Caption:
Tangent Sight, Attachment or Orientation Mounted to the Back of the Slot Elevation, The support is provided with a hook that engages in a square notch in the lock elevation, and is tightened with a screw from behind. It is a short square iron bar on top of a pyramid with grooves through the top, can move back and forth vertically. The set-up rod has three sides with scales, five scales in total., anonymous, Netherlands, 1845 - 1865, iron (metal), brass (alloy), h 11.7 cm × w 2 cm × d 11.7 cm