Threshing, or thrashing, is the process of loosening the edible part of grain (or other crop) from the straw to which it is attached. It is the step in grain preparation after reaping. Threshing does not remove the bran from the grain. History of threshing Through much of the history of agriculture, threshing was time-consuming and usually laborious, with a bushel of wheat taking about an hour. In the late 18th century, before threshing was mechanized, about one-quarter of agricultural labor was devoted to it. It is likely that in the earliest days of agriculture the little grain that was raised was shelled by hand, but as the quantity increased the grain was probably beaten out with a stick, or the sheaf beaten upon the ground. An improvement on this, as the quantity further increased, was the practice of the ancient Egyptians of spreading out the loosened sheaves on a circular enclosure of hard ground, and driving oxen, sheep or other animals round and round over it so as to tread out the grain. This enclosure was placed on an elevated piece of ground so that when the straw was removed the wind blew away the chaff and left the corn. A contemporary version of this in some locations is to spread the grain on the surface of a country road so the grain may be threshed by the wheels of passing vehicles. This method, however, damaged part of the grain, and it was partially superseded by the threshing sledge, a heavy frame mounted with three or more rollers, sometimes spiked, which revolved as it was drawn over the spread out corn by two oxen. A common sledge with a ridged or grooved bottom was also used. Similar methods to these were used by the ancient Greeks, and continued to be employed in the modern period in some places. In Italy the use of a tapering roller fastened to an upright shaft in the centre of the thrashing floor and pulled round from the outer end by oxen seems to be a descendant of the Roman or roller sledge. The flail, a pair of connected sticks used to beat the grain, evolved from the early method of using a single stick. It, with the earlier methods, was described by Pliny the Elder in his first-century CE Natural History: "The cereals are threshed in some places with the threshing board on