Cirocco tried to string them all together in her head. "I'll never remember all that."

"The only ones that matter right now are Oceanus, Hyperion, and Rhea. Actually, not all the names are Titans. One Titan is Themis, and I thought that would he confusing. And, well... ." He looked away, with a sheepish grin. "I just couldn't recall the names of two Titans. I used Metis, which is wisdom, and Dione."

Cirocco did not really care. The names were handy, and in their own way, systematic. "Let me guess about the rivers. More mythology?"

"Yeah. I picked the nine largest rivers in Hyperion-which

has got a hell of a lot of them, as you can see-and named them after- the Muses. Down south over there is Urania, Calliope, Terpsichore, and Euterpe, with Polyhymnia in the twilight zone and feeding into Rhea. And over here on the north slope, starting at the cast-is Melpomene. Closer to us are Thalia and Erato, which look like they make a system. And the one you came down is a feeder of the Clio, which is just about below us now."

Cirocco looked down and saw a blue ribbon winding through dense green forest, followed it back to the cliff face behind them, and gasped.

"So that Is where the river went," she said.

It arched from the cliff face, nearly half a kilometer below where they had been standing, looking solid and hard as metal for fifty meters before it began to break up. It fragmented rapidly from that point, reaching the ground as mist.

There were a dozen more plumes of water issuing from the cliff, none so close or spectacular, each with its attendant rain- bow. Froin her vantage point, the rainbows were lined up like croquet wickets. It was breathtaking, almost too beautiful to he real.

"I'd like to have the post card concession for this place," she said. Calvin laughed.

"You sell film for the camera, and I'll sell tickets to the rides. What do you think of this one?"

Cirocco glanced back at Gaby, still frozen to the window. "Reactions seem mixed. I like it okay. What's the name for

the big river? That one that all the others join?"

. "Ophion. The great serpent of the north wind. If you'll look closely, you can see that it comes out of a small lake back there at the twilight zone between Mnemosyne and Occanus. That lake must have a source, and I suspect it's Ophion flowing underground through the desert, but we can't see where it goes under. Other than that, it flows without a break, into seas and out of them on the other side."

Cirocco traced the convoluted path and could see that Calvin was right. "I think a geographer would tell you that it's not the same river going into a sea as it is coming out," she said. "But I know all the rules were made for Earth rivers. Okay, so we'll call it a circular river."

"That's where Bill and August are," Calvin said, pointing. "About halfway down the Clio, where that third tributary - "

"Bill and August. We were supposed to try and contact them. With all that commotion about getting on the blimp---"

"I borrowed your radio. They're up, and waiting for us. You can call them now, if you like."

Cirocco got her helmet ring and radio from Gaby. "Bill, can you hear me? This is Cirocco."

"Uh ... yeah, yeah! I hear you. How are you doing?"

"About as well as you'd expect, riding in the stomach of a blimp. What about you? Did you come through it all right? No injuries?"

"No, I'm fine. Listen, I wish ... I wish I could say how good it feels to hear your voice."

She felt a tear on her cheek, and brushed it away.

"It's good to hear you, Bill. When you fell out that window- oh, damn! You wouldn't remember that, would you."

"There's a lot of things I don't remember," he said. "We can straighten it all out later."

"I'm dying to see you. Do you have any hair?"

"It's growing in all over my body. We'd better let all this wait. We've got lots to talk about, me and you and Calvin and..."

"Gaby," she prompted, after what seemed like a very long pause.

"Gaby," he said, without much conviction. "You see I'm a bit confused about some things. But it shouldn't be a problem."

"Are you sure you're all right?" She felt cold suddenly, and rubbed her forearms briskly.

"Sure thing. When will you he here?"

Cirocco asked Calvin, who whistled a short tune. He was answered by another tune from somewhere overhead.

"Blimps don't have much idea of time," he said. "I'd say three or four hours."

"Is that any way to run an airline?"