Reduction plate by Jones, engraved "Thomas Jones 62 Charing Cross, London", outside dimensions of brass frame are 8 3/8" x 6 3/16" and nearly 1/4" thick, glass has cross lines on under surface 7" x 5", each inch divided into 12 parts, mahogany box 9" x 6 3/4" x 7/8" with Jones's card inside Reduction plate by Jones, with case. 1816-1850