Apparently nothing, except a continuation of those mysterious sounds.  That the box had increased in size I had, and have, no doubt whatever.  I should say that it had increased a good inch in every direction, at least half an inch while I had been looking on.  But while I stood looking its growth was suddenly and perceptibly stayed; it ceased to move.  Only the noise continued.

“I wonder how long it will be before anything worth happening does happen!  I suppose something is going to happen; there can’t be all this to-do for nothing.  If it is anything in the infernal machine line, and there is going to be an explosion, I might as well be here to see it.  I think I’ll have a pipe.”

I put on my dressing-gown.  I lit my pipe.  I sat and stared at the box.  I dare say I sat there for quite twenty minutes when, as before, without any sort of warning, the sound was stilled.  Its sudden cessation rather startled me.

“Has the mechanism again hung fire?  Or, this time, is the explosion coming off?” It did not come off; nothing came off.  “Isn’t the box even going to open?”

It did not open.  There was simply silence all at once, and that was all.  I sat there in expectation for some moments longer.  But I sat for nothing.  I rose.  I took the box in my hand.  I shook it.

“This puzzle is a puzzle.”  I held the box first to one ear, then to the other.  I gave it several sharp raps with my knuckles.  There was not an answering sound, not even the sort of reverberation which Pugh and I had noticed at first.  It seemed hollower than ever.  It was as though the soul of the box was dead.  “I suppose if I put you down, and extinguish the gas and return to bed, in about half an hour or so, just as I am dropping off to sleep, the performance will be recommenced.  Perhaps the third time will be lucky.”

But I was mistaken—­there was no third time.  When I returned to bed that time I returned to sleep, and I was allowed to sleep; there was no continuation of the performance, at least so far as I know.  For no sooner was I once more between the sheets than I was seized with an irresistible drowsiness, a drowsiness which so mastered me that I—­I imagine it must have been instantly—­sank into slumber which lasted till long after day had dawned.  Whether or not any more mysterious sounds issued from the bowels of Pugh’s puzzle is more than I can tell.  If they did, they did not succeed in rousing me.

And yet, when at last I did awake, I had a sort of consciousness that my waking had been caused by something strange.  What it was I could not surmise.  My own impression was that I had been awakened by the touch of a person’s hand.  But that impression must have been a mistaken one, because, as I could easily see by looking round the room, there was no one in the room to touch me.