New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1855-06-25
New0ork DAILY @ibmate
AN ENGINEER'S MONUMENT.
FrrrI TAs BeHalo Demoerorx

the territories of two different Governments, and sus-
tanning the uninterrupted Railroad traffic of the Prov
incss Of Canada with the United states 245 feet above
food of water which man has never been able TO
ferry, stands the monument OF Engineer John A.
Roebing. The Niagara Railway Suspension Bridge
Is the erandes and noet distinguishing achievement
of Art in this world IL is the proudest il is the most
beautiful and will prove TO be the most enduring
umeIt anywhere set up on this Continent.
Reeard this wonderful product of Engineering skll.
Its span s2l feet inches. Yet an engine, tender,
and passenger car loaded with men, and weighing
atop a. tuns depress the long floor in the center
buf 81 inches. The Bridge loaded with a loaded
Freight Train covering ifs whole length and weighing
3o6 tuns. Is detected in the middle only 10 inches
This extrepe depression is percepnble only TO pra,-
ticed eyes Tie sighier changes of level require 10
be ascertained with instruments. Delicate as lace
work and seemingly light and airy, 1t hangs there
high between Heaven ard the boiling Hood below,
solid than the earthbed of the adjacent railways
The conclusions of fast moving trains sensby felt
miles off through solid rocky coil In cities locomo-
tivts shake entire blocks OF stone dwellings, Inc
waters OF tie C6yuga Lake tremble under the wheels
of the Express Trans mile away from the bridge.
But Freight Train traversing John A. Roebings
Monument at the speed of nv. miles al hour, conmu-
nicates no jar 10 passengers walking on the carriage
way below. The land cables of the Bridge do not
trembe under 1.-THE slight conclusions of the SUPER
structure DO not 90 The SUBMITS OF tine towers.
This last fact in the stiffness of the work Is OF much
importance. Ii furnishes guaranty otthe durability OF
the masonry. Fast anchored with stone and grouted
great cables are immovable by any mechanical force
incidental TO the of the Bridge or the na:ura In
fuences il will be sui ect to. The ultimate strength
of these cables 1900 tuns The total weight OF the
material of the Bridge and of the traffic to which it
will ordinarily be subjected, is 2,262 tuns TO sustain
which The engineer has provided, in his beautiful and
scientific structure, strength OF 1000 tuns. lie
demonstrates too, that while the strength OF the cables
il Leary sx times great their ordinary tension,
that strength will never be impaired by vibration.
This was the question raised by The Democracy
wear &C o which excited such general and In some In
stances such angry discussion. Roebing treated our
doubts with cool reason and the stores OF extern
five engineering experience, which gave us to believe
that Arr had at last attained 10 method OF suspending
iron brdl Is for railroad use that SHOULD entirely oovi
ale the objections TO them flt by most of the IRON
masters Of the United States. lie has since that
demonstrated it in tie wonderful structure which will
make hun famous.
There are in the Bridge GA suspenders,' each
capable of sustaining 80 tuns-and all OF sustaining
s72O tuns Tie wight they have ordinarily to sup
port is only GOO tuns. But the Engineer has skill
fully distributed the weight of the burdens by the
means of "girders" aud :" trusses." These spread
the "a tuns weight Of a locomotive and tender over
length of 200 feet How ample is this provision made
for defective iron sudden strains
The anchor chains are composed OF links, each
feet long save the last which is 10 feet. The lowest
link is made of bars of iron, inch by Il. IL is Sc
cured TO cast-iron anchorlat 81 inches thick, aud
feet inches square. The other links are equally
strong The iron used was all made from Pennsylva-
Lila charcoal Ulster County, n. Y, and Salisbury pig
and can be depended upon for strength OF "a, 600
hounds 10 the square inch. The central portions OF
The ancLor-plaes through which the links pass is II
inches Tick. The excavations IN the solid rock were
not vertical They inclined from the river. The rock
upon which the work may rely on tae New York SIDE
OF the chasm is 100 feet long, 40 feet VIDE ana 70 lee.
deep 1t weighs leo pounds to the cubic foot, ana
presents resistance of l40o0 uns exclusive OF the
weight of the superintendent masonry and embank-
ment. -
TIE Towers are each Is feet square at the base GO
feet high above the arch and eight feet square at the
ton The hustone of which they are butt VIII sup
mort pressure Of 500 tuns each square foot with
out crushing While the greatest weight that can fall
upon the tower will rarely exceed 600 tuns pressure
Of 81. Coo tuus would be required to crush the top
course There are 1000 tuns weight III each OF tie
towers on the Newfork side.
The cables are 10 number, 10 inches in diameter,
and composed each of J, GAO small NO. wires Si1ty
wires form one square inch of solid section, making
the solid section of the entire cable CO. 40 square inches
wrapping nd included. These immense masses OF
wie are put together that each individual wire per
forms its duty, and in strain all work together. On
this Mr. Roe6ling, who is moderate as well Us a
modest man. feels justified in speaking with the wo.d
"perfeci" Each of the large cables Is composed of
smaller ones called strands" Each strand has $40
wires One is placed in the CENTER the rest are placed
around that. These strands were manufactured
nearly in the position the cables now oc-
cupy. The preparatory labors, such as oillng,
Strengthening, splicing and reeling, were done
in
strands were made at the same time, o1e for
each of the two cables under process OF construction
On the completion of one set temporary wire bands
were laid on about nine inches apart for the purpose
of the wires closely united and securing their relative
nostop They were then lowered TO occupy their per-
mapept position in the cable. On completion OF the
seven I air Of strands, two platform carriages were
mounted upon the cables for laying on CONTINUOUS
wrapping by means of Reblings patent wrapping ma
chiper. During this process the whole mass of wire
was again saturated with oil and paint, which together
with the wrapping will protectthem etfectuay
all OK, daton Five hundred tuns of this wire Is En-
pljsh American manufacturers dc not put In propo-
sails. That used was remarkably uniform and most
carefully made.
The law deduced from large use of wire rope in
Penntylvania il, that it's durability depends on It's
usage Ii will last much longer under heavy strains
moving slowly than it will under light strains moving
ronidIy THIS law was borne constantly in mind by
the engineer of the Niagara Railway Bridge The ca
bles and suspenders are, so TO speak, at rest Ihey
are so well protected too from ruat that they may
be reg arded as eternnly durable.
Among the interesting characierstcs OF this spen-
did architecture are ts elasticity The depression I'M
der load commences at tie ond, OF course, and goes
rapidly scross. After the passage OF tram the equi-
brum i perfectly restored, The elasticity oi the ca
bles is fully equal 10 this task and will never be lost
The equilibrium Of the Bridge is less affected 10 cold
weather than in warm. If change OF temperature OF
1909 should take place. the difference III the level OF
the floor would be feet inches.
its stayng that not the slightest motion is comnuni-
Gated 10 by tire severest gales Of wind that blow up
through the narrow gorge which it spans: 49,
Next 10 violent winds, suspensioI-brldge builders
dread the trottng of cattle across their structures
Mr. Roebling Gays that heavy train running 20 miles
an hour across his Bridge would do less injury 70 II
tIan would 20 steers passing on trot IL 10 the
,evorest test 10 that of troops marching In hme
to which bridges iron wooden, suspension or tubu,
lGr can be subjected Strict regulations are enforced
for the passage of hogs, horses and oxen, IN snan
bodies and always on walk.