In June, 1763, he “dug up abt. a load of Marle to spread over Wheat Land for experiment.”  In 1768 he came to the conclusion that most farmers began to cut their wheat too late, for of course cradling was a slow process—­scarcely four acres per day per cradler—­and if the acreage was large several days must elapse before the last of the grain could be cut, with the result that some of it became so ripe that many of the kernels were shattered out and lost before the straw could be got to the threshing floor.  By careful experiments he determined that the grain would not lose perceptibly in size and weight if the wheat were cut comparatively green.  In wheat-growing communities the discussion as to this question still rages—­extremists on one side will not cut their wheat till it is dead ripe, while those on the other begin to harvest it when it is almost sea-green.

In 1763 Washington entered into an agreement with John Carlyle and Robert Adams of Alexandria to sell to them all the wheat he would have to dispose of in the next seven years.  The price was to be three shillings and nine pence per bushel, that is, about ninety-one cents.  This would not be far from the average price of wheat to-day, but, on the one side, we should bear in mind that ninety-one cents then had much greater purchasing power than now, so that the price was really much greater, and, on the other, that the cost of raising wheat was larger then, owing to lack of self-binders, threshing machines and other labor-saving devices.

The wheat thus sold by Washington was to be delivered at the wharf at Alexandria or beside a boat or flat on Four Mile Run Creek.  The delivery for 1764 was 257-1/2 bushels; for 1765, 1,112-3/4 bushels; for 1766, 2,331-1/2 bushels; for 1767—­a bad year—­1,293-1/2 bushels; for 1768, 4,994-1/2 bushels of wheat and 4,304-1/2 bushels of corn; for 1769, 6,241-1/2 bushels of wheat.

Thereafter he ground a good part of his wheat and sold the flour.  He owned three mills, one in western Pennsylvania, already referred to, a second on Four Mile Run near Alexandria, and a third on the Mount Vernon estate.  This last mill had been in operation since his father’s day.  It was situated near the mouth of the stream known as Dogue Run, which was not very well suited for the purpose as it ran from the extreme of low water in summer to violent floods in winter and spring.  Thus his miller, William A. Poole, in a letter that wins the sweepstakes in phonetic spelling, complains in 1757 that he has been able to grind but little because “She fails by want of Water.”  At other times the Master sallies out in the rain with rescue crews to save the mill from floods and more than once the “tumbling dam” goes by the board in spite of all efforts.  The lack of water was partly remedied in 1771 by turning the water of Piney Branch into the Run, and about the same time a new and better mill was erected, while in 1797 further improvements were made.  During the whole period flatboats and small schooners could come to the wharf to take away the flour.  Corn and other grains were ground, as well as wheat, and the mill had considerable neighborhood custom, the toll exacted being one-eighth.  Only a few stones sticking in a bank now remain of the mill.