“There’s a good deal in that,” agreed Godfrey, with a little laugh.  “I admit that our arguing doesn’t seem to lead anywhere.  Come along,” and he led the way out among the trees.

“Now take these fireworks,” went on Simmonds, in a low tone, when we were sitting side by side on the limb.  “I don’t understand what they mean; but they must mean something.  Am I laying awake nights worrying about them?  Not me!  I’m just going to keep on watching till I find out what the meaning is.  I know you’re a great fellow for theory and deduction, and all that sort of thing, Godfrey, and I know you’ve pulled off some mighty clever stunts; but, after all, there’s nothing like patience.”

“Yes—­’it’s dogged as does it,’” agreed Godfrey.  “Patience is a great thing.  I only wish I had more of it.”

“It would be a good thing,” assented Simmonds, candidly; and then we fell silent, gazing out into the darkness.

“Surely,” said Godfrey, at last, “it must be twelve o’clock.”

Simmonds got out his watch and flashed upon it a ray from his electric torch.

“Yes,” he said, “it’s four minutes after.”

I felt Godfrey’s hand stiffen on my arm.

“Then there’s something wrong,” he whispered.  “You remember, Lester, what happened the other time that light failed to appear.  A man was murdered!”

The darkness into which I stared seemed suddenly to grow threatening and sinister, full of vague terrors.  Even Simmonds grew uneasy, and I could feel his arm twitching.

Godfrey put his foot on the ladder, and began to descend.  Simmonds and I followed him silently.

“I’m going over the wall,” he said, when we were on the ground.  “Something’s wrong, and we’ve got to find out what it is.”

“How will we get down?” asked Simmonds.  “There’s no ladder there.”

Godfrey considered a moment.

“We can stand on the top of the wall,” he said, at last, “and lift this ladder over.  It won’t be easy, but it can be done.  Go ahead, Lester, and be careful of the glass.”

I mounted the ladder, felt cautiously along the top of the wall and found a place where I could put my feet; Simmonds followed me, and then came Godfrey.  His was the difficult part, to draw up the ladder and lower it again.  As for me, it was all I could do to keep from falling.  I felt absurdly as though I were standing on a tremulous tight-rope, high in the air; but Godfrey managed it somehow and started down.

And at that instant, there shrilled through the night the high, piercing note of a police-whistle.  It rose and fell, rose and fell, rose and fell; and then came poignant silence.  The sound stabbed through me.  Without hesitation or thought of peril, I let myself go and plunged downward into the darkness.

CHAPTER XXIII

DEADLY PERIL