d the three men across the table.

"Quite so!" he said in his vacuous English voice. "Marshall wrote a 3
by inadvertence and changed it. He borrowed my penknife to erase the
figure."

My father and Lewis gaped like men who see a penned-in beast slip out
through an unimagined passage. There was silence. Then suddenly, in the
strained stillness of the room, old Doctor Gaeki laughed.

Gosford lifted his long pink face, with its cropped beard bringing out
the ugly mouth.

"Why do you laugh, my good man?" he said.

"I laugh," replied Gaeki, "because a figure 5 can have so many colors."

And now my father and Lewis were no less astonished than Mr. Gosford.

"Colors!" they said, for the changed figure in the will was black.

"Why, yes," replied the old man, "it is very pretty."

He reached across the table and drew over Mr. Gosford's memorandum
beside the will.

"You are progressive, sir," he went on; "you write in iron-nutgall ink,
just made, commercially, in this year of fifty-six by Mr. Stephens. But
we write here as Marshall wrote in 'fifty-four, with logwood."

He turned and fumbled in his little case of bottles.

"I carry a bit of acid for my people's indigestions. It has other uses."
He whipped out the stopper of his vial and dabbed Gosford's notes and
Marshall's signature.

"See!" he cried. "Your writing is blue, Mr. Gosford, and Marshall's
red!"

With an oath the trapped man struck at Gaeki's hand. The vial fell and
cracked on the table. The hydrochloric acid spread out over Marshall's
will. And under the chemical reagent the figure in the bequest of fifty
thousand dollars changed beautifully; the bar of the 5 turned blue, and
the remainder of it a deep purple-red like the body of the will.

"Gaeki," cried my father, "you have trapped a rogue!"

"And I have lost a measure of good acid," replied the old man. And he
began to gather up the bits of his broken bottle from the table.

VIII. The Hole in the Mahogany Panel

Sir Henry paused a moment, his finger between the pages of the ancient
diary.

"It is the inspirational quality in these cases," he said, "that
impresses me. It is very nearly absent in our modern methods of criminal
investigation. We depend now on a certain formal routine. I rarely find
a man in the whole of Scotland Yard with a trace of intuitive impulse to
lead him.... Observe how this old justice in Virginia bridged the gaps
between his incidents."

He paused.

"We ca