Hence we parted, and while Señor Rivero sauntered along the street in search of the house in question, I went into the café and ordered a bock. Full of anxiety lest, after all, this man Rabel should be a respectable citizen, I waited. Time passed slowly. Half an hour went by. I ordered a mazagran and sat smoking, trying to suppress my eagerness. An hour elapsed--an hour and a half--two hours! I waited yet another half-hour until the proprietor of the café began to look askance at me. Then I paid, and rising, went out into the street. It was now dark. There was no sign of my friend the Spanish police agent. He had disappeared! I stood upon the pavement full of anxiety and bewilderment. What could have happened to him? CHAPTER THE TWENTIETH MADEMOISELLE JACQUELOT I returned to my rather barely-furnished room at the Hôtel du Midi which overlooked the Place outside the station in the suburb across the river, and sank into a chair to reflect. The concierge--a lad who wore the concierge's cap--the concierge being off duty at his evening meal--informed me that my friend had not returned. He seemed an alert French lad of that type so frequently seen in Continental hotels. Señor Rivero had disappeared! For an hour I waited seated alone in my room reflecting deeply. My sole desire and fixed object was to solve the enigma of Gabrielle Tennison's unfortunate mental state and to bring to justice those unscrupulous blackguards responsible for it. As I sat there her pale beautiful face arose before me--the wonderful countenance of the girl who had, in such a strange and indescribable manner, taken possession of my soul. To analyse my feelings towards her was impossible. I put to myself the query why I loved her, but I was utterly unable to answer it. I loved her most passionately and devotedly. That was all. The tragedy of the situation was that I loved one who, alas! could not return my affection as a girl with her mental balance unaffected could do. Her poor unbalanced brain could never allow her to understand me, or to return my love. I was tired after the long sleepless journey from Spain, and I suppose I must have dozed in my chair. I awoke suddenly, hearing a tap upon the door, and an elderly chambermaid entered with a telegram. I tore it open and found it had been dispatched from Castelsarrasin, and was from Rivero, saying: "Absence unavoidable. Hope to be back by midnight." "Where is Castelsarrasin?" I inquired of the woman. "It is about sixteen kilomètres from here, m'sieur," replied the buxom woman in the strong accent of Toulouse. "It is on the road to Agen and the railway junction for Beaumont-de-Lomagne. Just a small town. They say that the name is a corruption of Castel-sur-Azin. At least my mother used to tell me so." What, I wondered, had taken the head of the Madrid detective force out there? He must be following some fresh clue.