trap.

When Frank threw open the door of the room again he uttered a cry of
alarm. The back stairway was a mass of flame. Although hardly more than
two minutes had passed since they came up those stairs, it was now
manifestly impossible to pass down again.

He slammed the door shut and found Jerry staring at him in the half
light.

"Talk to me about your fiery furnaces, that beats them all!" exclaimed
Frank's chum, as he let go the professor's shoulders. "What shall we do
now?"

Frank ran over to the window and threw up the sash. He looked out and
then came back to where Jerry stood, trembling with excitement. Frank was
as cool as ever in his life.

"There's a chance, Jerry," he shouted. "No fire below! Take hold here;
tear up these sheets and knot them into a rope. Work for your life, and
if the fire only holds back we may be able to save both the professor and
ourselves! But work! work!"




CHAPTER III

HEADED SOUTH