So, then, all was explained by the submarine explosion of this torpedo. Cyrus Harding could not be mistaken, as, during the war of the Union, he had had occasion to try these terrible engines of destruction. It was under the action of this cylinder, charged with some explosive substance, nitro-glycerine, picrate, or some other material of the same nature, that the water of the channel had been raised like a dome, the bottom of the brig crushed in, and she had sunk instantly, the damage done to her hull being so considerable that it was impossible to refloat her. The "Speedy" had not been able to withstand a torpedo that would have destroyed an ironclad as easily as a fishing-boat!

Yes! all was explained, everything — except the presence of the torpedo in the waters of the channel!

"My friends, then," said Cyrus Harding, "we can no longer be in doubt as to the presence of a mysterious being, a castaway like us, perhaps, abandoned on our island, and I say this in order that Ayrton may be acquainted with all the strange events which have occurred during these two years. Who this beneficent stranger is, whose intervention has, so fortunately for us, been manifested on many occasions, I cannot imagine. What his object can be in acting thus, in concealing himself after rendering us so many services, I cannot understand. But his services are not the less real, and are of such a nature that only a man possessed of prodigious power, could render them. Ayrton is indebted to him as much as we are, for, if it was the stranger who saved me from the waves after the fall from the balloon, evidently it was he who wrote the document, who placed the bottle in the channel, and who has made known to us the situation of our companion. I will add that it was he who guided that chest, provided with everything we wanted, and stranded it on Flotsam Point; that it was he who lighted that fire on the heights of the island, which permitted you to land; that it was he who fired that bullet found in the body of the peccary; that it was he who immersed that torpedo in the channel, which destroyed the brig; in a word, that all those inexplicable events, for which we could not assign a reason, are due to this mysterious being. Therefore, whoever he may be, whether shipwrecked, or exiled on our island, we shall be ungrateful, if we think ourselves freed from gratitude towards him. We have contracted a debt, and I hope that we shall one day pay it."

"You are right in speaking thus, my dear Cyrus," replied Gideon Spilett. "Yes, there is an almost all-powerful being, hidden in some part of the island, and whose influence has been singularly useful to our colony. I will add that the unknown appears to possess means of action which border on the supernatural, if in the events of practical life the supernatural were recognizable. Is it he who is in secret communication with us by the well in Granite House, and has he thus a knowledge of all our plans? Was it he who threw us that bottle, when the vessel made her first cruise? Was it he who threw Top out of the lake, and killed the dugong? Was it he, who as everything leads us to believe, saved you from the waves, and that under circumstances in which any one else would not have been able to act? If it was he, he possesses a power which renders him master of the elements."

The reporter's reasoning was just, and every one felt it to be so.

"Yes," rejoined Cyrus Harding, "if the intervention of a human being is not more questionable for us, I agree that he has at his disposal means of action beyond those possessed by humanity. There is a mystery still, but if we discover the man, the mystery will be discovered also. The question, then, is, ought we to respect the incognito of this generous being, or ought we to do everything to find him out? What is your opinion on the matter?"

"My opinion," said Pencroft, "is that, whoever he may be, he is a brave man, and he has my esteem!"

"Be it so," answered Harding, "but that is not an answer, Pen-croft."

"Master," then said Neb, "my idea is, that we may search as long as we like for this gentleman whom you are talking about, but that we shall not discover him till he pleases."

"That's not bad, what you say, Neb," observed Pencroft.

"I am of Neb's opinion," said Gideon Spilett, "but that is no reason for not attempting the adventure. Whether we find this mysterious being or not, we shall at least have fulfilled our duty towards him."

"And you, my boy, give us your opinion," said the engineer, turning to Herbert.

"Oh," cried Herbert, his countenance full of animation, "how I should like to thank him, he who saved you first, and who has now saved us!"

"Of course, my boy," replied Pencroft, "so would I and all of us. I am not inquisitive, but I would give one of my eyes to see this individual face to face! It seems to me that he must be handsome, tall, strong, with a splendid beard, radiant hair, and that he must be heated on the clouds, a great ball in his hands!"

"But, Pencroft," answered Spilett, "you are describing a picture of the Creator."

"Possibly, Mr. Spilett," replied the sailor, "but that is how I imagine him!"

"And you, Ayrton?" asked the engineer.

"Captain Harding," replied Ayrton, "I can give you no better advice in this matter. Whatever you do will be best, when you wish me to join you in your researches, I am ready to follow you."

"I thank you, Ayrton," answered Cyrus Harding, "but I should like a more direct answer to the question I put to you. You are our companion; you have already endangered your life several times for us, and you, as well as the rest, ought to be consulted in the matter of any important decision. Speak, therefore."

"Captain Harding," replied Ayrton, "I think that we ought to do everything to discover this unknown benefactor. Perhaps he is alone. Perhaps he is suffering. Perhaps he has a life to be renewed. I, too, as you said, have a debt of gratitude to pay him. It was he, it could be only he who must have come to Tabor Island, who found there the wretch you knew, and who made known to you that there was an unfortunate man there to be saved. Therefore it is, thanks to him, that I have become a man again. No, I will never forget him!"

"That is settled, then," said Cyrus Harding. "We will begin our researches as soon as possible. We will not leave a corner of the island unexplored. We will search into its most secret recesses, and will hope that our unknown friend will pardon us in consideration of our intentions!"

For several days the colonists were actively employed in haymaking and the harvest. Before putting their project of exploring the yet unknown parts of the island into execution, they wished to get all possible work finished. It was also the time for collecting the various vegetables from the Tabor Island plants. All was stowed away, and happily there was no want of room in Granite House, in which they might have housed all the treasures of the island. The products of the colony were there, methodically arranged, and in a safe place, as may be believed, sheltered as much from animals as from man.

There was no fear of damp in the middle of that thick mass of granite. Many natural excavations situated in the upper passage were enlarged either by pick-ax or mine, and Granite House thus became a general warehouse, containing all the provisions, arms, tools, and spare utensils — in a word, all the stores of the colony.

As to the guns obtained from the brig, they were pretty pieces of ordnance, which, at Pencroft's entreaty, were hoisted by means of tackle and pulleys, right up into Granite House; embrasures were made between the windows, and the shining muzzles of the guns could soon be seen through the granite cliff. From this height they commanded all Union Bay. It was like a little Gibraltar, and any vessel anchored off the islet would inevitably be exposed to the fire of this aerial battery.

"Captain," said Pencroft one day, it was the 8th of November, "now that our fortifications are finished, it would be a good thing if we tried the range of our guns."

"Do you think that is useful?" asked the engineer.

"It is more than useful, it is necessary! Without that how are we to know to what distance we can send one of those pretty shot with which we are provided?"

"Try them, Pencroft," replied the engineer. "However, I think that in making the experiment, we ought to employ, not the ordinary powder, the supply of which, I think, should remain untouched, but the pyroxile which will never fail us."

"Can the cannon support the shock of the pyroxile?" asked the reporter, who was not less anxious than Pencroft to try the artillery of Granite House.

"I believe so. However," added the engineer, "we will be prudent."

The engineer was right in thinking that the guns were of excellent make. Made of forged steel, and breech-loaders, they ought consequently to be able to bear a considerable charge, and also have an enormous range. In fact, as regards practical effect, the transit described by the ball ought to be as extended as possible, and this tension could only be obtained under the condition that the projectile should be impelled with a very great initial velocity.

"Now," said Harding to his companions, "the initial velocity is in proportion to the quantity of powder used. In the fabrication of these pieces, everything depends on employing a metal with the highest possible power of resistance, and steel is incontestably that metal of all others which resists the best. I have, therefore, reason to believe that our guns will bear without risk the expansion of the pyroxile gas, and will give excellent results."

"We shall be a great deal more certain of that when we have tried them!” answered Pencroft.

It is unnecessary to say that the four cannons were in perfect order. Since they had been taken from the water, the sailor had bestowed great care upon them. How many hours he had spent, in rubbing, greasing, and polishing them, and in cleaning the mechanism! And now the pieces were as brilliant as if they had been on board a frigate of the United States' Navy.

On this day, therefore, in presence of all the members of the colony, including Master Jup and Top, the four cannon were successively tried. They were charged with pyroxile, taking into consideration its explosive power, which, as has been said, is four times that of ordinary powder: the projectile to be fired was cylindroconic.

Pencroft, holding the end of the quick-match, stood ready to fire.

At Harding's signal, he fired. The shot, passing over the islet, fell into the sea at a distance which could not be calculated with exactitude.

The second gun was pointed at the rocks at the end of Flotsam Point, and the shot, striking a sharp rock nearly three miles from Granite House, made it fly into splinters. It was Herbert who had pointed this gun and fired it, and very proud he was of his first shot. Pencroft only was prouder than he! Such a shot, the honor of which belonged to his dear boy.

The third shot, aimed this time at the downs forming the upper side of Union Bay, struck the sand at a distance of four miles, then having ricocheted, was lost in the sea in a cloud of spray.

For the fourth piece Cyrus Harding slightly increased the charge, so as to try its extreme range. Then, all standing aside for fear of its bursting, the match was lighted by means of a long cord.

A tremendous report was heard, but the piece had held good, and the colonists rushing to the windows, saw the shot graze the rocks of Mandible Cape, nearly five miles from Granite House, and disappear in Shark Gulf.

"Well, captain," exclaimed Pencroft, whose cheers might have rivaled the reports themselves, "what do you say of our battery? All the pirates in the Pacific have only to present themselves before Granite House! Not one can land there now without our permission!"

"Believe me, Pencroft," replied the engineer, "it would be better not to have to make the experiment."

"Well," said the sailor, "what ought to be done with regard to those six villains who are roaming about the island? Are we to leave them to overrun our forests, our fields, our plantations. These pirates are regular jaguars, and it seems to me we ought not to hesitate to treat them as such! What do you think, Ayrton?" added Pencroft, turning to his companion.

Ayrton hesitated at first to reply, and Cyrus Harding regretted that Pencroft had so thoughtlessly put this question. And he was much moved when Ayrton replied in a humble tone,

"I have been one of those jaguars, Mr. Pencroft. I have no right to speak."

And with a slow step he walked away.

Pencroft understood.

"What a brute I am!" he exclaimed. "Poor Ayrton! He has as much right to speak here as any one!"

"Yes," said Gideon Spilett, "but his reserve does him honor, and it is right to respect the feeling which he has about his sad past."

"Certainly, Mr. Spilett," answered the sailor, "and there is no fear of my doing so again. I would rather bite my tongue off than cause Ayrton any pain! But to return to the question. It seems to me that these ruffians have no right to any pity, and that we ought to rid the island of them as soon as possible."

"Is that your opinion, Pencroft?" asked the engineer.

"Quite my opinion."

"And before hunting them mercilessly, you would not wait until they had committed some fresh act of hostility against us?"

"Isn't what they have done already enough?" asked Pencroft, who did not understand these scruples.

"They may adopt other sentiments!" said Harding, "and perhaps repent."

"They repent!" exclaimed the sailor, shrugging his shoulders. "Pencroft, think of Ayrton!" said Herbert, taking the sailor's hand. "He became an honest man again!"

Pencroft looked at his companions one after the other. He had never thought of his proposal being met with any objection. His rough nature could not allow that they ought to come to terms with the rascals who had landed on the island with Bob Harvey's accomplices, the murderers of the crew of the "Speedy," and he looked upon them as wild beasts which ought to be destroyed without delay and without remorse.

"Come!" said he. "Everybody is against me! You wish to be generous to those villains! Very well; I hope we mayn't repent it!"

"What danger shall we run," said Herbert, "if we take care to be always on our guard?"

"Hum!" observed the reporter, who had not given any decided opinion. "They are six and well armed. If they each lay hid in a corner, and each fired at one of us, they would soon be masters of the colony!"

"Why have they not done so?" said Herbert. "No doubt because it was not their interest to do it. Besides, we are six also."

"Well, well!" replied Pencroft, whom no reasoning could have convinced. "Let us leave these good people to do what they like, and don't think anything more about them!"

"Come, Pencroft," said Neb, "don't make yourself out so bad as all that! Suppose one of these unfortunate men were here before you, within good range of your gun, you would not fire."

"I would fire on him as I would on a mad dog, Neb," replied Pencroft coldly.

"Pencroft," said the engineer, "you have always shown much deference to my advice; will you, in this matter, yield to me?"

"I will do as you please, Captain Harding," answered the sailor, who was not at all convinced.

"Very well, wait, and we will not attack them unless we are attacked first."

Thus their behavior towards the pirates was agreed upon, although Pencroft augured nothing good from it. They were not to attack them, but were to be on their guard. After all, the island was large and fertile. If any sentiment of honesty yet remained in the bottom of their hearts, these wretches might perhaps be reclaimed. Was it not their interest in the situation in which they found themselves to begin a new life? At any rate, for humanity's sake alone, it would be right to wait. The colonists would no longer as before, be able to go and come without fear. Hitherto they had only wild beasts to guard against, and now six convicts of the worst description, perhaps, were roaming over their island. It was serious, certainly, and to less brave men, it would have been security lost! No matter! At present, the colonists had reason on their side against Pencroft. Would they be right in the future? That remained to be seen.