“Look!” she cried.  “They are blank—­those stock certificates he gave me.”

Drummond seized them roughly from her hands.

Where the signatures should have been there was nothing at all!

Across the face of the stock were the words in deep black, “Sample
certificate,” written in an angular, feminine hand.

What did it mean?  Halsey was as amazed as any of them.  Mechanically he turned to Constance.

“I didn’t say anything last night,” she remarked incisively.  “But I had my suspicions from the first.  I always look out for the purry kind of ‘my dear’ woman.  They have claws.  Last night I watched.  To-day I learned—­learned that you, Mr. Drummond, were nothing but a blackmailer, using these gamblers to do your dirty work.  Haddon, they would have thrown you out like a squeezed lemon as soon as the money you had was gone.  They would have taken the bribe that Drummond offered for the stock—­and they would have left you nothing but jail.  I learned all that over the telegraphone.  I learned their methods and, knowing them, even I could not be prevented from winning to-night”

Halsey moved as if to speak.  “But,” he asked eagerly, “the stock certificates—­what of them!”

“The stock?” she answered with deliberation.  “Did you ever hear that writing in quinoline will appear blue, but will soon fade away, while other writing in silver nitrate and ammonia, invisible at first, after a few hours appears black?  You wrote on those certificates in sympathetic ink that fades, I in ink that comes up soon.”

Mrs. Noble was crying softly to herself.  They still had her notes for thousands.

Halsey saw her.  Instantly he forgot his own case.  What was to be done about her?  He telegraphed a mute appeal to Constance, forgetful of himself now.  Constance was fingering the switch of the telegraphone.

“Drummond,” remarked Constance significantly, as though other secrets might still be contained in the marvelous little mechanical detective, “Drummond, don’t you think, for the sake of your own reputation as a detective, it might be as well to keep this thing quiet?”

For a moment the detective gripped his wrath and seemed to consider the damaging record of his conversation with Bella LeMar.

“Perhaps,” he agreed sullenly.

Constance reached into her chatelaine.  From it she drew an ordinary magnet, and slowly pulled off the armature.

“If I run this over the wires,” she hinted, holding it near the spools, “the record will be wiped out.”  She paused impressively.  “Let me have those I O U’s of Mrs. Noble’s.  By the way, you might as well give me that blank stock, too.  There is no use in that, now.”

As she laid the papers in a pile on the table before her she added the old forged certificates from Halsey’s pocket.  There it lay, the incriminating, ruining evidence.

Deliberately she passed the magnet over the thin steel wire, wiping out what it had recorded, as if the recording angel were blotting out from the book of life.