Sim Sim is a copious spring, which supplies a large bason the Arabs have dug for it near thirty feet deep. It lies west of Rashid, or a little to the southward of west. It is in a sandy desert, in the direct way to Beyla and Sennaar, and here the Daveina kept their flocks, equally secure from the fly and the troops of Sennaar, the two great enemies they have to fear; and being in the neighbourhood of Ras el Feel, they keep a large market there, supplying that country amply with provisions of all kinds, and getting from it, in return, what they have not in their own district. We were just two hours in coming to Rashid, for we were flying for our lives; the _Simoom_, or hot-wind, having struck us not long after we had set out from Imserrha, and our little company, all but myself, fell mortally sick with the quantity of poisonous vapour that they had imbibed. I apprehend, from Rashid to Imserrha it is about five miles; and though it is one of the most dangerous halting-places between Ras el Feel and Sennaar, yet we were so enervated, our stomachs so weak, and our head-achs so violent, that we could not pitch our tent, but each wrapping himself in his cloak, resigned himself immediately to sleep, under the cool shade of the large trees, invited by the pleasant breeze from the north, which seemed to be merely local, confined to this small grove, created probably by the vicinity of the water, and the agitation we had occasioned in it. In this helpless state to which we were reduced, I alone continued not weakened by the simoom, nor overcome by sleep. A Ganjar Arab, who drove an ass laden with salt, took this opportunity of stealing one of the mules, together with a lance and shield belonging to one of my servants. The country was so woody, and he had so much advantage of us in point of time, and we were in so weak and discouraged a state, that it was thought in vain to pursue him one step. So he got off with his booty, unless he was intercepted by some of those wild beasts, which he would find everywhere in his way, whether he returned to Ras el Feel, or the frontiers of Kuara, his own country. Having refreshed ourselves with a little sleep, the next thing was to fill our girbas, or skins, with water. But before we attempted this, I thought to try an experiment of mixing about twenty drops of spirit of nitre in a horn of water about the size of an ordinary tumbler. This I found greatly refreshed me, though my headach still continued. It had a much better effect upon my servants, to whom I gave it; for they all seemed immediately recovered, and their spirits much more so, from the reflection that they had with them a remedy they could trust to, if they should again be so unfortunate as to meet this poisonous wind or vapour.