Artillery Through the Ages

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In today's Spanish, _pasavolante_ means "fast action," a phrase
suggestive of the vicious impetuosity to be expected from such a small
but powerful cannon. Sometimes it was termed a _drajon_, the English
equivalent of which may be the drake, meaning "dragon"; but perhaps
its most popular name in the early days was _cerbatana_, from Cerebus,
the fierce three-headed dog of mythology. Strange things happen to
words: a _cerbatana_ in modern Spanish is a pea shooter.

_Sixteenth century Spanish cannon of the second class_

Spanish name Weight of ball Translation
(pounds)

Quarto canon 9 to 12 Quarter-cannon.
Tercio canon 16 Third-cannon.
Medio canon 24 Demicannon.
Canon de abatir 32 Siege cannon.
Doble canon 48 Double cannon.
Canon de bateria 60 Battering cannon.
Serpentino Serpentine.
Quebrantamuro or lombarda 70 to 90 Wallbreaker or lombard.
Basilisco 80 and up Basilisk.

The second class of guns were the only ones properly called "cannon"
in this early period. They were siege and battering pieces, and in
some few respects were similar to the howitzers of later years. A
typical Spanish cannon was only about two-thirds as long as a
culverin, and the bore walls were thinner. Naturally, the powder
charge was also reduced (half the ball's weight for a common cannon,
while a culverin took double that amount).

The Germans made their light cannon 18 calibers long. Most Spanish
siege and battering guns had this same proportion, for a shorter gun
would not burn all the powder efficiently, "which," said Collado, "is
a most grievous fault." However, small cannon of 18-caliber length
were too short; the muzzle blast tended to destroy the embrasure of
the parapet. For this reason, Spanish demicannon were as long as 24
calibers and the quarter-cannon ran up to 28. The 12-pounder
quarter-cannon, incidentally, was "culverined" or reinforced so that
it actually served in the field as a demiculverin.

The great weight of its projectile gave the double cannon its name.
The warden of the Castillo at Milan had some 130-pounders made, but
such huge pieces were of little use, except in permanent
fortifications. It took a huge crew to move them, their carriages
broke under the concentrated weight, and they consumed mountains of
munitions. The lombard, which apparently originated in Lombardy, and
the basilisk had the same disadvantages. The fabled basilisk was a
serpent whose very look was fatal. Its namesake in bronze was
tremendously heavy, with walls up to 4 calibers thick and a bore up to
30 calibers long. It was seldom used by the Europeans, but the Turkish
General Mustafa had a pair of basilisks at the siege of Malta, in
1565, that fired 150- and 200-pound balls. The 200-pounder gun broke
loose as it was being transferred to a homeward bound galley and sank
permanently to the bottom of the sea. Its mate was left on the island,
where it became an object of great curiosity.

The third class of ordnance included the guns firing stone
projectiles, such as the pedrero (or perrier, petrary, cannon petro,
etc.), the mortars, and the old bombards like Edinburgh Castle's
famous Mons Meg. Bars of wrought iron were welded together to form
Meg's tube, and iron rings were clamped around the outside of the
piece. In spite of many accidents, this coopering technique persisted
through the fifteenth century. Mons Meg was made in two sections that
screwed together, forming a piece 13 feet long and 5 tons in weight.

Pedreros (fig. 23c) were comparatively light. The foundryman used only
half the metal he would put into a culverin, for the stone projectile
weighed only a third as much as an iron ball of the same size, and the
bore walls could therefore be comparatively thin. They were made in
calibers up to 50-pounders. There was a chamber for the powder charge
and little danger of the gun's bursting, unless a foolhardy fellow
loaded it with an iron ball. The wall thicknesses of this gun are
shown in Figure 24, where the inner circle represents the diameter of
the chamber, the next arc the bore caliber, and the outer lines the
respective diameters at chase, trunnions, and vent.

[Illustration: Figure 24--HOW MUCH METAL WAS IN EARLY GUNS? The charts
compare the wall diameters of sixteenth-seventeenth century types. The
center circle represents the bore, while the three outer arcs show the
relative thickness of the bore wall at (1) the smallest diameter of
the chase, (2) at the trunnions, and (3) at the vent. The small arc
inside the bore indicates the powder chamber found in the pedrero and
mortar.]

Mortars (fig. 23d) were excellent for "putting great fear and terror
in the souls of the besieged." Every night the mortars would play upon
the town: "it keeps them in constant turmoil, due to the thought that
some ball will fall upon their house." Mortars were designed like
pedreros, except much shorter. The convenient way to charge them was
with _saquillos_ (small bags) of powder. "They require," said Collado,
"a larger mouthful than any other pieces."

Just as children range from slight to stocky in the same family, there
are light, medium, or heavy guns--all bearing the same family name.
The difference lies in how the piece was "fortified"; that is, how
thick the founder cast the bore walls. The English language has
inelegantly descriptive terms for the three degrees of
"fortification": (1) bastard, (2) legitimate, and (3)
double-fortified. The thicker-walled guns used more powder. Spanish
double-fortified culverins were charged with the full weight of the
ball in powder; four-fifths that amount went into the legitimate, and
only two-thirds for the bastard culverin. In a short culverin (say, 24
calibers long instead of 30), the gunner used 24/30 of a standard
charge.

The yardstick for fortifying a gun was its caliber. In a legitimate
culverin of 6-inch caliber, for instance, the bore wall at the vent
might be one caliber (16/16 of the bore diameter) or 6 inches thick;
at the trunnions it would be 10/16 or 4-1/8 inches, and at the
smallest diameter of the chase, 7/16 or 2-5/8 inches. This table
compares the three degrees of fortification used in Spanish culverins:

Wall thickness
in 8ths of caliber
Vent Trunnion Chase

Bastard culverin 7 5 3
Legitimate culverin 8 5-1/2 3-1/2
Double-fortified culverin 9 6-1/2 4

As with culverins, so with cannon. This is Collado's table showing the
fortification for Spanish cannon:

Wall thickness
in 8ths of caliber
Vent Trunnion Chase
Canon sencillo (light cannon) 6 4-1/2 2-1/2
Canon comun (common cannon) 7 5 3-1/2
Canon reforzado (reinforced cannon) 8 5-1/2 3-1/2

Since cast iron was weaker than bronze, the walls of cast-iron pieces
were even thicker than the culverins. Spanish iron guns were founded
with 300 pounds of metal for each pound of the ball, and in lengths
from 18 to 20 calibers. English, Irish, and Swedish iron guns of the
period, Collado noted, had slightly more metal in them than even the
Spaniards recommended.

[Illustration: Figure 25--SIXTEENTH CENTURY CHAMBERED CANNON.
a--"Bell-chambered" demicannon, b--Chambered demicannon.]

Another way the designers tried to gain strength without loading the
gun with metal was by using a powder chamber. A chambered cannon (fig.
25b) might be fortified like either the light or the common cannon,
but it would have a cylindrical chamber about two-thirds of a caliber
in diameter and four calibers long. It was not always easy, however,
to get the powder into the chamber. Collado reported that many a good
artillerist dumped the powder almost in the middle of the gun. When
his ladle hit the mouth of the chamber, he thought he was at the
bottom of the bore! The cylindrical chamber was somewhat improved by a
cone-shaped taper, which the Spaniards called _encampanado_ or
"bell-chambered." A _canon encampanado_ (fig. 25a) was a good
long-range gun, strong, yet light. But it was hard to cut a ladle for
the long, tapered chamber.

Of all these guns, the reinforced cannon was one of the best. Since it
had almost as much metal as a culverin, it lacked the defects of the
chambered pieces. A 60-pounder reinforced cannon fired a convenient
55-pound ball, was easy to move, load, and clean, and held up well
under any kind of service. It cooled quickly. Either cannon powder or
fine powder (up to two-thirds the ball's weight) could be used in it.
Reinforced cannon were an important factor in any enterprise, as King
Philip's famed "Twelve Apostles" proved during the Flanders wars.

_Fortification of sixteenth and seventeenth century guns_

------------------------+-------------------------+---------------------
| Thickness of bore wall |
| in 8ths of the caliber |
Spanish Guns +-------+---------+-------+ English guns
| Vent |Trunnions| Chase |
------------------------+-------+---------+-------+---------------------
| | | |
Light cannon; | | | |
bell-chambered cannon | 6 | 4-1/2 | 2-1/2 | Bastard cannon.
Demicannon | 6 | 5 | 3 |
Common cannon; common | | | |
siege cannon | 7 | 5 | 3-1/2 |
Light culverin; common | | | |
battering cannon | 7 | 5 | 3 | Bastard culverin;
| | | | legitimate cannon.
Common culverin; | | | |
reinforced cannon | 8 | 5-1/2 | 3-1/2 | Legitimate culverin;
| | | | double-fortified
| | | | cannon.
Legitimate culverin | 9 | 6-1/2 | 4 | Double-fortified
| | | | culverin.
Cast-iron cannon | 10 | 8 | 5 |
Pasavolante | 11-1/2| 8-1/2 | 5-1/2 |
------------------------+-------+---------+-------+---------------------

While there was little real progress in mobility until the days of
Gustavus Adolphus, the wheeled artillery carriage seems to have been
invented by the Venetians in the fifteenth century. The essential
parts of the design were early established: two large, heavy cheeks or
side pieces set on an axle and connected by transoms. The gun was
cradled between the cheeks, the rear ends of which formed a "trail"
for stabilizing and maneuvering the piece.

Wheels were perhaps the greatest problem. As early as the 1500's
carpenters and wheelwrights were debating whether dished wheels were
best. "They say," reported Collado, "that the [dished] wheel will
never twist when the artillery is on the march. Others say that a
wheel with spokes angled beyond the cask cannot carry the weight of
the piece without twisting the spoke, so the wheel does not last long.
I am of the same opinion, for it is certain that a perpendicular wheel
will suffer more weight than the other. The defect of twisting under
the pieces when on the march will be remedied by making the cart a
little wider than usual." However, advocates of the dished wheel
finally won.

SMOOTHBORES OF THE LATER PERIOD

From the guns of Queen Elizabeth's time came the 6-, 9-, 12-, 18-,
24-, 32-, and 42-pounder classifications adopted by Cromwell's
government and used by the English well through the eighteenth
century. On the Continent, during much of this period, the French were
acknowledged leaders. Louis XIV (1643-1715) brought several foreign
guns into his ordnance, standardizing a set of calibers (4-, 8-, 12-,
16-, 24-, 32-, and 48-pounders) quite different from Henry II's in the
previous century.

The cannon of the late 1600's was an ornate masterpiece of the
foundryman's art, covered with escutcheons, floral relief, scrolls,
and heavy moldings, the most characteristic of which was perhaps the
banded muzzle (figs. 23b-c, 25, 26a-b), that bulbous bit of
ornamentation which had been popular with designers since the days of
the bombards. The flared or bell-shaped muzzle (figs. 23a, 26c, 27),
did not supplant the banded muzzle until the eighteenth century, and,
while the flaring bell is a usual characteristic of ordnance founded
between 1730 and 1830, some banded-muzzle guns were made as late as
1746 (fig. 26a).

By 1750; however, design and construction were fairly well
standardized in a gun of much cleaner line than the cannon of 1650.
Although as yet there had been no sharp break with the older
traditions, the shape and weight of the cannon in relation to the
stresses of firing were becoming increasingly important to the men who
did the designing.

Conditions in eighteenth century England were more or less typical: in
the 1730's Surveyor-General Armstrong's formulae for gun design were
hardly more than continuations of the earlier ways. His guns were
about 20 calibers long, with these outside proportions:

1st reinforce = 2/7 of the gun's length.
2d reinforce = 1/7 plus 1 caliber.
chase = 4/7 less 1 caliber.

The trunnions, about a caliber in size, were located well forward
(3/7 of the gun's length) "to prevent the piece from kicking up
behind" when it was fired. Gunners blamed this bucking tendency on the
practice of centering the trunnions on the _lower_ line of the bore.
"But what will not people do to support an old custom let it be ever
so absurd?" asked John Mueller, the master gunner of Woolwich. In 1756,
Mueller raised the trunnions to the _center_ of the bore, an
improvement that greatly lessened the strain on the gun carriage.

[Illustration: Figure 26--EIGHTEENTH CENTURY CANNON, a--Spanish
bronze 24-pounder of 1746. b--French bronze 24-pounder of the early
1700's. c--English iron 6-pounder of the middle 1700's. The 6-pounder
is part of the armament at Castillo de San Marcos.]

[Illustration: Figure 27--SPANISH 24-POUNDER CAST-IRON GUN (1693).
Note the modern lines of this cannon, with its flat breech and slight
muzzle swell.]

The caliber of the gun continued to be the yardstick for "fortification"
of the bore walls:

Vent 16 parts
End of 1st reinforce 14-1/2 do
Beginning of second reinforce 13-1/2 do
End of second reinforce 12-1/2 do
Beginning of chase 11-1/2 do
End of chase 8 do

For both bronze and iron guns, the above figures were the same, but
for bronze, Armstrong divided the caliber into 16 parts; for iron it
was only 14 parts. The walls of an iron gun thus were slightly thicker
than those of a bronze one.

This eighteenth century cannon was a cast gun, but hoops and rings
gave it the built-up look of the barrel-stave bombard, when hoops were
really functional parts of the cannon. Reinforces made the gun look
like "three frustums of cones joined together, so as the lesser base
of the former is always greater than the greatest of the succeeding
one." Ornamental fillets, astragals, and moldings, borrowed from
architecture, increased the illusion of a sectional piece. Tests with
24-pounders of different lengths showed guns from 18 to 21 calibers
long gave generally the best performance, but what was true for the
24-pounder was not necessarily true for other pieces. Why was the
32-pounder "brass battering piece" 6 inches longer than its 42-pounder
brother? John Mueller wondered about such inconsistencies and set out
to devise a new system of ordnance for England.

Like many men before him, Mueller sought to increase the caliber of
cannon without increasing weight. He managed it in two ways: he
modified exterior design to save on metal, and he lessened the powder
charge to permit shortening and lightening the gun. Mueller's guns had
no heavy reinforces; the metal was distributed along the bore in a
taper from powder chamber to muzzle swell. But realizing man's
reluctance to accept new things, he carefully specified the location
and size for each molding on his gun, protesting all the while the
futility of such ornaments. Not until the last half of the next
century were the experts well enough versed in metallurgy and interior
ballistics to slough off all the useless metal.

So, using powder charges about one-third the weight of the projectile,
Mueller designed 14-caliber light field pieces and 15-caliber ship
guns. His garrison and battering cannon, where weight was no great
disadvantage, were 18 calibers long. The figures in the table
following represent the principal dimensions for the four types of
cannon--all cast-iron except for the bronze siege guns. The first line
in the table shows the length of the cannon. To proportion the rest of
the piece, Mueller divided the shot diameter into 24 parts and used it
as a yardstick. The caliber of the gun, for instance, was 25 parts, or
25/24th of the shot diameter. The few other dimensions--thickness of
the breech, length of the gun before the barrel began its taper,
fortification at vent and chase--were expressed the same way.

-----------------------------------+-------+--------+-------+---------
| Field | Ship | Siege | Garrison
-----------------------------------+-------+--------+-------+---------
Length in calibers | 14 | 15 | 18 | 18
(Other proportions in 24ths of the shot diameter) |
Caliber | 25 | 25 | 25 | 25
Thickness of breech | 14 | 24 | 16 | 24
Length from breech to taper | 39 | 49 | 40 | 49
Thickness at vent | 16 | 25 | 18 | 25
Thickness at muzzle | 8 | 12-1/2 | 9 | 12-1/2
-----------------------------------+-------+--------+-------+---------

The heaviest of Mueller's garrison guns averaged some 172 pounds of
iron for every pound of the shot, while a ship gun weighed only 146,
less than half the iron that went into the sixteenth century cannon.
And for a seafaring nation such as England, these were important
things. Perhaps the opposite table will give a fair idea of the
changes in English ordnance during the eighteenth century. It is based
upon John Mueller's lists of 1756; the "old" ordnance includes cannon
still in use during Mueller's time, while the "new" ordnance is
Mueller's own.

Windage in the English gun of 1750 was about 20 percent greater than
in French pieces. The English ratio of shot to caliber was 20:21;
across the channel it was 26:27. Thus, an English 9-pounder fired a
4.00-inch ball from a 4.20-inch bore; the French 9-pounder ball was
4.18 inches and the bore 4.34.

The English figured greater windage was both convenient and
economical: windage, said they, ought to be just as thick as the metal
in the gunner's ladle; standing shot stuck in the bore and unless it
could be loosened with the ladle, had to be fired away and lost. John
Mueller brushed aside such arguments impatiently. With a proper wad
over the shot, no dust or dirt could get in; and when the muzzle was
lowered, said Mueller, the shot "will roll out of course." Besides,
compared with increased accuracy, the loss of a shot was trifling.
Furthermore, with less room for the shot to bounce around the bore,
the cannon would "not be spoiled so soon." Mueller set the ratio of
shot to caliber as 24:25.

_Calibers and lengths of principal eighteenth century English cannon_

---------+-----------+---------------------+-----------+----------+
Caliber | Field | Ship | Siege | Garrison |
+-----------+----------+----------+-----------+----------+
| Iron | Bronze | Iron | Bronze | Iron |
+-----+-----+----+-----+-----+----+-----+-----+----+-----+
(pounder)| Old | New | Old| New | Old | New| Old | New | Old| New |
---------+-----+-----+----+-----+-----+----+-----+-----+----+-----+
1-1/2 | | | | | | | 6'0"| | | |
3 |3'6" |3'3" | |3'6" | 4'6"|3'6"| 7'0"| |4'6"| 4'2"|
4 | | | | | 6'0"| | | | | |
6 |4'6" |4'1" |8'0"|4'4" | 7'0"|4'4"| 8'0"| |6'6"| 5'3"|
9 | |4'8" | |5'0" | 7'0"|5'0"| 9'0"| |7'0"| 6'0"|
12 |5'0" |5'1" |9'0"|5'6" | 9'0"|5'6"| 9'0"| 6'7"|8'0"| 6'7"|
18 | |5'10"| |6'4" | 9'0"|6'4"| 9'6"| 8'4"|9'0"| 7'6"|
24 |5'6" |6'5" |9'6"|7'0" | 9'0"|7'0"| 9'6"| 8'4"|9'0"| 8'4"|
32 | | | |7'6" | 9'6"|7'6"|10'0"| 9'2"|9'6"| 9'2"|
36 | | | |7'10"| | | | 9'6"| | |
42 | | |9'6"|8'4" |10'0"|8'4"| 9'6"|10'0"| |10'0"|
48 | | | |8'6" | |8'6"| |10'6"| | |
---------+-----+-----+----+-----+-----+----+-----+-----+----+-----+

In the 1700's cast-iron guns became the principal artillery afloat and
ashore, yet cast bronze was superior in withstanding the stresses of
firing. Because of its toughness, less metal was needed in a bronze
gun than in a cast-iron one, so in spite of the fact that bronze is
about 20 percent heavier than iron, the bronze piece was usually the
lighter of the two. For "position" guns in permanent fortifications
where weight was no disadvantage, iron reigned supreme until the
advent of steel guns. But non-rusting bronze was always preferable
aboard ship or in seacoast forts.

Mueller strongly advocated bronze for ship guns. "Notwithstanding all
the precautions that can be taken to make iron Guns of a sufficient
strength," he said, "yet accidents will sometimes happen, either by
the mismanagement of the sailors, or by frosty weather, which renders
iron very brittle." A bronze 24-pounder cost L156, compared with L75
for the iron piece, but the initial saving was offset when the gun
wore out. The iron gun was then good for nothing except scrap at a
farthing per pound, while the bronze cannon could be recast "as often
as you please."

In 1740, Maritz of Switzerland made an outstanding contribution to the
technique of ordnance manufacture. Instead of hollow casting (that is,
forming the bore by casting the gun around a core), Maritz cast the
gun solid, then drilled the bore, thus improving its uniformity. But
although the bore might be drilled quite smooth, the outside of a
cast-iron gun was always rough. Bronze cannon, however, could be put
in the lathes to true up even the exterior. While after 1750 the
foundries seldom turned out bronze pieces as ornate as the Renaissance
culverins, a few decorations remained and many guns were still
personalized with names in raised letters on the gun. Castillo de San
Marcos has a 4-pounder "San Marcos," and, indeed, saints' names were
not uncommon on Spanish ordnance. Other typical names were _El
Espanto_ (The Terror), _El Destrozo_ (The Destroyer), _Generoso_
(Generous), _El Toro_ (The Bull), and _El Belicoso_ (The Quarrelsome
One).

In some instances, decoration was useful. The French, for instance, at
one time used different shapes of cascabels to denote certain
calibers; and even a fancy cascabel shaped like a lion's head was
always a handy place for anchoring breeching tackle or maneuvering
lines. The dolphins or handles atop bronze guns were never merely
ornaments. Usually they were at the balance point of the gun; tackle
run through them and hooked to the big tripod or "gin" lifted the
cannon from its carriage.

GARRISON AND SHIP GUNS

Cannon for permanent fortifications were of various sizes and
calibers, depending upon the terrain that had to be defended. At
Castillo de San Marcos, for instance, the strongest armament was on
the water front; lighter guns were on the land sector, an area
naturally protected by the difficult terrain existing in the colonial
period.

[Illustration: Figure 28--EIGHTEENTH CENTURY SPANISH GARRISON GUN.]

Before the Castillo was completed, guns were mounted only in the
bastions or projecting corners of the fort. A 1683 inventory clearly
shows that heaviest guns were in the San Agustin, or southeastern
bastion, commanding not only the harbor and its entrance but the town
of St. Augustine as well San Pablo, the northwestern bastion,
overlooked the land approach to the Castillo and the town gate; and,
though its armament was lighter, it was almost as numerous as that in
San Agustin. Bastion San Pedro to the southwest was within the town
limits, and its few light guns were a reserve for San Pablo. The
watchtower bastion of San Carlos overlooked the northern marshland and
the harbor; its armament was likewise small. The following list
details the variety and location of the ordnance:

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