It was very friable and so shallow that my scissors'-point picked it at once.

In five minutes' time the brick was clear, so that I easily lifted it out and set it on the floor.

The small black hole which was left was large enough to admit my hand.

I wasted no time thrusting it in, expecting to feel the box at once and draw it out.
But it was farther back than I expected, and while I was feeling about something gave way and fell with a slight, rustling noise down out of my reach.

Was it the box?
No, for in another instant I had come in contact with its broken edges and had drawn it out; the falling object must have been some extra mortar, and it had gone where?
I did not stop to consider then.