It was noon when they had their shack rebuilt to their liking, and they stopped for dinner.  There was quite a variety of stores in the airship, enough for a much larger party than that of our three friends, and they varied their meals as much as possible.  Of course all the stuff they had was canned, though there are some salted and smoked meats.  But canned food can be had in a variety of forms now-a-days, so the castaways did not lack much.

“What do you say to an exploring expedition this afternoon?” asked Tom, as they sat about after dinner.  “We ought to find out what kind of an island we’re on.”

“I agree with you,” came from Mr. Fenwick.  “Perhaps on the other side we will stand a much better chance of speaking some passing vessel.  I have been watching the horizon for some time, now, but I haven’t seen the sign of a ship.”

“All right, then we’ll explore, and see what sort of an island we have taken possession of,” went on Tom.

“And see if it isn’t already in possession of natives—­or cannibals,” suggested Mr. Damon.  “Bless my frying pan! but I should hate to be captured by cannibals at my time of life.”

“Don’t worry; there are none here,” Tom assured him again.

They set out on their journey around the island.  They agreed that it would be best to follow the beach around, as it was easier walking that way, since the interior of the place consisted of rugged rocks in a sort of miniature mountain chain.

“We will make a circuit of the place,” proposed Tom, “and then, if we can discover nothing, we’ll go inland.  The centre of the island is quite high, and we ought to be able to see in any direction for a great distance from the topmost peak.  We may be able to signal a vessel.”

“I hope so!” cried Mr. Damon.  “I want to send word home that I am all right.  My wife will worry when she learns that the airship, in which I set out, has disappeared.”

“I fancy we all would like to send word home,” added Mr. Fenwick.  “My wife never wanted me to build this airship, and, now that I have sailed in it, and have been wrecked, I know she’ll say ’I told you so,’ as soon as I get back to Philadelphia.”

Tom said nothing, but he thought to himself that it might be some time before Mrs. Fenwick would have a chance to utter those significant words to her husband.

Following the beach line, they walked for several miles.  The island was larger than they had supposed, and it soon became evident that it would take at least a day to get all around it.

“In which case we will need some lunch with us.” said Tom.  “I think the best thing we can do now is to return to camp, and get ready for a longer expedition to-morrow.”

Mr. Fenwick was of the same mind, but Mr. Damon called out: 

“Let’s go just beyond that cliff, and see what sort of a view is to be had from there.  Then we’ll turn back.”

To oblige him they followed.  They had not gone more than a hundred yards toward the cliff, than there came the preliminary rumbling and roaring that they had come to associate with an earthquake.  At the same time, the ground began to shiver and shake.