"Unload the wood from your packs. This is where you are glad you did
pack some stuff."

In a few minutes a fire was blazing, lighting up the interior of the
crater. The boys found themselves in a circular opening of almost
terrifying roughness and something like a quarter of a mile across.
Here, in ages past, the forces of Nature had been at work with fearful
earnestness. Weird shadows, mysterious shapes, somewhat resembling
moving figures, were thrown by the flickering blaze of the camp fire.
While the boys were exploring the crater Dad was busy getting the
supper ready, talking with Professor Zepplin as he worked.

The voices of the boys echoed from side to side of the crater, sounding
strange and unreal. The call to supper put an end to their explorations.
They sat down with keen edges to their appetites. It was their first
meal in the open on this journey. All were in high spirits.

"I think we should agree upon our work for the future," declared the
Professor.

"Work?" exclaimed Chunky, opening wide his big eyes.

"Yes. It is not going to be all play during this trip."

"We are willing to do our share," answered Ned.

"Yes, of course we are," chorused Walt and Stacy, though there was no
enthusiasm in the fat boy's tone.