Those
unscrupulous and cowardly men were in a veritable panic of fear, which
contrasted strangely with the calm, resigned attitude of Mary and her
uncle.

"We must get out! Some one must save us!" yelled Field.

"Jump from the window!" cried Melling.

"No, I can't permit that!" declared Mr. Keith, standing in their path.
"It would be sure death! As it is, there may be a chance."

"A chance? How?" asked Field. "Listen to that!"

Through the closed door of Mr. Keith's office could be heard the roar
and crackle of flames, while the very air was now stifling and hot,
filled with acrid smoke.

"We can only wait," said Mr. Keith, and he wet Mary's handkerchief in
the water and handed it to her to bind over her face.

"Is everything all right, Ned?" called Tom, as he turned on a little
more power, so that the Lucifer lunged ahead toward the great pillar of
fire that now reddened the sky for miles around.

"All ready," was the answer. "You only have to give the word when you
want us to let go."

"Let go!" cried Mr. Damon. "Bless my umbrella, Tom! We don't have to
jump out, do we?"

"He means to let go the extinguisher grenades," said Mr. Baxter. "Shall
we let them all go at once, Tom?" asked the chemist.

"No, drop half when I shoot over the first time. We'll see what effect
they have, and then come back with the rest."

"That's the idea!" cried Ned. "Well, give us the word when you're
ready, Tom."

"I will," was the answer of the young inventor, and with keen eyes he
began to set the automatic gages so those in charge of the grenades
would be able to drop them most effectively.

The flames were mounting higher and higher above the ill-fated Landmark
Building. It was a "land-mark" now, for miles around--a fearsome mark,
indeed.

"I hope every one is out of the place," said Ned, as the airship
approached nearer and the fierceness of the fire was more manifest.

"Bless my thermometer, you're right!" exclaimed Mr. Damon. "I don't see
how any one could live in that furnace."

Seen from above it appeared that the fire was engulfing the whole
building, while, as a matter of fact, only the central portion was yet
blazing. But it was only a question of time when the remainder would
ignite.

And it was to this fact--that the fire was rushing up the stairway and
elevator shafts as up a chimney--that Mary and her uncle, as well as
Field and Melling, owed their temporary safety.

Had Tom known that the girl he lov