Excellent! thought the visitor. It has stereoscopic eyes, nostrils, mouth, ears. Not the most attractive alien he had ever encountered; yet not the ugliest, either. Somewhere in between.

Khor held up both hands to show they were empty, then bowed slowly.

The calm one repeated the gesture with great dignity.

Khor spoke through the tele-band into the mind of his host. "My name is Khor."

The Greek showed his surprise. "You understand Greek? And you are able to speak into my mind?

How is this? Whence came you?"

Khor pointed to the band around his head, visible in outline under his body veil.

"Ah," said Eratosthenes. "A mental language device. Fantastic. But where-" He jerked. Strange thoughts... strange sounds... sights... smells... were forming in his head. He gasped. "You are from a distant world? A star?"

Khor nodded.

The geometer gulped. "Are you a G.o.d? The messenger Hermes perhaps?" (How could he be asking this? He didn't believe in G.o.ds!) "No. I am a mortal, like yourself. My people are a little more scientifically advanced than yours, that's all."

"Why are you here?"

"I was on a collection expedition. I work for a museum, the same as you. I was searching for certain plants... animals... I was loaded up, and on my way home, when a meteorite hit my ship. I had to land for repairs."

"I see. I think I see. Can I help you?"

"I don't know. I will need certain things. Certain... tapes. Certain oils. Some... alkali. And then perhaps some geodetic information."

"Such as?"

"The circ.u.mference of your world, Terra, considered as a sphere."

The Greek eyed his visitor sharply.

Khor hesitated. "Have I asked a forbidden question? Is something, how do you say it, taboo? Or perhaps you were not aware that Terra is a sphere?"

'''That I had indeed surmised. No, I was simply struck by the coincidence. I have been working on the problem for the past several weeks, and very recently, actually within the last few hours, I have obtained some sort of answer. But why do you need to know?"

"I can use Terra's rotational velocity to help fling the ship into escape orbit, when the time comes to leave. To deter-mine that velocity, I need to know Terra's circ.u.mference."

"I think I can provide a fair estimate.""Excellent."

Eratosthenes had to stop and think a moment. Khor needed the velocity of the rotating Earth? Well, of course. The Earth rotated. That's why the sun appeared to move around the Earth. But that wasn't all.

The Earth must revolve around the sun, from a very great distance, once a year. And that's why the sun appeared to move through the zodiac once a year. Actually, it was the Earth that was moving. The sun stood still. The heliocentric hypothesis wasn't a hypothesis. It was a fact. And if the Earth moved around the sun, so did all the five other planets: Mercury, Venus, Mars, Jupiter, Saturn. And so the sun was a star, much like millions of other stars. Did all those other stars out there have planets, with strange life forms, thinking, working, loving? His heart beat faster as he thought about it. Whom could he tell?

n.o.body. "A visitor from another star told me." Next stop, the madhouse. It made him smile just to think about it.

But back to reality, and the present. "So then, Khor, can I offer you the hospitality of my house? Not a Ptolemaic palace- but yet not a hovel, either. Food of all sorts, wines brought in from all parts of the world. Baths, hot and cold. Servants to a.s.sist you. You could relax while we dine, and you could describe your needs to me."

"Your offer is most attractive. Truly, I have a great need. But I do not wish to cause problems for you. I read in your mind certain names: Ptolemy... Hor-ent-yotf... even the female at your side, Ne-tiy.

Who are these people? How can they harm you?"

"Harm me? Perhaps the words are too strong. Ptolemy rules-owns-this land, called Egypt. He is a Greek, a for-eigner, and he tries to rule softly, and to give no great offense to the people, aside from taking their money. But Hor-ent-yotf, a high priest of the hawk-G.o.d Horus, likewise rules, in that he reigns over the minds and souls of the people. Ne-tiy is a slave, put in my house by Hor-ent-yotf. She is his property, even as his clothing and his cosmetic box are his property. Do you read my thoughts in this matter, honored stranger?"

"I do, and I reply with thoughts. You propose to do a thing offensive to Ptolemy, and horrifying to Hor-ent-yotf, and because of this thing the priest may kill you. Or perhaps make the female kill you. Is this the situation?"

"It is so."

"I find this quite alarming. Obviously, I do not understand your ways. Please explain."

"It is a very complex matter, O visitor from great dis-tances. Perhaps we can continue over cakes and wine?"

"Fourteen percent CH3CH2OH?"

"I beg your pardon?"

"Just thinking out loud. A pleasure, Eratosthenes. Just let me close up the bucket."

10. Repairs "To each his own custom," thought Eratosthenes. "We Greeks eat while reclining on an eating couch.

The Egyptians sit in chairs. But you stand."

"At all times," replied the thoughts of his visitor. "We stand to eat, drink, study, work, even to sleep.

Our skeletal structure requires it." His gloved hand clasped the wine cup and brought it to his lips through a slit in his body veil.

The Greek heard a "clack" as the metal goblet struck something hard. "Well then, let us look to your needs. First, strips of adhesive cloth. Tapes, you call them. That we have in abundance. It is the custom of the country to use them as bandages to wrap the bodies of the dead, in preparation for burial." He held up a piece of white cloth. "This is a rather fine linen, woven from the flax plant. Every Egyptian familysaves sc.r.a.ps of cloth against the inevitable burials. The pieces are ripped into strips: narrow bandages for the fingers, wider ones for the limbs and torso." He tore off a strip and handed it to Khor, who examined it closely.

"What makes it stick?" asked his visitor.

"They dip it in liquid balsam. It sets up hard in a couple of hours."

"It ought to work," said Khor. "Now, about the oil."

"We have several kinds: olive oil, from the fruits of the olive tree. It's used in cooking and in our lamps. Castor oil... several grades. This is from the castor bean. It has medicinal uses, and is also a fine lubricant. The army uses it in the oil packing for its chariot wheels. And linseed oil... which we boil and then use in paints and varnishes."

"Back up. This castor oil... is there a refined grade?"

"Indeed yes. Settled over charcoal and filtered through fine linen."

"I'd like to try that. And now one more thing. A bit of alkali."

"Alkali... ?" The geometer frowned.

"Sodium carbonate would do nicely. Hm. That's making it worse, isn't it? How to describe it... let me think. It would be bitter to the taste, very soluble in water, turns red wine blue. Fizzes in vinegar. Can be boiled with fats and oils to make soap..."

"Oh! Of course! Natron! We use it in embalming. It helps desiccate the corpse. But how would you use natron in your ship?"

"Simple. During wake-periods on my ship, my lungs give off a waste gas, which we call carbon dioxide. It can become toxic if allowed to reach high concentrations. The alkali absorbs it."

"Well then, I think the next step is to gather up these things and take them out to your ship. I'll call the servants. No-I can't. They're all down in the city, celebrating the New Year. You and I and Ne-tiy will have to do it."

"It's just as well. Less risk to the ship."

To the extent that any of the geometer's aplomb had left him, very nearly all of it had by now returned.

He said, "As you may have read in my mind, it is the practice for one of our Library clerks to go through every incoming ship to look for new books to copy. I wonder..."

"Ah, my friend. I have dozens of books, none in any Earth-language. The Maintenance of Ion Drives... Collect-ing on Airless Worlds... Operation of the Sleep Casket. Some with holos, for which you'd need a laser reader. But I tell you what. You like maps. Before I finally leave, I'll give you a sort of map."

"Fair enough."

An hour later Khor, Eratosthenes, and Ne-tiy had wound the last of the linen strips around the hydraulic tubes, refilled the depleted oil surge tank, and secured the amphora of natron in the storage locker.

"The balsam resin will require a couple of hours to cure and harden," said Eratosthenes. "And I am due at Ptolemy's palace very soon. May I suggest that you join me?"

"Won't I excite comment?"

"Hm. You're a bit taller than average. However, just keep covered with your body cape. I'll tell Ptolemy you're a foreign visitor and your religion requires the covering.""Is it an offense to you, my host, that I conceal my body from you in this way?"

The Cyrenian smiled. "Since you are my guest, it pleases me that you do as you see fit." He bowed.

"This way to the chariot."

11. Ptolemy on His Balcony On this night of the summer solstice, the beginning of the three weeks of madness celebrating the rising of the river. Ptolemy the Second, called Philadelphus, stood on his bal-cony and looked out over the royal harbor. Shading his eyes, he could barely make out the tiny light swinging in slow arcs in the blackness. At his request, the captain had fixed the lantern at the top of the mast of the royal barge.

Why? No reason given. He had simply said, do it, and it was done. Actually, it was a token of a promise to himself: tomorrow he would be on that ship, headed south on the Nile, with all concerns of state receding sternward.

For five thousand years the rulers of Egypt had made this trip. Tradition held that when the sun ceased his northward journey, pharaoh would set forth, sailing all the way to Thebes, to ensure a proper flood. If pharaoh did not thus set forth on the bosom of Hapi, the river would not rise. If the river did not rise, there would be no sowing, and no harvest. Famine would grip the land. The tax gatherers would gather little or nothing. The army could not be paid. The dynasty could fall.

Superst.i.tious nonsense?

Who was he to say?

It was best to go along with it. Anyhow, he always looked forward to the long trip on the river. He just wished Arsinoe' were still alive.

Noises in the streets below brought his eyes down to the parade of dancing torches. The annual infection had spread even here, to the guarded serenity of the royal quarter. In a way it was unsettling; yet on the whole it was rea.s.suring that the people were content to stay within their multi-millennial rut. No riots, no revolutions, no marches against the grana-ries. Not this week, anyhow. Let the beer flow!

He looked around as a woman in an elegant linen dress and cape parted the hangings and stepped out to join him. A thick black wig, artfully dusted with gold powder, fell to her shoulders. She was his concubine of the month. Her name was Pauni, daughter of a n.o.ble house. He named them for the current Egyptian month. It was the only way he could attach names to their beautiful faces. And so it had been, since the death of Arsinoe, his true sister-wife, twenty years ago. By Greek ideas, that marriage had been incest; but it was quite in the pharaonic tradition. A bit of irony: in the river tongue, the word for concubine was "sne-t," which meant "sister."

(Ah, Arsinoe, Arsinoe. I loved you greatly. You should not have died. It was the only unkind thing you ever did.) "Respect their traditions. Respect their religion. Worship their G.o.ds," his great father Ptolemy, Alexander's general, had told him. "Be pious. You lose nothing, and you will preserve the dynasty." He took the woman by the arm and they listened in silence to the revelry. "The old man was right," he muttered.

"Who, my lord?" said Pauni politely.

"My father. When the Persians conquered Egypt, they flouted the local religions. Ochus, the satrap, killed the sacred bull. The priests invoked a terrible curse on him, and on his masters in Persepolis. And so Alexander came, and destroyed Persia. He came to Egypt, and gave all honor to the priests. He sacrificed to Apis and other native G.o.ds. He made the great journey across the desert, without road or path, to the sanctuary of Ammon at Siwah. There the priests declared his divine descent, and that he was indeed the son of Ammon." He reflected. "Did I ever tell you about Alexander's trip across the desert to Siwah?"(Several times, my lord.) "No, sire, I don't recall that you did."

"Ah. Well, then. The storms had destroyed the roads. Even the guides were lost. The sun was pitiless, and the men were dropping from heat stroke. But trie G.o.ds sent a great flock of ravens, who flew in circles overhead, and shaded Alexander. And if the guides made a wrong turn, the birds screamed until they went straight again."

"Amazing," said Pauni.

The royal Greek sighed again. If only he didn't owe so much money to so many people. The Jews had helped him- and his father-finance the great light tower on Pharos. It had been finished these nine years, and the treasury was still paying. And the Egyptian priests. The public debt was soar-ing because of their demands for new temples. And then there was the standing army, all mercenaries, and they liked to be paid regularly, in hard clanking bra.s.s. And the navy. A thousand years ago Rameses had not been troubled with ships that sailed the Great Green. And two thousand years ago the pharaohs didn't even use money. There wasn't any. It hadn't been invented yet. Go, said Khufu to his peasants. Build me a tomb-pyramid. One million men, working twenty years. And they had done it, and not an obol paid out to anyone. Alas, how things had changed. "Who rules Egypt?" he mused softly. "Do I? No. Do the one million Greeks who have settled here? No. Well, then, do the priests and their seven million fellahin? Or is the land a hopeless anarchy?"

By now she was used to this. "Speaking of priests," Pauni reminded him gently, "the high priest of Horus is here. Also Rabbi Ben Shem. And then the other notables: Eratosthenes and his lady. The geometer brings a very strange guest, who covers his body with a long black veil. And then there are the consuls and amba.s.sadors-Claudius Pulcher the Roman, Ha-milcar Barca, the Carthaginian..."

Ptolemy suppressed a groan. Eratosthenes. He had tried to forget him, but of course it was impossible. The man of measures was going to make his report tonight. And what will you say, n.o.ble philosopher? How big is the world? As to that, say anything you like. But the shape! Declare Earth a flat square, or a disc, or a cylinder. Any of these. But you know you must not say "sphere" or "ball" or "globe." That's heresy, mathematician. Don't betray me, my brother Greek.

There is a long line waiting to take your place as curator of the great Library. And it isn't just me you should worry about. If you say "sphere," the local holies will have you floating in the ca.n.a.l before the night is out.

He paused. The girl looked up at him in grave concern. He thought: she knows I am fifty-nine, and that I am dying. Ah, to be young again. No, don't turn back. Let it be finally done. Nothing really matters very much anymore. From here on in, let us have peace. He smiled. "Perhaps we should rejoin our guests.''

12. Heresy A little cl.u.s.ter had already formed around the two amba.s.sa-dors. The Carthaginian was explaining something: "One of my purposes here is to obtain copies of the world map of Eratosthenes."

"And what good is that?" growled Claudius Pulcher, the Roman.

"Carthage will probably win our present war with Rome, n.o.ble amba.s.sador. If so, we will expand into Spain and Gaul. For that we will need good maps. If we lose-may Baal save us!-we will certainly need to recoup our fortunes, and we would look to western Europe for that. Again we would need good maps. Including-" (here he gave the stolid Pulcher a crafty leer) "a good showing of the pa.s.ses through the Alps."

"Pa.s.ses... ?"

"For our war elephants."The Roman genera! stared at him blankly. Then recognition dawned. "Oh-you mean from Gaul, over the mountains into Italy." He began to laugh. He laughed so hard he spilled his wine. "Excuse me."

He walked back to the credentia for a refill.

Ptolemy watched him for a moment, then turned back to the Carthaginian. "The great Alexander was always fearful of war elephants. He never really discovered how to cope with them. Quite an idea, Hamilcar Barca."

"But there's still a problem," said Eratosthenes. "We have several reports by travelers in the Library.

They all say the pa.s.ses are very narrow, barely wide enough for a horse. How will you get your elephants through?"

"You should read more of your own books, learned scroll-master," said Barca. "The mountains are made of calx.

Vinegar dissolves calx. We shall bring hundreds of casks of vinegar. The mountains shall melt away, and the great war beasts shall pa.s.s."

"Why does Carthage disclose its strategy to Rome in ad-vance?" asked Ptolemy.

The young Carthaginian grinned. "No harm in it at all. First, they think we lie, that we try to deceive them. There-fore, they won't bother to defend the pa.s.ses. Second, they're so confident that if and when they do fortify the pa.s.ses they would so tell us. Third, they are incapable of thinking in terms of empire for themselves, so they can't conceive that their enemies would have such impossible ideas. They lack imagination. They don't know what dreams are."

"They seem to have done very well despite these deficien-cies," demurred Eratosthenes. "Three hundred years ago they were just a fishing village on the Tiber. Now they rule the entire Italic peninsula.

Who needs dreams?"

"You have a point, mapmaker. Well then, reverse the case. We Phoenicians needed dreams, and we produced them. We have established trading outposts at the limits of the known world. We have sailed through the Pillars of Hercules to the Tin Islands. We have circ.u.mnavigated Africa. We have traded in the Black Sea. Our ships rule the Western Mediter-ranean, and business on great waters has made us rich. And all because we had a vision. We still have it, and with it, we shall beat the Romans."

"Peace, gentlemen," said Ptolemy. Wars and rumors of war made him uneasy. "Let us talk of other things. Eratos-thenes, how go the angles?"

"Today, my lord Ptolemy, the day of the summer solstice, I measured the angle of the sun at high noon. I found it to be seven degrees and ten minutes."

The Second Ptolemy smiled graciously, yet warily, and with a warning in his eyes. "And pray what is the signifi-cance of seven degrees and-what was it-?"