Encyclopaedia Britannica > Volume 3, Athens-BOI

294 B A L
Sweden and Zealand), tlie Great Belt (between Zealand
and Fiinen), and the Little Belt (between Fiinen and
Jutland). Each of these forms a distinct communication
between the Baltic and the Cattegat, which is the open
portion of the channel lying between the coast of Sweden
and the eastern side of Jutland ; while the Cattegat opens
freely into the Skager Rack, which is the continuation of
same open channel, between the southern end of Norway
and the north-west coast of Jutland, into the North Sea.
The length of the Baltic Sea, from Swinemiinde in
the S. to Tornea in the N., is nearly 900 miles; and its
greatest width, between Karlscrona and Memel, exceeds
200 miles. Its whole area, including the Gulfs of Bothnia
and Finland, is about 160,000 geographical square miles.
It runs first in an easterly direction as far as Memel, a
distance of 300 miles, and then northwards as far as lat.
59° 21' N., a distance of 350 miles, at which point it
separates into two great gulfs. One of these, the Gulf of
Finland, runs nearly due E.; the other, the Gulf of
Bothnia, almost N. The Gulf of Bothnia is 400 miles in
length, with an extreme breadth of 120 miles, but where
narrowest it does not exceed 40 miles. The archipelago of
Aland lies at its entrance. The Gulf of Finland is 280
miles in length, with a mean breadth of 60 or 70 miles.
The depth of the Baltic rarely exceeds 100 fathoms—
being greatest between the island of Bornholm and the
coast of Sweden, where it reaches 115 fathoms, and least
in the neighbourhood of the mouths of large rivers, which
bring down a great quantity of earthy matter, especially in
the spring, so that in many parts the bottom is being so
rapidly raised by its deposit that the mouths of rivers
formerly navigable are now inaccessible. This is especially
the case in the northern part of the Gulf of Bothnia, above
Quarken, where several tracts are now dry land which
were once water ; and also in the neighbourhood of Tornea,
where meadows now take the place of waters which were
traversed in boats by the French Academicians, when they
were measuring an arc of the meridian. Along the
southern coast the shallowness of the harbours is a great
obstacle to navigation, especially since they are closed by
ice for nearly one-third of the year. On the western side
it is not more than 15 fathoms deep ; and, in general, it is
only from 8 to 10 fathoms. On the S. it nowhere exceeds
50 fathoms. The Gulf of Finland suddenly shallows from
50 or 60 fathoms to 5, or even less. The average depth of
the Gulf of Bothnia is not greater than that of the rest of
the sea. Numerous rocky islands and reefs, many of them
level with the water, render the navigation of this sea
extremely dangerous.
The shore of the Baltic is generally low. Along the
southern coast it is for the most part sandy,—with sand¬
banks outside, and sand-hills and plains inland. Where
streams come down, there are often fresh-water lakes termed
haffs, which are separated from the sea by narrow spits
called nehrungs. Two of these haffs are of great extent;
one of them, termed the Frische Haff, lies between Danzig
and Konigsberg, which last town is situated on the part
of it most remote from the sea; the other, termed the
Kurische Haff, lies between Konigsberg and Memel, the
latter town being situated on the channel connecting the
haff with the sea. Near the entrance to the Gulf of Fin¬
land the coast becomes rocky, and continues to be so for
the most part around the gulfs both of Finland and
Bothnia, except towards the head of each; the rocks,
however, are never high. The shores of the southern part
of the Swedish peninsula are mostly high, but not rocky;
at Stockholm, however, there is an archipelago of rocky
islands, on some of which the town is partly built.
Drainage Area.—The Baltic may be considered as the
estuary of a great number of rivers, none of them individu-
T I C
ally of great size, but collectively draining a very large area,
which is estimated at about 717,000 square miles, or nearly
one-fifth of the entire area of Europe. This great drainage
area is remarkable for the small proportion of its boundary
that is formed by mountains or high table-lands,—its
greater part consisting of land of no considerable elevation,
which slopes down very gradually to its coast-line, and of
which a large proportion is covered by lakes. This is
especially the character of the drainage area of the Neva,
whose waters are immediately derived from the large shallow
Lake Ladoga, which receives the contributions of numerous
other lakes, Onega being the largest, though Lake Saima
in Finland, with its irregular prolongations, is scarcely less
extensive. The entire surface drained by the Neva is esti¬
mated at about 100,000 square miles, or nearly twenty
times that of the drainage area of the Thames. Through
Lake Onega, the Neva is connected with the Dwina and
the Volga by canals, through which small vessels can pass
from the Baltic into either the White Sea or the Caspian.
The Duna or South Dwina, which discharges itself into
the Gulf of Riga, is another important river, draining an
area of about 35,000 miles in West Russia, and having a
length of 520 miles, of which 405 miles are navigable.
The drainage area of the Niemen, which enters the Baltic
at Memel, is conterminous with that of the Duna, and is
of about the same extent; this river is navigable for more
than 400 miles from its outlet, and communicates with the
Dnieper by a canal through which vessels can pass from
the Baltic to the Black Sea. The Vistula, which receives
the waters of the whole area of Russian and Prussian
Poland, flowing past Warsaw into the Baltic at Dantzig, is
a very large and important river, having a length of 520
miles, of which 430 are navigable, and a drainage area of
72,000 square miles. And the Oder, rising in the hill
districts of Silesia, drains the extensive level areas of
Brandenberg and Pomerania, and discharges into an estuary,
that may be said to begin from Stettin, the water drawn
from an area of 45,000 square miles. Numerous rivers
discharge themselves into the Gulf of Bothnia, bringing
down water from the mountain ranges of Sweden and
Norway ; but their course is comparatively short and direct,
with few tributaries, so that, individually, they do not
attain any great size. The drainage of the more level
southern portion of Sweden is for the most part collected
by the great lakes Wener, Wetter, and Malar, of which
the first pours its water into the North Sea, and the others
into the Baltic. By means of a canal joining Lakes Wener
and Wetter vessels can pass directly from the Cattegat
into the Baltic.
Climate.—It is not only, however, the extent of its
drainage area, but the large proportion borne by the rain
and snow which fall upon that area to the amount dissipated
by evaporation from its surface, that goes to swell the aggre¬
gate of fresh water poured into the basin of the Baltic; for
there is probably no inhabited region of the whole globe
over which so large a quantity of snow falls, in proportion
to its area, as it does in the countries round this basin.
They receive, direct from the Atlantic, a vast amount of
moisture brought by its west and south-west winds ; and
even the winds which have already passed over the low
plains of Jutland and Northern Germany will have parted
with little of their moisture before reaching the Baltic
provinces of Russia. When these vapour-laden west and
south-west winds meet the cold dry east and north-east
winds of Siberia, their moisture is precipitated, in summer
as rain, and in winter as snow; and owing to the prevalence
of a low atmospheric temperature through a large part of
the year, the proportion lost by evaporation is extremely
small as compared with what passes off from other inland
seas. The large excess of the amount of fresh water dis-