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 attentions to the officer who commanded the Sword, and to his crew were useless.  The shock had torn open the after and middle compartments, and they paid with their lives the misfortune—­due to chance, as you observe—­of having discovered our mysterious retreat.”

On learning that Lieutenant Davon and his companions are dead, my heart is filled with anguish; but to keep up my role—­as they were persons with whom, presumably, I was not acquainted, and had never seen—­I am careful not to display any emotion.  I must, on no account, afford ground for the suspicion that there was any connivance between the commander of the Sword and me.  For aught I know, Engineer Serko may have reason to be very skeptical about the discovery of the tunnel being accidental.

What, however, I am most concerned about is that the unlooked-for occasion to recover my liberty was lost.  Shall I ever be afforded another chance?  However this may be, my notice reached the English authorities of the archipelago, and they now know where Ker Karraje is to be found.  When it is seen that the Sword does not return to Bermuda, there can be no doubt that another attempt will be made to get inside Back Cup, in which, had it not been for the inopportune return of the tug, I should no longer be a prisoner.

I have resumed my usual existence, and having allayed all mistrust, am permitted to wander freely about the cavern, as usual.

It is patent that the adventure has had no ill effect upon Thomas Roch.  Intelligent nursing brought him around, as it did me.  In full possession of his mental faculties he has returned to work, and spends the entire day in his laboratory.

The Ebba brought back from her last trip bales, boxes, and a quantity of objects of varied origin, and I conclude that a number of ships must have been pillaged during this marauding expedition.