On leaving M[=a]ther we commenced the ascent of the Kara Kotul or Black Pass, which lasted for seven long miles and was very fatiguing. The large masses of rock on either side the pathway were of a deep brown colour. From the length and steepness of the ascent, this pass must be higher than any we had hitherto surmounted; the descent on the other side is difficult in proportion. The approach to Doa[=u]b is through one of the most romantic glens conceivable. It is here that the Koollum river takes its rise; it flows due north and soon reaches a mountain meadow, where it unites with another stream coming from the east, whence the name of the Doa[=u]b (two waters) is given to this district. In this defile are scattered huge rocks, which have been dislodged from the overhanging precipices by the effects of frost or convulsions of the elements: in vain do these masses obstruct the progress of the waters of this river. The torrent dashing in cataracts over some of the large boulders and eddying round the base of others, pursues an agitated course until it reaches the desert, through which it glides more calmly, and combines with the Oxus beyond Koollum, whence the confluent waters proceed uninterruptedly to the sea of Aral. The banks of this river differ from those of the mountain streams in general; they were decked with the most beautiful wild flowers, which bloomed luxuriantly on the bushes, and growing from the deep clefts in the rock, scented the air with their perfume. The glen is here so filled with large blocks of granite, that to accomplish our passage through it, it was necessary to transfer by manual labour the loads of the baggage animals across the obstructing masses: the difficulties we encountered, and more particularly the romantic scene itself, are still imprinted on my memory.