The Republican. [volume] (Oakland, Md.) 1877-current, 1886-05-22
COLOR OF THE SEA.
Different Theories Advanced to Account
for Its Numerous Changes. p>-a


Different Theories Advanced to Account
for Its Numerous Changes. >.~sa
The changes in the color of the sea
have attracted the attention of sea-
faring men from the earliest times.
They struck with wonder. the Phe-
necians when first they ventured out Of
the Mediterranean into the Atlantic:
they excited the astonishment of Co
lumbus and terrified his companions
while in search of the far-famed India,
and they are no less surprise TO the
modern navigator, to whom the march
of discovery has left few unexplored
regions in store. Numerous theories
were offered in explanation of these
changes, some ascribing them to the
varying color of the sea bottom, some
to differences in depth, others the
presence of certain coloring substances,
others again to the chemical com
position of the water. Most of these
suggestions contained an element of
truth, although no one of them, taken
alton in color which had often been
observed to occur in the course of
few hours sail, and within a distance
measuring less than a ships length.
Of late years, as the reader is aware,
numerous scientific expeditions have
been fitted out and dispatched by the
Governments of England, Norway and
America for the express purpose of
exploring the secrets of the deep.
Among the problems which have now
for the first time received satisfactory
solution, new light has also been
thrown upon the conditions which
affect the color of the sea water in
every part of the ocean, thus complet-
ing the information for which we were
indebted to the unaided exertions of
earlier travellers. One of the most
remarkable and most widely distributed
contrasts of color is that which is
known to exist between the intensely
blue seas situated between the tropics
and the green seas of higher ATTITUDES.
1t appears, as the result of recent obser-
vations, and more especially of a series
of experiments made on board the
German frigate Gazelle, that there is
an intimate relation between the colors
of sea-water and the proportion of salt
held in solution by the latter. On
comparing the specific gravity of green
water with that of blue water it was
found that the latter is always heavier
than the former, and, therefore, con-
tains more salt, the two differently
eolOred waters heinU SuOnOced tO havn
the same temperature. In other words,
the greater or lesser intensity of the
blue color of sea water may be taken as
direct index of its sadness and of its
specific gravity, so that when we
observe the color of the water success
lively change from deep blue to a
blush green and dark green we may
conclude that the water has become
at the same time less salt and less
heavy. This result agrees with the
experience of navigators in every part
of the ocean, for as the vessel proceeds
from the dense and salt waters of the
tropical regions toward the lighter and
fresher waters of higher ATTITUDES and
of the polar regions the color of the
sea is seen to change from an intense
blue to greenish blue and green tint.
There are, however, numerous excep-
tons. Green seas are met with between
the tropics and blue seas are en-
countered in the temperate region, and
even within the Arctic circle, but these
exceptions, far from contradicting,
only tend to confirm the above rule
Science for AL.