“Well,” resumed Darry, “Bob and I went up stairs here at once. None of the offices on the third floor has been occupied for a long time. In the hall is a big box with a slanting cover, to hold fuel for tenants in winter time. Everything was dirty, and plainly across the dusty box cover it showed where someone had recently rested, or been pushed over against the wall. We pulled out the box. Sure enough, in the four-inch space behind the box was your money.” “Then a hot wire, and here you are,” observed Bob briskly. “See here, fellows,” said Frank, “I think I can figure this thing out.” “Go ahead,” encouraged Darry. “Markham sent that letter. He didn’t write, because he had no pencil. A pencil is usually an easy thing to get, so he must have been shut up somewhere. He found in his pocket a sheet of paper--” “Oh, by the way,” here interrupted Darry, “I forgot to explain something. I recognize the sheet of paper as a blank sample I gave Markham, enclosed in that same envelope, stamped, to give to Mr. Dawes up at the novelty works when he went there again. Mr. Dawes asked for a sample of one linen letter paper. If he wanted a lot, he was to write the amount on the sheet, and mail to us.” “Well,” continued Frank, “somehow Markham made paste--probably out of a piece of bread. He compiled that letter.” “But how did he get it mailed?” suggested Bob. “Suppose he was a prisoner, and threw it from a window into the road, chancing its discovery and mailing by some passer-by.” “That’s so,” nodded Darry. “I believe you are correct in your conclusions, Frank. As to the mailing lists, which Markham also had with him, that’s a later mystery to develop.” “Now then,” spoke Frank, “I think I can also figure out something else. I believe that Dale Wacker followed Markham. He was probably right on his heels when Markham entered this building. Markham saw him, got scared, and, to evade him, ran up to the third floor. There he found no rooms open to hide in. He was cornered, intimidated, maybe attacked by Wacker. He thought of that two hundred dollars, and dropped it behind the fuel box. Then--” Frank paused here, and shook his head in doubt and perplexity. “Poor Markham,” commented Bob. “It looks likely that he is held a prisoner somewhere. Maybe because his captor knows he threw away that package of money, and won’t let him go free till he tells where. Anyhow, he’s a good one, surmounting all the difficulties of his situation and getting that letter to you.” “I suppose you will take up the mail order business actively again, now you are in funds?” suggested Darry. “Surely,” said Frank. “Here, take the money and hurry up the catalogue.” Frank felt immensely relieved as he proceeded to his office. His mind, however, was full of plans looking to the discovery of Markham’s place of captivity.