拍品描述： Allender, John. ROCKER BALANCE MECHANICAL COUNTERFEIT DETECTOR WITH SIX SLOTTED COUNTERSUNK COIN HOLDERS.New London, Connecticut: 1854-1855. Brass arm with slotted holders for $20, $10, $5, $3, $2.50 and $1 gold pieces, with the $1 coin holder being doubly countersunk to accommodate both sizes of dollar coins then current. Arm stamped J. ALLENDER / PATENT PENDING. Oxidized and somewhat worn. Newman-Mallis IV-1-8. Allenders problems with the Patent Office are discussed in some detail in Eric P. Newman and A. George Malliss 1999 U.S. Coin Scales and Mechanical Counterfeit Detectors, the main work on the subject.From the Heather Hardin-Hudson Collection