Tertiating a gun is examining the thickness of metal, whether the bore is perfectly straight, the trunnions properly placed, &c. It is performed by means of calliper compasses, and other instruments.
Quadrating a gun is ascertaining if it is properly placed on its carriage, and if the wheels are of an equal height.
A Gun is honeycombed when the surface of the bore has cavities, or holes in it.
The Length of a gun is ascertained by measuring it from the rear of the base ring to the face of the muzzle.
The Calibre of a gun is the diameter of the bore.
To find the length of a gun, in feet and inches, its length in Calibres being known—
Divide the product of the number of Calibres and the diameter of the bore, in inches, by 12, and the quotient will be the length in feet and inches.
To find the Number of calibres in the Length of a gun.
Divide the length of the gun in inches by the number of inches in the calibre.
Gun metal is a compound of 8 lb. or 10 lb. of tin, to 100 lb. of copper. The property of tin being to harden, the largest proportion (10 lb.) is used for mortars, they requiring a greater degree of hardness than guns.