Only the 12-pdr. brass guns, and the 24 and 32-pdr. brass howitzers.
47. What is understood by the preponderance of a piece?
It is the excess of weight of the part in rear of the trunnions over that in front; it is measured by the weight which it is necessary to apply in the plane of the muzzle to balance the gun when suspended freely on the axis of the trunnions.
48. Why is this preponderance given?
To prevent the sudden dipping of the muzzle, in firing, and violent concussion on the carriage at the breech.
20]
49. What is bushing a piece of artillery?
Inserting a piece of metal about an inch in diameter (near the bottom of the bore), through the centre of which the vent has been previously drilled. It is screwed in.
50. What kind of metal is used for bushing bronze pieces?
Pure copper always, which is not so liable to run from heat as gun metal.