Tom carefully inspected the Whizzer which was the name of Mr. Fenwick’s airship, and, after some difficulties, succeeded in getting the electric craft in shape to make a flight.

Tom, Mr. Damon and Mr. Fenwick started to make a trip to Cape May in the Whizzer, but were caught in a terrific storm, and blown out to sea.  The wind became a hurricane, the airship was disabled, and wrecked in mid-air.  When it fell to earth it landed on one of the small West Indian islands, but what was the terror of the three castaways to find that the island was subject to earthquake shocks.

But the earth-tremors were not the only surprise in store for Tom and his two friends, On the island they found five men and two ladies, who, by strange chance, had been stranded there when the yacht Resolute, owned by Mr. George Hosbrook, was wrecked in the same storm that disabled the airship.  Mr. Hosbrook, a millionaire, was taking a party of friends to the West Indies.

When the castaways (among whom were Mr. and Mrs. Amos Nestor, parents of Mary Nestor, a girl of whom Tom was very fond) found that there was danger of the island being destroyed in an earthquake, they were in despair.  There seemed no way of being rescued, as the island was out of the line of regular ship travel.

Tom, however, was resourceful.  With the electrical apparatus from the wrecked airship, he built a wireless plant, and sent messages for help, broadcast over the ocean.

They were finally heard, and answered, by an operator on board the steamer Camberanian, which came on under forced draught, and rescued Tom and his friends.  It was only just in time, for, no sooner had they gotten aboard the steamer in lifeboats, than the whole island was destroyed by an earthquake shock.

But Tom, the parents of Mary Nestor, Mr. Damon, Mr. Fenwick, and all the others, got safely home.  Among the survivors from the yacht Resolute was a Mr. Barcoe Jenks, who now, most unexpectedly, had confronted Tom through the glass window of the jewelry store.  Mr. Jenks was a peculiar man.  Tom discovered this on Earthquake Island.  Mr. Jenks carried with him some stones which he said were diamonds.  He asserted that he had made them, but Tom did not know whether or not to believe this.

When it seemed that the castaways would not be saved Mr. Jenks offered Tom a large sum in these same diamonds for some plan whereby he might escape the earthquakes.  Mr. Jenks said there was a certain secret in connection with the manufactured diamonds that he had to solve—­that he had been defrauded of his rights—­and that a certain Phantom Mountain figured in it.  But Tom, at that time, paid little attention to Mr. Jenks’ talk.  The time was to come, however, when he would attach much importance to it.

When this story opens, Tom was more interested in Mr. Barcoe Jenks than in any one else, and was wondering what he wanted to see him about.  The young inventor could not quite understand how Mr. Track, the jeweler, could come back with a lad he suspected of being a thief, when the person who had acted so suspiciously, and who had knocked on the glass, was the queer man, Mr. Jenks.