The Sun.
London, England, 1863-01-23 00:00:00

THE SEVERN BRIDGES.

In the course of a few months the magnificent
iron railway bridge which is now being thrown
across the Severn at Coalbrook-dale will be com-
pleted, and another fine specimen of engineering
skill will be added to the already rich collection of
the surrounding neighbourhood.
Those who travel often in the western counties
must be familiar with the romantic valley of the
Severn, for from the railway which for many miles
follows the course of the river, the beautiful
country adjoining its wooded banks is viewed to
great advantage, and many are the spots of histo-
rical and local interest which may be pointed out
along the route. The whole couese of the river is
fraught with interesting reminiscences of our first
and most eminent engineers; and, indeed, to those
who have not been embittered against engineering
progress by some intrusion upon their favourite
landscape, there is a perfect romance attaching to
this scene of Telford's early labours. In this valley
Telford lived and worked for many years. Hidden
away among the rich deep wood of the vale is the
famous iron foundry, which may almost be consi-
dered the birth-place of the iron trade which has so
revolutionised this country.
These extensive premises were built early in last
century, and their proximity to the deep, rushing
stream of the Severn, which had long defied the
strength of wooden or stone bridges, first led to the
adoption of iron as a material for the construction
of large bridges. In 1773 Messrs. Reynolds and
Darby, the proprietors of this foundry,were invited
to carry out a design for constructing a bridge
across the Severn at Coalbrook-dale. Ironbridge
was the result of their labours; and although it
now appears very imperfect both in design and
workmanship, it was certainly no mean forerunner
of the stupendous structures of later engineers. To
construct an arch of one hundred feet was in those
days a bold undertaking. But the bridge was built,
and great must have been the astonishment of the
Severn villagers when they saw the beautiful banks
of their river bound together by a single iron link.
The arch is formed of nearly semicircular cast-iron
ribs of six inches square section ; the centre of it is
about 50 feet above the level of the river, sufficient
to allow the passage of flats and small craft sailing
up the river.
Nothwithstanding the complete success of this
undertaking, nearly twenty years elapsed before
a second attempt was made to construct iron
bridges upon a large scale, except, indeed, Mr.
Payne's wrought-iron bridge, which was built for
America in 1777, but was never erected. In 1793
the great Sunderland bridge was erected by Mr.
Burden, and about two years afterwards Mr. Tel-
ford constructed his first iron bridge at Buildwas,
about three miles above the original Ironbridge.
This bridge of Mr. Telford's is of a very peculiar
construction. It is a single segmental arch 130 feet
in span. The main arch is very flat, and formed of
cast-iron ribs, the spandrils being filled in with iron
panels ; two aditional ribs are bolted one on
either side to the vertical spandril rods which sup-
port the roadway; these ribs, being segments of a
smaller circle than the main ribs, rise from a lower
point in the abutments to about three feet above
the road at the crown of the arch, and thus form a
stiffening brace to the whole bridge; this brace
gives the bridge a somewhat curious appearance,
but it looks upon the whole very elegant and pretty
among the dark woods which shroud the old ruins
of Buildwas Abbey.
The point at which the new bridge is being
erected is about half way between the two old
ones. It is a fiat segmental arch, spanning the
river at a width of 200 feet, nearly equal to the
side arches of Southwark-bridge. The arch is
formed of cast-iron ribs, varying from 4 feet to 4
feet 6 inches in depth, with equal flanges on the
upper and under sides ; the ribs are cast in seg-
ments of about 25 feet ; the whole was cast and
fitted at the Coalbrook-dale foundry. The breaking
weight of one of the segments was found to be no
less than 450 tons placed at the centre. The ends
of the ribs are made to step into cast-iron chains,
which are embedded in the masonry of the abut-
ments, and form a kind of ball and socket joint,
which gives the iron work freedom for the expan-
sion caused by atmospheric changes.
The work is being ably carried out by the resi-
dent engineer, and the design is at the same time
well calculated. to give sufficient strength and
rigidity, and is of very sightly and elegant propor-
tions. It is, we believe, the largest arched iron
bridge that has yet been constructed in this
a railway.
country for the purpose of carrying

FALL OF A PORTION OF SEAKESPEARE'S CLIFF.
—DOVER, Thursday.—About a quarter to one
o'clock yesterday a portion of the cliff immortalised by the
name of " Shakespeare," slipped with majestic grandeur,
almost noiselessly, into the " confined deep," singing and
surging until the vast mass of chalk (consisting of several
tons) had found its subsidence in the frothing sea. The
portion of cliff that has thus disappeared was near the front
of the Dover double tunnel, and almost facing the viaduct
of the South Eastern Railway. The " high and bending
head" still looks fearfully upon the waters.