"Your handkerchief was found in this office, apparently having been dropped by the persons who blew the safe," and the long, slender fingers of The Thinking Machine were placed tip to tip as he talked. "It was not there the night before. The janitor who swept says so; Dunston, who happened to look, says so--; Miss Clarke and Dunston both say they saw you with a handkerchief as you left the bank. Therefore, that handkerchief reached that spot after you left and before the robbery was discovered."
The cashier nodded.
"You say you don't use perfume; that no one in your family uses it. If Mr. Hatch verifies this, it will help to exonerate you. But some person who handled that handkerchief after it left your possession and before it appeared, here did use perfume. Now who was that person? Who would have had an opportunity?
"We may safely dismiss the possibility that you lost the handkerchief, that it fell into the hands of burglars, that those burglars used perfume, that they brought it to your bank--your own bank, mind you!--and left it. The series of coincidences necessary to bring that about would not have occurred once in a million times."
The Thinking Machine sat silent for several minutes, squinting steadily at the ceiling.
"If it had been lost anywhere, in the laundry, say, the same rule of coincidence I have just applied would almost eliminate it. Therefore, because of an opportunity to get that handkerchief, we will assume--there is--there must be--some one employed in this bank who had some connection with or actually participated in the burglary."
The Thinking Machine spoke with perfect quiet, but the effect was electrical. The aged president staggered to his feet and stood staring at him dully; again the flush of crimson came into the face of the cashier.
"Some one," The Thinking Machine went on, evenly, "who either found the handkerchief and unwittingly lost it at the time of the burglary, or else stole it and deliberately left it. As I said, Mr. West seems eliminated. Had he been one of the robbers, he would not wittingly have left his handkerchief; we will still assume that he does not use perfume, therefore personally did not drop the handkerchief where it was found."
"Impossible! I can't believe it, and of my employees----" began Mr. Fraser.
"Please don't keep saying things are impossible," snapped The Thinking Machine. "It irritates me exceedingly. It all comes to the one vital question: Who in the bank uses perfume?"