greement. A
classic example of this case is found in the belt of untenanted land,
fifty to ninety kilometers wide, which China and Korea once maintained
as their boundary. No settler from either side was allowed to enter, and
all travel across the border had to use a single passway, where three
times annually a market was held.[356] On the Russo-Mongolian border
south of Lake Baikal, the town of Kiakhta, which was established in 1688
as an entrepot of trade between the two countries, is occupied in its
northern half by Russian factories and in its southern by the
Mongolian-Chinese quarters, while between the two is a neutral space
devoted to commerce.[357]

[Sidenote: Alien intrusions into border wastes.]

These border wastes do not always remain empty, however, even when their
integrity is respected by the two neighbors whom they serve to divide;
alien races often intrude into their unoccupied reaches. The boundary
wilderness between the Sudanese states of Wadai and Dar Fur harbors
several semi-independent states whose insignificance is a guarantee of
their safety from conquest.[358] Similarly in the wide border district
between the Creeks on the east and the Choctaws on the west were found
typical small, detached tribes--the Chatots and Thomez of forty huts
each on the Mobile River, the Tensas tribe with a hundred huts on the
Tensas River, and the Mobilians near the confluence of the Tombigby and
Alabama.[359] Along the desolate highland separating Norway and Sweden
the nomadic Lapps, with their reindeer herds, have penetrated southward
to 62 deg. North Latitude, reinforcing the natural barrier by another
barrier of alien race. From this point southward, the coniferous forests
begin and continue the border waste in the form of a zone some sixty
miles wide; this was unoccupied till about 1600, when into it slowly
filtered an immigration of Finns, whose descendants to-day constitute an
important part of the still thin population along the frontier to the
heights back of Christiania. Only thirty miles from the coast does the
border zone between Norway and Sweden, peopled chiefly by intruding
foreign stocks, Lapps and Finns, contract and finally merge into the
denser Scandinavian settlements.[360]

Where the border waste offers favorable conditions of life and the
intruding race has reached a higher status of civilization, it
multiplies in this unpeopled tract and soon spreads at the cost of its
less advanced neighbors