The Memphis appeal. [volume] (Memphis, Tenn.) 1886-1890, 1886-09-05
some GREAT BRIDGES.
MARVELLOUS TRIUMPHs OF ENGI.
NEERING SKILL.
Brooklyn's Mammoth Suspension
Compared With Others in Eu-
rope aud America.

Brooklyn Eagle: We, in the cities
OF New York and Brooklyn, have q
great interest in bridges, for have we
not the East river bridge ioiBing the
two citiesH Brooklynites are, perhaps,
more Justly proud OF it and interested
than the inhabitants OF the sister city,
for in common parlance is it not gen.
orally spoken of as "the Brooklyn
bridge?" There are many large
bridges in the world, but the beauii
full structure over the East river is
without rival. What is 1t gives it
this preeminence? tits certainly not
its length. In this respect 1t is far ex-
celled by the Victoria bridge at Mon
treal, and also by the unfortunate Tay
bridge at Dundee, in Scotland, which
is now being rebuilt. The Vic
toria bridge Is 10,SS0 feet long,
or within $50 feet of two miles;
the Tay bridge lie, or rather will
be, 1852 feet, or fifty feet over
two miles; while the Brooklyn bridge.
from entrance to exit, is only $3.50
feet. Neither is the hight OF the road
way at its center above high water
mark its distinguishing feature. Out
side OF It's beauty ss an engineering
structure, the chief and indeed strik-
ing feature of the bridge is the great
length OF the central span, 1895 feet 8
inches. This never had been exceeded
before, either in suspension bridges
like the Brooklyn bridge or in fixed or
stable bridges like the Britannia bridge
over the Menai Straits in England.
The longest approaching span in sus-
pension bridges is the Niagara bridge,
which has single span Of 800 feet,
and in fixed or stable bridges the
Britannia, which hiss two spans, the
longest 465 feet each. 1t is, how
ever, hardly fair to draw
paiallel between suspension and
fixed or stable bridges-their character
and formation are go entirely different.
Fixed or stable bridges can be made
to sustain greater lateral pressure
than suspension. The chief objection,
indeed, to suspension bridges is want
of stability, with consequent liability
of oscillation and with weakness in Ie-
sisting wind pre-: sure. With the fixed
or stable bridge, on the contrary, We
have the greatest amount OF stability
with the least amount of oscillation.
But this plan Of pre-eminence in
bridges is likely soon to be taken from
us, and that by the bridge over the
Forth in Scotland. The Scottish "folk"
would seem to cay in this instance
that they were going ito lick creation
and have the largest bridge on record.
In the Forth bridge this will be at
tanned. II is to have two spans OF ITO
feet each, which is not far short Of be-
ing four times as great as the spans OF
the Britannia bridge, and 115 feet
more than that OF the Brooklyn bridge.
The hight, too, Of the roadway at the
center OF the bridge at high water will
be $50 feet, while that OF our bridge is
only 1875 feet. The total length OF the
Forth bridge will be 1901 feet. 1t is q
fixed or stable bridge, end will be es
solid and steady IS the bridge over the
Menai Straits, the High bridge in Ed
inburgh, the Waterloo bridge in Lon
don or the High bridge of New York.
We are all familiar with the Brook
Ign bridge and the details Of its con-
struction. The realization seems
greater than the reality; for who.
twenty or thirty years ago, would
have thought of such a structure across
the East river2 But such is the law
OF proeressand advancement in science
and engineering, not to speak OF the
help lent by necessity, the mother OF
invention"
OF the Forth bridge little in a
general way is yet known or has been
written. AS a good example OF the
progress of engineering and bridge
architecture, not to speak of the enor-
nous capital and great interests in
volved in the undertaking, 1t well de-
serves few words. Anyone looking
at the map Of Scotland will see that
on the East coast there are two rivers,
the Forth and Tay, which prevent a
through and direct line OF COM
municstion from the English bor-
der to the North without going
considerably to the westward.
This prevents the railroad lines on the
east from competing iavorably with
their rivals on the west, who have
continuous lines Of communication
throughout the whole island. To do
away with the ferries OF the Forth and
Tay, and to bridge these rivers over,
was therefore reasonable. The East
ern railroads could hold through
traffic communication with the North;
but this only by round about road,
and by having running pow ers over
the lines OF their rival neighbors.
They wanted to get rid OF this and be
their own masters. Hence they de-
cided to bridge the two rivers as far to
the east as possible, for II the bridges
were not erected to the east the benefit
of direct road would be sacrificed or
greatly curtailed.
With this obi set in view the build.
ing of the great but unfortunate Tay
bridge Yves frat sanctioned in 1870,
This bridge was opened on May 81,
1873, and IL was then thought that half
of the difficulty was overcome. But
disappointment was in store. just ex-
actly one year an seven months later,
in the great storm on the night of the
28th Of December, 1879, the highest
portion of it was swept away while q
train going from south to north was
dashing across. Girders, piers and
train were suddenly epgulfed in the
boiling sea. Not a single life was saved.
Seventy.fve souls, it is said, met in
slant death. The new bridge now in
process Of erection is girder bridge
OF forty-one spans, with the longest
and central span 245 feet wide. II is
to be hoped that this bridge will have
long life and be more fortunate than
Its predecessors.
To complete the direct oommunica-
ton, powers were obtained FIRST in
1873 to proceed with the erection Of q
bridge across the Forth. Some prog
ress had been made with the prelimi-
nary works when the disastrous Tay
bridge accident occurred. The effect
on the Forth bridge construction may
be imagined. At first 1t approached q
panic, and abandonment was seriously
- 80 far fndn0d