"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.