The Sun.
London, England, 1864-09-21 00:00:00

The Railway Bridge at Blackfriars

---4.

Foot passengers passing over the temporary bridge a

.
Etackfliars may now eee the ruins of the old stone sttuc,
ture on the one side, and trains of engines and carria,ges on
the newly constructed railway bridge on the other—one

felling of the days of the last century, when Fitt guided the

destinies of the country, the other indicating the wonderful
resources of engineering science of the prasent day. When

the stone hriage now in course ot demolition was completed
politieil feeling ran high, and the names of Chatt am-plaeo,
Earl-street, and William-street, Blaekfriars, still attest the

regard which was felt for the great Minister. The bridge
itself was intended to have been called " Pitt Bridge." The
engineers and contractors who have spanned the Thames at
this spot will not, we fear, have any honour done to their
genius and enterprise such as that which the great States-
man received, and there will be no Cubitt-street Poto-
place to hand down to posterity the names of those who, in
a marvellously short period, have built the new Blackfriars-
bridge. Engineering science can point to no greater feat
than that performed in the completion of this bridge across
the Thames in little more than twelve months.
The first stone of the abutment on the Surrey side WAS laid

on the 21 of May in last year ; the bridge, so far as its con-
struction is concerned, was completed on the 21of June this
year, ballasting, laying the rails, painting, and fixing the
decorations only remaining to be done, and even these might
have been accomplished had there been any necessity for
finishing them before the viaduct was complete to Ludgate-
hill. The bridge is 930 ft in length, including abutments, and
the river is crossed by 5 spans of iron, each 160 ft long ; two of
these spans laid side by side from the width of the structure.
The mode of building was by cons+ ructing what is called an
American truss—that is, a powerful lattice-work of timber,
floored at the bottom, and strong enough to bear a load of
three tons per lineal foot. This was built with its ends
resting just below the heads of the iron piers to support the
permanent iron girders. Upon this staging of timber the
iron bridge was put together. Tho main girders were first
proceeded with, then the broad iron plates of the bottom
were placed on beams of timber sufficiently thick to admit
of the lower plates of the girders being a short distance
above the top, or heads, of the supporting columns. The
portions of ironwork were " keyed" to each other, and stout
iron angle irons at the side rivettcd cn to prevent any lateral
movement. When this part of the work was complete, a
floor of iron was obtained on which to proceed with the
building up of the cross-barred pieces, or lattice-work, of
the completed spans, and which serve to resist compres-
sion, and also to provide for the great tensile strain to which
the bridge must be subjected. So soon as all these diagonal

cross bars of iron were placed in position, and an immense
iron lattice side, 16 feet in height was formed, their ends

were rivetted and secured by broad flange pieces—and

when thus secured the structure was complete. It stood, it
is true, upon the timber staging, or truss—but when
this was removed, it was and is now perfectly self-sus.
taining. So soon as the last of the hundreds of thou-
sands of rivets were driven the timber was knocked from
under —it had done its work, and the bridge stood, sup-
ported only by its iron columns and abutments. The spans
of iron, though to the eye they appear perfectly horlzontal,
still are not so. They are "cambered," as it is termed, to
the extent of five inches—that is, they arched to that small

extent only—five inches in 160 feet. When, however, the
timber staging was removed, and the 600 tons of ironwork
in the span was left unsupported, the centre sunk to the
extent cf two inches, caused by the minute compression of
the plates in the upper flinge3, but when once the structure
had been thus compressed it became all the mere rigid from
the reduction of the curvature of the arch. The strain which
the bridge is calculated to stand is very greatly in excess of
that which can by possibility be brought upon it by the
ordinary working of the traffic. With the view of giving
additional strength there is a centre girder between the two
two outer latticed ones, which assists to carry the cross-
beams. This central girder is 41 feet in width, while those
at the sides are only three feet wide. The " struts" are
placed at intervals of four feet apart. They are bands of
iron about half an inch in thickness, and vary in width

from five to ten inches as the strain upon them increases
Each of them has to bear a compressive weight of three
or four tons, and the lattice work between them is for
the purpose of preventing their " buckling" up under the
pressure. Tho girders which cross the bridge transversely
are placed at distances of four feet to correspond with the
portion of the ties and strute, and upon these again are laid
longitudinal girders. By these transverse and longitudinal
girders the whole floor is therefore divided into a series of
square compartments el wrought iron of great depth and
strength. Above this framework of cells there is laid on a
wrought iron floor, covered with asphalt°, and over this
again the sleepers and ballast for the roadway. At the top
of the bridge are seen a number of bent or curved arches of
iron stretching from one side to the other. These are placed
in this position for the purpose c f preventing lateral vibra-
tion, and are secured to the upper flanges of the lattice gir-
ders. Between each pair of spans there is an open space to
allow for the contraction and expansion of the span move
ment, further facilitated by the iron roller frames upon
which they rest. The spaces are filled up with panels of
iron work, which will not prevent the slight movement
caused by the extremes of the temperature of summer and
winter. The supports for the bridge are the masonry abut-
ments on the Surrey and Middlesex sides, and four piers,
each consisting of three clusters of four iron columns, which
rest upon masonry rising from the bed of the river. They
have a noble appearance at high and low wet er, and their
massive iron capitals give a suitable finish to the work. The
abutments, too, are peculiarly bold and imposing in their
character. The iron terminals are in keeping with the other
parts of the structure. They consist of an ornamental iron
scroll, bearing upon it the words " London, Chatham, and
Dover Railway," and the motto " Invicta," surmounted by
the royal cypher and the date " 1861." The scroll includes
the shield of the City of London and the arms of the coun-
ties through which the railway passes. The terminals above
the columns are ornamented with iron bosses. The founda-
tions of the piers, as we have explained on previous occa-
sions, were formed by sinking iron caissons an average of 28
feet below the bed of river. This work has been carried out
with so much care that no subsidence has taken place in any
of the piers since they were completed. The bridge has been
built from the designs furnished by Mr Cubitt, the engineer
of the London, Chatham, and Dover Railway ; the contrac-
tors for the building were Messrs. Peto and Co.
The first engine, with a long train of carriages attached,
passed on Tuesday, half way across the new bridge towards
the northern side. The train was accompanied by Mr
Thomas, the resident manager, and Mr G. Sharp, inspector
of works. The levels were taken before the starting of the
train, and it was found that only the slightest deflection had
taken place. Another mcnith will elapse before the whole
of the permanent way of the bridge will be ready for exa-
mination by the Government Inspector, and the passenger
station, to be called the " Ludgate Station," now building
in Bridge-street, Blackfriars, will be ready for the public
accommodation. The principal object of testing the southern
half of the bridge has been to enable the managers of the
line to shunt the trains from the Blackfriars Station.—
Bailway News.

METROPOLITAN ORNITHOLOGY.—It is more espe
cially in the early morning in spring and summer
that the wanderer through the streets may best form an idea
of the extent to which the practice of keeping singing-birds
and poultry prevails in particular districts of London.
There, amid the closely-built and pent-up houses, in warm
sunny weather, may be heard the warbling of thousands of
larks, blackbirds, thrushes, and others; whilst from back-
yards, from areas, and even from cellars, come the crowing
of cocks, and other noises proper to the farmyard. In the
very densest and poorest quarters of, London, in the most
dingy streets, there may be seen poultry, including ducks and
geese, the two last of which, in the hot summer days, look
truly miserable objects. In parts of Islington, however, and
elsewhere, better accommodation, in the shape of yards of
considerable extent, is provided for these bipeds. Many of
the enclosures are hidden from the general view by blocks
of houses, but they frequently boast of tall and spreading
trees, remnants of bygone days, when the surrounding
space was still open country. They are likewise often pro-
vided with duck ponds, supplied by the natural springs
which yet exist in parts of Islington and Pentonvillo
Ducks, geese, and other poultry are here reared in consi-
derable numbers, and with tolerable success; but they
are rather noisy neighbours, particularly at break of
day. In one of the streets of Mayfair— not in itself an
important street, yet containing a few good houses—the
writer has had opportunities of observing a flock of poultry,
eight hens and a cock, which every day wander about,
exactly as they might do in a farm-yard. Ono evening,
passing through the street, he saw a single ben suddenly
vanish, as it were, into the bosom of the earth, and on com-
ing up to the spot, he found it was the last of the flock
which had at that moment dropped through an aperture in
a grating which covered a small area in front of the house.
Here, a common hen-ladder descending in the area ex-
plained how this little herd of poultry was kept ; namely, in
a cellar under the carriagc- way, whence, of course, the
cock is heard sounding his De Profiendis at all the proper
morning hours.—Chambers's Journal.

The eoloneley of the 18th Hussars has become
vacant by the death of Lieutenant-General Byam,
but neither as regards that regim nt or the Buffs, which,
as we mentioned last week, is also vacant, has any step
been taken to select a new colonel. With the exception of
Sir A. Clarke Kennedy, no line cavalry colonel has died
sines March, 1861, and the vacancy caused by his death was
given to Lieut.. Gen. J. Bloomfield Gough, whose claims
were indisputable on the score of long and distinguished
service in the field. Of the existing cavalry generals, none
of the seniors have seen active service in the field. At the
head of the list is Sir Charles O'Donnell, who has sewed
abroad ; but the next batch—Lieutenant• Generals Lord
Itosslyn, Hall, and Hankey—we believe have been en
gaged only on home service. Lord do Itos may be sup-
posed to have been rewarded for his military service by the
Deputy Lieutenancy of the Tower, which he has held for
some time, and until we go some way down among the
major-generals we do not light upon any striking claims on
the ground of good service. In the absence of any among
the seniors, it may be fairly conjectured that Sir Charles
0 Donnell, who has often ushibited a most soldierly
anxiety to serve on the field, is likely to have the 18th
Hussars.—Artny and .Navy Ciazate.