20. What is meant by the sights of a piece?
Artificial marks on the piece for determining the line of fire.
21. How are the sights determined?
Usually by means of the gunner’s level, when the trunnions are perfectly horizontal.
22. What is the line of metal or the natural line of sight?
It is a line drawn from the highest point of the base-ring to the highest point on the swell of the muzzle.
23. What is the axis of a piece?
An imaginary line passing through the centre of the bore.
24. What is the natural angle of sight?
It is the angle which the natural line of sight makes with the axis of the piece.