It was a question of her wedding dress, a gown of light grey silk, the stylishness of which she considered very amusing. Whenever she spoke of it, both she and the others began to laugh.

“It’s understood, my dear,” said Guillaume, likewise making merry over it. “We know it’s Cinderella’s court robe, eh? The fairy brocade and lace that are to make you very beautiful and for ever happy.”

However, the laughter ceased, and in the sudden silence which fell, it again seemed as if death were passing by with a great flapping of wings and an icy gust which chilled the hearts of everyone remaining there.

“It’s understood; so now I’m really off,” resumed Guillaume. “Au revoir, children.”

Then he sallied forth, without even turning round, and for a moment they could hear the firm tread of his feet over the garden gravel.

Pierre having invented a pretext was able to follow him a couple of minutes afterwards. As a matter of fact there was no need for him to dog Guillaume’s heels, for he knew where his brother was going. He was thoroughly convinced that he would find him at that doorway, conducting to the foundations of the basilica, whence he had seen him emerge two days before. And so he wasted no time in looking for him among the crowd of pilgrims going to the church. His only thought was to hurry on and reach Jahan’s workshop. And in accordance with his expectation, just as he arrived there, he perceived Guillaume slipping between the broken palings. The crush and the confusion prevailing among the concourse of believers favored Pierre as it had his brother, in such wise that he was able to follow the latter and enter the doorway without being noticed. Once there he had to pause and draw breath for a moment, so greatly did the beating of his heart oppress him.

A precipitous flight of steps, where all was steeped in darkness, descended from the narrow entry. It was with infinite precaution that Pierre ventured into the gloom, which ever grew denser and denser. He lowered his feet gently so as to make no noise, and feeling the walls with his hands, turned round and round as he went lower and lower into a kind of well. However, the descent was not a very long one. As soon as he found beaten ground beneath his feet he paused, no longer daring to stir for fear of betraying his presence. The darkness was like ink, and there was not a sound, a breath; the silence was complete.

How should he find his way? he wondered. Which direction ought he to take? He was still hesitating when some twenty paces away he suddenly saw a bright spark, the gleam of a lucifer. Guillaume was lighting a candle. Pierre recognised his broad shoulders, and from that moment he simply had to follow the flickering light along a walled and vaulted subterranean gallery. It seemed to be interminable and to run in a northerly direction, towards the nave of the basilica.

All at once the little light at last stopped, while Pierre, anxious to see what would happen, continued to advance, treading as softly as he could and remaining in the gloom. He found that Guillaume had stood his candle upon the ground in the middle of a kind of low rotunda under the crypt, and that he had knelt down and moved aside a long flagstone which seemed to cover a cavity. They were here among the foundations of the basilica; and one of the columns or piles of concrete poured into shafts in order to support the building could be seen. The gap, which the stone slab removed by Guillaume had covered, was by the very side of the pillar; it was either some natural surface flaw, or a deep fissure caused by some subsidence or settling of the soil. The heads of other pillars could be descried around, and these the cleft seemed to be reaching, for little slits branched out in all directions. Then, on seeing his brother leaning forward, like one who is for the last time examining a mine he has laid before applying a match to the fuse, Pierre suddenly understood the whole terrifying business. Considerable quantities of the new explosive had been brought to that spot. Guillaume had made the journey a score of times at carefully selected hours, and all his powder had been poured into the gap beside the pillar, spreading to the slightest rifts below, saturating the soil at a great depth, and in this wise forming a natural mine of incalculable force. And now the powder was flush with the flagstone which Guillaume has just moved aside. It was only necessary to throw a match there, and everything would be blown into the air!

For a moment an acute chill of horror rooted Pierre to the spot. He could neither have taken a step nor raised a cry. He pictured the swarming throng above him, the ten thousand pilgrims crowding the lofty naves of the basilica to witness the solemn consecration of the Host. Peal upon peal flew from “La Savoyarde,” incense smoked, and ten thousand voices raised a hymn of magnificence and praise. And all at once came thunder and earthquake, and a volcano opening and belching forth fire and smoke, and swallowing up the whole church and its multitude of worshippers. Breaking the concrete piles and rending the unsound soil, the explosion, which was certain to be one of extraordinary violence, would doubtless split the edifice atwain, and hurl one-half down the slopes descending towards Paris, whilst the other on the side of the apse would crumble and collapse upon the spot where it stood. And how fearful would be the avalanche; a broken forest of scaffoldings, a hail of stonework, rushing and bounding through the dust and smoke on to the roofs below; whilst the violence of the shock would threaten the whole of Montmartre, which, it seemed likely, must stagger and sink in one huge mass of ruins!