"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."