rst one monstrous aerial
battleship came to rest on the earth. At once the men in the field
surrounded her, seizing the ropes that were flung out, and made her
fast.

There was a good deal of noise. Men were calling in German of course.
But soon order was restored, and the only voices were those giving
commands. Suddenly Frank's face lighted up.

"Did you understand, Henri?" he said. "The men in the field are to be
the crews for the fighting. They have sailed here with only enough men
to steer them. And now all are ordered out, to stretch their legs!"

"Yes, I heard that order," said Henri.

"Now keep your eyes glued to them. What are they doing?"

They listened and watched intently.

"Just as I thought," said Frank. "See, they are going to fill the tanks.
There, they are attaching hose. And they have a pump--they surely must
have a pump, to send the petrol uphill!"

Meanwhile the other airship had come down, on the other side of the
barrels, and there as nearly as they could judge, the same procedure was
carried out.

"Watch, Henri! Are they pumping?" cried Frank.

"Yes!" said Henri. "Now--now--now is your time, Francois!"

Frank hesitated the fraction of a second.

"If it meant killing them, I could not do it," he said, solemnly. "But
they are all out of the airships. Now!"

On the word he closed the circuit he had made by connecting the loose
ends of the wire he had carried from his petrol filled hole to the two
batteries he had brought from the car. He had broken the circuit at the
other end, leaving the two wires separated by the fraction of an inch,
and cunningly held in place. The result was a spark--or would be, if he
had not erred.

And he had made no mistake! For as he closed the circuit, he saw a
flash of flame at the spot where he and Henri had dug the hole into
which the petrol had flowed from the barrel they had opened. The spark
had fired the explosive gas that results when petrol is mixed with air.
The flame ran along the shallow trench, and, amid a chorus of shrieks
from the Germans who scattered in all directions, the fire reached the
barrel. In a moment there was a loud explosion. The flame flew to the
other barrels--the whole neighborhood of the barrels, owing to the
mixture of the petrol and the air, was then filled with an explosive and
inflammable gas.

There was a great flash of flame, broken by a dozen sharp reports as one
barrel after another blew up.

And still, though the