"We're almost there," said Mr. Roumann, after about an hour's sail. "There are no guards this way, just as I hoped. We shall soon be enormously wealthy."
Nearer and nearer came the boat to the hills. When they were within a half mile of them Jack, who was in the bow, uttered a cry.
"A whirlpool! A whirlpool!" he shouted. "We're heading right into it!"
Mr. Roumann, who was steering, tried to turn the boat to one side, but the craft would not answer the helm.
"Shut off the power and reverse!" exclaimed Mr. Henderson, when he saw that the boat was still rushing into the dangerous swirl of water.
Mark, who was near the metal box, did so. But even the power of Cardite was of no avail against the awful suction of the whirlpool. The boat began to go around in a great circle, ever coming nearer and nearer to the black, swirling center.
"No wonder they needed no guards on the water side," gloomily observed Mr. Roumann as he stood up and looked at the hills. "The whirlpool is the best protector they could have."
In deadly peril, the adventurers watched their boat coming nearer and nearer to the terrible center of the angry waters.