The republic. [volume] (Washington [D.C.]) 1849-1853, 1851-05-10

How mosb thsss too IN, lodged arrangements
oonlribsted 10 lhe dsstructoa u shs lighthouse
~il not undertake ~ s4yi bat thai hoth ~efs high
~ ialusious there 10 no douta. Thn rnciosed
newspaper cou.mar ai'on, iscin man ~ho had
sn active part 81 perform Al tht Miuot iof the con-
tractor ~ho drilled me holes IA tbs rock. and ~he
erected the pllss in place. viii 10 show the
view taken Of Il By sound, praosieal mind.
With thsss details prsa-issd. precssd 10 state
the information have ouliscsed aud the coneln-
sions 20 ~hich have arrived.
On the 18Th instant desired my former assistsni
la tho work. Mr.. william Dennison. 10 Wait she
rock. examine he appearance, and collect such
fsess an might fAsi within bis rearh- u was NOT
until the s2d instant, however, that the ssa 90
swell had shated sulhcisntly 70 enable him 10 see
clearly The precise coadi,ioa % the foundation.
Even then the roll u toe sea prevented landing
upon the rocks bot. by lhe aid 81 very sspe-
rieneed boslmsn, the boat was kept within 10 issa
Of the rocks and. by going around 10 several times.
he Was enabled 20 make tho enclosed sketch which
represents tho present appearances 81 the piles.
IL viii be that tbs foot Of every pile is in its
place; and the accompanying report Of Ms. Desnl-
son ssysi II could not see the slightest change In
the rock whatsvor the piles aPpcarrdto be wedg.d
az hrm la the rock ever. could see the heads
Of the wedges Slightly projecting from the surface
Of the rock in the same position as when lsf by me
| ia November. 1873"
This 10 sufficient rcfataiioa Of the often repeated
s,ory u tho "split rock"--this, like other state
mcnts from the same source. being entirely untrue
"spali." as II IL called technically, knocked
of ono of the holes in drilling the rock in isss, Of
sort OF importance. because the hole was carried
| sufficiently deep below H.
The foundation Of tina structure then being pre-
csely ne il was left In $780, and the feet Of the piles
being now in place, il Is clear that there was mo-
thing there which yielded. We are 60 look else.
where, therefore, for the 81 the destruction Of
the lighthouse; and ,hs We have the means Of stat
| ing, think, without question.
AT four O'Clock on w ejnesday afternoon The issh,
10 hours before the light fe the deck or platform
which the keeper had placed In the second series Of
braces 40 feet above the rock. came ashore AT Co
hasset. Now, as this was entirely too bulky and
too heavy for the assistant keepers 10 move, IL 10
plain that the must have reached aud upIifted
IL from its place; the men were incapable Of doing
| it, This deck, being 40 feet above the rock, was
| % foet above the line OF low water, aud - feet
above high water, spring -tidos. according to the
tide tables furnished by the survey. (sec my
report TO the bureau OF isi7ls.) In other words,
the had at that time reached within feet
OF the base of the store OF the lighthouse. With
| out undertaking 10 speculate upon the probable
shock that the structure must have received from
piles 40 feet above the rock, Il IL enough TO know
that say at O'Clock in the afternoon, the had
reached within feet OF the body or solid part
| Of the structure. The still increasing (the
effect Of the continued gaie,) the night tide was
full at about midnight; and II required but slight
| increase in the height Of tho sea, after
| having reached the deck in tho second tier Of
braces, to bring il in contact with the main body
of the structure. When this took place il 10 plain
to perceive that such sea- acting upon the surface
of the building, at the end of lever SO or % feet
long, must be wellnigh irresistible; and doubt
not that the ghhous, was thus destroyed.
The conclusions which arrive at, therefore, are
these:
the structure.
| Second. That the platform, or deck, placed by
the keeper the second series of braces contrary
to the design of the builder Of the lighthouse. con-
tributed to the overthrow.
Third. That the guy, or 5a-inch hawser, at
tached by the keeper to the top Of the lighthouse
and extending 300 feet northwest, in direction
directly at right angles to the direction of the sea-
northeast, had most injurious tendency, and that
it was enough, in ITSELF to the overthrow Of
the lighthouse, had the not reached the body of
the structure 1t is easily to perceive that the force
of such a upon 300 feet of hcmpen rope of 8,
inches must have been immense when that rope
was attached to the weakest part of the building,
that is, the lantern deck, 60 feet above the rock
Since the destruction Of the Mino, the quest ion
has been several times asked, the structure
built upon correct principles and can such
lighthouse be made TO stand there? The answer,
in my opinion, il this The base Of stone struc-
ture at that exposed situation should BIO not less
than has been adopted for the principal towers ON
the coast of Great Britain The Bell Rock Car
lingford, Skerryvorc, and Mcnai have base Of 40
feet, the least, to 4s, the greatest the Eddystone
rock is about 80 feet at low water line, and the
diameter of the tower at high-water line, 10 feet
above, is 26 feet.
At the Mino, circle OF even 20 feet diameter at
low water cannot be had. There ia not in fact as
much space TO be had at low water as the diameter
Of the tower should be at high water while between
the two tides there is height of l6 feet to be pro-
vided for
Without any reference to the cost Of stone
structure, venture the opinion, after the expe-
riencc had there, that no tower can be made 70
stand, even If constructed upon the principle of
the Eddystonc; for it is to be remembered that
while the Eddystonc rock is bare at high water,
spring tides, the Minot is barely uncovered to the
diameter of % feet at low water, spring tides.
During the first seasons operations there, (s47,)
from July to October, three months, sixty hours
all the time that the could work upon the
rock. and this under the eye OF most viglant and
energetic contractor employed drill the holes in
| the rock.
structure similar in it's general characteristics
to the iron pile light il alone suited to the locality;
that 10 to say, structure which offers the least
sistance to the force Of the wave.
| The experiments of Mr.. Stevenson at the Skier
| ryvore have established that the maximum force
| of the in gale of wind determined by
! dynamometer, is about 5000 pounds per square
foot, about ~ pounds per square inch--a pres.
nearly double that exerted upon the piston Of
an ordinary condensing steam engine. A base Of
larger than that afforded at the Minot is re-
quiste to resist such pressures these. The
must be allowed free passage, there must he
| sufficient weight in the tower TO countervail the
| effect of The wave. To nroyide the necesSarv