The Geographical Journal (Journal of the Royal Geographical Society): Volume IX, No. 4 [‎218v] (107/172)

424
THE RIVER ODER.
region, the continental characteristics being, however, again modified
as°coinpared with such rivers as the Vistula. These circumstances^ of
position, together with the greater elevation of the southern part, give
to the Oder basin a climate almost uniform throughout its length.
A remarkable feature of the Oder basin is the absence of the ex
pansion and contraction observed in many rivers. The shape is in
effect a somewhat distorted rectangle, the north-western side standing
perpendicular to the south-western base-line, and the south-western side
forming an acute angle with it. The length of the base is approxi
mately 304 miles, and of the opposite side 245 miles, giving a mean
length of 274 miles; the perpendicular distance between these sides is
166 miles. The “centre of gravity” of this figure lies east of Lissa,
almost on the watershed The boundary between adjacent drainage basins. between the Bartsch and Obra, and on the
line dividing the German and Polish languages. Ihe lowest point ot
the main watershed The boundary between adjacent drainage basins. is at the Miihrische-Pforte, between Bolten and
Weisskirchen, where the Oder is separated from the Danube, and the
Atlantic from the Mediterranean, by a pass only 1000 feet above sea-
level. From the Miihrische-Pforte the watershed The boundary between adjacent drainage basins. extends westwards
for 682 miles, eastwards for 920 miles ; 354 miles in the former case,
and 103 miles in the latter, traversing mountains. The eastern part
runs through the plateau of Poland and Upper Silesia for 217 miles,
and the remaining 328 miles on the left of the main stream, and 600
miles on the right cross the low plains—amounting to 928 miles, 58 per
cent, of the whole.
The great extension of the plains of North Germany and Poland
towards the east gives the eastern sides of the river-systems an almost
independent character: a general south-to-north direction is combined
with an east-to-west stream draining the southern side of the rising
ground near the coast, and the joint flow carries the waters of the whole
eastern and north-eastern plain in each basin towards some point on the
lower course of the main stream. Thus the Warthe and Netze in the
Oder basin correspond to the Bug and Narew in the Vistula, the Havel
and Spree in the Elbe, and the Aller and Leine in the Weser. The
eastern tributaries are, therefore, for the most part rivers of the plain,
in contrast to those received higher up on the opposite side, which are
more frequently rapid mountain streams.
The point of junction with the Warthe accordingly forms, in the case
of the Oder, an obvious division between the lower and upper courses
of the river. A further division of the upper river is, however, desir
able ; and between the Warthe and Breslau may be called the middle
Oder, the term upper Oder being kept for the part between Breslau
and the source. This arrangement has many advantages from the
point of view of commerce and navigation, but the formation of the
river-valley gives a more scientific division at a point somewhat below
Breslau, near the confluence of the Lohe, Weistritz, and Weide with the