Rouletabille, as I have said, entered my room that morning of the 26th of October, 1892. He was looking redder than usual, and his eyes were bulging out of his head, as the phrase is, and altogether he appeared to be in a state of extreme excitement. He waved the “Matin” with a trembling hand, and cried:— “Well, my dear Sainclair,—have you read it?” “The Glandier crime?” “Yes; ‘The Yellow Room’!—What do you think of it?” “I think that it must have been the Devil or the Bête du Bon Dieu that committed the crime.” “Be serious!” “Well, I don’t much believe in murderers who make their escape through walls of solid brick. I think Daddy Jacques did wrong to leave behind him the weapon with which the crime was committed and, as he occupied the attic immediately above Mademoiselle Stangerson’s room, the builder’s job ordered by the examining magistrate will give us the key of the enigma and it will not be long before we learn by what natural trap, or by what secret door, the old fellow was able to slip in and out, and return immediately to the laboratory to Monsieur Stangerson, without his absence being noticed. That, of course, is only an hypothesis.” Rouletabille sat down in an armchair, lit his pipe, which he was never without, smoked for a few minutes in silence—no doubt to calm the excitement which, visibly, dominated him—and then replied:— “Young man,” he said, in a tone the sad irony of which I will not attempt to render, “young man, you are a lawyer and I doubt not your ability to save the guilty from conviction; but if you were a magistrate on the bench, how easy it would be for you to condemn innocent persons!—You are really gifted, young man!” He continued to smoke energetically, and then went on:— “No trap will be found, and the mystery of ‘The Yellow Room’ will become more and more mysterious. That’s why it interests me. The examining magistrate is right; nothing stranger than this crime has ever been known.” “Have you any idea of the way by which the murderer escaped?” I asked. “None,” replied Rouletabille—“none, for the present. But I have an idea as to the revolver; the murderer did not use it.” “Good Heavens! By whom, then, was it used?” “Why—by Mademoiselle Stangerson.” “I don’t understand,—or rather, I have never understood,” I said. Rouletabille shrugged his shoulders. “Is there nothing in this article in the ‘Matin’ by which you were particularly struck?” “Nothing,—I have found the whole of the story it tells equally strange.” “Well, but—the locked door—with the key on the inside?” “That’s the only perfectly natural thing in the whole article.” “Really!—And the bolt?” “The bolt?”