About noon, they began to advance with considerable swiftness upon us, the wind being very strong at north.  Eleven of them ranged alongside of us, about the distance of three miles.  The greatest diameter of the largest appeared to me at that distance as if it would measure ten feet.  They retired from us with a wind at S.E., leaving an impression upon my mind to which I can give no name, though surely one ingredient in it was fear, with a considerable deal of wonder and astonishment.  It was vain to think of flying; the swiftest horse, or fastest sailing ship, could be of no use to carry us out of this danger; and the full persuasion of this rivetted me to the spot where I stood, and let the camels gain on me so much, that, in my state of lameness, it was with some difficulty I could overtake them.  The effect this stupendous sight had upon Idris was to set him to his prayers, or rather to his charms; for, except the names of God and Mahomet, all the rest of his words were mere gibberish and nonsense.  Ismael the Turk violently abused him for not praying in the words of the Koran, at the same time maintaining, with great apparent wisdom, that nobody had charms to stop these moving sands but the inhabitants of Arabia Deserta.

From this day subordination, though it did not entirely cease, rapidly declined; all was discontent, murmuring, and fear.  Our water was greatly diminished, and that terrible death by thirst began to stare us in the face, owing, in a great measure, to our own imprudence.  Ismael, who had been left sentinel over the skins of water, had slept so soundly, that a Turcorory had opened one of the skins that had not been touched, in order to serve himself out of it at his own discretion.  I suppose that, hearing somebody stir, and fearing detection, the Turcorory had withdrawn himself as speedily as possible, without tying up the month of the girba, which we found in the morning with scarce a quart of water in it.

On the 16th, our men, if not gay, were in better spirits than I had seen them since we left Gooz.  The rugged top of Chiggre was before us, and we knew that there we would solace ourselves with plenty of good water.  As we were advancing, Idris suddenly cried out, “Fall upon your faces, for here is the simoom!” I saw from the southeast a haze come, in colour like the purple part of the rainbow, but not so compressed or thick.  It did not occupy twenty yards in breadth, and was about twelve feet high from the ground.  It was a kind of blush upon the air, and moved very rapidly, for I scarce could turn to fall upon the ground, with my head to the northward, when I felt the heat of its current plainly upon my face.  We all lay flat on the ground, as if dead, till Idris told us it was blown over.  The meteor or purple haze which I saw was indeed past, but the light air that still blew was of a heat to threaten suffocation.  For my part, I found distinctly in my breast that I had imbibed a part of it, nor was I free from an asthmatic sensation till I had been some months in Italy, at the baths of Poretta, nearly two years afterwards.