Green-Mountain freeman. [volume] (Montpelier, Vt.) 1844-1884, 1851-08-14
VOLUME VIII. NO. 33.
Height, Force, and Velocity of
Waves.

IN snlps, or witnessed the Jury OF storm on
rock-bound coast, cen realize the magnitude
and power of the waves of the ocean. BY
stretch of the imagination, nautical writers
sometimes speak of the wavee as running amoun-
tains high, but aggerated as is this statement
it is doubtful whether those who take it in
literal sense DO not really entertain more just
idea of the actual power of waves than those
who more philosophidaly measure their height
by feet and inches, and form corresponding
idea Of their force.
we have recently had u melancholy instance
of the force of the waves in the destruction of
a structure which some of our best engineers
considered impregnable to the assaults Of the el-
ements. This event has given an interest to the
Investigations which have been made as to the
height and force of the waves. We find upSn
comparing various authorities that there is
difference ofopnon in relation to these subjects.
1t was the commonly received opinion among
scientific men several years since, that no wave
rises more than ten feet above the ordinary level
of the water, which, with similar depression
would give height of twenty feet from the
bottom Of the hollow to the crest of the wave.
Humboldt, in his Cosmos, estimates the height
Of the waves ut twenty-five feet.
1t is not until quite recently, however, that
any careful investigation of the phenomena of
waves has been instituted. DR.. Scoresby in
paper read before the British Association at Ed
inburg, has thrown much light upon this inter-
esting inquiry. His researches were conducted
during two Atlantic voyages in a steamship,
under circumstances very favorable for observa-
ton. By an examination instituted during
hard gale, he found that the average height of
the waves was full fifteen feet and upwards, and
the mean highest waves about forty three feet
above the level Of the hollow. He also found
that after storm Of about thirty-8ix hours du-
ration, which had abated several hours before
the observation, so that tho waves had percepti-
bly, subsided waves were noticed of twenty-six
feet average elevation from ridge to hollow, and
even Of thirty feet They were, however of no
great extent on the ridge.
When waves meet with an obstruction their
height la increased. At a recent meeting of
the British Association, Thomas Stevenson, civ
IL englpecr, gave the result of some careful obs,
servatlons'made at the Bell Rock lighthouse,
from which it appears that on the Goth If Mo-
emoer, l57, in heavy ground swell, fter
Storm solid water rose at the Bell Rock light
mousse one hundred and siC feet above the level
- 0! inc sea. If NC looollecj figat, tne waves
;, nave been known to dash up the sides of the Ed
uysone light, to the height of the lantern, which
: IS over one hundred feet above the rock. We
: are informed by Mr.. Bennett, the keeper of the
= lighthouse late on Minot's Rock, that he has
d known the waves to rise at that structure above
l the couplings of the piles, which were thirty
: feet above the rock and about twenty five above
n the high-waer mark. Here, however, the piles
of the lighthouse offered but small resistance
t to the waves compared with solid structure,
and the only thing which would oe likely to raise
the water above the usual level, is its striking
J against the rock itself This, however, being
several feet below the level Of high water, would
tend rather to break the waves than to in-
crease their height. There is good reeson to
believe that during the recent stern which de-
atroyed the lighthouse, the waves struck the
store room, the bottom Of which was AZ feet
above the rock and allowing five feet extra for
the extraordinary rise Of the tide, thirty-two
feet above high.water mark
The length and velocity of waves vary. In
rounding the Cape of Good Hope, waves, or
rather swell, are met with, SO vast that few
ridges and few depressions occupy the extent
of mile. These waves propagate their motion
at the rate of thirty or forty miles per hour Mr..
A. G. Findley, in paper read before the Socie-
ty of Arts, stated that waves of three hundred
to four hundred feet in length from crest to crest
travel with velocity of twenty to twenty y-seven
and one.h half miles per hour, whether they are
five or fifty feet IN height, They travel for
great distances, and are often raised by distant
hurricanes, having been felt at St. Helena and
Ascension, which are six miles apart; and ne
, remarked that it Is probably that ground swells
often originate at the Cape of Hope, distance
J of three thousand miles. 1t is a common error
, 10 suppose that the water advances with the
wave 1t is the form only which advances, the
water rising and falling in the same place, ex-
} cept when it reaches beach, when 1t becomes
n really progressive from the fact that it cannot
4 sink directly down, and therefore falls over for
ward.
n These statements in relation to the height and
velocity of waves have perhaps prepared us to es-
3 innate with some dgree Of correctness, their
: force. When we see a column OF water, at
: least thirty feet in height, advancing with the
: speed of a railroad train we can readily lmag-
Inc that its force was almost irresistible. Mr..
8 Stevenson's observations on the force OF the
. waves, made by him with reference to the con-
e struction Of marine works, are of much interest
: and Importance. These observations were made
q bv means of the marine dynometer. He found
9 that during westerly gale on the -29th OF
a March, 1S45, force of three tons per Squire
foot was exerted at the Skerryvore Lighthouse,
in the Atlantic Ocean, In the German Ocean,
at the Bell Rock Lighthouse, the greatest result
y registered was three thousand and thirteen ios'
u or about one and half tons per square foot
10 These results are astonishing, and it is no won
der that in the encounters with such force, ,the
: largest ships are but toys, and wood and iron
:, almost as fragile as glass. Nothing but stone
: can bo expected to resist such force, and that
:. must be as firmly fastend as the ledges on which
3 the waves spend their fury Boston Journal.
!. THE Pope has issued rescript, that whoeV-
10 is found guilty of bringing into Rome, or trying
g. to carry into Rome, any copy of the Word OF
Of God in the Italian language, he shall be sent for
g, four years to the galeys.-Speech Of Hugh