wear that those two prints are forgeries?"

Mr. Singleton hesitated for a moment. He had been watching the judge and
the jury and had apparently misinterpreted their surprise, assuming it
to be due to his own remarkable powers of discrimination; and his
confidence had revived accordingly.

"Yes," he answered; "I swear that they are forgeries."

Anstey sat down, and Mr. Singleton, having passed his notes up to the
judge, retired from the box, giving place to his colleague.

Mr. Nash, who had listened with manifest satisfaction to the evidence,
stepped into the box with all his original confidence restored. His
selection of the true and the false thumb-prints was practically
identical with that of Mr. Singleton, and his knowledge of this fact led
him to state his conclusions with an air that was authoritative and even
dogmatic.

"I am quite satisfied of the correctness of my statements," he said, in
reply to Anstey's question, "and I am prepared to swear, and do swear,
that those thumb-prints which I have stated to be forgeries, are
forgeries, and that their detection presents no difficulty to an
observer who has an expert acquaintance with finger-prints."

"There is one question that I should like to ask," said the judge, when
the expert had left the box and Thorndyke had re-entered it to continue
his evidence. "The conclusions of the expert witnesses--manifestly _bona
fide_ conclusions, arrived at by individual judgement, without collusion
or comparison of results--are practically identical. They are virtually
in complete agreement. Now, the strange thing is this: their conclusions
are wrong in every instance" (here I nearly laughed aloud, for, as I
glanced at the two experts, the expression of smug satisfaction on their
countenances changed with lightning rapidity to a ludicrous spasm of
consternation); "not sometimes wrong and sometimes right, as would have
been the case if they had made mere guesses, but wrong every time. When
they are quite certain, they are quite wrong; and when they are
doubtful, they incline to the wrong conclusion. This is a very strange
coincidence, Dr. Thorndyke. Can you explain it?"

Thorndyke's face, which throughout the proceedings had been as
expressionless as that of a wooden figurehead, now relaxed into a dry
smile.

"I think I can, my lord," he replied. "The object of a forger in
executing a forgery is to produce deception on those who shall examine
the forgery."

"Ah!" said