CHARACTERISTICS AND DISTRIBUTION OF LAKES 539 
testing the degree of saltness in the water after, as compared 
with before, the disappearance of the ice, he came to the conclusion 
that a large part of the ice had been melted by the Salter warmer 
water which had displaced the surface film of fresh cold water, 
on account of currents set up by the wind. Henderson says ^ the 
lake is too salt for fish to live in it (salinity ^ 1'3 per cent., 0*6 per 
cent, being sodium chloride, and ()'4 per cent, sodium sulphate), and 
the only animal life he could find was a small Crustacean, probably a 
Gammarus. 
Koko-Nor (or Kuku-Nor, Blue Lake), lies ] 0,500 feet above sea- 
level, not far from the sources of the Hoang-Ho and Yangtse, and has 
a circumference of about 200 miles. 
Tengri-Nor (called Nam-tso, or " sky lake ''), in the vicinity of 
Lhassa, lies 15,190 feet above sea-level. It is the most easterly link 
in a vast lacustrine chain which stretches for hundreds of miles north- 
west and south-east across the plateau of Tibet, and which includes 
the large lakes Kyaring, Chargat, Zilling-tso (15,128 feet above sea- 
level), Ngangtse-tso (15,417 feet above sea-level, max. depth 27 feet). 
Dangra-yum-tso, Teri-nam-tso, "the heavenly lake'' (15,367 
feet above sea-level); Lapchung-tSO (17,039 feet above sea-level); 
Lake Lighten (16,709 feet above sea-level; depth over 213 feet; 
temperature of surface water at 11 a.m. in September, 43° Fahr.); 
Yeshil-kul (16,207 feet above sea-level ; maximum depth, 53 feet ; 
temperature of surface water at 1 p.m. in September, 49° Fahr.). 
South of Tengri-Nor, and separated from it by the River San-po, is 
the ring-shaped Lake Palti, or Tomdok, divided into two basins by a 
peninsula. 
Manasarowar ("the Holy Lake," Tso-mavang) and Rakas-tal 
(Langak-tso) lie to the south-east of Pangong Lake, between 30° and 
31° N. latitude. Very plainly marked shore lines are to be seen round 
rampart, at other times a mere line, but always close to the water's edge. The 
boulders in every way, except in their regularity of arrangement, resemble the 
glacial erratics which are scattered over the adjacent land-surface, and they only 
occur m regions where the winter sheet of ice reaches a consideral^le thickness, and 
where winter temperatures are extreme. The ice expands with a rise and con- 
tracts with a fall of temperature, and while the under surface of a thick layer of ice 
is kept more or less constantly at a temperature of 32° Fahr., owing to its contact 
with the water beneath, the upper layer contracts and expands with temperature 
variations in the air. The result is the formation of extensive cracks during severe 
frost, followed by expansion under a sudden rise of temperature, and the consequent 
buckling of the ice-sheet, which is pushed up over the shore at its margins. As 
it rises along a gently shelving shore it carries with it whatever solid bodies occur 
in the shallow water — hence the rampart formation. 
1 Geogr. Journ., vol. xv, p. 430, 1900. 
^ Frankland's analysis in Henderson and Hume, Lahore to YarJcand, p. 370, 
London. 
