seemed at first to be the sandy desert of the heart of Asia; but during the two hours of our stay on the pass, it expanded and rose, and we then knew it for the inevitable dust-haze which shrouds the country more than half the year.
We were looking down into the great enclosed basin which, as the map of Asia shows, occupies the very centre of the continent. It stretches east-northeast for fourteen hundred miles from Kashgar to Su-Chow, and has a maximum breadth from north to south of over four hundred miles. Except to the northeast, toward the Desert of Gobi, where there is a region of low, maturely dissected mountains, the basin is sharply bounded by lofty, newly uplifted plateaus, diversified with mountains which rise to a height of from 15,000 to 25,000 feet. The edges of the plateaus are marked by steep ranges, such as that of Kwen Lun on the south, forming the northern escarpment of Tibet and the Karakorum plateau, those of the heights of the Pamirs on the west, and the southern range of Tian Shan on the north. Within the ring of encircling mountains, the basin floor is composed of a broad desert zone of gravel surrounding a zone of vegetation in which most of the villages and towns are situated, and which in turn surrounds a great central desert tract of sand and salt. The entire basin, which is as large as the portion of the United States east of Lake Michigan and north of Tennessee (three times as large as Great Britain and Ireland), drains to the salt lake of Lop-Nor. At least it would drain thither, if most of the streams did not wither to nothing in vast slopes of gravel and plains of sand. The principal river, the Tarim, or
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