The advanced party, of which I was, unexpectedly left the route of Fezzan to the east, and turned sharp round to the south, through the gorge of a low mountain range, which we had had all along to the right. In this defile we proceeded an hour, but it had no natural opening at the end. We came at last to a very abrupt ascent of some hundred feet high, and mounted an elevated plateau. Once on the plateau, all was plain as far as the eye could see. The defile was tertiary formation, mere dull crumbling limestone; nothing in the shape and consistence of granite. We are now on the highway for Ghat, and it is said we shall arrive in fifteen days from the plateau. Saw on the plateau, for the first time of my life, the celebrated mirage, which our people call _Watta_, but the classic Arabic is _Es-Sarab_ (‮السّرب‬). At first sight, I thought it was salt, for it flamed in the sun white, like a salt-pit, or lagoon. There appeared some low hills in the midst of the white lake. As we proceeded, I saw what appeared like white foam running from east to west, as the sea-surf chafing the shore. It then occurred to me that this might be the mirage; and so it turned out, for as we approached the phenomenon, it retired and disappeared. The character of the mirage was evidently affected by the wind, for the foam appeared to run from east to west with the wind. In some of the white flaming lakes, shrubs and reeds stood out, as we find in shallow pools. Some high hills appeared suspended in the air, veritable "castles in the air." The weather was dull, the sun sometimes hidden, and it was noon when the phenomena were most observable. At Mazeen a few small birds were hopping and chirping, and two large crows followed us upon the plateau; also a butterfly and a few flies. These are the living creatures noticed to-day. The plateau, where I now write, is either covered with very small stones, some quite black, and others calcined or burnt, like brick-bats thrown from a kiln, or is altogether hardened and black earthy soil. The latter assists the mirage, for the phenomenon appears mostly on the earthy tracts of ground. In some parts is herbage for the camels. On the plateau we saw several small mounds of soft brown stone, crumbling to earth, which looked like Arab hovels at a distance. I went up to undeceive myself. These curious mounds have yet to crumble away before the plateau is a perfect plane. Course to-day mostly south, with a leaning to the west. Wind cold S.E. and E. The day as dull and dreary as in England. Our people occasionally mount the maharees, which look very haughty and imposing. A maharee would be a noble present for the Sultan of the Touaricks to send to the Queen.