Our course had been over an elevated rocky plain; but I had no idea of the height to which we had arrived.  Suddenly the ground broke up on either side of the track into rocky eminences, and we now came to the brow of a sharp descent.  The valley of Aroukeen wound as it were like a snake far down at the bottom of an immense hollow, surrounded on all sides by an amphitheatre of savage-looking mountains—­great stony swells, made hideous here and there by crags and ravines, and piled away on all sides in shattered magnificence.  This is the grandest desert prospect I have yet seen, and must strongly clash with the ordinary notion of the Great Sahara which untravelled geologists have represented as the recently-elevated bed of some ocean.  We must now have reached the summit of an inland Atlas, dividing the extreme limits of the Ghat territory from the, to us, mysterious kingdom of Aheer.

In Wady Aroukeen there are some of the finest tholukhs I have seen, reaching the height of thirty or forty feet.  There are, besides, two new species of trees, the adwa of Soudan, called, in Aheer, aborah:  they have not been observed before, and are natives of Bornou.  Their general aspect resembles the tholukh, but they have large prickles and a smooth roundish leaf.  There is a good deal of hasheesh in this valley.

We are now, they say, about twelve days from Aheer, exclusive of the stoppages; twelve days, I mean, of twelve hours a-piece.  These long stretches are desperately fatiguing, and trying to the health; but there is no remedy.  We must make these weary stages on account of the scarcity of water and herbage for the camels.  The Kailouees tie their camels by the lower jaw, and fasten the string to the baggage piled on the back of the preceding animal; and the long line moves on well this way.  The Tuaricks fasten their bridles, when they ride their maharees, by a round ring in the nose.

We had granite again to-day, and fine beds of felspar, pebbles, and rocks.  The geology of this portion of Sahara is very interesting, but no crystals have yet been found.  Yesterday and to-day, the wind has been high, moderating greatly the heat.  The wind is nearly always south-east.  The nights are resplendent.  Jupiter and Venus are seen close together in beautiful conjunction.  The constellation of the Scorpion rises higher in the south, whilst the Pole-star apparently falls.

I read nothing nowadays but a few verses of the Greek Testament, and write these miserable leaves of journal.  I must save my strength.  I am very weak as it is.  We have still got nearly forty days of actual travelling to make before we enter Soudan, but we hope Providence will allow us a little rest at Aheer.

10th.—­We moved on late this morning up Wady Aroukeen, one hour and a-half, to a place where we have better feeding for the camels; but it was scarcely worth the trouble of loading and unloading, as the animals could have been led up here to this portion of the wady.