After glancing over it in a masterly way, he leaned back in his chair
and bestowed upon me an explosion of sardonic, superior, collegiate
laughter.

"Well, you _are_ a fool, Jim," he said, when he could speak.

"It's your play," said I, patiently, fingering my double-six.

"Twenty," said Goodloe, making two crosses on the table with his chalk.

"Why am I a fool?" I asked. "Buried treasure has been found before in
many places."

"Because," said he, "in calculating the point on the river where
your line would strike you neglected to allow for the variation. The
variation there would be nine degrees west. Let me have your pencil."

Goodloe Banks figured rapidly on the back of an envelope.

"The distance, from north to south, of the line run from the Spanish
mission," said he, "is exactly twenty-two miles. It was run by a
pocket-compass, according to your story. Allowing for the variation,
the point on the Alamito River where you should have searched for your
treasure is exactly six miles and nine hundred and forty-five varas
farther west than the place you hit upon. Oh, what a fool you are, Jim!"

"What is this variation that you speak of?" I asked. "I thought figures
never lied."