“That path is, as you see, topped with gravel,” he said; “the man _must_ have passed along it going to the pavilion, since no traces of his steps have been found on the soft ground. The man didn’t have wings; he walked; but he walked on the gravel which left no impression of his tread. The gravel has, in fact, been trodden by many other feet, since the path is the most direct way between the pavilion and the château. As to the thicket, made of the sort of shrubs that don’t flourish in the rough season—laurels and fuchsias—it offered the murderer a sufficient hiding-place until it was time for him to make his way to the pavilion. It was while hiding in that clump of trees that he saw Monsieur and Mademoiselle Stangerson, and then Daddy Jacques, leave the pavilion. Gravel has been spread nearly, very nearly, up to the windows of the pavilion. The footprints of a man, parallel with the wall—marks which we will examine presently, and which I have already seen—prove that he only needed to make one stride to find himself in front of the vestibule window, left open by Daddy Jacques. The man drew himself up by his hands and entered the vestibule.” “After all it is very possible,” I said. “After all what? After all what?” cried Rouletabille. I begged of him not to be angry; but he was too much irritated to listen to me and declared, ironically, that he admired the prudent doubt with which certain people approached the most simple problems, risking nothing by saying “that is so,” or “that is not so.” Their intelligence would have produced about the same result if nature had forgotten to furnish their brain-pan with a little grey matter. As I appeared vexed, my young friend took me by the arm and admitted that he had not meant that for me; he thought more of me than that. “If I did not reason as I do in regard to this gravel,” he went on, “I should have to assume a balloon!—My dear fellow, the science of the aerostation of dirigible balloons is not yet developed enough for me to consider it and suppose that a murderer would drop from the clouds! So don’t say a thing is possible, when it could not be otherwise. We know now how the man entered by the window, and we also know the moment at which he entered,—during the five o’clock walk of the professor and his daughter. The fact of the presence of the chambermaid—who had come to clean up The Yellow Room—in the laboratory, when Monsieur Stangerson and his daughter returned from their walk, at half-past one, permits us to affirm that at half-past one the murderer was not in the chamber under the bed, unless he was in collusion with the chambermaid. What do you say, Monsieur Darzac?” Monsieur Darzac shook his head and said he was sure of the chambermaid’s fidelity, and that she was a thoroughly honest and devoted servant. “Besides,” he added, “at five o’clock Monsieur Stangerson went into the room to fetch his daughter’s hat.” “There is that also,” said Rouletabille.