"I'll be careful after this—but we are going to get the treasure, sure thing," he added, stoutly.
"I was afraid an earthquake might have played pranks with that cave," was Captain Barforth's comment. "An earthquake can shake down the top of a cave quicker than it can shake down anything else. It doesn't take much to do it."
The captain said he had a fair quantity of powder on board, to be used in the cannon for saluting and signalling. If they wanted dynamite, however, he'd have to run over to one of the big islands for it.
"And then we may have trouble getting it," he added. "We'd probably have to buy up the supply of some contractor who happened to have it on hand."
"I don't like to think of leaving the island while Merrick and his crowd are around," answered Anderson Rover.
On the following morning Mr. Rover and Captain Barforth went ashore, taking Dick, Tom and Sam along. The steam yacht was left in charge of Asa Carey, and the mate was told to remain close to the mouth of the reef and to send some of the others ashore armed if there came a signal of distress.
"We have enemies on this isle," said Captain Barforth. "And they may try to do us harm."
"I'll watch out," answered the mate, shortly. And then he turned away with a thoughtful look on his sour countenance. That there was something on his mind was evident.
The small boat was brought ashore at the point where the path led directly to the sunken cave. Although there was a lively breeze blowing, those landing did so without mishap. They had with them some tools for digging, and also a rock drill and some powder.
"It will do no harm to blast one or two of the rocks and see what is underneath," said Anderson Rover. "We may possibly be lucky enough to find some entrance into the cave, although I must confess I doubt it."