ndow from here."

Crewe smiled, but did not reply. Followed by Rolfe, he went back to the
tree by the library window, where he posted Rolfe with the end of the
tape in his hand. Then he walked slowly back across the garden in the
direction of the garage, keeping his eye on the library window on the
first floor from which Kemp, according to his evidence, had seen Sir
Horace leaning out after Holymead had left the house. He returned to the
tree, noting the measurement in his book as he did so, and then repeated
the process, walking backwards with his eye fixed on the window, but this
time taking a line more to the left. Again and again he repeated the
process, until finally he had walked backwards from the tree in narrow
segments of a big semicircle, finishing up on the boundary of the Italian
garden on the other side of the grounds, and almost directly opposite to
the garage from which he had started.

"There's no use going further back than that," he said, turning to
Inspector Chippenfield, who had followed him round, smoking one of
Crewe's cigars, and very much mystified by the whole proceedings, though
he would not have admitted it on any account. "At this point we
practically lose sight of the window altogether, except for an oblique
glimpse. Certainly Kemp would not come as far back as this--he would have
no object in doing so."

"I quite agree with you," said Inspector Chippenfield. "He would stand
more in the front of the house. The tree in front of the house doesn't
obstruct the view of the window to any extent."

The tree to which Inspector Chippenfield referred was a solitary
chestnut-tree, which grew close to the house a little distance from the
main entrance, and reached to a height of about forty feet. Its branches
were entirely bare of leaves, for the autumn frosts and winds had swept
the foliage away.

Rolfe, who had been watching Crewe's manoeuvres curiously, walked up to
them with the tape in his hand. He glanced at the library window on the
first floor as he reached them.

"Kemp could have seen the library window if he had stood here," he said.
"I should say that if the blind were up it would be possible to see right
into the room."

"What do you say, Chippenfield?" asked Crewe, turning to that officer.

Inspector Chippenfield had taken his stand stolidly on the centre path of
the Italian garden, directly in front of the window of the library.

"I say Kemp is a liar," he replied, knocking the