Joshua Fisher - Map of Delaware Bay

Map of Delaware Bay

Fisher continued his interest in the navigation of Delaware Bay, and at night studied navigation. He was encouraged in this endeavor by the pilots and ship captains who continued to need accurate information about the shoals and channels of Delaware Bay. Over the course of 20 years Fisher developed a detailed map of Delaware Bay with help from his brother-in-law, Samuel Rowland, and teacher Thomas Godfrey. The chart was very accurate for the day, showing observations of the exact latitude and longitude, and soundings, information about harbors, stream inlets, shoals, and ship channels. The chart was engraved by James Turner, funded by a group of local merchants and ship owners, and printed in 1756 in Philadelphia by printer John Davis.

Fisher was ordered not to publish the map by the Governor, Robert Hunter Morris, because a war appeared likely with France and he was concerned that the map might fall into enemy hands. Fisher sent out copies of the map anyway and explained that the map did not show the full way to Philadelphia, and the complexity of the navigation to Philadelphia would deter the enemy. The map was re-engraved in Philadelphia in 1775, duplicated and published in London in 1776, and widely sold and distributed. It remained the standard map for navigation to Philadelphia for almost a century.