However great the tension of the mind may be when concentrated on an idea which entirely absorbs it, we remain more or less subject to the thousand sensations that assail us. Thus, at the very moment when I rose and, in a whisper, repeated, "Château de Pré-Bony . . . de Pré-Bony," the vague impression that another had heard the address which Massignac had given began to take shape and consistency within me. Nay more, I perceived, _when it was too late_, that this other man, thanks to his position at my side, must have been able to read as I had read, the opening words of Théodore Massignac's letter. And that other man's able make-up suddenly dropped away before my eyes to reveal the pallid features of the man Velmot. I turned my head. The man had just made his way out of the band of onlookers who stood gathered round us and was slipping through the shifting masses of the crowd. I called out. I shouted his name. I dragged detectives in his wake. It was too late. And so the man Velmot, the implacable enemy who had not hesitated to torture Massignac in order to extract my uncle Dorgeroux's formula from him, knew that Bérangère was acquainted with the formula! And he had at the same time learnt, what he doubtless did not know before, where Bérangère was concealed. * * * * * The Château de Pré-Bony! Where was this country-house? In what corner of France had Bérangère taken refuge after the murder of her god-father? It could not be very far from Paris, seeing that she had once asked for my assistance and that, two days ago, she had come to the Yard. But, whatever the distance, how was I to find it? There were a thousand country-houses within a radius of twenty-five miles from Paris. "And yet," I said to myself, "the solution of the tragedy lies there, in that country-house. All is not lost and all may still be saved, but I have to get there. Though, the miraculous screen is destroyed, Massignac has given me the means of reconstructing it, but I have to get there. And I have to get there by day break, or Velmot will have Bérangère at his mercy." I spent the whole evening in enquiries. I consulted maps, gazetteers, directories. I asked everywhere; I telephoned. No one was able to supply the least hint as to the whereabouts of the Château de Pré-Bony. It was not until the morning, after an agitated night, that a more methodical scrutiny of recent events gave me the idea of beginning my investigations in the actual district where I knew that Bérangère had stayed. I hired a motor-car and had myself driven towards Bougival. I had no great hope. But my fear lest Velmot should discover Bérangère's retreat before I did caused me such intense suffering that I never ceased repeating to myself: "That's it. . . . I'm on the right track. . . . I'm certain to find Bérangère; and the villain shall not touch a hair of her head."