Part 7 (2/2)

In the last century, the bronze mortars metamorphosed into the great cast-iron mortars, such as ”The Dictator,” that mammoth Federal piece used against Petersburg, Va. Wrought-iron beds with a pair of rollers were built for them. In spite of their high trajectory, mortars could range well over a mile, as witness these figures for United States mortars of the 1860's, firing at 45 elevation:

_Ranges of U. S. Mortars in 1861_

Caliber Projectile Range weight (pounds) (yards)

8-inch siege 45 1,837 10-inch siege 90 2,100 12-inch seacoast 200 4,625 13-inch seacoast 200 4,325

At the siege of Fort Pulaski in 1862, however, General Gillmore complained that the mortars were highly inaccurate at mile-long range.

On this point, John Muller would have nodded his head emphatically. A hundred years before Gillmore's complaint, Muller had argued that a range of something less than 1,500 yards was ample for mortars or, for that matter, all guns. ”When the ranges are greater,” said Muller, ”they are so uncertain, and it is so difficult to judge how far the sh.e.l.l falls short, or exceeds the distance of the object, that it serves to no other purpose than to throw away the Powder and sh.e.l.l, without being able to do any execution.”

PETARDS

”Hoist with his own petard,” an ancient phrase signifying that one's carefully laid scheme has exploded, had truly graphic meaning in the old days when everybody knew what a petard was. Since the petard fired no projectile, it was hardly a gun. Roughly speaking, it was nothing but an iron bucket full of gunpowder. The petardier would hang it on a gate, something like hanging your hat on a nail, and blast the gate open by firing the charge.

Small petards weighed about 50 pounds; the large ones, around 70 pounds. They had to be heavy enough to be effective, yet light enough for a couple of men to lift up handily and hang on the target. The bucket part was packed full of the powder mixture, then a 2-1/2-inch-thick board was bolted to the rim in order to keep the powder in and the air out. An iron tube fuze was screwed into a small hole in the back or side of the weapon. When all was ready, the petardiers seized the two handles of the petard and carried it to the troublesome door. Here they set a screw, hung the explosive instrument upon it, lit the fuze, and ”retired.”

Petards were used frequently in King William's War of the 1680's to force the gates of small German towns. But on a well-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 sh.e.l.ls.

(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 b.a.l.l.s, 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 b.a.l.l.s 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 cannonb.a.l.l.s 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 pa.s.s. The Spanish term for this tool is very descriptive: _pasabala_, ”ball-pa.s.ser.”

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 s.h.i.+ps, 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 than bounce; it took the long, armor-piercing rifle projectile to force the development of the tremendously thick plate of modern times.

[Ill.u.s.tration: Figure 41--EIGHTEENTH CENTURY PROJECTILES. (Not to scale.)]

Round shot was very useful for knocking out enemy batteries. The gunner put his cannon on the flank of the hostile guns and used ricochet firing so that the ball, just clearing the defense wall, would bounce among the enemy guns, wound the crews, and break the gun carriages. In the destruction of fort walls, shot was essential. After dismounting the enemy pieces, the siege guns moved close enough to batter down the walls. The procedure was not as haphazard as it sounds. Cannon were brought as close as possible to the target, and the gunner literally cut out a low section with gunfire so that the wall above tumbled down into the moat and made a ramp right up to the breach. Firing at the upper part of the wall defeated its own purpose, for the rubble brought down only protected the foundation area, and the breach was so high that a.s.sault troops had to use ladders.

The most effective bombardment of Castillo de San Marcos occurred during the 1740 siege, and shot did the most damage. The heaviest English siege cannon were 18-pounders, over 1,000 yards from the fort.

Spanish Engineer Pedro Ruiz de Olano reported that the b.a.l.l.s did not penetrate the ma.s.sive main walls more than a foot and a half, but the parapets, being only 3 feet thick, suffered considerable damage. Some of the old parapets, Engineer Ruiz said, ”have been demolished, and the new ones have suffered very much owing to their recent construction.” (He meant that the new mortar had not sufficiently hardened.) Ruiz was not deceived about what would happen if hostile batteries were able to get closer; in such case, he thought, the enemy ”will no doubt succeed in destroying the parapets and dismounting the guns.”

Variations of round shot were bar shot and chain shot (fig. 41), two or more projectiles linked together for simultaneous firing. Bar shot appears in a Castillo inventory of 1706, and like chain shot, was for specialized work like cutting a s.h.i.+p's rigging. There is one apocryphal tale, however, about an experiment with chain shot as anti-personnel missiles: instead of charging a single cannon with the two b.a.l.l.s, two guns were used, side by side. The ball in one gun was chained to the ball in the other. The projectiles were to fly forth, stretching the long chain between them, mowing down a sizeable segment of the enemy. Instead, the chain wrapped the gun crews in a murderous embrace; one gun had fired late.

<script>