about three inches in diameter, and painted white to match the plaster,
was here let into the wall. What could be the object of it? With a fresh
nail the boy began to scratch off the paint from the surface of the disk,
in order to determine whether it were actually iron, or some other metal;
in so doing a small movable lid, like the screen of a keyhole, was pushed
aside, disclosing a little round aperture underneath. Archibald pushed the
nail into it, thereby informing himself that the hole went straight into
the wall, for a distance greater than the length of the nail; but how much
greater, and what was at the end of it, he could only conjecture.

We must imagine him now standing upon a chair, with the nail in his hand,
casting about in his mind for some means of probing this mysterious and
unexpected hole to the bottom. At this juncture he happens to glance
upward, and meets the intent regard of his pictured ancestor, who seems to
have been silently watching him all this time, and only to be prevented by
unavoidable circumstances from speaking out and telling him what to do
next. And there is that constant forefinger pointing--at what? At the
cavity in the floor, of course; but not of that alone; for if you observe,
this same new-found hole in the wall is a third point in the straight line
between the end of the forefinger and the hiding-place of the silver rod;
furthermore, the hole is, as nearly as can be estimated without actual
measurement, three feet distant from the forefinger, and five feet from
the rod; the problem of three above and five below has solved itself in
the twinkling of an eye, and it only remains to act accordingly!

Archibald sprang to the floor in no small excitement; but the first thing
he did was to see that both his doors were securely fastened. Then he
advanced upon the mystery with heightened color and beating heart, his
imagination revelling in the wildest forecasts of what might be in store;
and anon turning him cold with sickening apprehension lest it should prove