the movement of the deep ocean waters. These new techniques have
already given results of great value, which help to clarify the picture of
the general circulation of the water and to support theoretical reasoning
concerning the cause of the movements. New methods of measuring
waves in the open ocean have also yielded very valuable results. In this
branch of oceanography there is also a close connexion between meteor-
ology and the formation of waves, which are directly generated by the
winds which blow over the oceans. The waves, moving out from the
storm areas in the oceans, play their part in modifying the edge of the
land, helping to create the great variety of coastal forms.

The rhythmic flow of the tides is one of the most reliable of oceanic
phenomena, and it alone, at the moment, permits long-term forecasting,
such as waves will probably never allow. Even the tides, however, are
liable to a certain amount of modification, by meteorological conditions,
as the generation of storm surges indicates. Thus the connexion between
air and water is again manifest, and in extreme cases the effect is felt
with disastrous results on coasts where surges can form, such as the
North Sea. The tides are also responsible for one of the most impressive
phenomena of nature, the tidal bores which move up some rivers.

The oceans were the original home of life on Earth, and long before
creatures moved out of the sea and plants grew on dry land a complex
marine fauna and flora had evolved. Some of the creatures and plants
which now live in the sea are very small--they are nevertheless very
important; only the marine flora can create growing organisms from
the chemical elements which are found in sea water, with the aid of
sunshine which penetrates into the upper layers of water. The smallest
of these creations, the phytoplankton, form the broad base of the vast
triangle of marine life, which leads up to the higher forms of fish, which
are of great economic importance. These smaller organisms are also
important in their own right; their dead bodies sink down to cover great
areas of the ocean floor, where they have settled in sheltered ground for
long periods of time. They can, then, tell a story of the changing condi-
tions in which they lived, which is revealed to the scientist who obtains
cores of these deep sea oozes. From these data changes in climate over
the past geological period can be assessed.

It is, however, the living creatures of the oceans which are materially
more important; the oceans house a vast store of food, which may well
be needed to feed the growing world population. Despite great advances
in the techniques of fishing, the collecting of this food from the sea is still
in the stage of primitive hunting; whether sea farming will ever be
evolved to help feed the growing numbers is an interesting question.
The open sea, however, belongs to all nations; this kind of development,
therefore, depends on international co-operation, as the fish are not

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