Smaller plants huddled in shadows round the base of the bigger ones. Radnal knew seeds were scattered everywhere, waiting for the infrequent rains. But most of the ground was as barren as if the sea had disappeared yesterday, not five and a half million years before.

“I want all of you to drink plenty of water,” Radnal said. “In weather like this, you sweat more than you think. We’ve packed plenty aboard the donkeys, and we’ll replenish their carrying bladders tonight back at the lodge. Don’t be shy — heatstroke can kill you if you aren’t careful.”

“Warm water isn’t very satisfying to drink,” Lofosa grumbled.

“I am sorry, freelady, but Trench Park hasn’t the resources to haul a refrigerator around for anyone’s convenience,” Radnal said.

Despite Lofosa’s complaint, she and Evillia both drank regularly. Radnal scratched his head, wondering how the Krepalgan girls could seem so fuzzbrained but still muddle along without getting into real trouble.

Evillia had even brought along some flavoring packets, so while everyone else poured down blood-temperature water, she had blood-temperature fruit punch instead. The crystals also turned the water the color of blood. Radnal decided he could do without them.

They got to the Bitter Lake a little before noon. It was more a salt marsh than a lake; the Dalorz River did not drop enough water off the ancient continental shelf to keep a lake bed full against the tremendous evaporation in the eternally hot, eternally dry Bottomlands. Salt pans gleamed white around pools and patches of mud.

“Don’t let the donkeys eat anything here,” Radnal warned. “The water brings everything from the underground salt layer to the surface. Even Bottomlands plants have trouble adapting.”

That was emphatically true. Despite the water absent everywhere else in Trench Park, the landscape round the Bitter Lake was barren even by Bottomlands standards. Most of the few plants that did struggle to grow were tiny and stunted.

Benter vez Maprab, whose sole interest seemed to be horticulture, pointed to one of the exceptions. “What’s that, the ghost of a plant abandoned by the gods?”

“It looks like it,” Radnal said: the shrub had skinny, almost skeletal branches and leaves. Rather than being green, it was white with sparkles that shifted as the breeze shook it. “It’s a saltbush, and it’s found only around the Bitter Lake. It deposits the salts it picks up from ground water as crystals on all its aboveground parts. That does two things: it gets rid of the salt, and having the reflective coating lowers the plant’s effective temperature.”

“It also probably keeps the saltbush from getting eaten very often,” Toglo zev Pamdal said.

“Yes, but with a couple of exceptions,” Radnal said. “One is the humpless camel, which has its own ways of getting rid of excess salt. The other is my little friend the fat sand rat, although it prefers desert spurges, which are juicier.”

The Strongbrow woman looked around. “One of the things I expected to see when I came down here, both the first time and now, was lots of lizards and snakes and tortoises. I haven’t, and it puzzles me. I’d have thought the Bottomlands would be a perfect place for cold-blooded creatures to live.”

“If you look at dawn or dusk, Toglo zev, you’ll see plenty. But not in the heat of the day. Cold-blooded isn’t a good term for reptiles: they have a variable body temperature, not a constant one like birds or mammals. They warm themselves by basking, and cool down by staying out of the midday sun. If they didn’t, they’d cook.”

“I know just how they feel.” Evillia ran a hand through her thick dark hair. “You can stick eating tongs in me now, because I’m done all the way through.”

“It’s not so bad as that,” Radnal said. “I’m sure it’s under fifty hundredths, and it can get above fifty even here. And Trench Park doesn’t have any of the deepest parts of the Bottomlands. Down another couple of thousand cubits, the extreme temperatures go above sixty.”

The non-Tarteshans groaned. So did Toglo zev Pamdal and Peggol vez Menk. Tarteshem had a relatively mild climate; temperatures there went past forty hundredths only from late spring to early fall.

With morbid curiosity, Moblay Sopsirk’s son said, “What is the highest temperature ever recorded in the Bottomlands?”

“Just over sixty-six,” Radnal said. The tourists groaned again, louder.

Radnal led the line of donkeys around the Bitter Lake. He was careful not to get too close to the little water actually in the lake at this time of year. Sometimes a salt crust formed over mud; a donkey’s hoof could poke right through, trapping the animal and slicing its leg against the hard, sharp edge of the crust.

After a while, the tour guide asked, “Do you have all the pictures you want?” When no one denied it, he said, “Then we’ll head back toward the lodge.”

“Hold on.” Eltsac vez Martois pointed across the Bitter Lake. “What are those things over there?”

“I don’t see anything, Eltsac,” his wife said. “You must be looking at a what-do-you-call it, a mirage.” Then, grudgingly, a heartbeat later: “Oh.”

“It’s a herd of humpless camels,” Radnal said quietly. “Try not to spook them.”

The herd was a little one, a couple of long-necked males with a double handful of smaller females and a few young ones that seemed all leg and awkwardness. Unlike the donkeys, they ambled over the crust around the Bitter Lake. Their hooves were wide and soft, spreading under their weight to keep them from falling through.

A male stood guard as the rest of the herd drank at a scummy pool of water. Golobol looked distressed. “That horrid liquid, surely it will poison them,” he said. “I would not drink it to save my life.” His round brown face screwed up in disgust.

“If you drank it, it would end your days all the sooner. But humpless camels have evolved along with the Bottomlands; their kidneys are wonderfully efficient at extracting large amounts of salt.”

“Why don’t they have humps?” Lofosa asked. “Krepalgan camels have humps.” By her tone, what she was used to was right.

“I know Krepalgan camels have humps,” Radnal said. “But the camels in the southern half of the Double Continent don’t, and neither do these. With the Bottomlands beasts, I think the answer is that any lump of fat — which is what a hump is — is a liability in getting rid of heat.”

“In the days before motors, we used to ride our Krepalgan camels,” Evillia said. “Has anyone ever tamed your humpless ones?”

“That’s a good question,” Radnal said, beaming to hide his surprise at her coming up with a good question. He went on, “It has been tried many times, in fact. So far, it’s never worked. They’re too stubborn to do what a human being wants. If we had domesticated them, you’d be riding them now instead of these donkeys; they’re better suited to the terrain here.”

Toglo zev Pamdal scratched her mount’s ears. “They’re also uglier than donkeys.”

“Freelady — uh, Toglo zev — I can’t argue with you,” Radnal said. “They’re uglier than anything I can think of, with dispositions to match.”

As if insulted by words they couldn’t have heard, the humpless camels raised their heads and trotted away from the Bitter Lake. Their backs went up and down, up and down, in time to their rocking gait. Evillia said, “In Krepalga, we sometimes call camels desert barques. Now I see why: riding on one looks like it would make me seasick.”

The tourists laughed. So did Radnal. Making a joke in a language that wasn’t Evillia’s took some brains. Then why, Radnal wondered, did she act so empty-headed? But he shrugged; he’d seen a lot of people with brains do impressively stupid things.

“Why don’t the camels eat all the forage in Trench Park?” Benter vez Maprab asked. He sounded as if his concern was for the plants, not the humpless camels.