They looked their questions.
“And that was by climbing around the gas bag and opening it by hand.”
“Good gracious!” exclaimed Joe. “And Nat dared do such a thing!”
“He must have, and succeeded, too,” said the professor in a curiously tense voice, “the opening of that valve was the only thing that would result in our having dropped to a supportable region of the air.”
“But we are dropping no longer.”
The exclamation came from Mr. Tubbs.
“No. The automatic cut-off arrangement would have closed the valve when we had reached a warmer belt of atmosphere,” explained the professor, “but don’t let us lose time talking here. Scatter through the Discoverer and make a thorough search. He may have dropped unconscious somewhere.”
The anxiety with which the search was conducted may be imagined. The Discoverer was allowed to drift lazily along while they sought some trace of the missing lad, but the search resulted in nothing.
“There is only one conclusion to be reached,” said the professor in a solemn voice, “poor Nat paid the penalty of his bravery with his life. He——”
The man of science broke off, unable to command his voice, and at the same instant came a cry from above them—a hail from out of the air, it seemed: