In 1790, the first year that the U.S. Patent Office granted patents, three patents were granted. One was to Samual Hopkins for an improvement "in the making Pot ash and Pearl ash by a new Apparatus and Process." The second patent was for a new candle making process, and the other was for automated flour milling machinery. These patents were signed by George Washington, Attorney General Edmund Randolf, and Secretary of State Thomas Jefferson.
Oliver Evans, the inventor of the automated flour mill, was born a farm boy and learned what he could of machinery and science by reading what books he could find on the subjects. He had great machanical skills, and was brought into his older brothers partnership in a flour grinding mill. Working at the mill, he learned the workings of the mill, and how labor intensive the work was. Sacks of grain would be carried by hand to upper floors of the mill, and as it was ground the flour would be gathered in lower floors, sacked by hand, and carried off by hand.
He designed and built machinery that would operate off the power shaft turned by the water wheel, and perform all of the tasks of the mill using automated implements. He was the first to use the Archimedes Screw to lift dry material, and used belts and scoops to perform other tasks. It took many years to overcome the doubts of traditional millers, but eventually all mills were built on the Evans plan. In an Evans mill, the only work the miller had to do was to stop and start the machinery.
Illustration from Theodore Hazen's site on Flour Mill Automation, and Oliver Evan's Mills, with color and arrows added by Dr. Barbara J. Becker from her site, Spinning the Web of Ingenuity, which is part of her class on the History of Technology at U.C. Irvine.
Sites with information about Oliver Evans' mills include Theodore R. Hazen's site, Crabble Corn Mill is a restored Evans mill in England, Pierce Mill is a restored Evans mill in Washington D.C., and Colvin Mill is another D.C. mill. See also Roman mill at Barbegal.
Evans greatly improved the steam engine of Watt, recieved the first patent on an automobile, and built a steam powered automobile/ boat in 1805.