Incorporating was a crucial process in making powder, as sulphur, charcoal, and saltpeter were forcibly ground together under roll wheels weighing sixteen tons, and the quality of this work determined the quality of the powder. Powder production proceeded through a line of operations: refining and purifying saltpeter and sulphur, converting willow to charcoal in closed retorts, pulverizing charcoal and sulphur into dust, storing, weighing, and mixing dust with saltpeter, incorporating the ingredients, increasing the powder's density, breaking it into pieces and sifting it, polishing and rounding the grains, removing moisture, screening and packing the powder, and storing it before shipment. Cast iron wheels weighing about eight tons each rolled on top of the powder to mix and grind it, and the light sheet metal roof was designed to blow out over the creek in case of explosion while three heavy stone walls directed accidental blasts away from other buildings. Cast iron gears were made from eighteenth century patterns, with an extra gear used to apply auxiliary steam power in times of drought or flood, and on a wooden railed trestle powder was brought to the mills on hand-pushed flatcarts. The operating procedure began with selecting and weighing proper proportions of ingredients in the composition house, loading them into tubs, pushing them by flatcar to the mill, spreading the materials evenly, sprinkling them with water, and counting tools to ensure none remained in the operating area. The mill was then started slowly from a control gate and brought to ten rpm, checked periodically, stopped after between one and four hours depending on the type of powder, and the completed wheel cake was shoveled into empty tubs before the next charge was placed in the mill and the loaded car was pushed to the press house. Heavy I beams protected the gearing in case of explosion, and the mill drive transmitted power from the turbine to the roll wheels while reducing speed from one hundred eighty rpm at the turbine to ten rpm at the wheels. A vertical sliding gate controlled water flow in the flume pipe, water in the race stood seventeen feet above normal creek level, the tail race returned water to the creek, and a fifty-horsepower water turbine set two feet below the tail race to prevent cavitation was fed by a thirty-six-inch diameter cast iron flume pipe. A cypress tree on the property was planted in the late eighteenth century by Rumford Dawes, then owner of the Hagley property.