"Well, the consequence of this fall in temperature is that the
convalescent's mind turns toward thoughts of suicide. Then is the time
he should be watched by his friends. Then was the time Mr. Barrie
Kipson's friends did _not_ watch him. You remember the 21st, of
course. No? It was a most depressing day. Fog all around and mud under
foot. Very good. He resolves on suicide. He wishes to be unidentified,
if possible but forgets his season ticket. My experience is that a man
about to commit a crime always forgets something."

"But how do you account for the disappearance of the money?"

"The money has nothing to do with the matter. If he was a deep man, and
knew the stupidness of Scotland Yard, he probably sent the notes to an
enemy. If not, they may have been given to a friend. Nothing is more
calculated to prepare the mind for self-destruction than the prospect
of a night ride on the Scotch Express, and the view from the windows of
the train as it passes through the northern part of London is
particularly conducive to thoughts of annihilation."

"What became of the weapon?"

"That is just the point on which I wish to satisfy myself. Excuse me
for a moment."

Mr. Sherlaw Kombs drew down the window on the right hand side, and
examined the top of the casing minutely with a magnifying glass.
Presently he heaved a sigh of relief, and drew up the sash.

"Just as I expected," he remarked, speaking more to himself than to me.
"There is a slight dent on the top of the window-frame. It is of such a