Their hearts mingled in ardent brotherly affection, the most perfect and heroic affection that can blend men together. And they embraced one another whilst, with her babe on her breast, Marie, so gay, healthful and loyal, looked at them and smiled, with big tears gathering in her eyes.

Thomas, however, having finished his motor’s last toilet, had just set it in motion. It was a prodigy of lightness and strength, of no weight whatever in comparison with the power it displayed. And it worked with perfect smoothness, without noise or smell. The whole family was gathered round it in delight, when there came a timely visit, one from the learned and friendly Bertheroy, whom indeed Guillaume had asked to call, in order that he might see the motor working.

The great chemist at once expressed his admiration; and when he had examined the mechanism and understood how the explosive was employed as motive power—an idea which he had long recommended,—he tendered enthusiastic congratulations to Guillaume and Thomas. “You have created a little marvel,” said he, “one which may have far-reaching effects both socially and humanly. Yes, yes, pending the invention of the electrical motor which we have not yet arrived at, here is an ideal one, a system of mechanical traction for all sorts of vehicles. Even aerial navigation may now become a possibility, and the problem of force at home is finally solved. And what a grand step! What sudden progress! Distance again diminished, all roads thrown open, and men able to fraternise! This is a great boon, a splendid gift, my good friends, that you are bestowing on the world.”

Then he began to jest about the new explosive, whose prodigious power he had divined, and which he now found put to such a beneficent purpose. “And to think, Guillaume,” he said, “that I fancied you acted with so much mysteriousness and hid the formula of your powder from me because you had an idea of blowing up Paris!”

At this Guillaume became grave and somewhat pale. And he confessed the truth. “Well, I did for a moment think of it.”

However, Bertheroy went on laughing, as if he regarded this answer as mere repartee, though truth to tell he had felt a slight chill sweep through his hair. “Well, my friend,” he said, “you have done far better in offering the world this marvel, which by the way must have been both a difficult and dangerous matter. So here is a powder which was intended to exterminate people, and which in lieu thereof will now increase their comfort and welfare. In the long run things always end well, as I’m quite tired of saying.”

On beholding such lofty and tolerant good nature, Guillaume felt moved. Bertheroy’s words were true. What had been intended for purposes of destruction served the cause of progress; the subjugated, domesticated volcano became labour, peace and civilisation. Guillaume had even relinquished all idea of his engine of battle and victory; he had found sufficient satisfaction in this last invention of his, which would relieve men of some measure of weariness, and help to reduce their labour to just so much effort as there must always be. In this he detected some little advance towards Justice; at all events it was all that he himself could contribute to the cause. And when on turning towards the window he caught sight of the basilica of the Sacred Heart, he could not explain what insanity had at one moment come over him, and set him dreaming of idiotic and useless destruction. Some miasmal gust must have swept by, something born of want that scattered germs of anger and vengeance. But how blind it was to think that destruction and murder could ever bear good fruit, ever sow the soil with plenty and happiness! Violence cannot last, and all it does is to rouse man’s feeling of solidarity even among those on whose behalf one kills. The people, the great multitude, rebel against the isolated individual who seeks to wreak justice. No one man can take upon himself the part of the volcano; this is the whole terrestrial crust, the whole multitude which internal fire impels to rise and throw up either an Alpine chain or a better and freer society. And whatever heroism there may be in their madness, however great and contagious may be their thirst for martyrdom, murderers are never anything but murderers, whose deeds simply sow the seeds of horror. And if on the one hand Victor Mathis had avenged Salvat, he had also slain him, so universal had been the cry of reprobation roused by the second crime, which was yet more monstrous and more useless than the first.

Guillaume, laughing in his turn, replied to Bertheroy in words which showed how completely he was cured: “You are right,” he said, “all ends well since all contributes to truth and justice. Unfortunately, thousands of years are sometimes needed for any progress to be accomplished.... However, for my part, I am simply going to put my new explosive on the market, so that those who secure the necessary authorisation may manufacture it and grow rich. Henceforth it belongs to one and all.... And I’ve renounced all idea of revolutionising the world.”

But Bertheroy protested. This great official scientist, this member of the Institute laden with offices and honours, pointed to the little motor, and replied with all the vigour of his seventy years: “But that is revolution, the true, the only revolution. It is with things like that and not with stupid bombs that one revolutionises the world! It is not by destroying, but by creating, that you have just done the work of a revolutionist. And how many times already have I not told you that science alone is the world’s revolutionary force, the only force which, far above all paltry political incidents, the vain agitation of despots, priests, sectarians and ambitious people of all kinds, works for the benefit of those who will come after us, and prepares the triumph of truth, justice and peace.... Ah, my dear child, if you wish to overturn the world by striving to set a little more happiness in it, you have only to remain in your laboratory here, for human happiness can spring only from the furnace of the scientist.”

He spoke perhaps in a somewhat jesting way, but one could feel that he was convinced of it all, that he held everything excepting science in utter contempt. He had not even shown any surprise when Pierre had cast his cassock aside; and on finding him there with his wife and child he had not scrupled to show him as much affection as in the past.