be made from a variety of materials. The stones at Watson's Mill are made from pieces of very hard quartz called buhrstone. They were imported from France in 1859. The reason for this was that native stone from Canada and the United States would chip off into the final product. The face of the stone has a pattern of grooves, which is called the dress. Different types of millstones have different patterns - Watson's Mill's millstones have a 3/4 dress. The particular dress of the stone indicates what substance it ground. The grooves on the two stones are at different angles, and they act like scissors during milling. Only the top stone, the runner stone, turns, while the bottom bedstone remains stationary. The stones each weigh about 900 kilograms, which is about the weight of a Volkswagen Beetle. Two large iron cast wheels in front of the millstone are used by the miller to control the machinery. The small wheel allows the miller to raise and lower the top stone, or runner. The large wheel is used to open the gate to the turbine that turns the millstone. Since the top stone is so heavy, and spins quickly, a significant amount of heat is generated, which in turn warms the grist. It is important that the windows in the mill are open during milling, because dust particles are combustible. During the process, when the grist is warm and moist, it is difficult to separate the bran and chaff from the flour, so the grist needs to be cooled. The grist travels up to the attic in the grist elevator, where it falls into a machine called the auger, which cools and fluffs the grist. Bolter From the auger, the grist falls into the bolter. The bolter is a large sifting machine located on the second floor. The bolter separates the flour from the bran so that pure stone-ground whole wheat flour is the final product. Both products drop down to the main floor where they are separated into two different bags. The flour is then bagged into smaller portions which can be purchased at the mill. Feed Grinder The feed grinder introduced another method of grinding grain. Whereas the particular dress of the millstones limits what substance can be ground, the feed grinder was capable of grinding a variety of grains and seeds. This machine was mostly used to mix