With the assistance of the cashier of one of the local banks Elmer arranged to have a dummy package of money forwarded by mail from New York. It was supposed to contain thirty-five thousand dollars in cash, and all the formalities were complied with precisely as if thirty-five thousand-dollar bills were really inside the envelope, instead of as many sheets of blank paper carefully arranged. On the morning of the day the envelope was due to reach Columbus, Allison took up his position close to the grille in the lookout, his eyes strained to catch the slightest suspicious movement below. Hour after hour passed uneventfully until, almost immediately below him, he saw a man drop something on the floor. Two envelopes had slipped from his hands and he stooped to pick them up--that was all. But what carried a thrill to the operative in the lookout was the fact that one of the envelopes was the dummy sent from New York and that, when the man straightened up, he had only _one_ of the two in his hands. The dummy had disappeared! Allison rubbed his eyes and looked again. No, he was right. The postal clerk had, in some manner, disposed of the envelope supposed to contain thirty-five thousand dollars and he was going about his work in precisely the same way as before. "Wait a minute," Allison argued to himself. "There's something missing besides the envelope! What is it?" A moment later he had the clue to the whole affair--the jaws of the clerk, which Allison had previously and subconsciously noted were always hard at work on a wad of gum, now were at rest for the first time since the operative had entered the lookout! The chewing gum and the dummy packet had disappeared at the same time! It didn't take Elmer more than thirty seconds to reach Rogers's office, and he entered with the startling announcement that "an envelope containing thirty-five thousand dollars had just disappeared from the registry room." "What?" demanded the postmaster. "How do you know? I haven't received any report of it." "No, and you probably wouldn't for some time," Elmer retorted. "But it happens that I saw it disappear." "Then you know where it is?" "I can lay my hands on it--and probably the rest of the missing money--inside of one minute. Let's pay a visit to the registry room." Before entering the section, however, Allison took the precaution of posting men at both of the doors. "After I'm inside," he directed, "don't allow anyone to leave on any pretext whatever. And stand ready for trouble in case it develops. Come on, Mr. Rogers." Once in the room devoted to the handling of registered mail, Allison made directly for the desk under the lookout. The occupant regarded their approach with interest but, apparently, without a trace of anxiety. "I'd like to have that letter supposed to contain thirty-five thousand dollars which you dropped on the floor a few moments ago," Elmer remarked in a quiet, almost conversational tone.