been used to blow it. Nitroglycerin enough might have wrecked the building. The old “can-opener” is of course out of the question with a safe like this. No instrument could possibly rip a plate off this safe unless you gave the ripper unlimited time. There’s not a hint that thermit or the oxy-acetylene blow-pipe have been used. Not a spot on the safe indicates the presence of anything that can produce those high temperatures.’
‘Yet the telautomaton is gone!’ persisted Hastings.
Kennedy was looking about, making a quick search of the office.
As his eye travelled over the floor he took a step or two forward and bent down. Under a sanitary desk, near a window, he picked up what looked like a small piece of rubber tubing. He looked at it with interest, though it conveyed no idea to me. It was simply a piece of rubber tubing. Then he took another step to the window and raised it, looking out. Far below, some hundred or more feet, was the roof of the next building, itself no mean structure for height.
‘Have you searched the roof below?’ he asked, turning to Burke.
Burke shook his head. ‘How could anyone get in that way?’ he negatived.
‘Well—search the roof below,’ repeated Kennedy.
Even though he did not understand what good might come of such a strange request, Burke had known Kennedy long enough not to question his actions. He moved away, seeking one of his men whom he could send on the errand.
While we waited Kennedy continued to question Randall.
‘Mr Maddox was very careful of his key, I suppose?’ he ventured.
‘Yes, sir, very careful. So we all were of the combination, too. Not even my assistant knows that. If I should drop dead, there would be only one way to get it—to open that safety deposit box, and that must be done by someone with the proper authority. It has all been carefully safeguarded.’
‘You know of no one intmate with Mr Maddox—who might have obtained the key—or the combination?’
I wondered at what Kennedy was driving. Had he the little dancer, Paquita, in mind? Did he suspect that she might have wormed from Maddox the secret? Or was he, too, thinking of Shelby?
Randall shook his head, and Kennedy continued his quick examination of the office, questioning the assistant, who was unable to add anything of value.
So far there had been nothing to show that the robbery might not have been an inside job. As Kennedy was still pondering on the new mystery that confronted us Burke approached with the man whom he had sent to make the search.
His face indicated that he was puzzled. In his hand he was holding a disc that was something like the flat telephone receivers one sees often on interior office telephones. To it was attached a rubber tube like that which Kennedy had picked up in the office a few minutes before.
‘My man found this thing on the roof below,’ explained Burke, with a look of inquiry. ‘What do you suppose it is? How did it get there?’
Kennedy took the disc and began examining it carefully, fitting on the other rubber tube.
‘Perhaps it had served its purpose—was no longer of use,’ he meditated. ‘At any rate, if someone had to get away with that telautomaton he would not want to burden himself with anything else that was unnecessary. He might very well have discarded this.’
What the thing was I could not imagine. We all crowded about, examining it, not even Burke offering an explanation.
Suddenly Craig’s face lightened up. He thrust the tubes into his ears and walked over to a smaller safe that was still locked. As he turned the combination handle he held the black disc up close to the safe. The intent look on his face caused us all to watch without a word. Around and around he turned the handle slowly. Finally he stopped. Then, with a few quick turns, he gave the door a pull and it swung open on its oiled hinges.
We fairly gasped. ‘What is it?’ I demanded. ‘Magic?’
Kennedy smiled. ‘Not magic, but black science,’ he replied. ‘This is a burglar’s microphone.’
‘A burglar’s microphone?’ I repeated. ‘What’s that?’
‘Well,’ he explained, ‘the microphone is now used by burglars for picking combination locks. When you turn the lock a slight sound is made when the proper number comes opposite the working part. It can be heard by a sensitive ear, sometimes, I am told. However, it is imperceptible to most persons. But by using a microphone it is an easy matter to hear the sounds. Having listened to the fall of the tumblers, the expert can determine what are the real numbers of the combination and open the safe. That is what happened in this case.’
We followed Kennedy speechless. What was there to say? We had already seen him open a safe with it himself.
Though we were thus far on our way, we had not even a clue as to the identity of the criminal or criminals.
I recalled Burke’s own theory as he had expressed it. Could it be that someone had betrayed to a foreign government agent the priceless secret of the telautomaton?
‘AS long as I am back in the city,’ continued Kennedy, while we stared at one another, wondering what next move to make, ‘I think that I had better take the opportunity to make some investigations in my laboratory which would be impossible out at Westport.’
In the meantime Burke had been examining the burglar’s microphone, turning it over and over thoughtfully, as if in the hope that it might furnish some clue.
‘It might have been possible,’ he ruminated, ‘for someone to get into the building at night if the night watchman was off his guard and he had a key to the building. I suppose he might get out again, too, under the same circumstances.’
‘A good lead,’ agreed Kennedy. ‘While you are finding the night watchman and getting anything else along that line of reconstructing what actually did take place it will give me just the chance I need. Let us meet in two or three hours—say, at Mr Hastings’s office. Let me see, I believe your firm is Hastings and Halsey, isn’t it?’
‘Hastings and Halsey,’ repeated the lawyer. ‘You are quite welcome to meet again there. You know where it is, on Wall Street?’
We noted the number and Kennedy and I hurried up-town to the laboratory which we had left only a few short hours before.
Already there were waiting for him, by special messenger, the materials from the autopsy which had been promised by the Westport coroner, who for once had appreciated the importance of a case and had acted with speed and decision.
Kennedy lost no time in throwing off his coat and donning his acid-stained smock. For some minutes I watched him in silence as he arranged his jars and beakers and test-tubes for the study which he had in mind. He had taken some of the material and placed it over a Bunsen burner in an apparatus which looked like a miniature still. Another apparatus which
