barred, double
gate the small petard was useless, and the great petard would break
only the fore part of such a gate. Furthermore, as one would guess,
hanging a petard was a hazardous occupation; it went out of style in
the early 1700's.

PROJECTILES

There are four different types of artillery projectiles which, in one
form or another, have been used since very early times:

(1) Battering projectiles (solid shot).
(2) Exploding shells.
(3) Scatter shot (case or canister, grape, shrapnel).
(4) Incendiary and chemical projectiles.

SOLID SHOT

At Havana, Cuba, in the early days, there was an abundance of round
stones lying around, put there by Mother Nature. Artillerists at
Havana never lacked projectiles. Stone balls, cheap to manufacture,
relatively light and therefore well suited to the feeble construction
of early ordnance, were in general use for large caliber cannon in the
fourteenth century. There were experiments along other lines such as
those at Tournay in the 1330's with long, pointed projectiles.
Lead-coated stones were fairly popular, and solid lead balls were used
in some small pieces, but the stone ball was more or less standard.

Cast-iron shot had been introduced by 1400, and, with the improvement
of cannon during that century, iron shot gradually replaced stone. By
the end of the 1500's stone survived for use only in the pedreros,
murtherers, and other relics of the earlier period. Iron shot for the
smoothbore was a solid, round shot, cast in fairly accurate molds; the
mold marks that invariably show on all cannonballs were of small
importance, for the ball did not fit the bore tightly. After casting,
shot were checked with a ring gauge (fig. 41)--a hoop through which
each ball had to pass. The Spanish term for this tool is very
descriptive: _pasabala_, "ball-passer."

Shot was used mainly in the flat-trajectory cannon. The small caliber
guns fired nothing but shot, for small sizes of the other type
projectiles were not effective. Shot was the prescription when the
situation called for "great accuracy, at very long range," and
penetration. Fired at ships, a shot was capable of breaching the
planks (at 100-yard range a 24-pounder shot would penetrate 4-1/2 feet
of "sound and hard" oak). With a fair aim at the waterline, a gunner
could sink or seriously damage a vessel with a few rounds. On ironclad
targets like the _Monitor_ and _Merrimac_, however, round shot did
little more