Knowing that Thompson was somewhere in the country, I watched the house - especially at post-time in the morning - thinking Thompson was pretty likely to write to her. Sure enough, one morning the postman comes up, and delivers a letter at Mrs. Thompson's door. Little girl opens the door, and takes it in. We're not always sure of postmen, though the people at the post-offices are always very obliging. A postman may help us, or he may not, - just as it happens. However, I go across the road, and I say to the postman, after he has left the letter, "Good morning! how are you?" "How are YOU!" says he. "You've just delivered a letter for Mrs. Thompson." "Yes, I have." "You didn't happen to remark what the post-mark was, perhaps?" "No," says he, "I didn't." "Come," says I, "I'll be plain with you. I'm in a small way of business, and I have given Thompson credit, and I can't afford to lose what he owes me. I know he's got money, and I know he's in the country, and if you could tell me what the post-mark was, I should be very much obliged to you, and you'd do a service to a tradesman in a small way of business that can't afford a loss." "Well," he said, "I do assure you that I did not observe what the post-mark was; all I know is, that there was money in the letter - I should say a sovereign." This was enough for me, because of course I knew that Thompson having sent his wife money, it was probable she'd write to Thompson, by return of post, to acknowledge the receipt. So I said "Thankee" to the postman, and I kept on the watch. In the afternoon I saw the little girl come out. Of course I followed her. She went into a stationer's shop, and I needn't say to you that I looked in at the window. She bought some writing-paper and envelopes, and a pen. I think to myself, "That'll do!" - watch her home again - and don't go away, you may be sure, knowing that Mrs. Thompson was writing her letter to Tally-ho, and that the letter would be posted presently. In about an hour or so, out came the little girl again, with the letter in her hand. I went up, and said something to the child, whatever it might have been; but I couldn't see the direction of the letter, because she held it with the seal upwards. However, I observed that on the back of the letter there was what we call a kiss - a drop of wax by the side of the seal - and again, you understand, that was enough for me. I saw her post the letter, waited till she was gone, then went into the shop, and asked to see the Master. When he came out, I told him, "Now, I'm an Officer in the Detective Force; there's a letter with a kiss been posted here just now, for a man that I'm in search of; and what I have to ask of you, is, that you will let me look at the direction of that letter." He was very civil - took a lot of letters from the box in the window - shook 'em out on the counter with the faces downwards - and there among 'em was the identical letter with the kiss. It was directed, Mr. Thomas Pigeon, Post Office, B-, to be left till called for. Down I went to B- (a hundred and twenty miles or so) that night. Early next morning I went to the Post Office; saw the gentleman in charge of that department; told him who I was; and that my object was to see, and track, the party that should come for the letter for Mr. Thomas Pigeon. He was very polite, and said, "You shall have every assistance we can give you; you can wait inside the office; and we'll take care to let you know when anybody comes for the letter." Well, I waited there three days, and began to think that nobody ever WOULD come. At last the clerk whispered to me, "Here! Detective! Somebody's come for the letter!" "Keep him a minute," said I, and I ran round to the outside of the office. There I saw a young chap with the appearance of an Ostler, holding a horse by the bridle - stretching the bridle across the pavement, while he waited at the Post Office Window for the letter. I began to pat the horse, and that; and I said to the boy, "Why, this is Mr. Jones's Mare!" "No.