The gunner’s quadrant, or the breech-sight.
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11. How is the quadrant used?
After the direction has been given, the quadrant is applied, either by its longer branch to the face of the piece, or this branch is run into the bore parallel with the axis, or it may be applied to the upper surface of the lock-piece, making the allowance due to its inclination with the axis of the piece, which ought to be previously determined, and the elevating screw turned, or the quoin adjusted, until the required degree is indicated.
12. How is the breech-sight used?
It is first set to the elevation corresponding to the distance; it is then applied to the highest point of metal on the base-ring, and by the elevating screw, or quoin, the notch of the breech-sight, the highest point on the swell of the muzzle, and the object, are brought in the same line.
13. What is a line thus determined called?
An artificial line of sight.
14. In the absence of instruments, how may the elevation be given?
By placing one or more fingers of the left hand upon the base-ring, perpendicular to the axis, and using them as a breech-sight.