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."