by William Weir
Early Chinese writing records the use of what could only be gunpowder.
Why was there so much doubt about the Chinese?
Besides an enormous ethnic bias on the part of many Westerners, it seems the Chinese did not consider gunpowder a particularly important weapon. From about 1000 A.D. it had been mostly used for firecrackers. Martin van Creveld, in his Technology and War, points out that in the 12th century, the Chinese were using crude hand grenades. These were paper and bamboo tubes filled with gunpowder and pebbles or bits of broken porcelain. After another century, they had bamboo guns (devices like the bamboo grenades, but open at one end). Though, like the rockets and ceramic bombs the Mongols brought to Japan, none of these weapons were considered serious weapons. The gunpowder was weak, and so were the shells in which it was exploded. The bombs and rockets were mostly useful in scaring horses — or troops like the Japanese who had no experience with gunpowder.
Lieutenant Colonel H.W. Hine concluded, after much study, that the Oriental gunpowder used unrefined potassium nitrate, which made it impossible to get a powerful explosion.
The first written directions for refining potassium nitrate are in Roger Bacon’s letter to the Bishop of Paris. There was great interest in the process in Europe but little anywhere else. Warriors in medieval China ranked just above thieves in popular esteem. Nobody in power felt any need to develop more potent powder. The Mongols’ scientific tradition was non-existent. Besides, they were sure they had the ultimate weapon: the horse archer. And, until after guns had developed for several centuries, the Mongols were right. The Arabs and Turks also had complete faith in the supremacy of the horse archer.
In western Europe, however, the desire for better weapons was keen. The Crusades had demonstrated to the Europeans that they could not compete with horse archers on the open steppes. Nor, in their damp, forested homeland, could they develop effective horse archers of their own. But there was a continuous search for better weapons among warriors who never dreamed of leaving their homeland. Europe was a quarreling mass of dukedoms, principalities, and city-states. It was inhabited by armed nobles, armed townsmen, and armed mercenaries, all of whom were trying to find some weapon that would trump everyone else’s. Consequently, Europe developed the first effective guns. The Chinese learned to improve their guns only after they’d examined European models.
Japan, voluntarily cut off from the rest of the world, ignored guns completely until the 16th century. Then, for a short time, Japan had more handguns — but little artillery — than anywhere else in the world. Guns, however, let a low-born peasant who couldn’t even recognize a good sword kill any samurai master of swordsmanship. Therefore the samurai, who controlled Japan, stopped all development and most manufacturing of guns.
Europeans, on the other hand, not only adopted gunpowder, they continued to improve it. They increased the proportion of potassium nitrate to make a more powerful explosive. Then, because the three components of the mixture tended to separate, they mixed them wet and formed them into “corns,” which could not separate. Near the end of the gunpowder era, they molded the “corns”
into various sizes depending on the size and mission of the gun. Some were made with a hole through them to produce a powder than gave consistent gas pressure. As the outside of a corn burned, the surface decreased, causing pressure to drop. But as the inside of hole in the corn burned, the surface increased, producing more gas and raising the pressure. All this “burning,” of course, happened in about 1/100,000 of the blink of an eye.
Guns were not the only use of gunpowder. One use gave new life to one of the earliest techniques of siege craft.
Chapter 11
Digging Down and Blowing Up: Mines
Marine Corps photo from National Archives
Blowing up enemy fortifications is still being done. Here marines use a demolition charge to destroy a Japanese cave on Okinawa.
U.S. Grant’s Union armies were closing in on Richmond, capital of the Confederacy in 1864. Robert E. Lee’s men dug an elaborate system of trenches, bunkers, and strong points north of the city, so Grant tried to attack from the south while he held the Confederates in place north of Richmond. But Lee had begun fortifying the southern approach, around Petersburg, before the Yankee move. The Confederate fortifications were immensely strong around Petersburg. At one point, the troops of General Ambrose Burnside’s Ninth Corps were only 150 yards from an enemy salient protected by a mass of trenches and dugouts on a hill top. Confederate fire from the fort was so heavy there was no way to move forward.
“We could blow that damn fort out of existence if we could run a mine shaft under it,” said a soldier of the Forty-Eighth Pennsylvania Infantry. The forty-eighth, recruited in the anthracite district of Pennsylvania, was full of coal miners. Colonel Henry Pleasants, the regimental commander, overheard the soldier’s comment. Pleasants himself was a mining engineer in civilian life. He asked the army engineers about mining the fort. Mining enemy fortifications is an ancient tactic, one that was practiced long before explosives were discovered. The pre-explosive method was to tunnel under a fort’s walls, propping them up with timber as you dug. When the mine was completed, the besieger set fire to the timber, and the wall collapsed. But when Pleasants consulted the army engineers, they said the project was impossible. The tunnel would have to be 500 feet long — too long to allow for ventilation.
Pleasants was not discouraged. He convinced his superiors, right up to General George G. Meade, commander of the Army of the Potomac, that the project was feasible. Meade convinced Grant, the commander-in-chief. Grant gave Burnside’s Ninth Corps the job of blowing up the fort and opening the way to Petersburg. Burnside was delighted. Breaching the rebel line would make up for his bloody failure in the attack on Fredericksburg in 1862. He began training his only fresh troops, the eight African American regiments of the Fourth Division. When the mine went off, he expected that it would kill most of the enemy soldiers in the fort and stupify the survivors in the nearby trenches. The assault force was to run around the crater caused by the explosion and continue straight on into Petersburg. The troops following them would widen the breach, prevent the Confederates from closing it by blocking reserves, and follow the Fourth Division into the rebel city.
Meanwhile, Pleasants’s miners were tunneling toward the Confederate fort.
They got no help from the official engineers, so they improvised their own tools and scrounged up lumber to reinforce the shaft. Pleasants, using a borrowed the odolite (an instrument for measuring vertical and usually also horizontal angles), plotted the shaft and designed a ventilation system using a fire to create a draft and suck fresh air through the 511-foot tunnel. When they reached a point they calculated was under the Confederate position, the miners dug lateral shafts and filled them with 8,000 pounds of gunpowder.
The stage was set for an explosion that would be heard around the world.
Then at almost the last minute, Meade changed the plan. He decided that Burnside’s black troops were not up to leading the assault. Instead of the black division, the assault would be spearheaded by the division led by James H. Ledlie, a general with a mediocre combat record and serious drinking problem.
Ledlie’s troops had not been trained this unusual type of assault. The black Fourth Division would be the last of Burnside’s men to enter the breach.
The mine exploded with a deafening blast. The Confederate strongpoint was replaced by a hole 170 feet long, 60 feet wide and 30 feet deep. A battery of Confederate artillery and a whole infantry regiment were either blown into the air or buried under tons of dirt. Ledlie’s untrained riflemen dashed towards the crater while their commander stayed in his headquarters swilling rum. When the Union soldiers got to the crater, they stopped and stared, dumbfounded by the destruction. Some even ran down into the hole; Climbing out of it was not easy, they found. The other divisions, equally untrained, joined Ledlie’s in mill-ing around — and inside — the crater. The black division, the
only one trained to exploit the explosion, had trouble getting through the mob of white colleagues.
By that time, the Confederates had had time to gather their reserves and counterattack. The Union attack was a failure, and the Federal troops were driven back with heavy casualties.
Mining, which had been so devastating against ancient, medieval, and early modern stone forts, has not had nearly as much success against modern earthworks. It was tried again in World War I, opening the Battle of the Somme (see Chapter 27). In preparation for the attack on the German lines, British engineers had mined a German strongpoint called the Hawthorn Redoubt and placed 18 tons of high explosive under it. At 7:20 a.m., 10 minutes before the attack, they touched off the explosives. The blast practically leveled the hill and killed all the Germans manning the redoubt. It did not, however, affect the machine guns in the adjoining German positions. The infantry assault was a total failure. Few of the Tommies even reached the German lines, and the British lost 20,000 dead on that first day of the battle. Mining would have been more successful in the smoothbore era, when the range of small arms was less than 1/10 of that of rifled guns.
The origin of mines is lost in the mists of prehistory. There were two principal defenses against mines in those days. One, known to all fanciers of medieval castles, was the wet moat. At the time primitive mines were being used, there was no way to dig under a body of water while preventing the water from pouring down from the moat through the earth and filling the tunnel, if it didn’t collapse the tunnel outright.
The second defense was the countermine. To locate enemy mines, the defenders would listen intently, sometimes using inverted shields placed on the ground to amplify the noise. When the Turks were besieging Constantinople in 1553, Johann Grant, a German engineer helping to lead the defense, half-buried a line of drums just behind the city walls. He put some dried peas on each drum.
Vibrations of the drum made the peas dance and showed Grant where the Turks were digging. Grant then had his own men mine the Turkish mines. Some, he blew up with gunpowder; others, he filled with poisonous sulfur dioxide generated by burning sulfur; still others, he flooded. If nothing else was available, Grant sent infantry through his tunnel to the enemy tunnel, where they killed the Turkish diggers and pulled down the reinforcements of their tunnel, causing the enemy mine to collapse.
During the Turkish siege of Rhodes, the defenders, the Knights of St. John, reached into the past for an anti-mine weapon. They built a trebuchet (see Chapter 9) capable of shooting an enormous stone a short distance. The stone landed above the Turkish tunnel and collapsed it. The Knights also used countermines, as Suleiman the Magnificent recorded in his diary: “The miners meet the enemy, who uses a great quantity of flaming naphtha.” Pouring flaming naphtha from a countermine into a tunnel was an utterly devastating counterattack. The flames not only killed the miners, they burned the timber support of the tunnel, causing a cave-in.
Strangely, gunpowder had been in use in cannons for some time before it occurred to soldiers to use it in mines. For years, the approved technique was the age-old one of propping up the foundations of a wall with timber, and then burning the props. Even when gunpowder was first used, in the 15th century, historian Christopher Duffy says contemporary accounts indicate that it was merely used to help the underground fire burn more fiercely. The first use of gunpowder to blast down walls appears to have been in 1500, when Pedro Navarro captured a Turkish fortress on the island of Cephalonia.
The earliest mines were called mines because the same techniques were used that the men who burrowed into the earth in search of metals or other minerals used. When gunpowder was introduced, the military was again using a material that was also important in civilian mining, although the way it was used was quite different. Somehow, though, the military term “mine” came to be used for any quantity of explosives not used in guns, shells, or rockets that was used to harm an enemy, even if no tunneling was required. Explosive charges in the water, originally called “torpedoes,” became “mines.” Then, when explosives were placed on the surface of the ground or barely covered with earth, they were called “land mines,” as opposed to those intended to destroy shipping.
Chapter 12
The Walls Came Tumbling Down: Siege Guns
Soldiers in the early 19th century operate heavy siege mortars.
The Chinese first made guns of paper and bamboo, but neither substance could contain much pressure. That meant the gun could neither fire a very heavy missile or use a very heavy powder charge without bursting. And that meant that these paper and bamboo guns never became important weapons.
They were probably most useful for tossing light incendiary projectiles at inflammable targets. Even after they had metal cannons, the Japanese used them to shoot paper packages of oil-soaked gunpowder at the wooden superstruc-tures of samurai castles to burn them down.
Europeans, on the other hand, made their cannons of metal from the beginning. By the 13th century, when gunpowder became known in the West, Europe led the world in the technology of bronze casting. European bronze founders had learned the secrets of making large castings by decades of casting bells for Christian churches. Bronze was expensive, so some European gunmakers used iron instead. There were no European blast furnaces at that time, so the first iron cannons could not be cast. Instead, the gunmaker welded a large number of wrought iron rods together around a mandrel, then bound them together with iron hoops, heated red-hot and forced over the cylinder of welded rods. As the hoops cooled, they shrank and bound the rods tightly. The whole process resembled the manufacture of a barrel, which is why we now call the tube of a gun that the projectile passes through a barrel.
The early iron guns, having been welded around a cylindrical mandrel, were straight tubes. The bronze guns, however, were shaped on the outside like a flower vase, but the interior was cylindrical. The founders apparently wanted to put more metal around the part of the gun where the powder exploded. These earliest cannons fired balls of stone, lead, or brass and heavy, arrow-shaped projectiles. The earliest picture of a cannon we have is on a manuscript prepared by Walter de Milemete for his pupil, the future King Edward III of England. It shows one of these vase-shaped cannons being ignited by a man in armor. Emerging from the mouth of the cannon is a large arrow.
When he grew up, Edward III took three primitive cannons with him to France and used them at the battlefield of Crecy. These novel weapons may have helped panic the mercenary Genoese crossbowmen in the French army.
On the battlefield, the most potent feature of these early cannons was the flash and noise they made. They could scare horses and troops unfamiliar with gunpowder weapons. But for actual destruction, one of these small, primitive cannons didn’t compare with a good bow or crossbow.
That was not true when they were used for sieges. For sieges, medieval kings ordered enormous guns that shot stone balls weighing hundreds of pounds.
Some of these guns were so heavy they were cast in two pieces to make them easier to move. The halves were screwed together after they were dragged into position. When Mohammed the Conqueror, sultan of Turkey, laid siege to Constantinople, he told his gun founder, a renegade Hungarian named Urban, that he wanted the biggest guns ever seen. Urban told him it would be easier to cast the guns right in front of Constantinople than to move them from a foundry.
So they were cast just out of range of the defenders’ weapons.
Once they were in position, these huge cannons, called bombards, were completely immobile. They were enclosed in wooden frames that had been constructed around them. Immobility didn’t matter. The task of the gunners to was to shoot one huge cannonball after another at the same spot on a wall. It did not take long for the wall to collapse. That was an effect that could seldom be achieved with mechanical artillery.
The introduction of siege guns had a profound effect on the techniques of warfare, and an even more profound effect on European society in general.
Designers of fo
rtresses made the walls lower and thicker. They learned that while stone walls would shatter when hit by cannon balls, earth walls would just soak up the missiles. Earth walls, though, could be eroded by weather. Eventually, military engineers built earthen walls faced by stone and reinforced internally so that, if a breach was made in the stone, the dirt wouldn’t pour through the break, making a convenient ramp for attackers. The engineers surrounded their forts with deep, wide ditches. Outside these ditches were sloping embank-ments that hid all but the tops of the walls. This sort of embankment, called a glacis, was kept free of any vegetation but grass, so attacking infantry would have no cover. Just behind the top of the glacis, was a path called a covered way from which infantry could fire on attackers making their way up the glacis.
There were wide spots on the covered way where the defenders of a fort could assemble for counterattacks. At the corners of the forts, the engineers built arrowhead-shaped projections called bastions, where cannons could be placed to subject attackers to crossfire while the guns on the wall fired on them directly. On the flanks of the bastions, protected from fire from the front, were other cannons that could fire down the length of the ditch. In front of the fort proper, but within the ditch, were detached forts connected to the main fortress with draw bridges or tunnels. This type of cannon-fort took years or even centuries to develop. Most of the early development took place in Italy, where such “renaissance men” as Michelangelo added innovations that made European fortresses by far the strongest in the world.
