An Oblique Approach by David Drake and Eric Flint

Finally—finally!—true success. The facets flashed their exultation. aim itself broke into kaleidoscopic joy.

The knowledge which now erupted in the mind of the general Belisarius was no crude, simple thought. Instead, it was like a living diagram, a moving reality. He saw, as clearly as anything in his life, the way of the rockets. He saw the strange powder [gunpowder, he now knew] packed in the length of the rocket; the same powder, in greater quantities, which was packed in the front tip [warhead] of the device. He saw the gunpowder ignited by a long match held by a kshatriya warrior. He saw the powder erupt into flame, and saw how the flame burned. (And knew that the vision was moving at an inhuman pace, slowed by the jewel that he might follow the course of it.)

He saw the flame burn its way up, inside the length of the bamboo tube [fuselage]. He saw the raging gasses which were expelled from the rocket’s rear [exhaust], and knew the fury of the gasses was the force which drove the device into motion.

(A concept—action/reaction—flashed through his mind. He almost understood it, but was not concerned; soon, soon, he would.)

Watching, in his mind’s eye, the course of the flame burning its way through the gunpowder, Belisarius now understood the reason for the rocket’s erratic trajectory.

Part of it, he saw, was that the gunpowder was poorly mixed. (And he knew, now, that gunpowder was not a substance itself, but a combination of substances.) The powder was uneven and lumpy, like poorly threshed grain. Different pockets and sections of the powder burned unevenly, which produced a ragged and unpredictable exhaust.

Most of the problem, though, was that the rear opening through which the exhaust poured [venturi—but the thought was saturated with scorn] was itself poorly made. In fact, it wasn’t “made” at all. The venturi was nothing more than a ring of wood. The Indians simply cut the bamboo after one of the joints in the wood, and used the joint itself as the nozzle which concentrated and aimed the exhaust gasses. But the hole was ragged to begin with, no better than a crude carving; Belisarius could actually see in his mind the way in which the hot exhaust burned out the wood in its expulsion.

The companions of Belisarius feared for his sanity, then. The first pirates were even now clambering their way aboard the ship—and here was their general, their leader, cavorting about like a madman and raving lunatic nonsense about Greek and Armenian metalsmiths and the cunning of their craft. He was even cackling about the Emperor’s throne, and his roaring lions, and his birds!

But, they were relieved to see, the madness passed as soon as the first Arab head appeared above the rail. Belisarius removed the head with a sweep of his sword which was so quick, and so sure, and so certain, and so graceful, that none who saw doubted he was a man possessed.

” ‘Deadly with a blade, is Belisarius,’ ” muttered Valentinian. “But that’s ridiculous.”

“Stop bitching,” growled Anastasius. He brought his mace down upon another pirate head. And if there was little grace in the act, and not much in the way of quickness, the result was no less sure and certain.

Arabs now began pouring over the rails, port and starboard, all along the ship. There was a frenzied determination in that surge, far beyond battle-lust and greed. The surge was born of pure desperation. There were far too few galleys left intact, now, to bear the pirates safely back to shore. They must either conquer the great Indian vessel, or die.

The kshatriyas fled the rocket troughs and sheltered behind the Ye-tai. There, the kshatriyas formed a defensive ring around Venandakatra and the cluster of priests standing at the foot of the mainmast. But it was obvious that the lightly armed Malwa warriors, their rockets out of action, were nothing but a feeble last guard. The real defense of the ship now lay in the hands of the Ye-tai. The barbarians were not slow to deride the kshatriyas for their unmanliness.

But the derision was short-lived. Within seconds, the Ye-tai were too hard-pressed by the wave of pirates swarming aboard the ship to concern themselves with anything but survival.