or CALLIPER, properly denotes the diameter of any body; thus we say, two columns of the same caliber, the caliber of the bore of a gun, the caliber of a bull's eye, &c.

CALIBER Compasses, a sort of compasses made with arched legs to take the diameter of round or swelling bodies. See COMPASSES.

Caliber compasses are chiefly used by gunners for taking the diameters of the several parts of a piece of ordnance, or of bombs, bullets, &c. Their legs are therefore circular; and move on an arch of brass, wherein is marked the inches and half inches, to show how far the points of the compasses are opened or closed.

Some are also made for taking the diameter of the bore of a gun or mortar.

The gaugers also sometimes use calibers, to embrace the two heads of any cask, in order to find its length.

The caliber used by carpenters and joiners, is a piece of hard notched triangular-wood in the middle for the taking of measure.