, they were seized.

Against such odds little could be done, though our friends did not give
up without a struggle.

"What does this mean?" angrily demanded Tom Swift. "Who are you? What
are you doing aboard my craft? Who are--"

His words were lost in smothered tones, for one of his assailants put a
heavy cloth over his mouth, and tied it there, gagging him. Another
man, with a quick motion, whipped a rope about Tom's hands and feet,
and he was soon securely bound.

In like manner the others were treated, and, despite the struggles of
Mr. Damon, the two government men and Ned, they were soon put in a
position where they could do nothing--helplessly bound, and laid on a
bench in the main cabin, staring blankly up at the ceiling. Each one
was gagged so effectively that he could not utter more than a faint
moan.

Of the riot of thoughts that ran through the heads of each one, I leave
you to imagine.

What did it all mean? Where had the strange men come from? What did
they mean by thus assaulting Tom and his companions? And what had
happened to the others of the crew--Koku, Jerry Mound, the engineer,
and George Ventor, the assistant pilot?

These were only a few of the questions Tom asked himself, as he lay
there, bound and helpless. Doubtless Mr. Damon and the others were
asking themselves similar questions.

One thing was certain--whatever the stowaways, as Koku had called them,
had done, they had not neglected the Mars, for she was running along at
about the same speed, though in what direction Tom could not tell. He
strained to get a view of the compass on the forward wall of the cabin,
but he could not see it.

It had been a rough-and-tumble fight, by which our friends were made
prisoners, but no one seemed to have been seriously, or even slightly,
hurt. The invaders, under the leadership of the Frenchman, were rather
ruffled, but that was all.

Pantingly they stood in line, surveying their captives, while the man
with the mustache and imperial smiled in a rather superior fashion at
the row of bound ones. He spoke in his own tongue to the men, who, with
the exception of one, filed out, going, as Tom and the others could
note, to the engine-room in the rear.

"I hope I have not had to hurt any of you," the Frenchman observed,
with sarcastic politeness. "I regret the necessity that caused me to do
this, but, believe me, it was unavoidable."

He spoke with some accent, and Tom at once decided this was th