knotted rope.

He wished to make his investigations secretly, so as not to put Jones on
his guard. It would not have been safe to get into the flat by the
ordinary methods.

By using the fire escape of the building next door to the flat house,
Nick got to the roof.

The top of the air shaft was covered with a framework, in which large
panes of glass were set.

Nick removed one of them. Then he made his rope fast, and crept through
the space where the glass had been.

The Jones' flat was next to the top, so Nick had a short descent.

But there was an awful stretch of empty air under him as he hung there.

The shaft went to the basement floor, about seventy feet below the level
of the window which opened into the room occupied by the Jones' new
servant.

He found that window readily. One glance through it was enough to
satisfy him.

There sat the colored girl, reading a book. Nick's suspicions had been
correct.

Naturally he did not delay very long in the air shaft. He had a hard