Tangent Sight; Attachment; or Orientation Mounted to the Back of the Slot Elevation; for this the support is provided with a cam which engages in the lock elevation and is tightened with a screw from behind. The set-up bar is a short square iron bar; on top is pyramid-shaped with grooves through the top; it can move back and forth vertically. Demonstration and or test model.; anonymous; Netherlands; 1845 - 1865; iron (metal); brass (alloy); h 9 cm x w 12.4 cm x d 2 cm