88 
THROUGH ASIA 
of ninety-one miles from Usghen (3220 ft.) to Chuja 
(1310ft.) it falls 1910ft., or 21ft. in every mile. The 
Naryn, on the other hand, in a distance of eighty-seven 
miles, that is to say, from a point near the ruins of the 
fortress of Ketmen-tube (2800 ft.) to Jidda-kopo (1310 ft.), 
falls only 1490 ft., or 17 ft. in every mile. Although these 
differences in altitude are not very great, they are so far 
appreciable, that the Kara-daria, even in its lower reaches, 
is somewhat swifter than the Naryn. The other assertion, 
on the contrary, is not always right, for during the winter 
the Kara-daria is always much larger than the Naryn, 
sometimes even twice as large. This is due to the 
fact that the Naryn flows through a more northern and 
colder tract, and because it is on all sides surrounded by 
chains of high mountains, in which severe cold obtains ; 
while the Kara-daria has a more southerly course, through 
the eastern extension of the Fergana valley, where the 
winter temperature is considerably milder, and high moun- 
tains protect it from the cold north winds. 
The volume of the Naryn diminishes also owing to a large 
quantity of its drainage supply being locked up in the form 
of ice. This is particularly the case with regard to the 
small streams and tributaries which flow through the high 
side- valleys. In the tract through which the Kara-daria 
flows the winter temperature, on the contrary, is not so 
low, and the river, therefore, receives during the cold 
period of the year a comparatively large quantity of water, 
although here again the snowfall is less. The Kara-daria 
is thus deprived of a smaller quantity of its water through 
the formation of ice than the Naryn. In the spring, as 
soon as the ice and snow on the mountains surrounding 
the Naryn begin to melt, the river rises, and in a short 
time becomes much larger than its sister stream, which has 
not been able to collect any great provision of ice and 
snow within its bounds during the winter. 
The pile bridges that the Sarts have built across the 
Naryn and the Kara-daria greatly simplified the task of 
sounding those two rivers. On February 2nd, at two 
in the afternoon, the weather being favourable and the 
