Soon after he found he could hurl a rock with his good right arm, man
learned about trajectory--the curved path taken by a missile through
the air. A baseball describes a "flat" trajectory every time the
pitcher throws a hard, fast one. Youngsters tossing the ball to each
other over a tall fence use "curved" or "high" trajectory. In
artillery, where trajectory is equally important, there are three main
types of cannon: (1) the flat trajectory gun, throwing shot at the
target in relatively level flight; (2) the high trajectory mortar,
whose shell will clear high obstacles and descend upon the target from
above; and (3) the howitzer, an in-between piece of medium-high
trajectory, combining the mobility of the fieldpiece with the large
caliber of the mortar.
The Spaniard, Luis Collado, mathematician, historian, native of
Lebrija in Andalusia, and, in 1592, royal engineer of His Catholic
Majesty's Army in Lombardy and Piedmont, defined artillery broadly as
"a machine of infinite importance." Ordnance he divided into three
classes, admittedly following the rules of the "German masters, who
were admired above any other nation for their founding and handling of
artillery." Culverins and sakers (Fig. 23a) were guns of the first
class, designed to strike the enemy from long range. The battering
cannon (fig. 23b) were second class pieces; they were to destroy forts
and walls and dismount the enemy's machines. Third class guns fired
stone balls to break and sink ships and defend batteries from assault;
such guns included the pedrero, mortar, and bombard (fig. 23c, d).
Collado's explanation of how the various guns were invented is perhaps
naive, but nevertheless interesting: "Although the main intent of the
inventors of this machine [artillery] was to fire and offend the enemy
from both near and afar, since this offense must be in diverse ways it
so happened that they formed various classes in this manner: they came
to realize that men were not satisfied with the _espingardas_ [small
Moorish cannon], and for this reason the musket was made; and likewise
the _esmeril_ and the falconet. And although these fired longer shots,
they made the demisaker. To remedy a defect of that, the sakers were
made, and the demiculverins and culverins. While they were deemed
sufficient for making a long shot and striking the enemy from afar,
they were of little use as battering guns because they fire a small
ball. So they determined to found a second kind of piece, wherewith,
firing balls of much greater weight, they might realize their
intention. But discovering likewise that this second kind of piece was
too powerful, heavy and costly for batteries and for defense against
assaults or ships and galleys, they made a third class of piece,
lighter in metal and taking less powder, to fire balls of stone. These
are the commonly called _cañones de pedreros_. All the classes of
pieces are different in range, manufacture and design. Even the method
of charging them is different."
[Illustration: Figure 22--TRAJECTORIES. Maximum range of eighteenth
century guns was about 1 mile.
_Guns could:_ Batter heavy construction with solid shot at long or
short range; destroy fort parapets and, by ricochet fire, dismount
cannon; shoot grape, canister, or bombs against massed personnel.
_Mortars could:_ Reach targets behind obstructions; use high angle
fire to shoot bombs, destroying construction and personnel.
_Howitzers could:_ Move more easily in the field than mortars; reach
targets behind obstructions by high angle fire; shoot larger
projectiles than could field guns of similar weight.]
It was most important for the artillerist to understand the different
classes of guns. As Collado quaintly phrased it, "he who ignores the
present lecture on this _arte_ will, I assert, never do a good thing."
Cannon burst in the batteries every day because gunners were ignorant
of how the gun was made and what it was meant to do. Nor was such
ignorance confined to gunners alone. The will and whim of the prince
who ordered the ordnance or "the simple opinion of the unexpert
founder himself," were the guiding principles in gun founding. "I am
forced," wrote Collado, "to persuade the princes and advise the
founders that the making of artillery should always take into account
the purpose each piece must serve." This persuasion he undertook in
considerable detail.
[Illustration: Figure 23--SIXTEENTH CENTURY SPANISH ARTILLERY. Taken
from a 1592 manuscript, these drawings illustrate the three main
classes of artillery used by Spain during the early colonial period in
the New World, a--Culverin (Class 1). b--Cannon (Class 2). c--Pedrero
(Class 3). d--Mortar (Class 3).]
The first class of guns were the long-range pieces, comparatively
"rich" in metal. In the following table from Collado, the calibers and
ranges for most Spanish guns of this class are given, although as the
second column shows, at this period calibers were standardized only in
a general way. For translation where possible, and to list those
which became the most popular calibers, we have added a final column.
Most of the guns were probably of culverin length: 30- to 32-caliber.
_Sixteenth century Spanish cannon of the first class_
Name of Weight of Length Range in yards Popular
gun ball of gun Point- Maximum caliber
(pounds) (in calibers) blank
Esmeril 1/2 208 750 1/2-pounder
esmeril.
Falconete 1 to 2 1-pounder
falconet.
Falcón 3 to 4 417 2,500 3-pounder
falcon.
Pasavolante 1 to 15 40 to 44 500 4,166 6-pounder
pasavolante.
Media sacre 5 to 7 417 3,750 6-pounder
demisaker.
Sacre 7 to 10 9-pounder
saker.
Moyana 8 to 10 shorter than 9-pounder
saker moyenne.
Media
culebrina 10 to 18 833 5,000 12-pounder
demiculverin.
Tercio de
culebrina 14 to 22 18-pounder
third-culverin.
Culebrina 20, 24, 25, 30 to 32 1,742 6,666 24-pounder
culverin.
30, 40, 50
Culebrina
real 24 to 40 30 to 32 32-pounder
culverin royal.
Doble
culebrina 40 and up 30 to 32 48-pounder
culverin.
In view of the range Collado ascribes to the culverin, some remarks on
gun performances are in order. "Greatest random" was what the old-time
gunner called his maximum range, and random it was. Beyond point-blank
range, the gunner was never sure of hitting his target. So with
smoothbores, long range was never of great importance. Culverins, with
their thick walls, long bores, and heavy powder charges, achieved
distance; but second class guns like field "cannon," with less metal
and smaller charges, ranged about 1,600 yards at a maximum, while the
effective range was hardly more than 500. Heavier pieces, such as the
French 33-pounder battering cannon, might have a point-blank range of
720 yards; at 200-yard range its ball would penetrate from 12 to 24
feet of earthwork, depending on how "poor and hungry" the earth was.
At 130 yards a Dutch 48-pounder cannon put a ball 20 feet into a
strong earth rampart, while from 100 yards a 24-pounder siege cannon
would bury the ball 12 feet.
But generalizations on early cannon are difficult, for it is not easy
to find two "mathematicians" of the old days whose ordnance lists
agree. Spanish guns of the late 1500's do, however, appear to be
larger in caliber than pieces of similar name in other countries, as
is shown by comparing the culverins: the smallest Spanish _culebrina_
was a 20-pounder, but the French great _coulevrine_ of 1551 was a
15-pounder and the typical English culverin of that century was an
18-pounder. Furthermore, midway of the 1500's, Henry II greatly
simplified French ordnance by holding his artillery down to the
33-pounder cannon, 15-pounder great culverin, 7-1/2-pounder bastard
culverin, 2-pounder small culverin, a 1-pounder falcon, and a
1/2-pounder falconet. Therefore, any list like the one following must
have its faults:
_Principal English guns of the sixteenth century_
Caliber Length Weight Weight Powder
(inches) of gun of shot charge
Ft. In. (pounds) (pounds) (pounds)
Rabinet 1.0 300 0.3 0.18
Serpentine 1.5 400 .5 .3
Falconet 2.0 3 9 500 1.0 .4
Falcon 2.5 6 0 680 2.0 1.2
Minion 3.5 6 6 1,050 5.2 3
Saker 3.65 6 11 1,400 6 4
Culverin bastard 4.56 8 6 3,000 11 5.7
Demiculverin 4.0 3,400 8 6
Basilisk 5.0 4,000 14 9
Culverin 5.2 10 11 4,840 18 12
Pedrero 6.0 3,800 26 14
Demicannon 6.4 11 0 4,000 32 18
Bastard cannon 7.0 4,500 42 20
Cannon serpentine 7.0 5,500 42 25
Cannon 8.0 6,000 60 27
Cannon royal 8.54 8 6 8,000 74 30
Like many gun names, the word "culverin" has a metaphorical meaning.
It derives from the Latin _colubra_ (snake). Similarly, the light gun
called _áspide_ or aspic, meaning "asp-like," was named after the
venomous asp. But these digressions should not obscure the fact that
both culverins and demiculverins were highly esteemed on account of
their range and the effectiveness of fire. They were used for
precision shooting such as building demolition, and an expert gunner
could cut out a section of stone wall with these guns in short order.
As the fierce falcon hawk gave its name to the falcon and falconet, so
the saker was named for the saker hawk; rabinet, meaning "rooster,"
was therefore a suitable name for the falcon's small-bore cousin. The
9-pounder saker served well in any military enterprise, and the
_moyana_ (or the French _moyenne_, "middle-sized"), being a shorter
gun of saker caliber, was a good naval piece. The most powerful of the
smaller pieces, however, was the _pasavolante_, distinguishable by its
great length. It was between 40 and 44 calibers long! In addition, it
had thicker walls than any other small caliber gun, and the
combination of length and weight permitted an unusually heavy
charge--as much powder as the ball weighed. A 6-pound lead ball was
what the typical _pasavolante_ fired; another gun of the same caliber
firing an iron ball would be a 4-pounder. The point-blank range of
this Spanish gun was a football field's length farther than either the
falcon or demisaker.
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 _drajón_, 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 cañon 9 to 12 Quarter-cannon.
Tercio cañon 16 Third-cannon.
Medio cañon 24 Demicannon.
Cañon de abatir 32 Siege cannon.
Doble cañon 48 Double cannon.
Cañon de batería 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
Cañon sencillo (light cannon) 6 4-1/2 2-1/2
Cañon común (common cannon) 7 5 3-1/2
Cañon 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 _cañon 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.