"Six, you mean," laughed Tad.

The others had soon joined him.

"How far are we from the surface?" asked Walter.

"About five hundred feet down. We're in the bowels of the mountain for
sure, kid," answered the guide.

"That's pretty tough on the mountain. I'm afraid it will have a bad
case of indigestion," laughed Tad.

"You needn't be. It has swallowed tougher mouthfuls than you are,"
returned the guide, ever ready with an answer.

"Dad's able to give as good as you send," laughed Ned.

"That's good. All the better for us," nodded Tad. "What about some
light?"

"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.

"I am of the opinion that you boys should take turns in cooking the
meals, say one boy to cook for an entire day, another to take the job
on the following day."

"I'll cook my own," declared the guide. "No tenderfoot experiments
in my chuck."

"They know how to cook, Mr. Nance," explained the Professor.

"All right; they may cook for you," said the guide, with a note of
finality in his tone. He glanced up at the sky, held out his hand and
shook his head. Tad observed the movement.

"What is it?" asked the boy.

"It's going to snow," said Dad.

Tad laughed, glancing at his companions.

"What, s