New-York tribune., 1867-08-06

momentum The office of stays is twofod. They not
only assist the cables poweruy m the suppOrt u and
most efficient ueans for senng'the floor. Every stay
constitutes the hypothennse OF feeangliar m gPs
floor Mr. ROebling says that cables alone cannot ne
deDnrded unon for the maintenance Of perfect equil
brium between adjoining spans under the action OF
variable Winds that to perform this most Important duy
the Office OF stays il most efficient and direct The Oho
the Niagara and the Aegany bridges entirely free
from easily percepibe oscillatl0ns By the movement
lateral motion NAV be noticed in the cables and TO some
extent in the floor between the center OF he man span
and the towers but not i'm the center itself This motion
so ioht that few persons notice IT, IL Is owing 10 the
want of outside cables for the support OF te sueWaks
Mr. Roeblng thinks that If special Iab"aS tlSK was
laid down on the center Of the floor OF the ONO bridge
trains could run ut speed OF 20 miles per nor Mtno
producing any more vibrations thah are uSuy nUueed
nm the ructed iron truss bridges or ordinary
spans Ever since the 18th of March lsoo, from 80 10 40
trains have passed daily over the hlaSaLiI bl WIN a
the exception o the renewal Of the timber giders unu
some Othcp wooden parts which showed signs Oi ueV'
part Of the suspended system mas eyer , DSe % ~ Us
The work is considered just as strong this day as ~ was
the time when the first tram Oh cars psseu ovII'
kinds Of changes are known Wnoh may thy aoT ans @
strength of iron and other metals one OF tes chdsce
results from oxidation, and Is wen uueIStoou' I
change appears TO he caused by oeGuai Ecu y; ne
metal Mr. ROebing does not hold to the idea tlat Tue
efficiency of suspension bridge depends upon lic ni I
tenanee OF its equilibrium. HIS argument IS Uni h
Am systems which are subject 10 variable loads aud To the
kncadug action of passing weights comprQmIao nus niu.
larger and more important Is to be secured one
great and important advantage OF the suspension system
This appears like paradox, because just the OppOsc 10
Ss Mr. pi Eoabn f. the EngineernC Of this great
East River enterprise the public Of course, must nave
deep interest knowing what his views are NOT Oy III
regard to the projected work bur on Le kugeet oI S
pension bridges general lie says that hair century
of litigation before the Supreme Court leaves hc
OF navigation Just it in the year hOhnS
has been definitely settled, except that bridge company
with loose charter, may escape inlnct0ns ana 0Glgr
annOyances, by getting an act passe0 pr0c.lhhb 'l'
bridge public highway. lie says that just as soon rs
"s,,speus1H" IS uttered picture Is cOlJlleu up III
imagination full Of violent agitation Dut WLIle
and others shake their heads at suspension they 90
not reflect that every system Is suspended ana slI tno
aud not due to the suspension ITSELF lie says uaI
spans OF feet may be safely attempted on the tuDudr
plan, but it only be done at enormous waste ol mate
rals Each tube OF the Britannia Bridge weighs oO IlHs
gross and is AGO feet long The man span OF the ONO
lie claims that the latter will safely support 5000
ts, while onehaf this weight Will overtaX the strength
produce a proper architectural effect when designing
towers for a supension brgde of large dimen-
built but looks out Of place when the general impress
sion should be that Of simplicity, massiyenGss and
a conspicuous landmark across great river, which sep,
arates two large cities aboundng in highly ornametal
FORMER SUSPENSION BRIDGES.
Perhaps the most ancient suspension bridge In exist
ence is in the province Of Inman, China According 10
tradition II was built A. d. 65. Ito formed of chains sup
The entire length Of the span Is SO feet The first ones
which the ancient Peruvians erected were over me
from the bark Of trees In some instances regular Ioau
way was constructed but in most OF them transit was
effected by OF basket supported by the rope ana
drawn alternately from one side 10 the 0her Europe
has ALSO had numbers OF these bridges. They were EN-
pOyed France, at the seige OF PomtieIs, anu
across the river Clara. and elsewhere. Men Men
on re, mace 6s dpst dpa r y EESg bridge was
erected In England tho Tweed at Berwick, 1919
II Was constructed OF y chain cables placed either
side of the roadway length OF span, $40 leet yersed
sine 80 feet The Brighton Chain Bridge was built IN 1913,
and destroyed by gale Of wind IN the month OF NOyen
f4ur IT. I
Bridge finished I'm lo9 and In October los the road
way was totally destroyed by hurricane Inc bridge
$50 feet; clear hight Of the roadway above the water
lO2 feet This work sustained serious injury by violent
gale. The gale produced great oscillation OF the
main chains as To dash them against each other re,
currercc of such uutoward event was provided
against by suitable bgacig and otherwise The Conway
and Chester was bult i'm s26 length OF span 327 feet
The Hammersmith Bridge over the Thames was erected
III i-.4 length of span, ~ feet. In 1884 suspension
bridgr which /, considered remarkable because while ii
repealed AID tests, erected at Frey yburg in
switzerland IL has proved safe bridge 10 the present
In the United States the first suspension bridges
built 10y MI Finley, between 1926 ana $50 iHey Were Oh
small Dimensions and constructed with chain cables.
cables were alsays used Tie wheeling Bridge the
Ohio but in I5ls by q. E.iet, and blown down in
May, loJ s apan loo feet lhe cause OF thls MS
fortune due entirely 10 lack Of proper bracng The
wind seemed 10 strike beneath the roadway OF tie bridge
and shook 10 though 10 we're piece OF carpet being
cleaned The present bridge there IS we'll braccd and
has wlthstood very many severer wud-stOuns than the
which caused the accident TO It's predecessor The
Brlicw Bridge 40 Niagara was built III ls4s length or
feet. 10 removed u 1884, and It's cables iu-
corpordted IN bridge constructed by Mr. Rot bling Tie
bridge 10 LeVistoWn. seven miles below Niagara rails,
was bu n 1885, length Of span, lOO feet Tie bridge az
Niagara Is the finest ~ It's knd Ia the world The
detection s o. feet 1850 wires are employed IN the
cables The elevation OF the railway track above the
is 2i5 feet II finished in 1858. The suspension
aCuueduct the Allegheny River at Pittsburgh, Is
work. The Cincinnati Suspension Bridge. being the
last Of any great length put up ana, having the l-
est aud hghc, Improvements Is subject oI study N
connection with the erection OF the East River Bridge
That bridge was commenced IN 1886. On December l.
1906 Il thrown open 10 iost passengers and owing
the necessities OF the public I'm consequence of the Ice
IN the Ohio River and the inability Of the ety to
u became necessary To the bridge iOr vehicles
than was originally designed, which was done on
the morning OF January /, 1861.