s right, there certainly was something within; something which
seemed to echo back my tapping, almost as if it were a living thing. I
mentioned this to Pugh.

"But you don't think that there is something alive inside the box? There
can't be. The box must be air-tight, probably as much air-tight as an
exhausted receiver."

"How do we know that? How can we tell that no minute interstices have been
left for the express purpose of ventilation?" I continued tapping with the
hammer. I noticed one peculiarity, that it was only when I held the box in
a particular position, and tapped at a certain spot, there came the
answering taps from within. "I tell you what it is, Pugh, what I hear is
the reverberation of some machinery."

"Do you think so?"

"I'm sure of it."

"Give the box to me." Pugh put the box to his ear. He tapped. "It sounds
to me like the echoing tick, tick of some great beetle; like the sort of
noise which a deathwatch makes, you know."

Trust Pugh to find a remarkable explanation for a simple fact; if the
explanation leans toward the supernatural, so much the more satisfactory
to Pugh. I knew better.

"The sound which you hear is merely the throbbing or the trembling of the
mechanism with which it is intended that the box should be opened. The
mechanism is placed just where you are tapping it with the hammer. Every
tap causes it to jar."

"It sounds to me like the ticking of a deathwatch. However, on such
subjects, Tress, I know what you are."

"My dear Pugh, give it an extra hard tap, and you will see."

He gave it an extra hard tap. The moment he had done so, he started.

"I've done it now."

"What have you done?"

"Broken something, I fancy." He listened intently, with his ear to the
box. "No--it seems all right. And yet I could have sworn I had damaged
something; I heard it smash."

"Give me the box." He gave it me. In my turn, I listened. I shook the box.
Pugh must have been mistaken. Nothing rattled; there was not a sound; the
box was as empty as before. I gave a smart tap with the hammer, as Pugh
had done. Then there certainly was a curious sound. To my ear, it sounded
like the smashing of glass. "I wonder if there is anything fragile inside
your precious puzzle, Pugh, and, if so, if we are shivering it by
degrees?"

II

"What _is_ that noise?"

I lay in bed in that curious condition which is between sleep and waking.
When, at last, I _knew_ that I was awake, I asked myself what it