The appearance of these phantoms of the plain, as Bruce terms them, sent their guide to his prayers, and together with the danger which they were now in of perishing of thirst, produced in the whole party nothing but murmuring, discontent, and insubordination. Next day the moving sand-pillars again appeared. The sublimity of the scene,—a boundless desert, level as the sea, condemned to eternal desolation, without sounds or signs of life, animal or vegetable; the arid soil, drained of every particle of moisture, reduced by perpetual attrition to almost impalpable atoms, and raised aloft by whirlwinds into prodigious columns, which, as if instinct with life, glided along with preternatural rapidity,—all this, I say, no language, however magnificent, or exalted by metaphor and poetical fervour, could ever present in its proper terrors to the mind. These pillars on their second appearance were more numerous, but of inferior dimensions to those seen at Waadi Halboub. They had probably been careering over the waste in the darkness and silence of night; as, immediately after sunrise, they were observed, like a thick wood, reaching to the clouds, and almost darkening the sun, whose slanting rays, shining through them as they moved along, like enormous shadows, before the wind, gave them the appearance of pillars of fire. Our traveller’s attendants now became desperate: the Greeks shrieked out that the day of judgment was come; Ismael, a Turk, said it was hell; and the Africans exclaimed that the world was on fire. Bruce now demanded of their guide whether he had ever before witnessed such a sight. “Frequently,” replied the man, “but I have never seen a worse.” He added, however, that from the redness of the air, he dreaded the approach of something much more terrible than these fiery columns,—the _simoom_, which almost invariably ensued upon such a disposition of the atmosphere. This information greatly increased the apprehensions of the traveller; but he entreated the man to conceal his suspicions from their companions.