Artillery Through the Ages
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Albert Manucy >> Artillery Through the Ages
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[Illustration: Figure 37--SPANISH 5-INCH BRONZE MORTAR (1788).]
The mortar was mounted on a "bed"--a pair of wooden cheeks held
together by transoms. Since a bed had no wheels, the piece was
transported on a mortar wagon or sling cart. In the battery, the
mortar was generally bedded upon a level wooden platform; aboard ship,
it was a revolving platform, so that the piece could be quickly aimed
right or left. The mortar's weight, plus the high angle of elevation,
kept it pretty well in place when it was fired, although English
artillerists took the additional precaution of lashing it down.
The mortar did not use a wad, because a wad prevented the fuze of the
shell from igniting. To the layman, it may seem strange that the shell
was never loaded with the fuze toward the powder charge of the gun.
But the fuze was always toward the muzzle and away from the blast, a
practice which dated from the early days when mortars were discharged
by "double firing": the gunner lit the fuze of the shell with one hand
and the priming of the mortar with the other. Not until the late
1600's did the method of letting the powder blast ignite the fuze
become general. It was a change that greatly simplified the use of the
arm and, no doubt, caused the mortarman to heave a sigh of relief.
[Illustration: Figure 38--SPANISH 10-INCH BRONZE MORTAR (1759-88).
a--Dolphin, or handle, b--Bore, c--Powder chamber.]
Most mortars were equipped with dolphins, either singly or in pairs,
which were used for lifting the weapon onto its bed. Often there was a
little bracketed cup--a priming pan--under the vent, a handy gadget
that saved spilling a lot of powder at the almost vertical breech. As
with other bronze cannon, mortars were embellished with shields,
scrolls, names, and other decoration.
About 1750, the French mortar had a bore length 1-1/2 diameters of the
shell; in England, the bore was 2 diameters for the smaller calibers
and 3 for the 10- and 13-inchers. The extra length added a great deal
of weight to the English mortars: the 13-inch weighed 25
hundredweight, while the French equivalent weighed only about half
that much. Mueller complained that mortar designers slavishly copied
what they saw in other guns. For instance, he said, the reinforce was
unnecessary; it "... overloads the Mortar with a heap of useless
metal, and that in a place where the least strength is required, yet
as if this unnecessary metal was not sufficient, they add a great
projection at the mouth, which serves to no other purpose than to make
the Mortar top-heavy. The mouldings are likewise jumbled together,
without any taste or method, tho' they are taken from architecture."
Field mortars in use during Mueller's time included 4.6-, 5.8-, 8-,
10-, and 13-inch "land" mortars and 10- and 13-inch "sea" mortars.
Mueller, of course, redesigned them.
[Illustration: Figure 39--COEHORN MORTAR. The British General
Oglethorpe used 20 coehorns in his 1740 bombardment of St. Augustine.
These small mortars were also used extensively during the War Between
the States.]
The small mortars called coehorns (fig. 39) were invented by the famed
Dutch military engineer, Baron van Menno Coehoorn, and used by him in
1673 to the great discomfit of French garrisons. Oglethorpe had many
of them in his 1740 bombardment of St. Augustine when the Spanish,
trying to translate coehorn into their own tongue, called them
_cuernos de vaca_--"cow horns." They continued in use through the U.
S. Civil War, and some of them may still be seen in the battlefield
parks today.
Bombs and carcasses were usual for mortar firing, but stone
projectiles remained in use as late as 1800 for the pedrero class
(fig. 43). Mortar projectiles were quite formidable; even in the
sixteenth century missiles weighing 100 or more pounds were not
uncommon, and the 13-inch mortar of 1860 fired a 200-pound shell. The
larger projectiles had to be whipped up to the muzzle with block and
tackle.
[Illustration: Figure 40--THE "DICTATOR." This huge 13-inch mortar was
used by the Federal artillery in the bombardment of Petersburg, Va.,
1864-65.]
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 deg. 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 Mueller would have nodded his head emphatically. A
hundred years before Gillmore's complaint, Mueller 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 Mueller,
"they are so uncertain, and it is so difficult to judge how far the
shell falls short, or exceeds the distance of the object, that it
serves to no other purpose than to throw away the Powder and shell,
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 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 than bounce; it took the long, armor-piercing rifle
projectile to force the development of the tremendously thick plate of
modern times.
[Illustration: 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 assault 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 balls did not
penetrate the massive 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 ship'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 balls, 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.
EXPLOSIVE SHELLS
The word "bomb" comes to us from the French, who derived it from the
Latin. But the Romans got it originally from the Greek _bombos_,
meaning a deep, hollow sound. "Bombard" is a derivation. Today bomb is
pronounced "balm," but in the early days it was commonly pronounced
"bum." The modern equivalent of the "bum" is an HE shell.
The first recorded use of explosive shells was by the Venetians in
1376. Their bombs were hemispheres of stone or bronze, joined together
with hoops and exploded by means of a primitive powder fuze. Shells
filled with explosive or incendiary mixtures were standard for
mortars, after 1550, but they did not come into general use for
flat-trajectory weapons until early in the nineteenth century,
whereafter the term "shell" gradually won out over "bomb."
In any event, this projectile was one of the most effective ever used
in the smoothbore against earthworks, buildings, and for general
bombardment. A delayed action shell, diabolically timed to roll
amongst the ranks with its fuze burning, was calculated to "disorder
the stoutest men," since they could not know at what awful instant the
bomb would burst.
A bombshell was simply a hollow, cast-iron sphere. It had a single
hole where the powder was funneled in--full, but not enough to pack
too tightly when the fuze was driven in. Until the 1800's, the larger
bombs were not always smooth spheres, but had either a projecting
neck, or collar, for the fuze hole or a pair of rings at each side of
the hole for easier handling (fig. 41). In later years, however, such
projections were replaced by two "ears," little recesses beside the
fuze hole. A pair of tongs (something like ice tongs) seized the shell
by the ears and lifted it up to the gun bore.
During most of the eighteenth century, shells were cast thicker at the
base than at the fuze hole on the theory that they were (1) better
able to resist the shock of firing from the cannon and (2) more likely
to fall with the heavy part underneath, leaving the fuze uppermost and
less liable to extinguishment. Mueller scoffed at the idea of
"choaking" a fuze, which, he said, burnt as well in water as in any
other element. Furthermore, he preferred to use shells "everywhere
equally thick, because they would then burst into a greater number of
pieces." In later years, the shells were scored on the interior to
ensure their breaking into many fragments.
FUZES
[Illustration: Figure 42--NINETEENTH CENTURY PROJECTILE FUZES.
a--Cross-section of Bormann fuze, b--Top of Bormann fuze, c--Wooden
fuze for spherical shell, d--Wood-and-paper fuze for spherical shell,
e--Percussion fuze.]
The eighteenth century fuze was a wooden tube several inches long,
with a powder composition tamped into its hole much like the
nineteenth century fuze (fig. 42c). The hole was only a quarter of an
inch in diameter, but the head of the fuze was hollowed out like a
cup, and "mealed" (fine) powder, moistened with "spirits of wine"
(alcohol), was pressed into the hollow to make a larger igniting
surface. To time the fuze, a cannoneer cut the cylinder at the proper
length with his fuze-saw, or drilled a small hole (G) where the fire
could flash out at the right time. Some English fuzes at this period
were also made by drawing two strands of a quick match into the hole,
instead of filling it with powder composition. The ends of the match
were crossed into a sort of rosette at the head of the fuze. Paper
caps to protect the powder composition covered the heads of these
fuzes and had to be removed before the shell was put into the gun.
Bombs were not filled with powder very long before use, and fuzes were
not put into the projectiles until the time of firing. To force the
fuze into the hole of the shell, the cannoneer covered the fuze head
with tow, put a fuze-setter on it, and hammered the setter with a
mallet, "drifting" the fuze until the head stuck out of the shell only
2/10 of an inch. If the fuze had to be withdrawn, there was a fuze
extractor for the job. This tool gripped the fuze head tightly, and
turning a screw slowly pulled out the fuze.
Wooden tube fuzes were used almost as long as the spherical shell. A
United States 12-inch mortar fuze (fig. 42c), 7 inches long and
burning 49 seconds, was much like the earlier fuze. During the 1800's,
however, other types came into wide use.
The conical paper-case fuze (fig. 42d), inserted in a metal or wooden
plug that fitted the fuze hole, contained composition whose rate of
burning was shown by the color of the paper. A black fuze burned an
inch every 2 seconds. Red burned 3 seconds, green 4, and yellow 5
seconds per inch. Paper fuzes were 2 inches long, and could be cut
shorter if necessary. Since firing a shell from a 24-pounder to burst
at 2,000 yards meant a time flight of 6 seconds, a red fuze would
serve without cutting, or a green fuze could be cut to 1-1/2 inches.
Sea-coast fuzes of similar type were used in the 15-inch Rodmans until
these big smoothbores were finally discarded sometime after 1900.
The Bormann fuze (fig. 42a), the quickest of the oldtimers to set, was
used for many years by the U. S. Field Artillery in spherical shell
and shrapnel. Its pewter case, which screwed into the shell, contained
a time ring of powder composition (A). Over this ring the top of the
fuze case was marked in seconds. To set the fuze, the gunner merely
had to cut the case at the proper mark--at four for 4 seconds, three
for 3 seconds, and so on--to expose the ring of powder to the powder
blast of the gun. The ring burned until it reached the zero end and
set off the fine powder in the center of the case; the powder flash
then blew out a tin plate in the bottom of the fuze and ignited the
shell charge. Its short burning time (about 6 seconds) made the
Bormann fuze obsolete as field gun ranges increased. The main trouble
with this fuze, however, was that it did not always ignite!
The percussion fuze was an extremely important development of the
nineteenth century, particularly for the long-range rifles. The shock
of impact caused this fuze to explode the shell at almost the instant
of striking. Percussion fuzes were made in two general types: the
front fuze, for the nose of an elongated projectile; and the base
fuze, at the center of the projectile base. The base fuze was used
with armor-piercing projectiles where it was desirable to have the
shell penetrate the target for some distance before bursting. Both
types were built on the same principles.
A Hotchkiss front percussion fuze (fig. 42e) had a brass case which
screwed into the shell. Inside the case was a plunger (A) containing a
priming charge of powder, topped with a cap of fulminate. A brass wire
at the base of the plunger was a safety device to keep the cap away
from a sharp point at the top of the fuze until the shell struck the
target. When the gun was fired, the shock of discharge dropped a lead
plug (B) from the base of the fuze into the projectile cavity,
permitting the plunger to drop to the bottom of the fuze and rest
there, held by the spread wire, while the shell was in flight. Upon
impact, the plunger was thrown forward, the cap struck the point and
ignited the priming charge, which in turn fired the bursting charge of
the shell.
SCATTER PROJECTILES
When one of our progenitors wrathfully seized a handful of pebbles and
flung them at the flock of birds in his garden, he discovered the
principle of the scatter projectile. Perhaps its simplest application
was in the stone mortar (fig. 43). For this weapon, round stones about
the size of a man's fist (and, by 1750, hand grenades) were dumped
into a two-handled basket and let down into the bore. This primitive
charge was used at close range against personnel in a fortification,
where the effect of the descending projectiles would be uncommonly
like a short but severe barrage of over-sized hailstones. There were
6,000 stones in the ammunition inventory for Castillo de San Marcos in
1707.
[Illustration: Figure 43--SPANISH 16-INCH PEDRERO (1788). This mortar
fired baskets of stones.]
One of the earliest kinds of scatter projectiles was case shot, or
canister, used at Constantinople in 1453. The name comes from its
case, or can, usually metal, which was filled with scrap, musket
balls, or slugs (fig. 41). Somewhat similar, but with larger iron
balls and no metal case, was grape shot, so-called from the grape-like
appearance of the clustered balls. A stand of grape in the 1700's
consisted of a wooden disk at the base of a short wooden rod that
served as the core around which the balls stood (fig. 41). The whole
assembly was bagged in cloth and reinforced with a net of heavy cord.
In later years grape was made by bagging two or three tiers of balls,
each tier separated by an iron disk. Grape could disable men at almost
900 yards and was much used during the 1700's. Eventually, it was
almost replaced by case shot, which was more effective at shorter
ranges (400 to 700 yards). Incidentally, there were 2,000 sacks of
grape at the Castillo in 1740, more than any other type projectile.
Spherical case shot (fig. 41) was an attempt to carry the
effectiveness of grape and canister beyond its previous range, by
means of a bursting shell. It was the forerunner of the shrapnel used
so much in World War I and was invented by Lt. Henry Shrapnel, of the
British Army, in 1784. There had been previous attempts to produce a
projectile of this kind, such as the German Zimmerman's "hail shot" of
1573--case shot with a bursting charge and a primitive time fuze--but
Shrapnel's invention was the first air-bursting case shot which, in
technical words, "imparted directional velocity" to the bullets it
contained. Shrapnel's new shell was first used against the French in
1808, but was not called by its inventor's name until 1852.
INCENDIARIES AND CHEMICAL PROJECTILES
Incendiary missiles, such as buckets or barrels filled with a fiercely
burning composition, had been used from earliest times, long before
cannon. These crude incendiaries survived through the 1700's as, for
instance, the flaming cargoes of fire ships that were sent amidst the
enemy fleet. But in the year 1672 there appeared an iron shell called
a carcass (fig. 41), filled with pitch and other materials that burned
at intense heat for about 8 minutes. The flame escaped through vents,
three to five in number, around the fuze hole of the shell. The
carcass was standard ammunition until smoothbores went out of use. The
United States ordnance manual of 1861 lists carcasses for 12-, 18-,
24-, 32-, and 42-pounder guns as well as 8-, 10-, and 13-inch mortars.
During the late 1500's, the heating of iron cannon balls to serve as
incendiaries was suggested, but not for another 200 years was the idea
successfully carried out. Hot shot was nothing but round shot, heated
to a red glow over a grate or in a furnace. It was fired from cannon
at such inflammable targets as wooden ships or powder magazines.
During the siege of Gibraltar in 1782, the English fired and destroyed
a part of Spain's fleet with hot shot; and in United States seacoast
forts shot furnaces were standard equipment during the first half of
the 1800's. The little shot furnace at Castillo de San Marcos National
Monument was built during the 1840's; a giant furnace of 1862 still
remains at Fort Jefferson National Monument. Few other examples are
left.
Loading hot shot was not particularly dangerous. After the powder
charge was in the gun with a dry wad in front of it, another wad of
wet straw, or clay, was put into the barrel. When the cherry-red shot
was rammed home, the wet wad prevented a premature explosion of the
charge. According to the _Ordnance Manual_, the shot could cool in the
gun without setting off the charge! Hot shot was superseded, about
1850, by Martin's shell, filled with molten iron.
The smoke shell appeared in 1681, but was never extensively used.
Similarly, a form of gas projectile, called a "stink shell," was
invented by a Confederate officer during the Civil War. Because of its
"inhumanity," and probably because it was not thought valuable enough
to offset its propaganda value to the enemy, it was not popular. These
were the beginnings of the modern chemical shells.
In connection with chemical warfare, it is of interest to review the
Hussite siege of Castle Karlstein, near Prague, in the first quarter
of the fifteenth century. The Hussites emplaced 46 small cannon, 5
large cannon, and 5 catapults. The big guns would shoot once or twice
a day, and the little ones from six to a dozen rounds.
Marble pillars from Prague churches furnished the cannonballs. Many
projectiles for the catapults, however, were rotting carcasses and
other filth, hurled over the castle walls to cause disease and break
the morale of the besieged. But the intrepid defenders neutralized
these "chemical bursts" with lime and arsenic. After firing 10,930
cannonballs, 932 stone fragments, 13 fire barrels, and 1,822 tons of
filth, the Hussites gave up.
FIXED AMMUNITION
In early days, due partly to the roughly made balls, wads were very
important as a means of confining the powder and increasing its
efficiency. Wads could be made of almost any suitable material at
hand, but perhaps straw or hay ones were most common. The hay was
first twisted into a 1-inch rope, then a length of the rope was folded
together several times and finally rolled up into a short cylinder, a
little larger than the bore. After the handier sabots came into use,
however, wads were needed only to keep the ball from rolling out when
the muzzle was down, or for hot shot firing.
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