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CHAPTER XII
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Methods of 00eahographical Research
UNTIL the nineteenth century the great oceans of the
world were comparatively little known to man.
That is
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to Say, although by then much of the actual geography
of the seas had been mapped out, the World that lived
beneath the surface of the water and the conditions to be
found there were as a closed book to mankind.
At this day ‘our knowledge is considerably increased and
a study of the ways and means by which the discoveries
_
îhave_ been made discloses the obvious dependence of
oceanography upon the advance of other branches of
science and the im‘rärovements of mechanical engineering.
For exploring the greatest depths of the ocean,_ 'f'0r instance,
the advantagesto be gained by the employment of steam
or motor winches .for hauling inthe great-weights of gear
and rope are manifest.
The introduction of wire cable to
replace the hemp ropes
in 1874 inaugurated & noteworthy
advance.
The ropes required for heavy work had, of
necessity, to be extremely thick, and the space required to
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stow man'y thousands of fathoms of such material was_‘ great, whereas very much thinner wire provides the Same”
strength and takes up ihnitely less r00m, and;- can be kept
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wound upon the drum of the haulirig Winch.
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One of the rst investigations in a study of the sea was
to nd the depths at which the sea oor laybelow the surface
from place to place.
While originally the purposes of
sounding-Were to aid in navigation, and the depths in Only
comparatively shallow waters
were
sought, with
the»
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,