Weekly national intelligencer., 1851-05-03
HEIGHT AND POWER OF WAVES.

which waves are sometimes rolled up IN storm. We saw
il stated in ourns but few days since that
more than ten feet high while Humboldt, in his
Cosmos, estimates their extreme altitude twenty-five feet
Recently, however careful Investigation of the phe
Of has been instituted which shows results en-
sey variance with the estimates we have mentioned and
mois in accordance with the popular idea of rolling
mountains high.
Dr. scorssy, paper read before the British Associa-
tion a Edinburgh has thrown much light upon this inter-
espg inquiry His researches of which find
10 the Boston Journal conducted during Atlantic
voyages in steamship under circumstances very favorable
fos obsevaon By examination instituted during hard
ss be found that the average height Of the full
een ees and upwards. and the highest about
yrse feet sbovsthe level Of the hollow. He also ou,d
sax sics Of about thhty-six hours duration, which
had abaed several hours before the observation that tho
waves had percepby ubsded noticed of twenty
six feet average elevation from ridge to hollow, and Of
thirty feet They were, however, Of great the
ridge.
When meet with obstruction, their height is in
creased. AT cent meeting of the British Association,
Thomas Stevenson, Esq Civil Engiaesr, gave the results of
soma careful observations made at the Bell Rock light
house, from whih it appears that, the 2Ota November,
s47, in heavy ground swell, after storm, solid
at the Bell RocEghhouse hundred and sir feet above
the level Of the sa If ecoect right" says the print
from which lave quoted, 'the have been known
to dash up the es of the Eddstone light the height of
the lantern whth is hundred feet above the rock
We inford by Mr.. Benne', the keeper Of the light
house late on Nnos Rock, that he has known the
rise that structure above the couplings Of the piles, which
hiryfv feet above the rock, and about twenty five
feet above the ligh water mark.
esHere, however, the piles Of the lighthouse offered but
small resi.tan to the waves, compared with solid struc-
ure, and the nly thing which would be likely raise the
water above h usual level is its striking against the rock
ITSELF This however, being several feet below the level Of
high WATER vpsd tend rather to break the than
increase their height. There good to believe that
during the recent which destroyed the lighthouse
waves struck he the bottom Of which forty
feet above the ock and allowing five feet extra for the
extraordinary rise of the tide, thrytwo feet above high
| wster mark.
"The length and velocity Of vary. In rounding
the Cape Of Good Hope, not unfrequeny met
with vast hat ridges and few depressions occupy
the extent oi me These propagate their motion
at the rate ofhiry forty miles hour Mr. A. G. Find
ley in paper read before the Society of Arts stated that
Of from three hundred to four hundred feet in length
from travel with velocity Of twenty twenty
and one-haf miles per hour whether they fifty
feet in total height They travel great distances
and often raised by distant hurricanes having been felt
ST. Helena and Ascension, which six hundred miles
apart and be remarked that probable that ground svels
often originate the Cape Of Good Hope distance Of three
thousand miles Dr. Sccresby, to whose investigation
have already alluded carefully estimated the velocity Of the
waves and found to be At the rate Of 80 81 English
miles per hour. He estimated $50 feet the prsbabe
distance Of the the width passed between
and crest is common to suppose that the wate
advances with the is the form only which advances
the water rising and falling in the place. except when
reaches beach, when becomes really progressive from the
fact that sink directly down. and therefore falls
forward.
"These statements in relation to the height and velocity
Of have perhaps prepared readers estimate with
some degree Of correctness their force. When we see
column of WATER at least thirty feet in height, advancing
with the speed Of railroad train, readily imagine that
lis force almost irresistible We have already mentioned
the investigations of Mr. Stevenson. His observations
the force Of the waves made BY him with reference the
construction of marine works. of much interest and inn
pcrance. These observations made by of the
marine dynomeer He found that during westerly gale
on the 29th March, ls45 force of three tons per square
foot was exerted at the Skeyvore lighthouse, n the Atlantic
ocean, In the German ocean, at the Bell Rock lighthouse
the greatest result registered pounds about
and half tons per square foot These results asonsh
ing, and is wonder that in the encounter with such
oce the largest ships but toys and wood and iron almost
fragile glass; Nothing but stone be expected
ss such foce and that must be firmly fastened the
lodges on which the waves spend their fury"
The following additional facts about Lighthouses, which
may be interesting in this connexion, ale reported in the
London Athensum: .A.
The Eddystone lighthouse, having been built Of wood in
1893, carried away FIVE years after it's erection. II
shortly afterwards reconstructed of the material the
lower part being filled with stone or concrete it then lasted
for forty years, when consumed by fire. In 1859
Smeaon completed the present lighthouse, which 6s feet
high and the base 2s feet in diameter eng barely less than
the surface of the rock which il stands II s built Of
stone the stones dove'aled together, and jogg
termed SO a. TO prevent the of from sliding
each other situated in the midst Of the sea- nine
ten miles distant from Plymouth. The Bell rock lighthouse
stands rock Of the same name on the east coast of Scot
land It surrounded by the sea, and is 100 feet high, and
40 feet in diameter the base. II built by Robert Ste
venson and finished n 1870 Its construction is similar
that of the Eddystone The Skeryvoe lighthouse built
by Alan Stevenson Of the architect of the Bedrock light
house. The Of stone in this structure is than
double that used in the Bell rock and FIVE times that
tanned ia the Eddysone The tower 10 l3S feet high, and
the diameter at the bsse s AZ feet. II stands gnsiss
rock the of which just large enough for the founda
ton In constructing this lighthouse the architect appears
to have chiefly relied the weight rather than the
tension Of the Materials for efficient resistance the impact
of the waves. The stones dove,aed joggled
but nails used merely 10 keep the work together
been constructed Of cast ron One designed by Mr. Alex
ander Gordon, and made by Messs Cotam e. Halen has
been erected at Bermuda is 80 feet high Mesrs Walker
and Burgess have recently constructed efficient lighthouses
iron piles which red in the sand by of screw,
invented by Mitchell The Maplin and Chspman lights at
the mouth Of the Thames and those Fleetwood and Beast
are on this principle Professor Cowper invited attention
the mode which these structures rendered compact
means Of iron braces The Sources of Light and mode
Of diusing next advered TO- Common fres FIRST Of
wood and then Of GOALS originally used furnish light
coal fire employed for this purpose in the Isle Of Man
for $50 years, as late the year 1860 Talow candles
succeeded candles fastened wooden rods Gas they
some arranged before booths in fars) burnt
in the Eddystone lighthouse for forty years after
peted by Smeaton. Then lamps with twisted cotton