ld not imagine. At any rate, they were not at their posts.

In the Great Power House.

The chamber was an immense square room at least a hundred feet in height
and 400 feet on a side, and almost filling the wall opposite to us was
an intricate display of machinery, wheels, levers, rods and polished
plates. This we had no doubt was one end of the great engine which opened
and shut the great gates that could dam an ocean.

"There is no one in sight," said Colonel Smith.

"Then we must act quickly," said Mr. Edison.

"Where," he said, turning to Aina, "is the handle by turning which you
saw the Martian close the gates?"

Aina looked about in bewilderment. The mechanism before us was so
complicated that even an expert mechanician would have been excusable
for finding himself unable to understand it. There were scores of knobs
and handles, all glistening in the electric light, any one of which,
so far as the uninstructed could tell, might have been the master key
that controlled the whole complex apparatus.

The Magic Lever!

"Quick," said Mr. Edison, "where is it?"

The girl in her confusion ran this way and that, gazing hopelessly upon
the machinery, but evidently utterly unable to help us.

To remain here inactive was not merely to invite destruction for
ourselves, but was sure to bring certain failure upon the purpose of
the expedition. All of us began instantly to look about in search of
the proper handle, seizing every crank and wheel in sight and striving
to turn it.

"Stop that!" shouted Mr. Edison, "you may set the whole thing wrong. Don't
touch anything until we have found the right lever."

But to find that seemed to most of us now utterly beyond the power of man.

It was at this critical moment that the wonderful depth and reach of
Mr. Edison's mechanical genius displayed itself. He stepped back, ran
his eye quickly over the whole immense mass of wheels, handles, bolts,
bars and levers, paused for an instant, as if making up his mind, then
said decidedly, "There it is," and, stepping quickly forward, selected a
small wheel amid a dozen others, all furnished at the circumference with
handles like those of a pilot's wheel, and, giving it a quick wrench,
turned it half way around.

Surprised by the Enemy.

At this instant, a startling shout fell upon our ears. There was
a thunderous clatter behind us, and, turning, we saw three gigantic
Martians rushing forward.

Chapter XV.

"Swe