e was the case--you had no further use for him and were
about to get rid of us both."

"Is it possible, Mr. Hart, that you could have thought such a thing!"
continued Serko in his sarcastic way.

"I did, until having been able to remove the bandage from my eyes, I
perceived that I was in the tug."

"It was not the tug, but a boat of the same kind that had got through
the tunnel."

"A submarine boat?" I ejaculate.

"Yes, and manned by persons whose mission was to kidnap you and Thomas
Roch."

"Kidnap us?" I echo, continuing to feign surprise.

"And," adds Engineer Serko, "I want to know what you think about the
matter."

"What I think about it? Well, it appears to me that there is only one
plausible explanation possible. If the secret of your retreat has not
been betrayed--and I cannot conceive how you could have been betrayed
or what imprudence you or yours could have committed--my opinion is
that this submarine boat was exploring the bottom of the sea in this
neighborhood, that she must have found her way into the tunnel,
that she rose to the surface of the lagoon, that her crew, greatly
surprised to find themselves inside an inhabited cavern, seized hold
of the first persons they came across, Thomas Roch and myself, and
others as well perhaps, for of course I do not know----"

Engineer Serko has become serious again. Does he realize the inanity
of the hypothesis I try to pass off on him? Does he think I know more
than I will say? However this may be, he accepts my professed view,
and says:

"In effect, Mr. Hart, it must have happened as you suggest, and when
the stranger tried to make her way out through the tunnel just as the
tug was entering, there was a collision--a collision of which she was
the victim. But we are not the kind of people to allow our fellow-men
to perish before our eyes. Moreover, the disappearance of Thomas Roch
and yourself was almost immediately discovered. Two such valuable
lives had to be saved at all hazards. We set to work. There are many
expert divers among our men. They hastily donned their suits and
descended to the bottom of the lagoon. They passed lines around the
hull of the _Sword_----"

"The _Sword_?" I exclaim.

"That is the name we saw painted on the bow of the vessel when we
raised her to the surface. What satisfaction we experienced when we
recovered you--unconscious, it is true, but still breathing--and were
able to bring you back to life! Unfortunately all our