"I believe she is!" yelled Tom. "Oh, if it only works!"

The tank was still moving, though more slowly. Still the crackle of the
wireless was heard.

And then, just as Tom shut off his own motor and let the Hawk glide on
her downward way in a volplane to earth, the great, ponderous tank came
to a stop, on the very edge of the precipice at the foot of which
rolled the river.

"Whew!" whistled Ned, as the aircraft rolled along the ground near the
war machine. "That was touch and go, Tom! They stopped her just in
time."

"You mean the wireless stopped her," said Tom quietly. "I'm very much
afraid that if Koku and the others are alive they're still prisoners in
the craft."

"The wireless!" gasped Ned, as he and his chum got out of the Hawk. "Do
you mean that you stopped her by wireless, Tom?"

"That's what I did. It was a desperate chance, but I took it. I had
just installed in the tank a system of wireless control, so she could
be guided as some torpedos and submarines are, by wireless impulses
from the shore.

"Only I'd never given the tank system a tryout. It was all installed,
and had worked perfectly on the small model I constructed. And when I
saw her running away, out of control as she was, I realized the
wireless was the only thing that would stop her, if that would. It
might operate just opposite to what I wanted, though, and increase her
speed."

"But I took the chance. I set the airship wireless current to working,
and tuned it in to coincide with the control of the tank. Then, by
means of the wireless impulse I shut off the motors, which can be
stopped or started by hand or by electricity. I shut 'em off."

"And only just in time!" cried Ned. "Whew, Tom Swift, but that was a
close call!"

"I realize that myself!" said the young inventor. "This is a new idea
and has to be worked out further for our newer tanks."

"Gee!" ejaculated Ned. "Out of date before got into use! Now let's see
about our friends!"

It was the work of but a moment to enter the tank, and, after making
sure that the machinery was all right, Tom and Ned made their way to
the interior. In one of the smallest rooms they found Koku and the
others bound with ropes, and in a bad way. Koku was so tied with cords
and hemp as to resemble a bale of Manilla cable.

"Cut 'em loose, Ned!" cried Tom, and the bonds were soon severed. Then
came explanations.

As has been told, one of the plotters, whose identity was not learned
until la