ot rid
of by an outflowing current which may be named the "Baltic Stream." The
following general laws may be laid down with regard to this:--

1. That the Baltic Stream must be a surface current, because it originates
from a redundancy of fresh water.

2. That, on account of the earth's rotation, the main part of the Baltic
Stream must keep close to the coast of the Scandinavian peninsula.

3. That it must be a periodic stream, because the discharge of the rivers
into the Baltic varies with the season of the year. In spring and summer
the water from the Baltic is sufficiently abundant to inundate the whole
surface of the Kattegat and Skagerrak, but in winter the sources of the
Baltic current are for the most part dried up by the freezing of the land
water.

All the waters which enter the Skagerrak or Kattegat as undercurrents can
be found at the surface of the North Sea (_q.v._). They may be divided
according to their origin and salinity as follows:--

(a) _Ocean water_ of 35 _pro mille_ salinity or more.

(b) _North Sea water_, the predominant water in the North Sea area, of 34
to 35 _pro mille_ salinity.

(c) _Bank water_, 32 to 34 _pro mille_, which forms a broad edging covering
the coast banks of Holland, Germany, Denmark and Norway.

The deepest water stratum in the Skagerrak is certainly of oceanic origin;
it has been found to suffer changes of long period, and it is probably not
always composed of water derived from the same part or the same depth of
the North Atlantic; this water is, as a rule, deficient in oxygen. The
"North Sea" water, of 34 to 35 _pro mille_ salinity, does not appear at the
surface in the Skagerrak, except as a strip along part of the coast of
Jutland, but it is always found as an undercurrent overlying the oceanic
water. It enters into all the deep coast channels, and into the Christiania
fjord, but it is not always found in the deep channels of the Kattegat. The
principal time of inflow of North Sea water is during spring and summer.
The bank-water of 32 to 34 _pro mille_ salinity is found all along the
continental coast of the North Sea and North Atlantic, and it may therefore
enter the Skagerrak either from the North Sea or from the north along the
coast of Norway. It is probable indeed that an influx of this water occurs
from both directions--in August and September from the south, and in the
late winter and early spring from the north. The seasonal changes in the
distribution of