San Antonio daily light. [volume] (San Antonio, Tex.) 1886-1907, 1888-03-16
FACTS ABOUT THE SEA.
The Salt of the Sea-Something About the
Waves-How the Depth is Measured.

all the rivers of the world. 1t is the
cistern which finally catches all the rain
that falls not only upon its own surface,
but upon the roofs of our homes. All
this water is removed again by evapora-
ton as fast as it is supplied. 1t is esti-
mated that every year layer OF the en-
tire sea fourteen feet thick is taken up
into the clouds. This vapor is fresh, and
if all the water could be removed in the
same way and none of it returned it is
calculated that there would be left
layer al salt 230 feet thick On the bed Of
the Atlantic.
This is upon the supposition that three
feet depth of water contains one inch
depth OF salt, and that the average depth
OF the ocean is three miles.
At depth of about $500 feet the
temperature is uniform, varying but .
trihe between the poles and the equator.
The colder water is below. 1t is re-
ported that in many deep bays on the
coast of Norway the water often begins
to freeze at the bottom before it does at
the surface.
At this depth waves are not felt
Waves do not travel-that is, the water
does not move forward, although it seems
to do so; it stays in the same place. The
rising and falling moves on.
We measure waves by their height
and by the distance from crest to crest.
In deep water this latter distance is
about fifteen times the height OF the
waves. In shallow water the proper
ton is less, and this makes choppy
sea.
The force of the waves is in proportion
to their height. 1t is said that the sea
strikes on Bell rock with the force of
seventeen tons to each square yard.
The pressure o. the water ceases as we
go down. At the depth of mile this
pressure is reckoned at more than ton
to the square inch-that is, more than
1873 times the pressure of the atmos-
phere.
To get correct sounding in deep water
is difficult. A shot weighing thirty
pounds carries down the line. Through
this sinker hole is bored, and through
the hole is passed rod of iron which
moves easily back and forth. In the
end OF the bar cup is dug out, and the
inside is coated with lard. The bar is
made fast to the line and sling holds
the shot on.
When the bar, which extends below the
shot, touches the bottom, the sling I'M
hooks and the shot slides OF. The cup
in the end OF the bar holds some OF the
sand, or whatever may be on the bottom,
and a cover shuts over the cup to keep
The water from washing the sand out. In
this way we learn the character OF the
deep sea bottom.
1t will be seen at once that we can
know the depressions of the bottom OF
the ocean more easily and more accur-
ately than we can learn the elevation of
the land. AS consequence we have
better typographical map of much of
that surface than we have of the CONT
nents.
The depths of the sea presents some
interesting considerations. If the At
lantlc were lowered 6564 feet it would be
reduced to half its present width. If it
were lowered little more than three
miles there would be dry land all the
way between Newfoundland and Ireland.
If the Mediterranean were lowered $50
feet, Africa would be joined to Italy and
three separate seas would remain.