I got a real taxi at last, and got out at the arcade, giving the man a quarter, although ten cents would have been plenty as a tip. I looked at him, and I felt that he could be trusted. "This," I said, holding up the money, "is the price of silence." But if he was trustworthy he was not subtle, and he said: "The what, miss?" "If any one asks if you have driven me here, YOU HAVE NOT" I explained, in an impressive manner. He examined the quarter, even striking a match to look at it. Then he replied: "I have not!" and drove away. Concealing my nervousness as best I could, I entered the doomed building. There was only a hall boy there, asleep in the elevator, and I looked at the thing with the names on it. "Mr. Grosvenor" was on the fourth floor. I wakened the boy, and he yawned and took me to the fourth floor. My hands were stiff with nervousness by that time, but the boy was half asleep, and evidently he took me for some one who belonged there, for he said "Goodnight" to me, and went on down. There was a square landing with two doors, and "Grosvenor" was on one. I tried it gently. It was unlocked. "FACILUS DESCENSUS IN AVERNU." I am not defending myself. What I did was the result of desperation. But I cannot even write of my sensations as I stepped through that fatal portal, without a sinking of the heart. I had, however, had sufficient foresight to prepare an alibi. In case there was someone present in the apartment I intended to tell a falsehood, I regret to confess, and to say that I had got off at the wrong floor. There was a sort of hall, with a clock and a table, and a shaded electric lamp, and beyond that the door was open into a sitting room. There was a small light burning there, and the remains of a wood fire in the fireplace. There was no cabinet however. Everything was perfectly quiet, and I went over to the fire and warmed my hands. My nails were quite blue, but I was strangely calm. I took off mother's veil, and my mackintosh, so I would be free to work, and I then looked around the room. There were a number of photographs of rather smart looking girls, and I curled my lip scornfully. He might have fooled them but he could not deceive me. And it added to my bitterness to think that at that moment the villain was dancing--and flirting probably--while I was driven to actual theft to secure the letter that placed me in his power. When I had stopped shivering I went to his desk. There were a lot of letters on the top, all addressed to him as Grosvenor. It struck me suddenly as strange that if he was only visiting, under an assumed name, in order to see me, that so many people should be writing to him as Mr. Grosvenor. And it did not look like the room of a man who was visiting, unless he took a freight car with him on his travels. THERE WAS A MYSTERY. All at once I knew it.