at the War Office where the Hirsch formula is kept. We are the only people
who have ever known it, except the inventor himself and the Minister
for War; but the Minister permitted it to save Hirsch from fighting.
After that we really can't support Dubosc if his revelation
is a mare's nest."

"And it is?" asked Father Brown.

"It is," said his friend gloomily. "It is a clumsy forgery
by somebody who knew nothing of the real hiding-place. It says the paper
is in the cupboard on the right of the Secretary's desk. As a fact
the cupboard with the secret drawer is some way to the left of the desk.
It says the grey envelope contains a long document written in red ink.
It isn't written in red ink, but in ordinary black ink.
It's manifestly absurd to say that Hirsch can have made a mistake
about a paper that nobody knew of but himself; or can have tried
to help a foreign thief by telling him to fumble in the wrong drawer.
I think we must chuck it up and apologize to old Carrots."

Father Brown seemed to cogitate; he lifted a little whitebait
on his fork. "You are sure the grey envelope was in the left cupboard?"
he asked.

"Positive," replied Flambeau. "The grey envelope--
it was a white envelope really--was--"

Father Brown put down the small silver fish and the fork and
stared across at his companion. "What?" he asked, in an altered voice.

"Well, what?" repeated Flambeau, eating heartily.