Poissan's laboratory was at the top of a sort of loft building a dozen stories or so high. It was a peculiar building, with several entrances besides a freight elevator at the rear and fire-escapes that led to adjoining lower roofs.
We stopped around the corner in the shadow, and Kennedy and Andrews talked earnestly. As near as I could make out Kennedy was insisting that it would be best for Andrews and his men not to enter the building at all, but wait down-stairs while he and I went up. At last the arrangement was agreed on.
“Here,” said Kennedy, undoing a package he had carried, “is a little electric bell with a couple of fresh dry batteries attached to it, and wires that will reach at least four hundred feet. You and the men wait in the shadow here by this side entrance for five minutes after Jameson and I go up. Then you must engage the night watchman in some way. While he is away you will find two wires dangling down the elevator shaft. Attach them to these wires from the bell and the batteries—these two—you know how to do that. The wires will be hanging in the third shaft—only one elevator is running at night, the first. The moment you hear the bell begin to ring; jump into the elevator and come up to the twelfth floor—we'll need you.”
As Kennedy and I rode up in the elevator I could not help thinking what an ideal place a down-town office building is for committing a crime, even at this early hour of the evening. If the streets were deserted, the office-buildings were positively uncanny in their grim, black silence with only here and there a light.
The elevator in the first shaft shot down again to the ground floor, and as it disappeared Kennedy took two spools of wire from his pocket and hastily shoved them through the lattice work the third elevator shaft. They quickly unrolled, and I could hear them strike the top of the empty car below in the basement. That meant that Andrews on the ground floor could reach the wires and attach them to the bell.
Quickly in the darkness Kennedy attached the ends of the wires to the curious little coil I had seen him working on in the laboratory, and we proceeded down the hall to the rooms occupied by Poissan, Kennedy had allowed for the wire to reach from the elevator-shaft up this hall, also, and as he walked he paid it out in such a manner that it fell on the floor close to the wall, where, in the darkness, it would never be noticed or stumbled over.
Around an “L” in the hall I could see a ground-glass window with a light shining through it. Kennedy stopped at the window and quickly placed the little coil on the ledge, close up against the glass, with the wires running from it down the hall. Then we entered.
“On time to the minute, Professor,” exclaimed Poissan, snapping his watch. “And this, I presume, is the banker who is interested in my great discovery of making artificial diamonds of any size or colour?” he added, indicating me.
“Yes,” answered Craig, “as I told you, a son of Mr. T. Pierpont Spencer.”
I shook hands with as much dignity as I could assume, for the role of impersonation was a new one to me.