Creeping slowly up the shoulder of Mount Scott, the rising sun cast its first wan rays upon the slope of the northwest rim. The crest of the Rim was alive with a shimmering, opalescent light, for during the night the breeze from the north had stooped and brushed the earth with the summer's first white frost. The breeze had died, however, and now the air was hushed and still. Even the lake, far below, lay motionless in the gunmetal shadow of Cloud Cap. Gradually the sun cleared the shoulder of Scott, and its warmth became perceptible. And then occurred a curious thing. I became aware of a murmuring as of leaves stirred by a gentle breeze, but the air was motionless. I walked to where a group of hemlocks stood, seemingly immobile. Standing beneath them I looked up, but not a branch moved, not a twig quivered. Still that rustling murmur continued, and the air remained motionless. I walked back to my original place and listened. It was fainter now. The rustling had sunk to the merest whisper. I strained my ears. The sound was gone. The sun was well up now, and I could hear the throbbing of a motor approaching from the Diamond Lake Junction. Puzzled, I walked back to the cabin for my permit book.

For two days I pondered that peculiar susurration, that rustling of leaves from invisible trees. And three chilly mornings I rose before sunrise to be at the Rim to hear it. On the third morning I solved the mystery - mere by accident than by logic. Again everything was silent; the air motionless and the lake without a ripple. Again the earth was white with frost. Then, as the sun rose, the same gradually increasing rustle commenced, seeming to rise from the ground itself. I sat staring vacantly down the slope of the Rim, wondering. A slight movement a few feet down the slope attracted my eye, but I was too slow to catch it. Again I stared at the ground, this time with purpose. Four feet before my eyes a pebble shifted and rolled over twice. Another. And another. The whole slope was in motion toward the Lake! The mystery was solved!

During the night tiny frost crystals had formed beneath these light pumice pebbles, raising them ever so slightly. The sudden heat of the rising sun melted these fragile supporting crystals instantaneously, and the pebbles dropped suddenly. Sometimes they would settle back into place, but more generally the abrupt shift of the pebble's equilibrium, situated as it was on a steep slope, would cause it to roll downward for a distance varying from a fraction of an inch to as much as four inches. The infinitesimal sound produced by this process, when multiplied several thousand fold, had produced in its totality a sound resembling that produced by a breeze in the forest. And thus slowly, with infinite patience, Nature was making use of one of her varied tools to accomplish here work of wearing down the Rim.