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| IIIF Color HighRes |
| Scientific Results of a Journey in Central Asia, 1899-1902 : vol.1 |
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| SKETCH FROM THE ETTEK-TARIM, SHOWING THE FOREST THICKEST ON THE EAST SIDE OF THE OLD REVER-BED. | |
| The Tagh-kum as compared with the prevailing wind. |
Citation Information
THE ETTEK-TARIM — TAGH-KUM. 413
a patch of thick and beautiful living forest. One circumstance which is conspicuous throughout the course of the river is that the vegetation on the left or eastern bank is everywhere richer than that on the opposite bank, this peculiarity being particularly noticeable during the second half of the day's march. The reason of this is no doubt the same as that which causes the eastern
side of the level floor of the desert bajirs, along the
foot of the steep dune-flank, to be bare and protected o-q a
~a
against the encroachments of the descending sand, whilst~0•,~ the finer particles which the wind whips off the summit t °
§Æ9,xâ
are deposited against the western side. Similarly the • °:1 ~ a
forest, being under the lee side of the steep dune-wave 0 o ,d •
is likewise protected against the wind, and its abrading .1 s y a
and erosive influence, still further intensified by the drift- ?&° °
sand it brings with it; whereas on the west bank the `~_--_ 4• O° y
forest is more exposed to the wind. These conditions arep:°fy; ;
illustrated in the accompanying fi ure / 66 . The bigger °
p 4 ° v~9% PV rn o
g \3 gg re
arrows indicate the path of the lighter particles of sand, %% o bps• ze v
,QL°'dt, q the smaller the path of the coarser drift-sand. In point V '$°r~
of quantity however the former must be excessively small ,' t i
as compared with the sand which drops immediately at the foot of the steep leeward slope, and which is the actual cause of the dune-wave's advance towards the
west. The dotted area in the vertical section coincidesrjg, 365. SKETCH FROM THE ETTEKwith the zone in which the effect of the prevailing wind TARIM, SHOWING THE FOREST
is nil or insignificant, and where consequently but little Ti ICK HE ON THE EAST SIDE
g q Y OF THE OLD RIVER BED.
sand accumulates; in the bajirs farthest north we observed
that not a single particle of sand has strayed on to these areas. In the valley of the Ettek-tarim, which resembles one long bajir, this circumstance is however less sharply accentuated than in the desert depressions. Its eastern sand-wave is not so high, and the breadth of the valley is greater; besides which the forest must have a certain effect upon the wind and the arrangement of the sand. Hence soil absolutely free from sand is a rarity in this trench.
~---- 4
-
;
,,~" f ✓ ~
~ \ Lee
~ ~ ', ✓f,i
/ ~ . , zr..'•~
. /.
W
Fig. 366.
As compared with the former Tarim, which emptied itself into Lop-nor, the Ettek-tarim is a relatively recent formation; indeed its existence would appear to have been quite brief, merely a passing episode in the history of the great river;
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