Engineer Serko made no response to this observation, which, for that matter, was unanswerable.

I continued: 

“Therefore a squadron sent by the maritime powers who have an interest in breaking up this island would not hesitate to approach and shell it.  Now, I argue from this that as this squadron has not yet appeared, it is not likely to come at all, and that nothing is known as to Ker Karraje’s whereabouts, and you must admit that this hypothesis is the most cheerful one, as far as you are concerned.”

“That may be,” Engineer Serko replied, “but what is, is.  Whether they are aware of the fact or no, if warships approach within five or six miles of this island they will be sunk before they have had time to fire a single shot!”

“Well, and what then?”

“What then?  Why the probability is that no others would care to repeat the experiment.”

“That, again, may be.  But these warships would invest you beyond the dangerous zone, and the Ebba would not be able to put in to the ports she previously visited with the Count d’Artigas.  In this event, how would you be able to provision the island?”

Engineer Serko remained silent.

This argument, which he must already have brooded over, was too logical to be refuted or dismissed, and I have an idea that the pirates contemplate abandoning Back Cup.

Nevertheless, not relishing being cornered, he continued: 

“We should still have the tug, and what the Ebba could not do, this would.”

“The tug?” I cried.  “But if Ker Karraje’s secrets are known, do you suppose the powers are not also aware of the existence of the Count d’Artigas’ submarine boat?”

Engineer Serko looked at me suspiciously.

“Mr. Hart,” he said, “you appear to me to carry your deductions rather far.”

“I, Mr. Serko?”

“Yes, and I think you talk about all this like a man who knows more than he ought to.”

This remark brought me up abruptly.  It was evident that my arguments might give rise to the suspicion that I was not altogether irresponsible for the recent incident.  Engineer Serko scrutinized me sharply as though he would read my innermost thoughts.

“Mr. Serko,” I observed, “by profession, as well as by inclination, I am accustomed to reason upon everything.  This is why I communicated to you the result of my reasoning, which you can take into consideration or not, as you like.”

Thereupon we separate.  But I fancy my lack of reserve may have excited suspicions which may not be easy to allay.

From this interview, however, I gleaned a precious bit of information, namely, that the dangerous zone of Roch’s fulgurator is between five and six miles off.  Perhaps, during the next equinoctial tides, another notice to this effect in another keg may also reach a safe destination.

But how many weary months to wait before the orifice of the tunnel will again be uncovered!