Such a mill represented a considerable investment of capital, and it was this initial cost as much as any other factor that determined the pattern of mill ownership in Virginia. So far as records survive to tell the story, all of the colony’s early mills were built on plantations, either by well-to-do colonial officials or by syndicates of neighboring planters. Most of these early mills, if not all of them, were built primarily to grind the owner’s produce. Since few but the very largest plantations could keep a mill busy at grinding home-grown grain, most plantation mills also did custom grinding for nearby farmers. A mill formerly owned by John Robinson, speaker of the House of Burgesses, collected enough toll in this fashion to feed a “family” of nearly sixty persons, plus several horses. [Illustration: _Two tower mills and three post mills can be seen on this map, redrawn from a “Sketch of the East end of the Peninsula Where on is Hampton.” On the same peninsula, thirty miles to the northwest, lies Williamsburg. The original map is at the University of Michigan among the papers of Sir Henry Clinton, commander-in-chief of British forces during part of the American Revolution._] It was out of this combination plantation-custom type of mill that the merchant mill finally developed in Virginia. The first William Byrd was well ahead of his fellow planters in developing milling as a business, although he lagged far behind John Pearson of Massachusetts. In 1685 Byrd had erected two water grist mills at the falls of the James River—the very power site of which Captain Newport’s exploring party had remarked. He asked a friend in London to hunt up and send over one or two honest millers to run the mills and sent inquiries to the West Indies about selling the flour he expected to make. Despite Byrd’s example, commercial or “merchant” milling, as it was known, gained little headway in the colony until the next century was two-thirds over. Then, when wheat became important to the tobacco growers as a second export crop, quite a few planters added a second pair of stones to their mills and began shipping barrels of flour along with hogsheads of tobacco. The additions were usually buhr or “burr” stones from France, preferred for high-quality grinding because their structure included sharp-edged quartz cavities. In 1769, for instance, George Washington rebuilt his mill on Dogue Run near Mount Vernon, and imported French stones to grind export flour. Robert Carter, probably Virginia’s wealthiest planter-businessman at the time, had been experimenting with other crops on his tobacco-exhausted acres and had fixed on wheat as the best substitute for the “Imperial weed.” By 1772 Carter was buying wheat in 8,000 and 10,000 bushel lots to grind in his mill near Nomini Hall.