The enlarged and improved map of the British colonies, with the geographical and historical analysis, accompanying it, of Lewis Evans, which was published by B. Franklin in 1754, had a controlling effect on all geographers and statesmen of the day, and was an important element in diffusing a correct geographical knowledge of the colonies at large, and particularly of the great valley of the Mississippi, agreeably to modern ideas of its physical extent. It was a great work for the time, and for many years remained the standard of reference. In some of its features, it was never excelled. Mr. Jefferson quotes it, in his Notes on Virginia, and draws from it some interesting opinions concerning Indian history, as in the allusion to the locality and place of final refuge of the Eries. It was from the period of the publication of this memoir that the plan of an "Ohio colony," in which Dr. Franklin had an active agency, appears to have had its origin. Lewis Evans was not only an eminent geographer himself, but his map and memoir, as will appear on reference to them, embrace the discoveries of his predecessors and contemporary explorers, as Conrad Wiser and others, in the West. The adventurous military reconnoissance of Washington to fort Le Boeuf, on lake Erie, was subsequent to this publication. Evans's map and analysis, being the best extant, served as the basis of the published materials used for the topographical guidance of General Braddock on his march over the Alleghany mountains. Washington, himself an eminent geographer, was present in that memorable march; and so judicious and well selected were its movements, through defiles and over eminences, found to be, that the best results of engineering skill, when the commissioners came to lay out the great Cumberland road, could not mend them. Such continued also to be the basis of our general geographical knowledge of the West, at the period of the final capture of fort Du Quesne by General Forbes, and the change of its name in compliment to the eminent British statesman, Pitt.