"Let us suppose nothing, Mr. Andrews," interrupted Kennedy. "At
least not yet. Let me see; it is now ten minutes after eight.
Poissan's place is only a few blocks from here. I'd like to get
there a few minutes early. Let's start."

As we left the office, Andrews signalled to the two men outside,
and they quietly followed a few feet in the rear, but without
seeming to be with us.

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