THE GORGE OF TENGHI-TAR 263 
vations as to the volume of water carried down by the 
stream. By this the rainfall of the past day or two had 
begun to come down from the mountains, and the flood 
had already risen very considerably. Yesterday it was 
clear as crystal ; to-day it was grey and muddy, and boiled 
along tumultuously among the stones. The breadth of the 
torrent increased to 53 feet, its depth to a maximum of 
2 1-6 inches, its volume to 250 cubic feet in the second. 
At midday the temperature of the water was 50°9 Fahr. 
(io°5 C.). The variations which the current underwent 
during the course of the day will show how sensitive these 
mountain - brooks are to precipitation and temperature. 
By three o’clock in the afternoon the water had sunk '6 
of an inch. This was owing to the fact, that the highest 
rills which fed the stream froze during the night. But at 
five o’clock, by which time that morning’s rains had got 
down to Pasrabat, the stream rose i'38 of an inch. At 
seven o’clock it was 6'3 inches above the height of my 
first measurement ; but in consequence of the steepness of 
the banks, the breadth had not increased more than about 
3i feet. The noisy brawling of the current, now of a 
brownish-grey colour, sounded duller and heavier than in 
the earlier part of the day ; for the stones and pieces of 
rock which protruded above the surface in the morning, 
checking the flow of the water, and causing it to splash up 
into the air, were now entirely submerged. Now that the 
outpour of the rains had got down as far as our camp, the 
volume was more than twice as great as in the morning, 
being 495 cubic feet in the second. At the same time 
the temperature was 49'’5 Fahr. (9°; C.). By eight o’clock 
the current had risen yet another '8 of an inch, and 
the temperature had fallen to 48°g Fahr. (9°4 C.), and 
another hour later the figures were '4 of an inch and 48°4 
Pahr. (9°i C.) respectively. All this goes to show that, 
as the volume of the water increased, it took a pro- 
portionally longer time for it to attain to the temperature 
which prevailed in the lower valleys. 
At seven o’clock next morning the flood stood at about 
the same level as when I took my first observation ; but 
