This pre-1900 rim lock set (box lock) mounts on the outside of the door. The door knob spindle goes through the box. There are two lock mechanisms. The door knob and spindle controls the plunger that slides inside and out within the keeper (mounted on the frame), and there is a dead bolt controlled by a the key. The bolt can also be locked into place with a button on the top of the box.
This may be a Corbin Hardware Company item because of the large “C” embossed on the front of the rim lock. The cast iron box is highly decorated (In the Victorian motif) on both sides. This way, either side of the box lock can be used on the door. Locks such as this were used in Victorian homes on the passage doors. The door knobs that were paired with this rim lock were the porcelains or decorated steel knobs.
The rim lock measures 4 1/6 inches across, 3 1/4 inches vertically, and 5/8 inch thick. The keeper, that goes on the frame and matches the lock, is 3 1/4 inches long and 3/4 inch wide.
This old lock is quite special because of the bronze (or copper) highlights. A key is included.