“Listen to me, all of you. I may not survive this journey. Whatever happens, it is essential that at least one of us return to Rome with what we’ve learned, and get the information to Antonina and John of Rhodes.”
Valentinian began to make some little protest, but Belisarius waved him down.
“That’s stupid, Valentinian, and you know it better than anyone. A thousand things can kill you on the field of battle—or off it—and I’m no more immune to them than anyone. What is important is the information.”
He glanced again in the direction of the Rajputs, but the cavalrymen were still maintaining a polite distance.
“I’ve already explained to you how the cannons work,” he said. He cocked an eye at Menander. The young Thracian immediately recited the formula for gunpowder and the complex series of steps by which it was properly prepared. His words had the singsong character of one repeating oft-memorized data.
Belisarius nodded. “It’s the wetting and the grinding that’s key. Remember that.” He made a small nodding gesture toward the distant cannons. “The Malwa gunpowder is really pretty poor stuff, compared to what’s possible. And so is their metalworking.”
Examining one of the cannons, he sat slightly straighter in his saddle.
“Watch,” he commanded. “They’re about to fire. Watch the trajectory of the cannonball.”
Menander and the other two cataphracts followed his gaze. A moment later, they saw one of the Malwa soldiers take a long iron bar out of a small forge. The bar was bent ninety degrees at the tip, and the protruding two inches glowed red from heat. Gingerly, he inserted the firing bar into a small hole in the breach of the cannon. The mouth of the cannon belched a huge cloud of smoke, followed almost instantly by the roaring sound of the blast.
The recoil jerked the cannon back into its cradle. Menander saw the gunner lose his grip on the firing bar. The bar was spun against another of the Malwa soldiers, who backed up hastily, frantic to avoid the still-glowing tip. Menander did not envy the Malwa gunners. Theirs was a risky task. Two days earlier, he had seen a recoiling cannon shatter its cradle and crush one of its gunners.
Menander and the other Romans followed the cannonball’s trajectory all the way to its impact against the great wall of Ranapur. Even from the distance, they could see the wall shiver, and pieces of brickwork splinter and fall to the ground.
Belisarius glanced at his companions. All of them were frowning—the veterans with simple puzzlement, but Menander with concentration.
“It didn’t fly straight,” announced the young cataphract. “It shot off at an angle. It should have hit the wall fifteen or twenty feet to the east.”
“Exactly,” said Belisarius with satisfaction. “If you watch carefully, and keep track, you’ll eventually notice that the cannonfire is very erratic. Occasionally they shoot straight. But more often the ball will sail off at an angle—and the elevation’s just as haphazard.”
“Why?” asked Menander.
“It’s the clearance,” replied the general. “What’s called windage. In order for a cannon to shoot straight, the ball has to fit snugly in the bore. That requires two things—an even, precise bore all the way through the cannon barrel, and cannonballs that are sized to match.”
Anastasius puffed out his cheeks. “That’s a tall order, general. Even for Greek artisans.”
Belisarius nodded. “Yes, it is. But the better the fit, the better the fire. The Malwa don’t even make the attempt. Those cannonballs aren’t much more than crude stones—they’d do better to use iron—and the cannon barrels are simply castings. They’re not machined at all. Even the casting process, I suspect, is pretty crude.”
Valentinian scowled. “How would you machine something that big in the first place?” he demanded. “Especially metal.”
Belisarius smiled. “I wouldn’t even try, Valentinian. For cannons the size of these, sloppy accuracy isn’t really that much of a problem. But let’s examine the question from a different angle. How hard would it be to machine a very small cannon?”
“Very hard,” said Anastasius instantly. His father was a blacksmith, and had put his boy to work at an early age. “Any kind of machining is difficult, even with wood. Almost nobody tries to do it with metal. But—yes, if it was small enough—”