"Of course," said Samos.

"It is unusual that you should invite me to your house," I said, "to inform me that you have nothing to report."

"Do you think you are the only one upon Gor who labors occasionally in the cause of Priest-Kings?" asked Samos.

"I suppose not," I said. "Why?" I asked. I did not understand the question.

"How little we know of our world," sighed Samos.

"I do not understand," I said.

"Tell me what you know of the Cartius," he said.

"It is an important subequatorial waterway," I said. "It flows west by northwest, entering the rain forests and emptying into Lake Ushindi, which lake is drained by the Kamba and the Nyoka rivers. The Kamba flows directly into Thassa. The Nyoka flows into Schendi harbor, which is the harbor of the port of Schendi, and moves thence to Thassa." Schendi was an equatorial free port, well known on Gor. It is also the home port of the League of Black Slavers.

"It was, at one time, conjectured," said Samos, "that the Cartius proper was a tributary of the Vosk."

"I had been taught that," I said.

"We now know that the Thassa Cartius and the subequatorial Cartius are not the same river."

"It had been thought, and shown on many maps," I said, "that the subequatorial Cartius not only flowed into Lake Ushindi, but emerged northward, traversing the sloping western flatlands to join the Vosk at Turmus." Turmus was the last major river port on the Vosk before the almost impassable marshes of the delta.

"Calculations performed by the black geographer, Ramani, of the island of Anango, suggested that given the elevations involved the two rivers could not be the same. His pupil, Shaba, was the first civilized man to circumnavigate Lake Ushindi. He discovered that the Cartius, as was known, enters Lake Ushindi, but that only two rivers flow out of Ushindi, the Kamba and Nyoka. The actual source of the tributary to the Vosk, now called the Thassa Cartius, as you know, was found five years later by the. explorer, Ramus of Tabor, who, with a small expedition, over a period of nine months, fought and bartered his way through the river tribes, beyond the six cataracts, to the Ven highlands. The Thassa Cartius, with its own tributaries, drains the highlands and the descending plains."

"That has been known to me for over a year," I said. "Why do you speak of it now?"

"We are ignorant of so many things," mused Samos.

I shrugged. Much of Gor was terra incognita. Few knew well the lands on the east of the Voltai and Thentis ranges, for example, or what lay west of the farther islands, near Cos and Tyros. It was more irritating, of course, to realize that even considerable areas of territory above Schendi, south of the Vosk, and west of Ar, were unknown. "There was good reason to speculate that the Cartius entered the Vosk, by way of Lake Ushindi," I said.

"I know," said Samos, "tradition, and the directions and flow of the rivers. Who would have understood, of the cities, that they were not the same?"

"Even the bargemen of the Cartius proper, the subequatorial Cartius, and those of the Thassa Cartius, far to the north, thought the rivers to be but one waterway."

"Yes," said Samos. "And until the calculations of Ramani, and the expeditions of Shaba and Ramus, who had reason to believe otherwise?"

"The rain forests closed the Cartius proper for most civilized persons from the south," I said, "and what trading took place tended to be confined to the ubarates of the southern shore of Lake Ushindi. It was convenient then, for trading purposes, to make use of either the Kamba or the Nyoka to reach Thassa."

"That precluded the need to find a northwest passage from Ushindi," said Samos.

"Particularly since it was known of the hostility of the river tribes on what is now called the Thassa Cartius."

"Yes," said Samos.

"But surely, before the expedition of Shaba," I said, "others must have searched for the exit of the Cartius from Ushindi."

"It seems likely they were slain by the tribes of the northern shores of Ushindi," said Samos.

"How is it that the expedition of Shaba was successful?" I asked.

"Have you heard of Bila Huruma?" asked Samos.

"A little," I said.

"He is a black Ubar," said Samos, "bloody and brilliant, a man of vision and power, who has united the six ubarates of the southern shores of Ushindi, united them by the knife and the stabbing spear, and has extended his hegemony to the northern shores, where he exacts tribute, kailiauk tusks and women, from the confederacy of the hundred villages. Shaba 's nine boats had fixed at their masts the tufted shields of the officialdom of Bila Huruma."

"That guaranteed their safety," I said.

"They were attacked, several times," said Samos, "but they survived. I think it true, however, had it not been for the authority of Bila Huruma, Ubar of Ushindi, they could not have completed their work."

"The hegemony of Bila Huruma over the northern shores, then, is substantial hut incomplete," I said.

"Surely the hegemony is resented," said Samos, "as would seem borne out by the fact that some attacks did take place on the expedition of Shaba."

"He must be a brave man," I said.

"He brought six of his boats through, and most of his men," said Samos.

"I find it impressive," I said, "that a man such as Bila Huruma would be interested in supporting a geographical expedition."

"He was interested in finding the northwest passage from Ushindi," said Samos. "It could mean the opening up of a considerable number of new markets, the enhancement of trade, the discovery of a valuable commercial avenue for the merchandise of the north and the products of the south."

"It might avoid, too, the dangers of shipment upon Thassa," I said, "and provide, as well, a road to conquest and the acquisition of new territory."

"Yes," said Samos. "You think like a warrior," he said.

"But Shaba 's work," I said, "as I understand it demonstrated that no such passage exists."

"Yes," said Samos, "that is a consequence of his expedition. But surely, even if you are not familiar with the role of Bila Huruma in these things, you have heard of the further discoveries of Shaba."

"To the west of Lake Ushindi," I said, "there are floodlands, marshes and bogs, through which a considerable amount of water drains into the lake. With considerable hardship, limiting himself to forty men, and temporarily abandoning all but two boats, which were half dragged and thrust through the marshes eastward, after two months, Shaba reached the western shore of what we now know as Lake Ngao."

"Yes," said Samos.

"It is fully as large as Lake Ushindi, if not larger," I said, "the second of the great equatorial lakes."

"Yes," said Samos.

I conjectured that it must have been a marvelous moment when Shaba and his men, toiling with ropes and poles, wading and shoveling, brought their two craft to the clear vista of vast, deep Lake Ngao. They had returned then, exhausted, to the balance of their party and boats, which had been waiting for them at the eastern shore of Ushindi.

" Shaba then continued the circumnavigation of Lake Ushindi," said Samos. "He charted accurately, for the first time, the entry of the Cartius proper, the subequatorial Cartius, into Ushindi. He then continued west until he reached the six ubarates and the heartland of Bila Huruma."

"He was doubtless welcomed as a hero," I said.

"Yes," said Samos. "And well he should have been."

"The next year," I said, "he mounted a new expedition, with eleven boats and a thousand men, an expedition financed, I now suppose, by Bila Huruma, to explore Lake Ngao, to circumnavigate it as he had Ushindi."

"Precisely," said Samos.

"And it was there that he discovered that Lake Ngao was fed, incredibly enough, by only one major river, as its eastern extremity, a river vast enough to challenge even the Vosk in its breadth and might, a river which he called the Ua."