Sulun dutifully thought about that, thought of the water poured down the funnel, through the trapdoor valve, into the heated brass tube above the brazier, then through the hollowed—and moving—ball-and-socket joint, then into the spinning chamber. What weakness? Where?
The heating tube? Too little water, too little steam, and the -jetted chamber wouldn't spin. Too much water would cool the tube, make too little steam, and again the chamber wouldn't spin. Fill the brazier too scantily and you'd have not enough heat; again, no steam, no spinning. Fill it too full, let the flames or even the coals overlap the tube . . .
"The tube might soften, melt, warp," he admitted, "but that would require so much heat, so much wood—"
"Believe me, if it can be done wrong, some fool sailor will do it. It will not be Natural Philosophers who use this engine at sea."
"True, true . . ." Sulun studied the assembly for a long moment, then abruptly smiled. There was indeed one simple way to keep some fool of a sailor from overloading the brazier. He reached for the metal snips.
"What are you doing with the brazier?" Yanados asked, peeping over his shoulder.
"Making it smaller and shorter," Sulun smiled, plying the heavy shears.
Snip, snip, snip—and the brazier's legs were shortened. Snap, snap, snap—and the bowl of the brazier lost its original rim. Sulun carefully tucked the little model back to its place in the assembly. He scratched some notes on a nearby tablet.
"What would that do?" Yanados asked.
"Small brazier, small fire," Sulun explained. "Load the brazier full as you can, the coals still won't reach the tube and melt it. Hmmm, it wouldn't hurt to make the tube thicker, too. . . ." He scribbled more notes.
"Just be certain no fool can work it wrong," said Yanados, padding toward the door.
Not until after she was gone did Sulun think to wonder how she knew so much about the habits and failings of sailors.
The moon wore away her horns, and nothing improved. Morning reports with Entori grew ever more difficult and unpredictable; his shipping interests did marvelously well on the short Sabis-Mez run, carrying refugees south and food north, but elsewhere on the Inland Sea the trade was dangerous and the old man's temper likewise. Always he exhorted Sulun to hurry with the engine.
At least, Sulun told himself after leaving the master's study in a shower of abuse, the engine model was finished. It worked after a fashion; the tiny valves clearly weren't very efficient, but the rotating platform and gears managed well enough. No sense putting it off; he should begin making the full-sized engine for Entori's ship, as he'd promised.
That meant that Omis would have to put aside work on the bombard to cast and shape the brass fittings for the engine.
"Ah, well," Sulun consoled himself as he entered the courtyard, "It shouldn't take more than a day or two. . . ."
He noticed, as he walked past the end of the morning-report line, that one of the maids was missing.
"Ran away," snorted the housekeeper, when asked. "That lazy slut must have had a better offer from some uphill house. Didn't leave word, either; just out the door and gone."
"Went out shopping yesterday," the porter said, "and never came back."
Sulun left them arguing and went off to see Omis, but the permanent unease in the back of his mind grew another degree thicker. It would be wise, he decided, to start moving as much gear as possible to the river workshop. Starting today.
"The heat's awful," Doshi grumbled, slapping the reins irritably across the lagging mules' rumps. "Only fools go hauling loads about at noon."
"Only fools go out without guards at any other time," Arizun snapped, casting a quick look around the almost empty street. "You haven't seen much of the city since the bad times came, have you?"
"Oh, I know there are more thieves and beggars about, but good gods, there are three of us. And we're armed." Doshi tapped his toes on the hatchet hidden under the carts seat. "And we're not on foot. No need for this."
"Wagoners have been robbed before, and you should keep that closer to hand." Arizun tapped the bulge at his belt under his light cloak. "And three of us wouldn't be enough against a good-sized gang."
"Keep your voices soft," Yanados warned from her perch at the back of the cart. "Don't draw any more attention than we must."
"You've both gone mad with suspicion," Doshi scoffed, in a near whisper. "That or gone silly for the ungodly fun of carrying weapons about. I swear, you're turning barbarous yourselves. Nobody goes armed unless they're looking for trouble—"
"Or expecting it to look for them," Arizun growled. "Keep your eyes on the street, fool."
"Be careful who you call a fool," Doshi muttered, steering the mule team around a corner. "You haven't read half the books—now, what's this mess?"
Several buildings down, the street was half blocked with a tumble of broken furniture and assorted garbage. A man on foot could have passed it, but the mule cart would have considerable trouble.
Arizun saw it, gasped, seized the reins from Doshi, and yanked the mules to a hoof-clattering halt. "Back up!" he hissed. "Back the way we came, fast!"
"What—"
"Damnation!" Yanados yelled, making them both turn and look, as she yanked her hatchet free.
Behind them, perhaps half a dozen ragged bravos—some of them quite young, a few older men—slid out of the doorways to block the street. They carried assorted bludgeons and short knives. They stalked toward the halted cart, smiling grimly, not even bothering to give the traditional stand-and-deliver challenge.
"Back up!" Arizun repeated, shoving the reins at Doshi. Then he scrambled into the back of the cart and fumbled at something under the sacks.
Yanados hissed through her teeth, crouched at the cart's tail, and swung her hatchet in a slow, warning arc. The approaching gang slowed and spread out, still smiling.
Doshi might have argued about backing into a fight, but just then his eye caught motion near the trash pile ahead. Three more club-wielding boys were slinking out of cover, coming toward the mules. Doshi gulped; wasted a precious second fumbling for the hatchet under the seat, and began hauling furiously on the mules' reins. The mules, finally understanding that there was danger ahead, squealed and backed. The toughs ahead moved faster, starting to run.
The six thugs behind the cart stopped where they were, crouched, waiting for the prey to come to them, waited to jump for the tailgate.
Yanados reached out and swung at the nearest, making him hop backward. He recovered and tried to lunge in under her arm, but she caught him backhand on the return stroke. The back of the hatchet head thwacked meanly against his head, dropping him to the ground with a shocked yell and a sudden spurt of bright blood.
The other toughs yelled in outrage, and charged the cart.
Right then, Arizun came up from the cart bed with a short bow in one hand and an arrow in the other. He loaded, snap-aimed, and fired past Yanados, catching one of the boys high in the chest. The boy screeched, dropped his club and knife, stumbled to his knees, and began tugging at the arrow. The others skidded to a stop, unwilling to face arrows. Yanados whooped and swung her hatchet at the nearest, making him dance away.
The thugs ahead of the wagon ran toward the mules, the nearest reaching for the bridles. Doshi, guessing what they meant to do, hauled furiously on the reins, shouting incoherently at the mules. The frightened beasts reared, braying, flailing the air with their hooves, making the attackers scramble out of the way. Doshi used the instant's respite to clutch the reins in one hand and fumble under the seat for the cart-whip with the other.