER2385]