Rising from the table and donning their furs Jack and Mark went out on the deck.  They glanced up at the gas bag, and found it was filling out from the pressure of the vapor being pumped into it from the machine.

“I wonder if we’d have time to walk out on the ice a little?” asked Mark.  “I haven’t had a chance to look around, we’ve been so busy since we landed.”

“We’ll ask the captain,” spoke Jack.  “I’d like a little stroll myself.”

The inventor had no objections.

“Don’t go far away,” he cautioned.  “We’ll start very soon now, and don’t go near those animals.”

The boys promised, and then, climbing over the rail, and down the ice hummocks they walked along a broad level expanse that stretched out for about a mile.

They had not gone far before Jack, who was in the lead, came to a halt.

“Look here!” he called to Mark, who came hurrying up.

“What is it?”

“There’s a pile of bones frozen into the ice!  Looks as if there had been a fight here between bears and sea lions, and this is all that was left.  They ate each other up, all but the bones, which became covered with ice.”

“Those aren’t animal bones, Jack!”

“Why not?”

“See, there is the skull of a man!  And another!  There are a dozen skulls!” and Mark pointed to where they showed from underneath the crystal ice.

“You’re right!” Jack shouted.  “And see!  Here is something that looks like a copper cylinder!  Maybe it has something inside!  We must tell Professor Henderson!”

Full of the importance of their discovery, the boys hastened back to the airship.  The old inventor was much interested.  Directing Washington to keep a careful eye on the gas machine, and taking an axe with him, the captain returned with the boys to where the bones were.

“They are certainly the remains of human beings,” was the professor’s opinion.  “I don’t know that it would be any service to dig them out, but that copper cylinder may be of value.”

A few blows with the axe served to chop out the object.  It was about two feet long and nearly three inches in diameter, and seemed to be securely sealed.

“We’ll take it back to the ship and open it,” said the inventor.  “It is too cold to do it here.”

Back to the Monarch they hurried.  Then, with a file, the professor removed one end of the copper case.  From within he drew out a roll of paper, a watch, a knife and a few trinkets such as a man would carry about him.

“Some white man did this!” exclaimed the old inventor, his hands trembling with eagerness as he unrolled the paper.  “Let us see if he has left any word behind to tell of his death.”

All crowded around while Amos Henderson glanced at the mysterious message that had so curiously come to them.  Some of the writing was very faint, but by the aid of a magnifying glass it was deciphered.  Then, amid a deep silence the professor read the paper.