drawing-room mantelpiece. On the opposite side of the room was a large,
massively-constructed copying camera, the front of which, carrying the
lens, was fixed, and an easel or copyholder travelled on parallel guides
towards, or away, from it, on a long stand.

This apparatus Thorndyke proceeded to explain to our visitors while
Polton was fixing the "Thumbograph" in a holder attached to the easel.

"You see," he said, in answer to a question from Miss Gibson, "I have a
good deal to do with signatures, cheques and disputed documents of
various kinds. Now a skilled eye, aided by a pocket-lens, can make out
very minute details on a cheque or bank-note; but it is not possible to
lend one's skilled eye to a judge or juryman, so that it is often very
convenient to be able to hand them a photograph in which the
magnification is already done, which they can compare with the original.
Small things, when magnified, develop quite unexpected characters; for
instance, you have handled a good many postage stamps, I suppose, but
have you ever noticed the little white spots in the upper corner of a
penny stamp, or even the difference in the foliage on the two sides of
the wreath?"

Miss Gibson admitted that she had not.

"Very few people have, I suppose, excepting stamp-collectors," continued
Thorndyke; "but now just glance at this and you will find these
unnoticed details forced upon your attention." As he spoke, he handed
her a photograph, which he had taken from a drawer, showing a penny
stamp enlarged to a length of eight inches.

While the ladies were marvelling over this production, Polton proceeded