That night, the two tropical tramps stole a small boat with a one-cylinder motor, and started up the river.
It was a hard journey, but they were used to river and jungle work, and the object they had in view was enough to make them discount trouble. They speculated upon what manner of treasure it was they would find in the cavern of the Matto Grosso mine. It might be precious stones, it might be gold. Certainly it was something very valuable.
They carried little supplies, but they were heavily armed. For food, they might hunt and also depend on the caches left by their friend, Juan the peon.
Three hundred miles from Manaos, they came to the landing where old Gurlone had unloaded his boats. The two tramps drew their own craft up on shore a quarter of a mile away, keeping out of sight, and hid the boat in dense brush. Then they crept up the river bank, keeping out of sight of the boatmen, who were preparing for the return voyage, and cut into the jungle so as to strike the trail of the caravan ahead.
For several hours they followed the path easily. They found palm trees blazed with new marks, and these they were sure their friend Juan had left for them. But the trail was easy to keep without these. The supplies had been loaded on burros, which had been awaiting the boats.
That night, they camped beside a small stream. They were but twenty-four hours behind Professor Gurlone and his party, and the food Juan had cached for them was in good condition.
They were up at daybreak, and pressed on, armed to the teeth and ready for a fight.
"What's that?" said Durkin, stopping so suddenly that Maget ran into him.
They had been walking at a swift pace along the jungle path, the giant trees forming a canopy overhead. Monkeys screamed at them, birds flitted a hundred feet above them in the roof of the forest.
The sun beat on the jungle top, but few rays lightened the gloom beneath.
From up ahead sounded a frightful scream, followed by a long drawn out wailing. Maget glanced at Durkin, and the latter shrugged, and pressed on. But he gripped his rifle tightly, for the cries were eery.
From time to time the two stopped to catch better the direction of the wails. At last, they located the spot where the injured person lay.