Now they had reached the second flight of stairs.  A burst of red fire further along the hall served to show them for a brief space of time how matters stood.  Up the stairs they stumbled, gaining the upper landing.  Again Jerry turned to the left.

“He said the last room, didn’t he?” he gasped.

“Yes, go on!” answered Frank, still gripping his comrade’s garment.

“Then here’s the door!”

“Shut?”

“Yes, and locked, too!  What shall we do?” exclaimed Jerry.

“Kick it in—­any old way, but we must be quick!” answered the other.

Then the two threw themselves upon the door.  It quickly gave way before their combined assault.  They pushed into the room.  The smoke had gained a footing here, but on account of the closed door it was not nearly so bad as in the halls.

Immediately they saw a figure stretched across the bed.  The balloonist had evidently been overcome by sleep before he thought to undress, and dropped over just as he had come from his lame brother’s house.

“Wake up, professor, the house is on fire!” shouted Frank in the ear of the man.

Jerry, meanwhile, was shaking him vigorously; but all their efforts seemed to be of no avail.  The man slept on as peacefully as though a babe, such was the power of the drug he had taken.

“We can’t stay here long,” said Frank, as the smoke thickened in the room.  “And as he won’t wake up, why, we’ll have to try and carry or drag him down.”

Fortunately, the man was not a very large person, or they might have despaired of ever accomplishing such a thing.

“Take hold on that side, Jerry.  Now, lift, and drag his heels.  That’s the only way we can do,” exclaimed Frank, who feared that even short as their stay in that room had been they would find conditions changed for the worse when they again reached the hall.

The professor paid not the least attention to what they were doing.  He had possibly taken an overdose of his sleeping-powder, and only for the coming of the two chums must have perished miserably, like a rat in a 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!”