Doyle left with alacrity. For once he could understand Kennedy's method and approve it.
Half an hour later we entered the Wilford apartment-house, taking care to do so at a time when the elevator was not down at the ground floor. As far as we knew, no one interested had seen us come in. That was the one chance we were forced to take. Its only disadvantage was that it made it necessary for us to walk up eight flights of stairs, and even then to go carefully, lest we meet some one in the hall.
However, we found Apartment K at last without any difficulty, opened the door, and admitted ourselves quietly. Doyle had located the dictagraph in this room, two floors below the apartment of the Wilfords', in this vacant suite.
As we entered, I saw that in the room were merely a deal table and a couple of chairs. On the table lay the box containing the receiving end of the dictagraph, to which already were fitted the head and ear pieces for listening. The switch on the table was marked, showing the various rooms in which the transmitters had been placed and arranged so that one might follow from one room to another, if necessary. There was paper for notes on the table, too, but otherwise the room was bare.
Kennedy adjusted the ear-pieces over his head, much as a wireless operator might have done, and, noting how he did it, I followed suit.
Then we waited. I could hear the clicks as he moved the switch past one connection after another, trying out the various rooms to see whether there was any one in them or not.
There was no one in the living-room, but as we listened we could hear the striking of a small clock on the mantel. From room to room we went, in imagination, almost as if we had been there, but able to go about unobserved. Had Honora been clever enough to penetrate our ruse? Or had Doyle and McCabe executed their end of the scheme clumsily?
We waited impatiently, wondering whether, after all, it was a fools' errand for us.
Suddenly I could hear a dull, rhythmical noise above the mild buzzing of the dictagraph.
"What's that?" I asked, almost in a whisper, which was involuntary.