THROUGH ASIA 
1 82 
its barren, naked surfaces, puts you in mind of a typical 
lunar landscape. 
Unlike similar tracts of Asia which possess no drainage 
outlet, the depression of Kara-kul does not suffer from 
accumulations of sand. The explanation of this no doubt 
is that the finer products of denudation are swept up by 
the constant violent windstorms which prevail in that 
region, and are carried away to be deposited in parts of 
the continent where the atmospheric conditions are per- 
manently calmer. Sandstorms and duststorms are indeed 
by no means a rare visitation of the Pamir plateau. It 
is very probably to them that the so-called “yellow snow” 
owes its origin ; for an examination of the snowdrifts to 
which that name is given reveals the presence of extremely 
fine particles of yellowish soil. 
The most powerful agencies of disintegration in this part 
of the w'orld are the winds and the enormous and sudden 
variations of the temperature. I saw striking evidences 
of their power on the little island in Lake Kara-kul, in 
huge blocks of syenite and clay - slate ground, scooped 
out, polished into the most fantastic shapes. The varia- 
tions of temperature arc enormous, not only in winter, but 
also in summer. At P'ort Pamir, at seven o’clock in the 
morning ot iith January 1894, the thermometer recorded 
a temperature of -36°Fahr. (-37°8 C.) ; one hour after 
noon it was 53°6 Fahr. (12° C.) In the sun — a difference of 
nearly 90° Fahr. (50° C.) in the course of only six hours! 
The amount of radiation is almost Inconceivable. At a 
time when the temperature of the air was just at the 
freezing - point, the black - bulb insolation thermometer 
actually registered 133° to 136° Fahr. (56° to 58° C.). 
These stupendous forces labour on unrestingly century 
after century, wearing down the solid structure of the 
continent — In this an imperfect image or analogue of the 
earth itself, which is but the last surviving wreck of 
substances which have been in process of formation and 
re-formation throtigh countless aeons of time. 
This region of exclusively Internal drainage Is girdled 
round by a zone of what Von Richthofen cadis Transitional 
