He thought of the Prefect of Police, of the meeting that was to take place at Fauville’s house on the Boulevard Suchet.  The meeting had begun.  The police were watching the house.  And this reminded him of the sheet of paper found by Weber in the eighth volume of Shakespeare’s plays, and of the sentence written on it, which the Prefect had read out: 

“Bear in mind that the explosion is independent of the letters, and that it will take place at three o’clock in the morning.”

“Yes,” thought Don Luis, accepting M. Desmalions’s reasoning, “yes, in ten days’ time.  As there have been only three letters, the fourth will appear to-night; and the explosion will not take place until the fifth letter appears—­that is in ten days from now.”

He repeated: 

“In ten days—­with the fifth letter—­in ten days—­”

And suddenly he gave a start of fright.  A horrible vision had flashed across his mind, a vision only too real.  The explosion was to occur that very night!  And all at once, knowing that he knew the truth, all at once, in a revival of his usual clear-sightedness, he accepted the theory as certain.

No doubt only three letters had appeared out of the mysterious darkness, but four letters ought to have appeared, because one of them had appeared not on the date fixed, but ten days later; and this for a reason which Don Luis knew.  Besides, it was not a question of all this.  It was not a question of seeking the truth amid this confusion of dates and letters, amid this intricate tangle in which no one could lay claim to any certainty,

No; one thing alone stood out above the situation:  the sentence, “Bear in mind that the explosion is independent of the letters.”  And, as the explosion was put down for the night of the twenty-fifth of May, it would occur that very night, at three o’clock in the morning!

“Help!  Help!” he cried.

This time he did not hesitate.  So far, he had had the courage to remain huddled in his prison and to wait for the miracle that might come to his assistance; but he preferred to face every danger and undergo every penalty rather than abandon the Prefect of Police, Weber, Mazeroux, and their companions to the death that threatened them.

“Help!  Help!”

Fauville’s house would be blown up in three or four hours.  That he knew with the greatest certainty.  Just as punctually as the mysterious letters had reached their destination in spite of all the obstacles in the way, so the explosion would occur at the hour named.  The infernal artificer of the accursed work had wished it so.  At three o’clock in the morning there would be nothing left of the Fauvilles’ house.

“Help!  Help!”

He recovered enough strength to raise desperate shouts and to make his voice carry beyond the stones and beyond the wainscoting.

Then, when there seemed to be no answer to his call, he stopped and listened for a long time.  There was not a sound.  The silence was absolute.