CHAPTER X
MARK'S STRANGE ACTIONS
Jack Darrow fairly burst into the big shed where the two scientists were at work over the ruined motor. They looked up at his excitable entrance, and Mr. Henderson called out:
"Why, Jack, what's the matter?"
"Quite a lot, I'm afraid," answered the lad, and there was that in his voice which alarmed the professors.
"What do you mean?" inquired Mr. Roumann, laying aside some of the damaged motor plates.
"Mark's gone!" gasped Jack.
"Gone! Where?" exclaimed Mr. Henderson.
"I don't know, but he went to the deserted house, where we thought the mysterious man was hiding, and since then I can't find him."
Then the frightened lad proceeded to explain what he and Mark had undertaken, and the outcome of it; how his chum had failed to meet him at the rendezvous, and how Jack had searched through the old house without result.