Morgon considered. The gentle, rhythmic clop of hooves and the distant voice of the river sounded frail against the silence, which seemed impervious to any shout. He thought back to the previous night, trying to find again the source of inexhaustible energy, private and undefined, that had overwhelmed him to produce the silent shout. The sun, leaping from behind a bend in the road, suddenly showered his path with stars. The unbroken blue of the sky quivered with a great, soundless note. He drew a breath of the hidden sound and loosed a shout.
  There was an answering shout from the mountains. For a second he listened to it without surprise. Then he saw Deth stop ahead of him; his face turned back in surprise. He dismounted, wrenched at the pack-horse's reins, and Morgon, suddenly placing the sound, slid off his horse and drew it to the wall of the cliff. He crouched flat beside it as the hiss and rattle of stones swept towards them, bounced on the road and down the slope.
  The rumble shook through bare peaks and hidden forests. A boulder half the size of a horse struck the cliff edge above their heads, sailed lightly over them and flung itself down the slope towards the river, crushing a tree as it passed. Then the silence, regathered and locked into place, strained at their ears in triumph.
 ...He said after a moment, blankly, "That was stupid."