bling throughout the whole of the
vast structure. Tom threw back a lever and Ned, peering from a side
observation slot, beheld a strange sight.

Like the main arm of some great steam shovel, two long, latticed
girders of steel shot out from the sides of the tank. They gave a half
turn, as they were pulled forward by the steel ropes, so that they lay
with their broader surfaces uppermost.

Straight across the stream they were pulled, their clawlike ends coming
to a rest on the opposite bank. Then they were tightened into place by
a backward pull on the operating cables, and Tom, with a sigh of
relief, announced:

"Well, so far so good!"

"Do we go over now?" inquired Ned.

"Over the top--yes, I hope," answered Tom, with a laugh. "How about
you down there?" he called to the engine room through a telephone which
could only be used when the machinery was not in action, there being
too much noise to permit the use of any but visual signals after that.

"All right," came back the answer. "We're ready when you are."

"Then here we go!" said Tom. "Hold fast, Ned! Of course there's no real
telling what will happen, though I believe we'll come out of it alive."

"Cheerful prospect," murmured Ned.

The grippers were now in place. It only remained for the tank to propel
herself over them, pick them up on the other side of Tinkle Creek, and
proceed on her course.

Tom Swift hesitated a moment, one hand on the starting lever and the
other on the steering wheel. Then, with a glance at Ned, half whimsical
and half resolute, Tom started Tank A on what might prove to be her
last journey.

Slowly the ponderous caterpillar belts moved around on the sprocket
wheels. They ground with a clash of steel on the surface of the
spanners. So long was the tank that the forward end, or the "nose," was
halfway across the stream before the bottom part of the endless belts
gripped the latticed bridge.

"If we fall, we'll span the creek, not fall into it," murmured Ned, as
he looked from the observation slot.

"That's what I counted on," Tom said. "We'll get out, even if we do
fall."

But Tank A was not destined to fall. In another moment her entire
weight rested on the novel and transportable bridge Tom Swift had
evolved. Then, as the gripping ends of the girders sank farther into
the soil, the tank went on her way.

Slowly, at half speed, she crawled over the steel beams, making
progress over the creek and as safely above the water