LAKES WITHOUT END 
1047 
Tibetan plateau. The irregular shore -line was edged 
with scum, and the breakers rolled against the slaty 
gravel with a curious metallic sound, no doubt the com- 
bined effect of the attenuated atmosphere and the high 
specific gravity of the water. It will readily be under- 
stood that the extreme rarefaction of the atmosphere 
must exercise an influence upon the acoustic properties 
of sound. For example, upon those lofty solitudes we 
were obliged to speak louder and more distinctly than 
usual ; and I could not hear my watch tick unless I held 
it close to my ear. 
At eleven o’clock in the morning the temperature 
of the air was still 30°9 Fahr. ( — o°6 C.), whilst at 
the same hour that of the water was 45 ^ Fahr. 
(7°3 C.), a fall of several degrees since the preceding 
day. Here for the first time we observed the track 
of a bear ; indeed we followed it nearly all day. 
Further on a fox had come down to the lake. Again 
we crossed a number of small streams flowing from 
the Arka-tagh. Most of them formed a delta, more or 
less developed, with long tongues of sand jutting out still 
further into the lake ; and these were always pointed 
towards the east or south-east, a fact which must probably 
be ascribed to the pressure exercised by the west wind. 
During the march we lost a donkey. After we en- 
camped we lost two more, also a cream-coloured horse 
which had done excellent service, carrying my instrument- 
cases all the way from Korla to Lop-nor, and thence 
via Cherchen to Khotan, and finally from Ivhotan to the 
present place. Our poor beasts were beginning to show 
terrible signs of the hard travelling. Not a day passed 
but we lost one, sometimes more. Their carcasses did not 
corrupt, but in the pure, cold, attenuated air simply 
shrivelled up to mummies; and there they now he as 
memorials of the road we took through the wilds of 
Northern Tibet. The difficulties of the journey were 
greatly increased owing to the pasturage being less 
frequent, and of inferior quality, to that we met with 
during the first days of our march through the Tibetan 
