"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.