“Now, we’ll stay here until night,” Captain Joe said, “and then we’ll see what we can do towards finding that cavern and dropping down into the lost channel. We ought to explore it in one night with the help of our searchlights.”
The plan mapped out by the captain was successfully carried out. Leaving Jule on board the Rambler, the other members of the party crept cautiously ashore that night, and were led directly to the cavern by Clay. They were not disturbed during the journey. Off to the east, they saw the reflection of a campfire and the sound of many voices showed the boys that the outlaws were not at all anxious to conceal their presence.
The opening leading from the cavern to the channel of the stream was large enough for even Captain Joe to pass through with comfort. Directly under the opening was a ledge of rock and here the boys landed. Almost at the point of entry they saw marks on the wall which indicated that at some distant time an inscription had been carved there.
“We can’t read the words,” Clay said, flashing his searchlight over the wall, “but at least it tells us that this is somewhere near the scene of the old-time operations.”
Alex, who had been poking about around an angle of rock, now gave a great shout of delight which called the boys to his side.
“There’s your old safe!” he cried, pointing up to a niche in the wall, “and it’s dollars to doughnuts that the lost charter and the jewels are inside of it!”
It was the work of only a few moments to bring the safe down from the ledge of rock to where the boys stood. It was merely a box of steel, not more than a foot in diameter each way, and was evidently constructed with thin walls for its weight was not great. However, it was tightly closed and the boys could see no means by which it might be opened. There was not even a keyhole or a button.
“We’ll take it back to the Rambler,” Captain Joe said. “Perhaps we can find a way to open it there.”
“We’ll find a way to open it,” Alex exclaimed, “when we get hold of the document Max was looking for in the cabin of the Cartier.”
“Good idea!” Captain Joe replied. “If you wait long enough, you’ll always find something like intelligence in the head of a boy!”