Cyril had lain down on the quay and was deep in slumber. “Come along, Cyril,” I said. “Professor? Tempus fugit!”

“Do you know how late it is?” Terence said, waving his pocket watch in front of my nose. “Drat! It’s nearly eleven.”

I sat down at the oars and put the carpetbag between my knees. “Don’t worry,” I said. “It’s all clear sailing from here.”

CHAPTER TEN

Amazingly, we did have clear sailing, or, rather, rowing. The river was smooth and empty, with a fresh breeze blowing across it. The sun glittered brightly on the water. I remembered my seat, kept my knees both open and closed, feathered, kept the trim, and pulled strongly, and by noon we were through Clifton Lock and could see the chalk cliff of Clifton Hampden with the church perched atop it.

The map called this stretch “the least picturesque on the Thames” and suggested we travel by rail to Goring to avoid it. Looking at the lush green meadows, crisscrossed with flowering hedges, the riverbanks lined with tall poplars, it was hard to imagine what the picturesque stretches would look like.

There were flowers everywhere — buttercups and Queen Anne’s lace and lavender lady’s smock in the meadows, lilies and blue flags growing along the banks, roses and ivy — leaved snapdragons in the lockhouse gardens. There were even flowers in the river. The waterlilies had pink cup-shaped blossoms, and the rushes were topped with nosegays of purple and white. Iridescent blue-green dragonflies darted between them, and monstrous butterflies flitted past the boat and came to rest momentarily on the overbalanced luggage, threatening to topple it over.

Off in the distance, a spire could be glimpsed rising above a clump of elm trees. The only thing lacking was a rainbow. No wonder the Victorians had waxed sentimental about nature.

Terence took the oars, and we rowed round a curve in the river, past a thatched cottage decked with morning glories and toward an arched bridge built of golden-tinted stone.

“Dreadful what’s been done to the river,” Terence said, gesturing at the bridge. “Railway bridges and embankment cuts and gasworks. They’ve completely spoilt the scenery.”

We passed under the bridge and round the curve. There were scarcely any boats on the river. We passed two men in a fishing punt, moored under a beech tree, and they waved at us and held up an enormous string of fish. I was grateful Professor Peddick was asleep. And Princess Arjumand.

I’d checked on her when Terence and I changed places, and she was still out cold. Curled up inside the carpetbag with her paws tucked under her furry chin, she didn’t look capable of altering history, let alone destroying the continuum. But then neither had David’s slingshot or Fleming’s moldy petri dish or the barrel full of jumble sale odds and ends Abraham Lincoln had bought for a dollar.

But in a chaotic system, anything from a cat to a cart to a cold could be significant, and every point was a crisis point. The barrel had held a complete edition of Blackstone’s Commentaries, which Lincoln could never have afforded to buy. They had made it possible for him to become a lawyer.

But a chaotic system has feedforward loops, too, and interference patterns and counterbalances, and the vast majority of actions cancel each other out. Most rainstorms don’t defeat armadas, most tips don’t cause revolutions, and most of the things one buys at a jumble sale don’t do anything but gather dust.

So the chances of the cat changing the course of history, even if she’d been missing four days, were infinitesimal, especially if we continued to make such excellent time.

“I say,” Terence said, unpacking the bread and cheese he’d bought for lunch in Abingdon, “if we’re able to keep this up, we should be able to make Day’s Lock by one,” he said. “There’s nobody on the river.”

Except for a single boat coming up the river toward us with three men in it, all in blazers and mustaches, and with a small dog perched on the bow, looking alertly ahead. As they drew nearer, their voices came to us clearly across the river.

“How much farther before it’s your turn, Jay?” the rower said to the one lying in the bow.

“You’ve only been rowing ten minutes, Harris,” the one in the bow said.

“Well, then, how far to the next lock?”

The third man, who was stouter than the other two, said, “When do we stop for tea?” and picked up a banjo.

The dog caught sight of our boat and began barking. “Stop that, Montmorency,” the bow-lier said. “Barking’s rude.”

“Terence!” I said, half-rising to my feet. “That boat!”

He glanced over his shoulder. “It won’t hit us. Just hold the lines steady.”

The banjo player strummed a few out-of-tune bars and began to sing.

“Oh, don’t sing, George,” rower and bow-lier said in unison.

“And don’t you get any ideas about singing either, Harris.” Jay added.

“Why not?” he said indignantly.

“Because you only think you can sing,” George said.

“Yes,” Jay said. “Remember ‘The Ruler of the Queen’s Navy’?”

“Diddle-diddle-diddle-diddle-diddle-diddle-dee,” George sang.

“It is them!” I said. “Terence, do you know who that is? It’s Three Men in a Boat, To Say Nothing of the Dog.”

“Dog?” Terence said contemptuously. “You call that a dog?” He looked fondly at Cyril, who was snoring in the bottom of the boat. “Cyril could swallow him in one bite.”

“You don’t understand,” I said. “It’s the Three Men in a Boat. The tin of pineapple and George’s banjo and the maze.”

“The maze?” Terence said blankly.

“Yes, you know, Harris went in the Hampton Court Maze with this map and all these people followed him and the map didn’t work and they got hopelessly lost and they had to call out for the keeper to come and get them out.”

I leaned out for a better look. There they were, Jerome K. Jerome and the two friends he had immortalized (to say nothing of the dog) on that historic trip up the Thames. They had no idea they were going to be famous a hundred and fifty years from now, that their adventures with the cheese and the steam launch and the swans would be read by countless generations.

“Watch your nose!” Terence said, and I said, “Exactly. I love that bit, where Jerome is going through the lock at Hampton Court and someone calls out, ‘Look at your nose!’ and he thinks they mean his nose and they mean the nose of the boat has gotten caught in the lock!”

“Ned!” Terence said, and the three men in the boat waved and shouted, and Jerome K. Jerome stood up and began gesturing with his outstretched arm.

I waved back. “Have a wonderful trip!” I called. “Watch out for swans!” and pitched over backward.

My feet went up in the air, the oars hit the water with a splash, and the luggage in the bow toppled over. Still on my back, I made a grab for the carpetbag and tried to sit up.

So did Professor Peddick. “What happened?” he said, blinking sleepily.

“Ned didn’t watch where he was going,” Terence said, grabbing for the Gladstone bag, and I saw that we had hit the bank head-on. Just like Jerome K. Jerome had done in Chapter Six.