Washington sentinel., 1854-06-06
The Tubular Bridge.

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Many of our readers have heard of the fa-
nous tubular bridge built across the Menai
straits, in Wales, and we give, from one Of the
capital letters of the editor Of the New York
Observer, the most intelligent and satisfactory
description of that noted structure we have
ever met with. He says
aThe tubular bridge over the Menai straits
/ regard as the greatest mechanical wonder Of
the world The problem to be solved by the
architect was this: to build bridge 1900 feet
over an arm of the sea, so high in the air as to
permit the loftiest mast to pass under it, and
without piers to obstruct navigation. The point
on the straits selected for the purpose was for
tunately provided with rock rising from the
water, and nearly in the midst OF the straits.
This was the base Of pier, but then the bridge,
without draw, must stretch 472 feet to one
Shore and AGO to the other, and at the height
of at least hundred feet above the sea. Mr.
Stephenson, the architect, devised, and under
his superintendence was executed, this work,
which promises to stand an enduring monu-
ment of integrity, enterprise, and perseverance,
under difficulties the most disheartening, and
to ordinary minds insurmountabe. To the work
he brought as the first and chief element Of
success, his own genius and courage, and to
these he added 1900 men, for whom cottages
were built along the shore, as the labor of years
was before them.
The bridge is to be Of iron, nothing else. 1t
is tohold itself up without an arch, and without
steel cables to bind it to rocky shores. 1t isto
be built on the shore, hoated on the water, then
raised perpendicularly, and stretched horizon
tally from land to land.
Can it be done? The world laughed, and
the wise men said no, it could not be done, and
it would fall of its own weight, if it were DONE
The men of science pushed on the mighty work
Plates of iron we're rveted together, and tube,
not round, as people suppose, but square, rather
rectangular, being 80 feet high land IA feet
wide, was built. The labor of this army ex-
tended through four and half years. Two
millions Of rivets hold these iron plates in their
tenacious grasp, and the tubes weigh no less
than 1866 tonsl During three years, these
shores presented the busiest and most exciting
of peaceful scenes. The work went on, and at
last it was done. Hydraulic presses were made
to raise the mighty weight, and inch by inch
they rose, till, in three weeks from the time
they began to ascend, they were planted on the
lofty. pier, and stood sublime They did not
break Of their own weight. They did not bend.
But would they bear the pressure of train
loaded, laundering over this awful chasm, or
would the mass of iron crush and fall into
ruins, like rent world, when the first train Of
rail cars, with its living burthen, should trust
itself on the treacherous bridge.
The train was ready, not with burden of
living men and fair women, to re-enact the
Norwalk tragedy, ian event that dishonors our
country in the eyes Of Europe but loaded with
iron and stone, to four times the weight Of any
train that would ever be required to pass over the
trembling structure. Mr.. Stephenson, the archi-
tect, mounts the locomotive himself, the engi-
neer and solitary passenger He moves on,
and reaching midway of the longest tube, he
arrests the train, and pauses there, that the
heaviest pressure may at once be felt, and the
grand experiment be tested once for all. It
was not rash and hair-brained feat 1t was
the calm confidence of man Of calculation
who knew what he was doing, and that he was
safe. The sinking Of that long line, with the
tremendous weight to which it was there sub
jected, was less than half an inch! The expe-
riment was tested. Itcost five millions of dol
lars, and was cheap at that.
/ walked through it and then by a fight of
narrow steps ascended to the top Of it, and
walked out on the fat roof on which the strain
comes, and when / saw the power of those
concatenated plates, it was impossible to have
the sensation Of fear, while felt sure the struc
ture will stand till some convulsion Of nature
shakes the sea and earth. s