"Naturally," I answer.

Then pumping him still more closely, I go on:

"So, what no one else has been able to obtain from Thomas Roch--"

"We obtained without much difficulty."

"By paying him."

"By paying him an incredible price--and, moreover, by causing to vibrate what in him is a very sensitive chord."

"What chord?"

"That of vengeance!"

"Vengeance?--against whom?"

"Against all those who have made themselves his enemies by discouraging him, by spurning him, expelling him, by constraining him to go a-begging from country to country with an invention of incontestable superiority! Now all notion of patriotism is extinct in his soul. He has now but one thought, one ferocious desire: to avenge himself upon those who have denied him--and even upon all mankind!

Really, Mr. Hart, your governments of Europe and America committed a stupendous blunder in refusing to pay Roch the price his fulgurator is worth!"

And Engineer Serko describes enthusiastically the various advantages of the new explosive which, he says, is incontestably superior to any yet invented.

"And what a destructive effect it has," he adds. "It is a.n.a.logous to that of the Zalinski sh.e.l.l, but is a hundred times more powerful, and requires no machine for firing it, as it flies through the air on its own wings, so to speak."

I listen in the hope that Engineer Serko will give away a part of the secret, but in vain. He is careful not to say more than he wants to.

"Has Thomas Roch," I ask, "made you acquainted with the composition of his explosive?"

"Yes, Mr. Hart--if it is all the same to you--and we shall shortly have considerable quant.i.ties of it stored in a safe place."

"But will there not be a great and ever-impending danger in acc.u.mulating large quant.i.ties of it? If an accident were to happen it would be all up with the island of----!"

Once more the name of Back Cup was on the point of escaping me.

They might consider me too well-informed if they were aware that in addition to being acquainted with the Count d'Artigas' real name I also know where his stronghold is situated.

Luckily Engineer Serko has not remarked my reticence, and he replies:

"There will be no cause for alarm. Thomas Roch's explosive will not burn unless subjected to a special deflagrator. Neither fire nor shock will explode it."

"And has Thomas Roch also sold you the secret of his deflagrator?"

"Not yet, Mr. Hart, but it will not be long before the bargain is concluded. Therefore, I repeat, no danger is to be apprehended, and you need not keep awake of nights on that account. A thousand devils, sir! We have no desire to be blown up with our cavern and treasures! A few more years of good business and we shall divide the profits, which will be large enough to enable each one of us to live as he thinks proper and enjoy life to the top of his bent--after the dissolution of the firm of Ker Karraje and Co. I may add that though there is no danger of an explosion, we have everything to fear from a denunciation--which you are in the position to make, Mr. Hart.

Therefore, if you take my advice, you will, like a sensible man, resign yourself to the inevitable until the disbanding of the company.

We shall then see what in the interest of our security is best to be done with you!"

It will be admitted that these words are not exactly calculated to rea.s.sure me. However, a lot of things may happen ere then. I have learned one good thing from this conversation, and that is that if Thomas Roch has sold his explosive to Ker Karraje and Co., he has at any rate, kept the secret of his deflagrator, without which the explosive is of no more value than the dust of the highway.

But before terminating the interview I think I ought to make a very natural observation to Mr. Serko.

"Sir," I say, "you are now acquainted with the composition of Thomas Roch's explosive. Does it really possess the destructive power that the inventor attributes to it? Has it ever been tried? May you not have purchased a composition as inert as a pinch of snuff?"

"You are doubtless better informed upon this point than you pretend, Mr. Hart. Nevertheless, I thank you for the interest you manifest in our affairs, and am able to rea.s.sure you. The other night we made a series of decisive experiments. With only a few grains of this substance great blocks of rock were reduced to impalpable dust!"

This explanation evidently applies to the detonation I heard.

"Thus, my dear colleague," continues Engineer Serko, "I can a.s.sure you that our expectations have been answered. The effects of the explosive surpa.s.s anything that could have been imagined. A few thousand tons of it would burst our spheroid and scatter the fragments into s.p.a.ce. You can be absolutely certain that it is capable of destroying no matter what vessel at a distance considerably greater than that attained by present projectiles and within a zone of at least a mile. The weak point in the invention is that rather too much time has to be expended in regulating the firing."

Engineer Serko stops short, as though reluctant to give any further information, but finally adds:

"Therefore, I end as I began, Mr. Hart. Resign yourself to the inevitable. Accept your new existence without reserve. Give yourself up to the tranquil delights of this subterranean life. If one is in good health, one preserves it; if one has lost one's health, one recovers it here. That is what is happening to your fellow countryman.

Yes, the best thing you can do is to resign yourself to your lot."

Thereupon this giver of good advice leaves me, after saluting me with a friendly gesture, like a man whose good intentions merit appreciation. But what irony there is in his words, in his glance, in his att.i.tude. Shall I ever be able to get even with him?

I now know that at any rate it is not easy to regulate the aim of Roch's auto-propulsive engine. It is probable that it always bursts at the same distance, and that beyond the zone in which the effects of the fulgurator are so terrible, and once it has been pa.s.sed, a ship is safe from its effects. If I could only inform the world of this vital fact!

_August 20_.--For two days no incident worth recording has occurred. I have explored Back Cup to its extreme limits. At night when the long perspective of arched columns are illuminated by the electric lamps, I am almost religiously impressed when I gaze upon the natural wonders of this cavern, which has become my prison. I have never given up hope of finding somewhere in the walls a fissure of some kind of which the pirates are ignorant and through which I could make my escape. It is true that once outside I should have to wait till a pa.s.sing ship hove in sight. My evasion would speedily be known at the Beehive, and I should soon be recaptured, unless--a happy thought strikes me--unless I could get at the _Ebba's_ boat that was drawn up high and dry on the little sandy beach in the creek. In this I might be able to make my way to St. George or Hamilton.

This evening--it was about nine o'clock--I stretched myself on a bed of sand at the foot of one of the columns, about one hundred yards to the east of the lagoon. Shortly afterwards I heard footsteps, then voices. Hiding myself as best I could behind the rocky base of the pillar, I listened with all my ears.

I recognized the voices as those of Ker Karraje and Engineer Serko.

The two men stopped close to where I was lying, and continued their conversation in English--which is the language generally used in Back Cup. I was therefore able to understand all that they said.

They were talking about Thomas Roch, or rather his fulgurator.

"In a week's time," said Ker Karraje, "I shall put to sea in the _Ebba_, and fetch the sections of the engines that are being cast in that Virginian foundry."

"And when they are here," observed Engineer Serko, "I will piece them together and fix up the frames for firing them. But beforehand, there is a job to be done which it seems to me is indispensable."

"What is that?"

"To cut a tunnel through the wall of the cavern."

"Through the wall of the cavern?"

"Oh! nothing but a narrow pa.s.sage through which only one man at a time could squeeze, a hole easy enough to block, and the outside end of which would be hidden among the rocks."

"Of what use could it be to us, Serko?"

"I have often thought about the utility of having some other way of getting out besides the submarine tunnel. We never know what the future may have in store for us."

"But the walls are so thick and hard," objected Ker Karraje.

"Oh, with a few grains of Roch's explosive I undertake to reduce the rock to such fine powder that we shall be able to blow it away with our breath," Serko replied.

It can easily be imagined with what interest and eagerness I listened to this. Here was a ray of hope. It. was proposed to open up communication with the outside by a tunnel in the wall, and this held out the possibility of escape.

As this thought flashed through my mind, Ker Karraje said: