The southern press. [volume] (Washington [D.C.]) 1850-1852, 1851-05-02

about the height to which waves are sometime
rolled up in = STERN. We cav it stated In SOM
journal, bat few days since, that waves neve
run more than ten feet high, while Humboldt
| in his Cosmos, estimates their extreme aftitUd
1t twenty-five feet Recently, however, NOR
careful investigation Of the phenomena OF waves
has been instituted, which shows results en-
tiroIy at variance with the estimates we hav,
mentioned, and more in accordance with th'
popular idea Of waves rolling mountains high.
DR.. Hcoresby, in q paper read before the Brit
ish association at Edinburg, has thrown much
light upon this interesting inquiry. His re-
searches. an account Of which we find In the
Boston Journal, were conducted during two At
lantc voyages in a steamship, under circum
stances very favorable for observation. 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 high
est waves about forty -three feet above the level
of the hollow. He al-o found that after storm,
of about thirty-six hours duration, which had
abated several hours before the observation, so
that the waves had perceptbIy subsidized, waves
were noticed Of tweuty-six feet average elevn-
ton from ridge to hollow, and even Of thirty
feet. They were, however, Of no great extent
on the RIDGE
height is increased. At recent meeting Of the
British Association, Thomas Stevenson, esq,
civil engineer, gave the results Of some careful
observations made at the Bell Rock lighthouse,
from which 1t appears that on the Goth Novem-
Der, l847, in heavy ground swell, after storm,
solid water rose at the Bell Rock lighthouse one
hundred and sic feet above the level of the sea.
/" If we recollect right" says the print from
which we have quoted, " the waves have been
known to dash up the sides of the Eddystone
light. to the height of the lantern which is over
one hundred feet above the rock. We are in
formed by Mr. Bennett, the keeper of the light
house late on Minot's Rock, that he has known
the waves to rise at that structure above the
couplings Of the piles, which were thirty five feet
above the rock, and about twenty five above the
high water mark.
Here, however, the piles of the lighthouse
offered but small resistance to the waves CON-
pared with solid structure, and the only thing
which would be likely to raise the water above
the usual level, is its striking against the rock
itself This, however, being several feet below
the level of high water, would tend rather to
break the waves than to increase their height.
There is good reason to believe that during the
recent storm which destroyed the lighthouse,
the waves struck the store-room, the bottom OF
which was forty-seven feet above the rosk, 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, are
not unfrequenty 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 forty miles per hour. Mr..
A. G. Findley, in paper read before the Society
of Arts, stated that waves Of from three hundred
to four hundred feet in length from crest, travel
with velocity Of twenty to twenty seven and
one-half miles per hour, whether they are fifty
or ffty-four feet in total height. They travel
for great distances, and are often raised by dis
tant hurricanes, having been felt at st. Helena
and Ascension, which are six hundred miles
apart and he remarked that it is probable that
ground swells often originate at the Cape OF
Good Hope, n distance of three thousand miles.
DR.. Scoresbv, to whose Investigation we have
already alluded, carefully estimated, the velocity
Of the waves. and found it to be at the rate of
30. Ct Engli statue miles re hour. H. IS i.
mated $50 feet as the probable mean distance
of the waves, or the width passed over between
crest and crest 1t is common error to sup
pose that the water advances with the wave. 1t
is the form only which advances, the water ris-
ing and fall ng in the same place, except when
it reaches beach, when ii becomes really pro-
pressive from the fact that it cannot sink direct
w down. and therefore falls over forward.
"These statements in relation to the height
and velocity of waves have perhaps prepared our
readers to estimate, with some degree of correct
ness, their force. When we see column of
water, at least thirty feet in height, advancing
with the speed Of railroad train, we can readily
imagine that its force is almost irresistible. We
have already mentioned the Investigations of
Mr.. Stevenson. His observations on the force
of the waves. made by him with reference to the
construction of marine works, are Of much in
terest and Importance These observations were
made by means Of the marine dynometer. He
found that during westerly gale on the 29th
March, 1915, n force of three tons per square
foot was exerted at the Skerryvore lighthouse,
in the Atlantic ocean, In the German ocean, at
the Bell Rock lighthouse, the greatest result
registered was 3,Ol3 pounds, or about one and
n half tons per square foot. These results are
astonishing, and it is no wonder that in the en-
counter with such force, the largest ships are
but toys, and wood and iron almost as fragile MS
glass Nothing but stone can be expected to
resist such a force, and that must be as firmly
fastened ss the lodges on which the waves spend
their fury"
The following additional facts about light
houses, which may be ntering in this connection,
are reported in the London AhenGum
"The Eddystone lighthouse, having been
bnt of wood ia 1893, was carried away five
years after its erection. 1t was shortly after
wards reconstructed of the same material, the
lower part being filled with stone or concrete;
il then lasted for forty years, when il was con-
sumed by fire In 1859, Smeaton completed the
present lighthouse, which is So feet high, and the
base &c feet in diameter, (being barely less than
the surface Of the rock on which it stands) II
is built of stone; the stones are dovetailed to
gether, aud "joggled" as it is termed, 30 to
prevent the courses of stones from sliding on
each other. n is situated in the midst of the
sea, nine or ten miles distant from Plymouth.
The Bedrock lighthouse stands on a rock of
the same name on the east coast of Scotland
It ia surrounded by the sea, and is 100 feet high,
and ~ feet in diameter at the base. 1t was
built by Robert Stevenson, and finished in 1910
Its construction is similar to that Of the Eddy
stone. The Skerrevore lighthouse was built by
A Ia, Stoyapoor non of tLn or.b;f,.t or ~. D.