any further. Before I had arranged two smaller skins, had filled them with the water of the large one, had tied ropes to them, and had loaded them upon my ass, the caravan had gained a great distance ahead, so that following their footsteps in the sand, I could not rejoin them till late after sunset. It is in such cases that the want of a servant or companion is chiefly felt; for slave traders show no sort of compassion for the embarrassments of their fellow creatures. We marched this evening about six hours, over stony ground, and encamped late at night in Wady Kowa, (وادي كوع), a valley full of pasturage. The direction during the day was S. by E. _16th March._ After a few hours rest we again started. Our road lay over a sandy flat. High mountains appeared far in the east. At the end of three hours we halted in Wady Safyha (وادي صَفيحه), which cannot properly be called a valley, being a strip of lower land, running across the plain, where the rain water collects, and produces some trees and shrubs. Such spots in the Arabian deserts are called Ghadyr (غدير). After mid-day we continued over the plain. During the whole day’s march we were surrounded on all sides by lakes of mirage, called by the Arabs Serab. Its colour was of the purest azure, and so clear that the shadows of the mountains which bordered the horizon were reflected on it with the greatest precision, and the delusion of its being a sheet of water was thus rendered still more perfect. I had often seen the mirage in Syria and Egypt, but always found it of a whitish colour, rather resembling a morning mist, seldom lying steady on the plain, but in continual vibration; but here it was very different, and had the most perfect resemblance to water. The great dryness of the air and earth in this desert may be the cause of the difference. The appearance of water approached also much nearer, than in Syria and Egypt, being often not more than two hundred paces from us, whereas I had never seen it before at a distance of less than half a mile. There were at one time about a dozen of these false lakes round us, each separated from the other, and for the most part in the low grounds. After about eight hours march we stopped at Wady Om Doum (وادي اُم دوم). The name indicates the existence of Doum trees, but I could see no trees of any kind. I have observed that the vallies south of Omgat run generally from east to west, while those to the north of that place were parallel to our route. Our direction was still S. by E.