“But suppose Serbot does attack here?”

“We’ll drive him off from the blockhouse. When he sees that we are well fortified, he is sure to withdraw until he can bring up more men. Your Wai Wais will have taken care of them. That’s when we’ll surprise him by dashing out to the boats and starting down the river.”

They spent the rest of the day bringing the supplies in from the boats and putting the blockhouse into shape. The small windows of the square, squatty building were equipped with screens, but most of them were in poor condition. Mr. Brewster insisted upon repairing them first.

“Let’s get fortified against mosquitoes and other insects for tonight,” he suggested. “During the evening, we can strengthen the shutters and fix loopholes so as to fight off Serbot and his pests tomorrow or whenever they come this way.”

While the others worked late into the evening, Joe Nara strode about wearing a gun belt with two revolvers poking from its holsters, ready for trouble. Later Nara and his Wai Wais slept under netting on their monterias, so as to get a good rest.

In the blockhouse, the other members of the party took turns at guard duty through the night. At dawn, Jacome awakened Biff, who was scheduled to take over at that time. From one of the screened windows, Biff saw the squatty figures of Igo and Ubi emerge from Nara’s monteria. They roused the other Indians, and soon were stealthily moving off among the trees, to seek a trail to the rapids.

The next few hours were the longest that Biff had ever experienced. The others woke up, had breakfast, and strolled about the camp. But the very air seemed charged with expectancy. It would probably be mid-afternoon, perhaps even later in the day, before a move came from the other camp—if a move came at all.

Mr. Brewster, Hal Whitman, and Jacome were all carrying their rifles, fully loaded, but that was purely a matter of precaution.

“Nara’s party can’t have reached the rapids yet,” Mr. Brewster told Biff and Kamuka. “Even so, they won’t make a move unless Serbot starts out with his main force. If he sends some men ahead, they may try some sniping so, naturally, we must be ready. But that will show their hand—”

A sudden interruption came from the surrounding trees, the blasts of a dozen guns or more. Mr. Brewster wheeled and fired back from the spot where he was standing, midway between the blockhouse and the boats. Mr. Whitman and Jacome were nearer the blockhouse. They turned and fired, too.