The small raft was afloat.  Mrs. Anderson and Mrs. Nestor, weeping hysterically, waded out through the water to get aboard.

“Have we food?” cried Mr. Damon.  “Bless my kitchen range! but I nearly forgot that.”

“There isn’t any food left to take,” answered Mrs. Anderson.

“Shove off!” cried Captain Mentor.

At that instant a haze which had hung over the water, was blown to one side.  The horizon suddenly cleared.  Tom Swift looked up and gave a cry.

“The steamer!  The steamer!  The CAMBARANIAN!” he shouted, pointing to it.

The others joined in his exclamations of joy, for there, rushing toward Earthquake Island was a great steamer, crowding on all speed!

“Saved!  Saved!” cried Mrs. Nestor, sinking to her knees even in the water.

“It came just in time!” murmured Mr. Hosbrook.

“Now I can make my diamonds,” whispered Mr. Jenks to Tom.

“Push off!  Push off!” cried Mr. Parker.  “The island will sink, soon!”

“I think we will be safer on the island than on the raft,” declared Captain Mentor.  “We had better land again.”

They left the little raft, and stood on the shore of the island.  Eagerly they watched the approach of the steamer.  They could make out hands and handkerchiefs waving to them now.  There was eager hope in every heart.

Suddenly, some distance out in the water, and near where the big raft was anchored, there was a curious upheaval of the ocean.  It was as if a submarine mine had exploded!  The sea swirled and foamed!

“It’s a good thing we didn’t go out there,” observed Captain Mentor.  “We would have been swamped, sure as guns.”

Almost as he spoke the big raft was tossed high into the air, and fell back, breaking up.  The castaways shuddered.  Yet were they any safer on the island?  They fancied they could feel the little part of it that remained trembling under their feet.

“The steamer is stopping!” cried Mr. Damon.

Surely enough the CAMBARANIAN had slowed up.  Was she not going to complete the rescue she had begun?

“She’s going to launch her lifeboats,” declared Captain Mentor.  “Her commander dare not approach too close, not knowing the water.  He might hit on a rock.”

A moment later and two lifeboats were lowered, and, urged on by the sturdy arms of the sailors, they bounded over the waves.  The sea seemed to be more and more agitated.

“It is the beginning of the end,” murmured Mr. Parker.  “The island will soon disappear.”

“Will you be quiet?” demanded Mr. Damon, giving the scientist a nudge in the ribs.

The lifeboats were close at hand now.

“Are you all there?” shouted some one, evidently in command.

“All here,” answered Tom.

“Then hurry aboard.  There seems to be something going on in these waters—­perhaps a submarine volcano eruption.  We must get away in a hurry!”