THE GOBI AND SAHARA DESERTS.
down with terrific force, and for an hour or two afterwards large rivers continued to flow, silting up the wells (always dug on the lower ground) with mud and sand. It would be impossible to travel here without a guide thoroughly acquainted with the country; for destruction lies in wait for you at every step. In fact this desert, like that of Ala-shan, is so terrible that, in comparison with it, the deserts of Northern Tibet may be called fruitful. There, at all events, you may often find water and good pasture-land in the valleys; here, there is neither the one nor the other, not even a single oasis; everywhere the silence of the valley of death.
The well-known Sahara can hardly be more terrible than these deserts, which extend for many hundreds of miles in length and breadth. The Hurku hills, where we crossed, are the northern definition of the wildest and most sterile part of the Gobi, and form a distinct chain with a direction from SE. to WNW.; how far either way we could not say positively; but, according to the information we received from the natives, they are prolonged for a great distance towards the south-east, reaching the mountains bordering the valley of the Hoang-ho, while on
- In the Sahara desert we find the same diversity in composition and altitude; the same immense tracts of shingly and saline soil; the same loose drifting sands, with occasional patches of rocky ground covered with thorny scrub, while at distant intervals an oasis or islet of vegetation occurs. Such are also the characteristics of the great deserts of Persia and Arabia, which form the prolongation eastward and northward of the Sahara — 'the whole tract from the Sahara to the (Gobi or) Shamo pointing at once to similarity of conditions and sameness of geological origin.' (See Page's Physical Geography, p. 104.) — M.