"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."