s.

"All ready!" shouted Ned.

"Let go!" cried Tom, and with a click of springs the fire extinguishers
dropped from the bottom of the Lucifer into the very heart of the
flames in the Landmark Building.

There was a blast as from a furnace seventy times heated, a choking and
gasping for breath on the part of the occupants of the airship, a
shriveling, as it seemed, of the naked flesh, and then, when it
appeared that all of them must be engulfed in the great heat, the
airship passed out of the zone of fire.

A rush of cool air followed, reviving them all, and then, when out of
the swirls of smoke, Ned, looking back, cried:

"Good work, Tom! Good work!"

"Did we hit it?" cried the young inventor. "She's half gone!" declared
Mr. Baxter. "Can you give her the rest of the load?"

"I'm going to try!" declared Tom.

"Bless my bank balance!" shouted Mr. Damon, "are we going through that
awful furnace again?"

"It will not be so bad this time," observed Ned. "The fire is half out
now. Tom's stuff did the trick!"

Indeed it was evident, as Tom sent the Lucifer around in a sharp turn,
that the fire had been largely smothered by the gas that now lay over
it like a wet blanket. But there was still some fire spouting up.

"Give her all we have!" yelled Tom, as, once more, he prepared to cross
the zone of fire.

"Right," sang out Ned.

Once more the Lucifer swept over the burning building. Down shot the
remaining grenades, falling into the mass of flames and bursting,
though the reports could not be heard because of the tumult in the
streets below. For the firemen and spectators had seen the sudden dying
down of the fire, they had caught sight of a shadowy shape in the
night, hovering over the blazing building, and they wondered what it
all meant.

"How is it?" asked Tom, as he guided the craft back to get a view of
his work.

"That settles it!" answered Ned. "There isn't fire enough now to broil
a beefsteak!"

This was not exactly true, for the blaze was not entirely subdued. But
the flames had all been killed off in the higher parts of the Landmark
Building, and what remained could easily be dealt with by the firemen
on the ground. They proceeded to make short work of the remainder of
the conflagration, the while wondering who had so effectively aided
them from the clouds.

"Well," observed Tom, as he saw how effectively he had smothered the
great fire, "it's of no use to go on now. I haven't an ounce of
chem