I rose presently, found my cap in a closet under the stairs, and went out into the moon-flooded wood toward the lake. The tangle was not so great when you knew the way, and there was indeed, as I had found, the faint suggestion of a path. The moon glorified a broad highway across the water; the air was sharp and still. The houses in the summer colony were vaguely defined, but the sight of them gave me no cheer. The tilt of her tam-o’-shanter as she paddled away into the sunset had conveyed an impression of spirit and dignity that I could not adjust to any imaginable expiation.

These reflections carried me to the borders of St. Agatha’s, and I followed the wall to the gate, climbed up, and sat down in the shadow of the pillar farthest from the lake. Lights shone scatteringly in the buildings of St. Agatha’s, but the place was wholly silent. I drew out a cigarette and was about to light it when I heard a sound as of a tread on stone. There was, I knew, no stone pavement at hand, but peering toward the lake I saw a man walking boldly along the top of the wall toward me. The moonlight threw his figure into clear relief. Several times he paused, bent down and rapped upon the wall with an object he carried in his hand.

Only a few hours before I had heard a similar sound rising from the wainscoting of my own room in Glenarm House. Evidently the stone wall, too, was under suspicion!

Tap, tap, tap! The man with the hammer was examining the farther side of the gate, and very likely he would carry his investigations beyond it. I drew up my legs and crouched in the shadow of the pillar, revolver in hand. I was not anxious for an encounter; I much preferred to wait for a disclosure of the purpose that lay behind this mysterious tapping upon walls on my grandfather’s estate.

But the matter was taken out of my own hands before I had a chance to debate it. The man dropped to the ground, sounded the stone base under the gate, likewise the pillars, evidently without results, struck a spiteful crack upon the iron bars, then stood up abruptly and looked me straight in the eyes. It was Morgan, the caretaker of the summer colony.

“Good evening, Mr. Morgan,” I said, settling the revolver into my hand.

There was no doubt about his surprise; he fell back, staring at me hard, and instinctively drawing the hammer over his shoulder as though to fling it at me.

“Just stay where you are a moment, Morgan,” I said pleasantly, and dropped to a sitting position on the wall for greater ease in talking to him.

He stood sullenly, the hammer dangling at arm’s length, while my revolver covered his head.