Thomas blushed. "How childish of me," he said.

"Never mind," said Josef. He stood up. "Weren't you playing with Papa's old things just now, his medical-school things?"

"Right here," Thomas said. He threw himself on the floor and rolled under the bed. A moment later, a small wooden crate emerged, covered in dust-furred spider silk, its lid hinged on crooked loops of wire.

Josef knelt and lifted the lid, revealing odd bits of apparatus and scientific supplies that had survived their father's medical education. Adrift in a surf of ancient excelsior were a broken Erlenmeyer flask, a glass pear-shaped tube with a penny-head stopper, a pair of crucible tongs, the leather-clad box that contained the remains of a portable Zeiss microscope (long since rendered inoperable by Josef, who had once attempted to use it to get a better look at Pola Negri's loins in a blurry bathing photo torn from a newspaper), and a few odd items.

"Thomas?"

"It's nice under here. I'm not a claustrophobe. I could stay under here for weeks."

"Wasn't there…" Josef dug deep into the rustling pile of shavings. "Didn't we used to have-"

"What?" Thomas slid out from under the bed.

Josef held up a long, glinting glass wand and brandished it as Kornblum himself might have done. "A thermometer," he said.

"What for? Whose temperature are you going to take?"

"The river's," Josef said.

At four o'clock on the morning of Friday, September 27, 1935, the temperature of the water of the River Moldau, black as a church bell and ringing against the stone embankment at the north end of Kampa Island, stood at 22.2° on the Celsius scale. The night was moonless, and a fog lay over the river like an arras drawn across by a conjuror's hand. A sharp wind rattled the seedpods in the bare limbs of the island's acacias. The Kavalier brothers had come prepared for cold weather. Josef had dressed them in wool from head to toe, with two pairs of socks each. In the pack he wore on his back, he carried a piece of rope, a strand of chain, the thermometer, half a veal sausage, a padlock, and a change of clothes with two extra pairs of socks for himself. He also carried a portable oil brazier, borrowed from a school friend whose family went in for alpinism. Although he did not plan to spend much time in the water-no longer, he calculated, than a minute and twenty-seven seconds-he had been practicing in a bathtub filled with cold water, and he knew that, even in the steam-heated comfort of the bathroom at home, it took several minutes to rid oneself of the chill.

In all his life, Thomas Kavalier had never been up so early. He had never seen the streets of Prague so empty, the housefronts so sunken in gloom, like a row of lanterns with the wicks snuffed. The corners he knew, the shops, the carved lions on a balustrade he passed daily on his way to school, looked strange and momentous. Light spread in a feeble vapor from the streetlamps, and the corners were flooded in shadow. He kept imagining that he would turn around and see their father chasing after them in his dressing gown and slippers. Josef walked quickly, and Thomas had to hurry to keep up with him. Cold air burned his cheeks. They stopped several times, for reasons that were never clear to Thomas, to lurk in a doorway, or shelter behind the swelling fender of a parked Skoda. They passed the open side door of a bakery, and Thomas was briefly overwhelmed by whiteness: a tiled white wall, a pale man dressed all in white, a cloud of flour roiling over a shining white mountain of dough. To Thomas's astonishment, there were all manner of people about at this hour, tradesmen, cabdrivers, two drunken men singing, even a woman crossing the Charles Bridge in a long black coat, smoking and muttering to herself. And policemen. They were obliged to sneak past two en route to Kampa. Thomas was a contentedly law-abiding child, with fond feelings toward policemen. He was also afraid of them. His notion of prisons and jails had been keenly influenced by reading Dumas, and he had not the slightest doubt that little boys would, without compunction, be interred in them.

He began to be sorry to have come along. He wished he had never come up with the idea of having Josef prove his mettle to the members of the Hofzinser Club. It was not that he doubted his brother's ability. This never would have occurred to him. He was just afraid: of the night, the shadows, and the darkness, of policemen, his father's temper, spiders, robbers, drunks, ladies in overcoats, and especially, this morning, of the river, darker than anything else in Prague.

Josef, for his part, was afraid only of being stopped. Not caught; there could be nothing illegal, he reasoned, about tying yourself up and then trying to swim out of a laundry bag. He didn't imagine the police or his parents would look favorably on the idea-he supposed he might even be prosecuted for swimming in the river out of season-but he was not afraid of punishment. He just did not want anything to prevent him from practicing his escape. He was on a tight schedule. Yesterday he had mailed an invitation to the president of the Hofzinser Club:

The honored members of the Hofzinser Club

are cordially invited

to witness another astounding feat of autoliberation

by that prodigy of escapistry

CAVALIERI

at CharlesBridge

Sunday, 29 September 1935

at half past four in the morning.

He was pleased with the wording, but it left him only two more days to get ready. For the past two weeks, he had been picking locks with his hands immersed in a sinkful of cold water, and wriggling free of hisropes and loosing his chains in the bathtub. Tonight he would try the "feat of autoliberation" from the shore of Kampa. Then, two days later, if all went well, he would have Thomas push him over the railing of the Charles Bridge. He had absolutely no doubt that he would be able to pull off the trick. Holding his breath for a minute and a half posed no difficulty for him. Thanks to Kornblum's training, he could go for nearly twice that time without drawing a breath. Twenty-two degrees Celsius was colder than the water in the pipes at home, but again, he was not planning to stay in it for long. A razor blade, for cutting the laundry sack, was safely concealed between layers of the sole of his left shoe, and Kornblum's tension wrench and a miniature pick Josef had made from the wire bristle of a street sweeper's push broom were housed so comfortably in his cheeks that he was barely conscious of their presence. Such considerations as the impact of his head on the water or on one of the stone piers of the bridge, his paralyzing stage fright in front of that eminent audience, or helplessly sinking did not intrude upon his idee fixe.

"I'm ready," he said, handing the thermometer to his little brother. It was an icicle in Thomas's hand. "Let's get me into the bag."

He picked up the laundry sack they had pilfered from their housekeeper's closet, held it open, and stepped into the wide mouth of the bag as though into a pair of trousers. Then he took the length of chain Thomas offered him and wrapped it between and around his ankles several times before linking the ends with a heavy Ratsel he had bought from an ironmonger. Next he held out his wrists to Thomas, who, as he had been instructed, bound them together with the rope and tied it tightly in a hitch and a pair of square knots. Josef crouched, and Thomas cinched the sack over his head. "On Sunday we'll have you put chains and locks on the cord," Josef said, his voice muffled in a way that disturbed his brother.

"But then how will you get out?" The boy's hands trembled. He pulled his woolen gloves back on.

"They'll be just for effect. I'm not coming out that way." The bag suddenly ballooned, and Thomas took a step backward. Inside the sack, Josef was bent forward, reaching out with both arms extended, seeking the ground. The bag toppled over. "Oh!"