..
SEA WATER
-
235
_
were
covered uniformly with water down to & depth 01
fty-three miles the speed of this wave around its surface
would be about 1,000 miles an hour.
Owing to the com—
parative shallowness of our oceans hOWever it has only
about half this speed.
'
’
The surface of our earth is not uniforme covered with
water, but possesses great land masses whi0h jut out into the
'
ocean and tend to 'cOmplicate the results of these tidal
forces so that & -truly- satisfactorytheory of the tides has
-notyet been evolved.
It is however safe to say that the
primary cause is that given above.
The only region on the earth where the ocean forms a
_
continuous band'around the globe, uninterrupted by land
masses, is in the southern ocean and there is a theory that
around this belt sweeps the great t_idal wave, a “ primary
wave.” — This wave is supposed to give off secondary.
'
or _“ derived waves,” which move
in a northerly direction
up the other oceans.
Such a wave moves up the Atlantic
Ocean at a speed of about 500 miles an hour (Fig.
_
In
ocean the wave is only two or threeieet in
height, so that the tides in oceanic islands are very small.
.
But as the water shallows round the edge of the ocean
the
speed of the tida1 wave is enormously reduced 'bÿiriCtion
and the height of the tidès becomes
Thusthe
’
height otthe tide at the Azores is about ve feet,.- that
around the _Sci‘lly Isles sixteen feet, and that at Swansea.
-
_
_
1 Asgthe —t_idé. runs
narr0w channels
_
«.
ténds,tdbeb0ted
thereîqre”ïe highest
’
tidés are found in suCh channels as
,
the mouth ofthe
Sev‘erh, Where the tide may, reach nearly as much as fty
_
feet at Chepstow.
'
.
..
__
There are produced around our coasts two hightideS m
«
the twenty-four h0urs and-two low tides, but _owing to the
.
fact that the
the…earth the
,
SEA WATER
-
235
_
were
covered uniformly with water down to & depth 01
fty-three miles the speed of this wave around its surface
would be about 1,000 miles an hour.
Owing to the com—
parative shallowness of our oceans hOWever it has only
about half this speed.
'
’
The surface of our earth is not uniforme covered with
water, but possesses great land masses whi0h jut out into the
'
ocean and tend to 'cOmplicate the results of these tidal
forces so that & -truly- satisfactorytheory of the tides has
-notyet been evolved.
It is however safe to say that the
primary cause is that given above.
The only region on the earth where the ocean forms a
_
continuous band'around the globe, uninterrupted by land
masses, is in the southern ocean and there is a theory that
around this belt sweeps the great t_idal wave, a “ primary
wave.” — This wave is supposed to give off secondary.
'
or _“ derived waves,” which move
in a northerly direction
up the other oceans.
Such a wave moves up the Atlantic
Ocean at a speed of about 500 miles an hour (Fig.
_
In
ocean the wave is only two or threeieet in
height, so that the tides in oceanic islands are very small.
.
But as the water shallows round the edge of the ocean
the
speed of the tida1 wave is enormously reduced 'bÿiriCtion
and the height of the tidès becomes
Thusthe
’
height otthe tide at the Azores is about ve feet,.- that
around the _Sci‘lly Isles sixteen feet, and that at Swansea.
-
_
_
1 Asgthe —t_idé. runs
narr0w channels
_
«.
ténds,tdbeb0ted
thereîqre”ïe highest
’
tidés are found in suCh channels as
,
the mouth ofthe
Sev‘erh, Where the tide may, reach nearly as much as fty
_
feet at Chepstow.
'
.
..
__
There are produced around our coasts two hightideS m
«
the twenty-four h0urs and-two low tides, but _owing to the
.
fact that the
the…earth the
,