It is true the tug would be able to land the Count d'Artigas somewhere on the American coast where, money being no object, he could easily buy or order another vessel. But no matter. If Back Cup is only destroyed before Ker Karraje has Roch's fulgurator at his disposal I shall render thanks to heaven.

A few hours later, at the usual time, I quit my cell. All is quiet at the Beehive. The men are going about their business as usual. The tug is moored near the jetty. Thomas Roch is going to his laboratory, and Ker Karraje and Engineer Serko are tranquilly pacing backwards and forwards by the lake and chatting. The island therefore could not have been attacked during the night. Yet I was awakened by the report of cannon, this I will swear.

At this moment Ker Karraje goes off towards his abode and Engineer Serko, smilingly ironical, as usual, advances to meet me.

"Well, Mr. Simon Hart," he says, "are you getting accustomed to your tranquil existence? Do you appreciate at their just merit the advantages of this enchanted grotto? Have you given up all hope of recovering your liberty some day or other?"

What is the use of waxing wroth with this jester? I reply calmly:

"No, sir. I have not given up hope, and I still expect that I shall be released."

"What! Mr. Hart, separate ourselves from a man whom we all esteem--and I from a colleague who perhaps, in the course of Thomas Roch's fits of delirium, has learned some of his secrets? You are not serious!"

So this is why they are keeping me a prisoner in Back Cup! They suppose that I am in part familiar with Koch's invention, and they hope to force me to tell what I know if Thomas Koch refuses to give up his secret. This is the reason why I was kidnapped with him, and why I have not been accommodated with an involuntary plunge in the lagoon with a stone fastened to my neck. I see it all now, and it is just as well to know it.

"Very serious," I affirm, in response to the last remark of my interlocutor.

"Well," he continues, "if I had the honor to be Simon Hart, the engineer, I should reason as follows: 'Given, on the one hand, the personality of Ker Karraje, the reasons which incited him to select such a mysterious retreat as this cavern, the necessity of the said cavern being kept from any attempt to discover it, not only in the interest of the Count d'Artigas, but in that of his companions--'"

"Of his accomplices, if you please."

"'Of his accomplices,' then--'and on the other hand, given the fact that I know the real name of the Count d'Artigas and in what mysterious safe he keeps his riches--'"

"Riches stolen, and stained with blood, Mr. Serko."

"'Riches stolen and stained with blood,' if you like--'I ought to understand that this question of liberty cannot be settled in accordance with my desires.'"

It is useless to argue the point under these conditions, and I switch the conversation on to another line.

"May I ask," I continue, "how you came to find out that Gaydon, the warder, was Simon Hart, the engineer?"

"I see no reason for keeping you in ignorance on the subject, my dear colleague. It was largely by hazard. We had certain relations with the manufactory in New Jersey with which you were connected, and which you quitted suddenly one day under somewhat singular circumstances. Well, during a visit I made to Healthful House some months before the Count d'Artigas went there, I saw and recognized you."

"You?"

"My very self, and from that moment I promised myself the pleasure of having you for a fellow-passenger on board the _Ebba_."

I do not recall ever having seen this Serko at Healthful House, but what he says is very likely true.

"I hope your whim of having me for a companion will cost you dear, some day or other," I say to myself.

Then, abruptly, I go on:

"If I am not mistaken, you have succeeded in inducing Thomas Roch to disclose the secret of his fulgurator?"

"Yes, Mr. Hart. We paid millions for it. But millions, you know, are nothing to us. We have only the trouble of taking them! Therefore we filled all his pockets--covered him with millions!"

"Of what use are these millions to him if he is not allowed to enjoy them outside?"

"That, Mr.