This is a patented, self-sealing closure for a metal preserving can. Made of alloy, it is embossed, �Spratts Patent July 8th 1864, Improved. Wells and Provost Proprietors, N. Y.� This one was dug in the Union Mills area and is in excellent condition but for the center hole made to open the can. It comes from the George Whiting collection and is identical to the one shown on p. 179 of Phillips' Excavated Artifacts, Supplement I (plate 9).