The boats came in to the shelving beach.  There was a little stretch of water between them and the sand.  Through this the castaways waded, and soon they were grasped by the sailors and helped in.  In the reaction of their worriment Mrs. Anderson and Mrs. Nestor were both weeping, but their tears were those of joy.

“Give way now, men!” cried the mate in charge of the boats.  “We must get back to the ship!”

The sea was now swirling angrily, but the sailors, who had been in worse turmoils than this, rowed on steadily.

“We feared you would not get here in time,” said Tom to the mate.

“We were under forced draught most of the way,” was his answer.  “Your wireless message came just in time.  An hour later and our operator would have gone to bed.”

The young inventor realized by what a narrow margin they had been rescued.

“The island will soon sink,” predicted Mr. Parker, as they reached the steamer, and boarded her.  Captain Valasquez, who was in command, warmly welcomed the castaways.

“We will hear your story later,” he said.  “Just now I want to get out of these dangerous waters.”

He gave the order for full speed, and, as the CAMBARANIAN got under way, Tom, and the others, standing on the deck, looked back at Earthquake Island.

Suddenly there sounded a dull, rumbling report.  The whole ocean about the island seemed to upheave.  There was a gigantic shower of spray, a sound like an explosion, and when the waters subsided the island had sunk from sight.

“I told you it would go,” cried Mr. Parker, triumphantly, but the horror of it all—­the horror of the fate that would have been theirs had they remained there an hour longer—­held the castaways dumb.  The scientist’s honor of having correctly predicted the destruction of the island was an empty one.

The agitation of the sea rocked even the mighty CAMBARANIAN and, had our friends been aboard the frail raft, they would surely have perished in the sea.  As it was, they were safe—­saved by Tom Swift’s wireless message.

The steamer resumed her voyage, and the castaways told their story.  Captain Valasquez refused to receive the large amount of money Mr. Hasbrook and Mr. Jenks would have paid him for the rescue, accepting only a sum he figured that he had lost by the delay, which was not a great deal.  The castaways were given the best aboard the ship, and their stories were listened to by the other passengers with bated breath.

In due time they were landed in New York, and Mr. and Mrs. Nestor accompanied Tom to Shopton.  Mr. Damon, with many blessings also accompanied them, going to his home in Waterfield.  Later it was learned that the other boats from the resolute had been picked up, and the sailors and guests were all saved.

Of course, as soon as our friends had been rescued by the steamer, the wireless operator aboard her, with whom Tom soon struck up an acquaintance, sent messages to the relatives of the castaways, apprising them of their safety.