GW was taking elevations west of Dogue Run to determine the best route for a millrace to his new mill. Several months earlier he had been thinking of supplying the new mill with water by having a race dug to it from the pond near his old mill (GW to Charles West, 6 June 1769, DLC:GW). But now he had another plan in mind. The dam near the old mill would be replaced with one farther up Dogue Run, a short distance above the place where it is joined by Piney Branch. From the new Dogue Run dam, a race would be dug southwest to a point on Piney Branch, a few hundred yards above its mouth, where a second dam would be built. Then the race, which would be about two miles in total length, would parallel Dogue Run along the higher ground west of the run down to the new mill, where it would pass through the building into Dogue Creek (vaughan description begins Samuel Vaughan. “Minutes Made by S. V. from Stage to Stage on a Tour to Fort Pitt or Pittsburgh in Company with Mr. Michl. Morgan Obrian, from Thence by S. V. Only through Virginia, Maryland, & Pensylvania (18 June to 4 Sept. 1787).” Manuscript diary in the collection of the descendants of Samuel Vaughan. description ends , 56; Warrington Gillingham’s map of Mount Vernon, muir description begins Dorothy Troth Muir. Potomac Interlude: The Story of Woodlawn Mansion and the Mount Vernon Neighborhood, 1846–1943. Washington, D.C., 1943. description ends , between pp. 90 and 91). The idea for this arrangement may have come from John Ball or John Ballendine. Its advantage over GW’s first idea was that it would make possible a higher head of water at the mill, because the race would begin at a greater elevation on Dogue Run and would remain near that level by following the higher terrain to the west.

Crawford came today to report on his surveys for GW in western Pennsylvania.