The Sun.
London, England, 1847-07-24 00:00:00

THE BRITANNIA BRIDGE.
A NEW WONDER OF THE WORLD,

The following descripticn of this stupendous work is
given by a carrespor.e.ent of the Mane/46.4er Examiacr :
The Menai Strait is an arm of the sea, separating
the island county of Anglesea from Carnarvonshire on
the mainland of Wales. It is fourteen miles long, vary-
ing from 200 yards to two miles in width. An impetu-
ous tide sweeps through it, which, at one time, with
the mid water and under water rocks, rendered its na-
vigation exceedingly dangerous. The worst of the
rocky dangers have been removed, and vessels of the
largest size may now pass Carnarvon Bay, on the south
of Anglesea, to Bangor Bay, on the north, without sail-
ing round Anglesea. should the stormy weather or con-
trary winds at Holyhead render the passage of the Menai
Strait preferable.
The necessity of a passage across the Strait was, ori-
ginally, to connect the island and the mainland; and
while that was all, the passage was by ferry boats upon
the water. Ultimately the harbour of Holyhead. on the
extreme west of Anglesea, the nearest point to Ireland,
was decided upon as the English landing place. Roads
were made from England through Wales, and a bridge,
unequalled in beauty and magnificence, suspended by
ponderous chains, on lofty piers, was thrown across the
Strait, at a narrow point about two miles from Bangor.
In process of time it was deemed expedient to super-
sede the turnpike roads leading to Holyhead by a rail-
way. At first it was proposed to use the suspension
bridge for the railway trains, by having stations at each
end, at which the locomotive engines would be detached,
and between which a stationary engine would draw the
trains. The bridge was declared capable of sustaining
a weight of 2,600 tons, of which 1,094 tons were its
own weight; thus giving a surplus strenth of 150 tons.
If the bridge was covered with loaded railway carriages
over all its length, and on each of its roadways (it is
divided into two, with a spacious pathway between),
the weight of the carriages would have been 265 tons.
leaving still surplus strength of 621 tons. But other
objections to its use !or railway trains arose, chief of
which was its undulatory motion.
One would suppose that the wind would cause it it to
swing to and fro, rather than to heave up and down in
undulations. But it has hardly any sideway or swing-
ing motion. Nor had it now as much of the undulatory
motion ss it once bad. Mr. Fisher, the resident engi-
neer, told me that he had known it heave six feet above
and deflect six feet below the level in gales of wind. It
has been improved by adding weight to the roadway,
and tension rods between the chains, so as to prevent
that extreme motion which in gales of wind ran along it
like a heaving wave from end to end, tearing up the
flooring which formed the paths and waggon tracks.
Still, it is undulatory. I stood on it in a gale, and felt it
heaving beneath me as a ship heaves when a billow
passes underneath. This being a characteristic insepa-
rable from its construction, it was resolved that a new
bridge should be erected for the use of the railway on a
new principle. The inventive genius of Robert Stephen-
son declared that this new bridge should be two iron
tubes, or railway tunnnels made of iron plates, laid
parallel to each other, on piers built on the rocks be-
neath.
if we suppose ourselves stationed in a boat in the
middle of the Menai Strait, a few hundred yards distant
from the new bridge on the south side, and suppose it
finished, we shall see a wonder of the world of this kind;
first, there is the middle pier rising out of the water
founded on the Britannia rock, from which the bridge
takes its name. This rock can be seen at low water.
The breadth of this pier is 62 feet by 53 feet and a quar-
ter of an inch. The blocks of stone are seven and eight
feet long by three and four feet in breadth and deepness,
and they rise, stone upon stone, until the pier is two
hundred and thirty feet high.
At the distance of four hundred and sixty feet on each
side of this centre pier there rise, near to the water's
edge, two other piers of the same gigantic breadth and
height; while on each side of these two piers, at this dis-
tance of two hundred and fifty feet, there rise two walls.
Continuing outwards, the wall on our right hand, on the
Carnarvon shore, does not extend its ponderous bulk far
back, for the land is high and bold, and the railway
comes along its elevated brow and at once lays hold of
the bridge. But on our left hand, which is the Anglesea
shore, the wall is the forehead and end of a mighty em-
bankment, on which the railway is raised to the level of
the bridge.
There, then, are the four spaces before us, across
which, in the iron tubes the railway is laid, namely, two
spaces on each side of the centre pier of 460 feet each—
(let the reader measure 460 feet on a street or on a
road, and he will wonder at the vastness of this struc-
ture); aid two more spaoer of 250 feet respectively, at
each end. The tubes are eight in number, each of them
30 feet on the exterior aide, and 27 feet high in the in-
terior. Each is 14 feet wide, and they are laid in couples
parallel to each other. Taking ourselves in our boat
underneath the bridge, and looking up, glancing from
the Carnarvon side of the Strait, we see two tubes, ra-
ther, we should say, masses of iron, for they do not
seem to be tubes, lying side by side from the wall al-
ready named across the space of 250 feet. They have
each a hold upon the stone work, several feet at each
end, and they rest upon moveable rollers and balls made
of gun metal, the hardest known; those rollers and balls
resting on beds of metal, and moving outwards or in-
wards as the massive tubes or iron expand with heat or
contract with cold.
Next we see two others of the same height and width,
viz., thirty feet high and fourteen feet wide, lying side
by side across the next space of 460 feet, and resting on
the masonry as the others. Thirdly, we see two more
lying side by side across a space of 460 feet; and lastly,
two crossing the space of 250 feet. In the whole, with
the breadth of the piers and the landward buildings, the
length of the bridge is one-third of a mile.
In height the three piers are as already said, 230 feet.
But they are seventy feet higher than the tubes. These
are so masssive that their actual elevation above the
water seems less than it really is; and so dead and in-
elegant to the eye that it was necessary to raise the
piers seventy feet above them, to give a show of ele-
gance to the structure. Measuring from low water mark
to the bottom of the tubes, the height is 130 feet, the
tubes being thirty feet on the side, and the piers seventy
feet above their upper surface. As ornaments to the
two walls which rise upon each shore, are four lions,
two at each end of the bridge. The lions contain about
8,000 cubic feet of stone. They lie couched, and yet
the height of each is twelve feet; the greatest breadth
across the body is nine feet; the length twenty-five feet;
the breadth of each paw two feet four inches.
As we are now so high as to see the lions in detail,
we may look into the interior of the iron tubes. They-
are made of plates of iron of various thicknesses,
rivetted together. The iron increases in thickness as
we proceed towards the centre. We now see that the
roofs of the tubes are formed of cells, and also the floors.
Those cells are formed of iron plates set on edge, the
cells of the roof being within a fraction of one foot nine
inches square, and those of the floor being one foot nine
inches wide, and two feet three inches deep.' The rails
on which the trains run are laid on those cells of the
floor. The flat bottom, the two upright sides, and the
flat roof of each tube are formed of plates, the thinnest of
which is a quarter of an inch, and the thickest twelve-
sixteenths of an inch, but the number of them laid to-
gether and the internal joining cannot be yet explained.
The weight of each of the four long tubes will be about
1,300 tons ; the weight of each of the four short ones
about 600 tons. In the whole there will be at least
7,600 tons of iron used. No contracting estimate of the
expense of the iron part of the work has been made, as
the work may cost more or less, according to circum-
stances. The masonry was contracted fer by B. J.
Nowell and Co. at 130,0001 ; but, from alterations in the
plans, it will cost (suppose no farther alterations be
made) 200,0001. They expect to finish the masonry by
August, 1848. It will contain one million and a half of
cubic feet of stone.
When I was there in May fifty vessels, of sixty or
seventy tons each, were employed in conveying the
stones to the works; the red sandstone, of which the in-
side courses are built, from Runcorn—the blue limestone,
of which the outside courses are built, from the sea
shores of Anglesea. The quarries en the Anglesea
shores opened for this work extended over twenty miles.
In the whole there were 1,300 men employed, 600 of
them at the bridge, the fortnightly wages of the latter
amounted to 1,3001. 3,000 cubic feet of timber had been
used at that time for stages and scaffolding. Two steam
engines were at work on each shore, and a third was
being erected on the Britannia Rock, in the centre of the
Strait, to hoist the stones, grind mortar, saw timber, and
limestone
into falling from
the
perform other heavy work. Oa each shore there was a
ilritnoneskilonf,
thethehewers chips
chips of the red sandstone being ground to powder to
make mortar with the lime. There were seventeen
e of
being the
burned
lime; and
gauntries with travelling crabs on each for moving the
blocks of stone. Railways diverged and converged, on
which trucks run along; and every heavyweight in the
building of this wonderful structure was moved_ as
_d
take
if men
were gods, who only willed that huge blocks should
motion, and they took it.
The building of the iron tubes had not then begun ;
shore about a
quarter of a mile. Theates of iron are
inpl
but the stages upon which they are to be built are
erected, extending along the Carnarvon
prepara-
tion at different places in England and Scotland, and
they will be conveyed separately to
then be to-
gether on these stages. The tubes
Walelsi,
in this
way. We shall imagine ourselves
con-
veyed from the shore and elevated to their places
and put
hile the
p
removed
from the stage upon the shore. and raised to
its lofty
mighty thing is in process of being do-nrees;enehtaecwh of them
requiring only about six or eight hours to
elevation.
for ? We are on the share of Carnarvon, looking
Imagine, then, the day. Is it not a scene worth liv-
ingacross the rapid tide now flowing, to the high shores of
Anglesea. A mile below, on the wooded slope, is the
beautiful residence of the Marquis of Anglesea ; and
on the hill nearly opposite to us, overlooking the great
weak of this great day, is the column erected to com-
memorate the Marquis and Waterloo, the column ,
he
hav-
ing the familiar name of " Lord Anglesea's Leg, '
having got this column on the Anglesea hills because he
lost a leg on the plains of Belgium. May Stephenson
achieve a triumph in art this day, as undoubted as was
the triumph of war of Wellington and Anglesea on that
day ! How glorious for him and for England if he
does I But why say if? He will triumph. lie risks
nothing here ; he flee reduced everything to certainty.
The tide is now favourable. .A line of barges lying
side by side have been placed beneath the stage on which
one of the great masses of iron has been built. The stage
is removed, and the tube of 1,300 tons rests upon the
barges. They are towed out linen the water with their
monster freight, are brought round, and drawn forward
until they and it occupy the space between two of the
piers. They are moored and made fast there. The out-
side width of the tube being fourteen feet, there is a
groove in each of the piers wider than that ; and at the
bottom of the piers stones have been lett out to admit
the ends of the tubes into the grooves. Those groves
extend upwards as high as the iron is to be elevated,
namely, one hundred and thirty feet. At a height con-
siderably above that, within an archway which is in