Modern Use of Black Powder
Aside from gradual improvement in the formula, no great change in powder making came until 1860, when Gen. Thomas J. Rodman of the U. S. Ordnance Department began to tailor the powder to the caliber of the gun. The action of ordinary cannon powder was too sudden. The whole charge was consumed before the projectile had fairly started on its way, and the strain on the gun was terrific. Rodman compressed powder into disks that fitted the bore of the gun. The disks were an inch or two thick, and pierced with holes. With this arrangement, a minimum of powder surface was exposed at the beginning of combustion, but as the fire ate the holes larger (compare fig. 20f), the burning area actually increased, producing a greater volume of gas as the projectile moved forward. Rodman thus laid the foundation for the “progressive burning” pellets of modern powders (fig. 20).
For a number of reasons General Rodman did not take his “perforated cake cartridge” beyond the experimental stage, and his “Mammoth” powder, such a familiar item in the powder magazines of the latter 1800’s, was a compromise. As a block of wood burns steadier and longer than a quick-blazing pile of twigs, so the 3/4-inch grains of mammoth powder gave a “softer” explosion, but one with more “push” and more uniform pressure along the bore of the gun.
It was in the second year of the Civil War that Alfred Nobel started the manufacture of nitroglycerin explosives in Europe. Smokeless powders came into use, the explosive properties of picric acid were discovered, and melanite, ballistite, and cordite appeared in the last quarter of the century, so that by 1890 nitrocellulose and nitroglycerin-base powders had generally replaced black powder as a propellant.
Still, black powder had many important uses. Its sensitivity to flame, high rate of combustion, and high temperature of explosion made it a very suitable igniter or “booster,” to insure the complete ignition of the propellant. Further, it was the main element in such modern projectile fuzes as the ring fuze of the U. S. Field Artillery, which was long standard for bursts shorter than 25 seconds. This fuze was in the nose of the shell and consisted essentially of a plunger, primer, and rings grooved to hold a 9-inch train of compressed black powder. To set the fuze, the fuze man merely turned a movable ring to the proper time mark. Turning the zero mark toward the channel leading to the shell’s bursting charge shortened the burning distance of the train, while turning zero away from the channel, of course, did the opposite. When the projectile left the gun, the shock made the plunger ignite the primer (compare fig. 42e) and fire the powder train, which then burned for the set time before reaching the shell charge. It was a technical improvement over the tubular sheet-iron fuze of the Venetians, but the principle was about the same.
The Early Smoothbore Cannon
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.”
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.
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.
| Name of gun | Weight of ball (pounds) | Length of gun (in calibers) | Range in yards | Popular caliber | |
|---|---|---|---|---|---|
| Point-blank | Maximum | ||||
| 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 saker | 9-pounder 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, 40, 50 | 30 to 32 | 1,742 | 6,666 | 24-pounder culverin. |
| 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:
| Caliber (inches) | Length | Weight of gun (pounds) | Weight of shot (pounds) | Powder charge (pounds) | ||
|---|---|---|---|---|---|---|
| Ft. | In. | |||||
| 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.
| Spanish name | Weight of ball (pounds) | Translation |
|---|---|---|
| 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 | 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.
| Spanish Guns | Thickness of bore wall in 8ths of the caliber | 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.