1Enclosure: Drawing of a Threshing Machine, 6 April 1798 (Jefferson Papers)
a.a.a.a. is the axis of the great spur wheel, and is at the same time the upper of the two cylinders for drawing in the grain. these cylinders are fluted b.b.b.b. is the under cylinder. they are fluted, and the under one has a small cast iron wheel toothed on the edge (like those in a wheat fan) having a broken joint in it’s axis (like those in Martin’s drills) which permits the under cylinder...