use he is physically alert than because he is mentally
impatient. I knew that I knew the other walk, too, but I could not
remember what it was. What wild creature had I met on my travels that
tore along on tiptoe in that extraordinary style? Then I heard a clink
of plates somewhere; and the answer stood up as plain as St. Peter's. It
was the walk of a waiter--that walk with the body slanted forward, the
eyes looking down, the ball of the toe spurning away the ground, the
coat tails and napkin flying. Then I thought for a minute and a half
more. And I believe I saw the manner of the crime, as clearly as if I
were going to commit it."

Colonel Pound looked at him keenly, but the speaker's mild grey eyes
were fixed upon the ceiling with almost empty wistfulness.

"A crime," he said slowly, "is like any other work of art. Don't look
surprised; crimes are by no means the only works of art that come from
an infernal workshop. But every work of art, divine or diabolic, has
one indispensable mark--I mean, that the centre of it is simple, however
much the fulfilment may be complicated. Thus, in Hamlet, let us say,
the grotesqueness of the grave-digger, the flowers of the mad girl, the
fantastic finery of Osric, the pallor of the ghost and the grin of
the skull are all oddities in a sort of tangled wreath round one plain
tragic figure of a man in black. Well, this also," he said, getting
slowly down from his seat with a smile, "this also is the plain tragedy
of a man in black. Yes," he went on, seeing the colonel look up in some
wonder, "the whole of this tale turns on a black coat. In this, as in
Hamlet, there are the rococo excrescences--yourselves, let us say. There
is the dead waiter, who was there when he could not be there. There is
the invisible hand that swept your table clear of silver and melted
into air. But every clever crime is founded ultimately on some one quite
simple fact--some fact that is not itself mysterious. The mystification
comes in covering it up, in leading men's thoughts away from it. This
large and subtle and (in the ordinary course) most profitable crime, was
built on the plain fact that a gentleman's evening dress is the same as
a waiter's. All the rest was acting, and thundering good acting, too."

"Still," said the colonel, getting up and frowning at his boots, "I am
not sure that I understand."

"Colonel," said Father Brown, "I tell you that this archangel of
impudence who stole your forks walk