Part 4

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.

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.

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.

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 Müller, the master gunner of Woolwich. In 1756, Müller raised the trunnions to the _center_ of the bore, an improvement that greatly lessened the strain on the gun carriage.

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 Müller wondered about such inconsistencies and set out to devise a new system of ordnance for England.

Like many men before him, Müller 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. Müller'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, Müller 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, Müller 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 Müller'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 Müller's lists of 1756; the "old" ordnance includes cannon still in use during Müller's time, while the "new" ordnance is Müller'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.