r, and one morning the ferry-boat lay frozen in so fast we could
walk on the ice around it. Out in the current, however, the water was
open, and we broke asunder our fetters with axes and crowbars. A
constant roar of grinding and scraping ice accompanied us all day long,
and during the nights we had to anchor the ferry-boat out in the
swiftest part of the current to prevent it being frozen in.

On December 7 broad fringes of ice lay along both banks, and all day we
danced among drifting ice as in a bath of broken crockery. At night we
had a whole flotilla of canoes with lanterns and torches to clear the
way, when suddenly the boat swung round with a bump, and we found that
the river was frozen over right across. This did not disturb us, for on
the bank we saw the flames of a wood fire, and found that it was burning
at the camp of our camel caravan.

THE WANDERING LAKE

The place where the ferry-boat was frozen in for the winter is called
New Lake (see map, p. 90). Just at this spot the Tarim bends southwards,
falling farther down into a very shallow lake called Lop-nor. The whole
country here is so flat that with the naked eye no inequalities can be
detected. Therefore the river often changes its bed, sometimes for short
and sometimes for long distances. Formerly the river did not bend
southwards, but proceeded straight on eastwards, terminating in another
lake also called Lop-nor, which lay in the northern part of the desert,
and which is mentioned in old Chinese geographies.

The peculiarity of Lop-nor is, then, that the lake moves about, and, in
conjunction with the lower course of the Tarim, swings like a pendulum
between north and south. I made many excursions in that part of the
desert where the Lop-nor formerly lay, and mapped out the old river-bed
and the old lake. There I discovered ruins of villages and farms,
ancient canoes and household utensils, tree trunks dry as tinder and
roots of reeds and rushes. In a mud house I found also a whole
collection of Chinese manuscripts, which threw much light on the state
of the country at the time when men could exist there. These writings
were more than 1600 years old.

The explanation of the lake's wanderings is this. At the time of high
water the Tarim is always full of silt, and the old lake was very
shallow. The lake, therefore, was silted up with mud and decaying
vegetation, and by the same process the bed of the river was raised. At
last came the time when t