UP THE ALAI VALLEY 
133 
of inconsiderable dimensions. Taking the results of my 
observations and measurements as a basis, I calculate that 
on an average one cubic yard of snow out of the total 
quantity on each square yard of land -surface goes to 
feed the rivers in the form of water. The snow as it 
lies is of extraordinary density, and only about one-fourth 
of its volume melts and becomes converted into water. 
If we estimate that the aggregate snowfall of the Alai 
valley and the mountain -slopes which surround it covers 
2.870.000. 000 square yards, we may reckon the aggre- 
gate volume of water which they yield at 19,500,000,000 
cubic feet, or a solid cube of water measuring 2700 feet 
on each of its sides. 'I'his estimate can scarcely be con- 
sidered exce.ssive, when it is borne in mind, that the 
volume of the river during the period of high flood, in the 
middle of the summer, is out of all comparison greater 
than during the colder seasons of the year. If we assume 
a volume of eight hundred and eighty cubic feet in the 
second as the mean for the whole of the year, the figures 
work out at an annual aggregate volume of close upon 
27.800.000. 000 cubic feet. A calculation made upon such 
insufficient data can obviously be nothing more than an 
approximation. It is self-evident that the excess precipi- 
tation must be set down to the summer rains. 
During the winter violent westerly winds blow up the 
valley of the Alai with great constancy and regularity. 
Easterly winds also occur, but are very rare. The high 
mountain chains on the north and south of the valley 
shelter it against northerly and southerly winds ; although 
it does occasionally blow from the south-east. During 
the summer the air is stiller, and the wind blows seldom, 
and then with but little force. The west wind is called 
Kara-teghin khamal, the east wind Irkestam khamal, and 
the south-east wind Murghab kharnal, after the various 
districts from which they blow. 
In the valley of Fergana the spring rains come in the 
middle of March. In the Alai valley, on the other side 
of the mountains, the same month is the season of the 
sarik-kar or yellow snow, the name given to the last 
