highly detailed and finely executed original 19th century antique american ornamental cast bronze doorknob backplate. fabricated around 1870-75 by the metal compression casting co., boston, ma., russell & erwin mfg., co., new britain, ct. the interior passage door plate contains a single keyhole with swinging cover lost long ago. very fine and crisp casting detail employed through the compression casting method patented during the late 1860's. the backplate contains a lightly incised design patent date around the collar or thimble. uniform surface patina. 6-1/2" x 2".