Then he fell into a reverie, as he frequently did. An idea for a
fascinating story crept unbidden into his mind. He gazed vaguely around
him. Some little noise outside attracted his attention, the kind of noise
made by a sweep's brushes up a chimney. David turned idly towards the
open window. The top of it was but faintly illuminated by the light of
the conservatory gleaming dully on the transparency over the glass. But
David's eyes were keen, and he could see distinctly a man's thumb crooked
downwards over the frame of the ash. Somebody had swarmed up the
telephone holdfasts and was getting in through the window. Steel slipped
well into the shadow, but not before an idea had come to him. He removed
the rolled-up Rembrandt from the table and slipped it behind a row of
books in the book-case. Then he looked up again at the crooked thumb.

He would recognise that thumb again anywhere. It was flat like the head
of a snake, and the nail was no larger than a pea--a thumb that had
evidently been cruelly smashed at one time. The owner of the thumb might
have been a common burglar, but in the light of recent events David was
not inclined to think so. At any rate he felt disposed to give his theory
every chance. He saw a long, fustian-clad arm follow the scarred thumb,
and a hand grope all over the table.

"Curse me," a foggy voice whispered, hoarsely. "It ain't here. And the
bloke told me--"

The voice said no more, for David grabbed at the arm and caught the wrist
in a vice-like grip. Instantly another arm shot over the window and an
ugly piece of iron piping was swung perilously near Steel's head.
Unfortunately, he could see no face. As he jumped back to avoid a blow
his grasp relaxed, there was a dull thud outside, followed by the tearing
scratch of boots against a wall and the hollow clatter of flying feet.