ather Brown had added quite composedly, "Why does he really hide the
secret of what he does with the purple wig? Because it isn't the sort of
secret we suppose."

The Duke came round the corner and resumed his seat at the head of the
table with all his native dignity. The embarrassment of the librarian
left him hovering on his hind legs, like a huge bear. The Duke addressed
the priest with great seriousness. "Father Brown," he said, "Doctor
Mull informs me that you have come here to make a request. I no longer
profess an observance of the religion of my fathers; but for their
sakes, and for the sake of the days when we met before, I am very
willing to hear you. But I presume you would rather be heard in
private."

Whatever I retain of the gentleman made me stand up. Whatever I have
attained of the journalist made me stand still. Before this paralysis
could pass, the priest had made a momentarily detaining motion. "If,"
he said, "your Grace will permit me my real petition, or if I retain any
right to advise you, I would urge that as many people as possible should
be present. All over this country I have found hundreds, even of my own
faith and flock, whose imaginations are poisoned by the spell which I
implore you to break. I wish we could have all Devonshire here to see
you do it."

"To see me do what?" asked the Duke, arching his eyebrows.

"To see you take off your wig," said Father Brown.

The Duke's face did not move; but he looked at his petitioner with a
glassy stare which was the most awful expression I have ever seen on a
human face. I could see the librarian's great legs wavering under him
like the shadows of stems in a pool; and I could not banish from my own
brain the fancy that the trees all around us were filling softly in the
silence with devils instead of birds.

"I spare you," said the Duke in a voice of inhuman pity. "I refuse. If
I gave you the faintest hint of the load of horror I have to bear alone,
you would lie shrieking at these feet of mine and begging to know no
more. I will spare you the hint. You shall not spell the first letter of
what is written on the altar of the Unknown God."

"I know the Unknown God," said the little priest, with an unconscious
grandeur of certitude that stood up like a granite tower. "I know his
name; it is Satan. The true God was made flesh and dwelt among us. And
I say to you, wherever you find men ruled merely by mystery, it is the
mystery of iniquity. If the