"I did," was his response, "thinking it would be your wish that I should do no more business to-day." "Why should you think that?" "Because of what was passing through Mr. Dowsett's mind." "I ask you to pardon me for my display of passion. What was Mr. Dowsett thinking of?" "Of two very simple matters," said Devlin; "the time of day and an address. The time was fifteen minutes past three, the address, 28 Athelstan Road." "Nothing more?" I inquired, much puzzled. "Nothing more." I pondered a moment; I could draw no immediate conclusion from material so bare. I asked Devlin what he could make of it; he replied, politely, that it was for me, not for him, to make what I could of it. A suggestion presented itself. "At fifteen minutes past three," I said, "Mr. Dowsett has an appointment with some person at 28 Athelstan Road." "Possibly," said Devlin. "Have you a 'London Directory'?" "I have not; nor, I imagine, will you easily find one in this neighbourhood." "A simpler plan," I said, "perhaps will be to go to Mr. Dowsett's house, to which he has most likely returned, and set watch there for him, keeping ourselves well out of sight. It is now twenty minutes past one; we can reach his house in ten minutes. He will hardly leave it for his appointment till two, or a little past. We will follow him secretly, and ascertain whom he is going to see, and his purpose. I am determined now to adopt bold measures. Behind this frightful mystery there is another, which shall be brought to light. You will accompany me?" "I am at your orders," said Devlin. We left the house together, and in the time I specified were within a few yards of Mr. Dowsett's residence. Aware of the importance of not attracting attention, I looked about for a means of escaping observation. Nearly opposite Mr. Dowsett's dwelling was a public-house, in the first-floor window of which I saw a placard, "Billiards. Pool." I concluded that it was the window of a billiard-room, and without hesitation I entered the public-house, followed by Devlin, and mounted the stairs. The room, as I supposed, contained a billiard-table; the marker, a very pale and very thin youth, was practising the spot stroke. "Billiards, sir?" he asked, as we entered. "Yes," I said, "we wish to play a private game. How much an hour?" "Eighteenpence." "Here are five shillings," I said, "for a couple of hours. We shall not want you to mark. Don't let us be disturbed." The pale thin youth took the money, laid down his cue, and left us to ourselves. When he was gone I placed a chair at an angle against the handle of the door, there being no key in the lock, and thus prevented the entrance of any person without notice. It was the leisure time of the day, and there was little fear of our being disturbed. The extra gratuity I had given to the marker would insure privacy. As I took my station at the window, from which Mr. Dowsett's house was in full view, Devlin nodded approval of my proceedings.