634 
THROUGH ASIA 
events were followed a year later by a highly dramatic 
sequel. 
My original plan of travelling into Northern Tibet was 
completely knocked on the head. I had lost my instru- 
ments for measuring altitudes, and my equipment was 
sadly crippled. The only course now open to me was 
to return to Kashg'ar, and re-equip and repair my losses. 
Although it was a longer road, I chose the route via 
Ak-su. And yet within less than a twelvemonth I could 
not resist travelling in Marco Polo’s footsteps from Kash- 
gar to Khotan. But before I give a brief account of our 
return to Kashgar, I should like to say a few words about 
those portions of the courses of the Yarkand-daria and 
the Khotan-daria which came under my own observation. 
A comparison of these two rivers, which flow pretty 
nearly parallel to one another, and seek the same goal, 
shows that they are in more than one re.spect dissimilar. 
The Yarkand-daria is the most important river in East 
Turkestan. Its channel is plainly marked and deeply 
eroded ; and it contains water all the year round. Indeed 
in the month of June its flood rises to portentous dimen- 
sions. h-xcept when it is ice-bound in winter, the river 
can only be crossed by means of ferries. The Khotan- 
daria, on the other hand, remains dry during the greater 
part of the year ; it is only in the height of the summer 
that its channel holds any quantity of water. But it is 
so broad and shallow, that the only place where a ferry 
can be used is at Khotan. The river flows through the 
worst section of the Pakla-makan Desert, and has a far 
harder fight of it with the drift-sand than its sister stream 
to the west. Indeed the sand is seriously threatening to 
choke it up, and cut it off from the main river, the 
Yarkand-daria or Tarim, which it flow's into — a fate 
which, as we shall see later on, has already overtaken the 
Keriya-daria. 
Again, the belt of forest which accompanies the 
\ arkand-daria is frequently interrupted by steppes and 
marshes; whereas the Khotan-daria is accompanied by 
its forest-belts all the way to the confluence of the two 
