"They are the sentinels who guard this region--and they have espied us!" We heard a harsh cry from the Indian. Following his gaze, we saw that several of the unnatural cloud-shapes had appeared on the summit toward which we were climbing, above the megalithic ruins. Some arose half hidden by the walls, as if from behind a breastwork; others stood, as it were, on the topmost towers and battlements, bulking in portentous menace, like the cumuli of a thunder-storm. Then, with terrifying swiftness, many more of the cloud-presences towered simultaneously from the four quarters, emerging from behind the gaunt peaks or assuming sudden visibility in mid-air. With equal and effortless speed, as if convoked by an unheard command, they gathered in converging lines upon the eyre-like ruins. We the climbers, and the whole slope about us and the valley below, were plunged in a twilight weird and awesome as that of central eclipse. The air was still windless, but it weighed upon us as if burdened with the wings of a thousand cacodemons. I remember that I was overwhelmingly conscious of our exposed position, for we had paused on a wide landing of the mountain-hewn steps. We could easily have concealed ourselves amid the huge fragments on the surrounding slope; but, for the nonce, we were incapable of the simplest movement. In a close-ranged army, the Clouds mustered above and around us. They rose into the very zenith, swelling to insuperable vastness, and darkening like Tartarean gods. The sun had disappeared, leaving no faintest beam to prove that it still hung unfallen and undestroyed in the heavens. I felt that I was crushed into the very stone by the eyeless regard of that awful assemblage, judging and condemning. We had trespassed upon a region conquered long ago by strange elemental entities; we had approached their very citadel--and now we must meet the doom our rashness had invited. Such thoughts, like a black lightning, flared in my brain. Now, for the first time, I became aware of sound--if the word can be applied to a sensation so anomalous. It was as if the oppression that weighed upon me had grown audible; as if palpable thunders poured over and past me. I felt, I heard them in every nerve, and they roared through my brain like torrents from the opened flood-gates of some tremendous weir in a world of genii. Downward upon us, with limbless atlantean stridings, there swept the cloudy cohorts. Their swiftness was that of supernatural things. The air was riven as if by the tumult of a thousand tempests, was rife with an unmeasured elemental malignity. I recall but partially the events that ensued; but the impression of insufferable darkness, of demonic clamor and trampling, and the pressure of thunderous burdenous onset, remains forever indelible. Also, there were voices that called out with the stridor of clarions in a war of gods, uttering ominous syllables that the ear of man could never seize.