2 chocked the wheels. No. 3 rewound
his lanyard, and the gunner, having watched the shot, returned to his
post.

_The development of heavy ordnance through the ages is a subject with
many fascinating ramifications, but this survey has of necessity been
brief._ _It has only been possible to indicate the general pattern.
Most of the interesting details must await the publication of much
larger volumes. It is hoped, however, that enough information has been
included herein to enhance the enjoyment that comes from inspecting
the great variety of cannon and projectiles that are to be seen
throughout the National Park System._

GLOSSARY

Most technical phrases are explained in the text and illustrations
(see fig. 51). For convenient reference, however, some important words
are defined below:

*Ballistics*--the science dealing with the motion of projectiles.

*Barbette carriage*--as used here, a traverse carriage on which a gun
is mounted to fire over a parapet.

*Bomb, bombshell*--see projectiles.

Breechblock--a movable piece which closes the breech of a cannon.

*Caliber*--diameter of the bore; also used to express bore length. A
30-caliber gun has a bore length 30 times the diameter of the bore.

*Cartridge*--a bag or case holding a complete powder charge for the
cannon, and in some instances also containing the projectile.

*Casemate carriage*--as used here, a traverse carriage in a fort
gunroom (casemate). The gun fired through an embrasure or loophole in
the wall of the room.

*Chamber*--the part of the bore which holds the propelling charge,
especially when of different diameter than the rest of the bore; in
chambered muzzle-loaders, the chamber diameter was smaller than that
of the bore.

*Elevation*--the angle between the axis of a piece and the horizontal
plane.

*Fuze*--a device to ignite the charge of a shell or other projectile.

*Grommet*--a rope ring used as a wad to hold a cannonball in place in
the bore.

*Gun*--any firearm; in the limited sense, a long cannon with high
muzzle velocity and flat trajectory.

*Howitzer*--a short cannon, intermediate between the gun and mortar.

*Lay*--to aim a gun.

*Limber*--a two-wheeled vehicle to which the gun trail is attached for
transport.

*Mandrel*--a metal bar, used as a core around which metal may be
forged or otherwise shaped.

*Mortar*--a very short cannon used for high or curved trajectory
firing.

*Point-blank*--as used here,