Green-Mountain freeman. [volume] (Montpelier, Vt.) 1844-1884, 1877-04-25

The engineers employed by the Niagara
suspension bridge company to examine
and report upon the stability of the sus-
pension bridge have completed their work,
and report, in effect, that the foundation,
cables, etc, are in good condition, and
the bridge entirely safe for the carriage of
regular trains. Out of the IA. $50 wires
constituting the four mammoth cables sup
porting The structure, less than dozen
were found seriously corroded, and these
were in the first anchorage examined. In
short, the removal of the masonry re-
vealcd the fact that the bridge is perfectly
safe the number of wires damaged (Which
will be Immediately spliced and rcplaced)
are so few compared with the whole rs to
be hardly worthy of mention. A reporter
Of the Buffalo Commercial AdrertiSer wit
messed some experiments, Thursday, and
says of them: mo unprejudiced person
could see what our party saw and not be
convinced that the bridge is Us substantial
and servicable now us it has been at any
time during the twenty-five years it has
b1"n in use. After removing the prepara-
tion of Spanish brown paint, oil and
cement, with which the wires had been
covered for preservation, they were found
to be III perfect condition, the iron in au
excellent state of preservation, and the
grain of the metal distinctly m trked and
cleal ly traceable. TO be sure, spots OF
rust were here and there to be seen on the
surface; but, with the exception of the
dozen wires already mentioned, no mate
rial damage has been done. That the met
al had undergone no apparent chang
since it was placed in position could read.
ilv he discovered by any casual observer
This, however, was not satisfactory to Col
Paine, and he has made series OF expert
ments which will be likely to attract much
attention in the scientific world. They
show conclusively that the long use of III
bridge, the jarring and straining to which
the wires have been amasl continually
subjected for nearly II quarter of cen
tury, have not in the lie st impaired tht
quality or tenacily # the iron"
This bridge was built by Mr. Roehing,
in lS53-54. 1t has four towers. each nne
W feet IN height, and constructed of eat
stone blocks eighteen inches thick. Tn
and the top eight feet square, the cap
stone being ten feet square. Each towe
is surmounled with an iron saddle witt
rollers, upon which rest the cables, tirml,
holding the saddle in position The roll
ers allow the cables TO move easily, 81
that in contraction and expansion there i
no additi nal strain upon them or the tow
ers. At all other points of bearing ar
cut stone caps securing everything from
the action of the elements. A massive
arch connects the towers some twenty fee
| from the base, above which is the RAILWAY
track, and below, the carriage way. Tn
anchor pit, cut in the solid rock, is twenty
four by twenty feet and twenty-four fee
deep, with drifts for anchor plates, weigh
ing 6000 pounds each, to which are nj
lached chains with links $50 pounds each
which reach up through the gains " Gu
in the rock, where they connect with mas
sive wrought-ron shafts, over the ends c
which is looped the wire that forms tn
cables. The wires, brought 10 II tension
of 1900 pounds, are looped upon the shaft
at The anchorage, which is filled with ma
sonry and concrete, rendering it almos
solid rock The wire for the cables wa
put through a process of boiling in oil
with II glutinous mixture, being kept il
the caldron thirty minutes, and then drie
in the sun. 1t passed through this pro
cess three times, the wire being thorough
lY annealed and rendered impervious t
water. 1t WAS then spliced Each cabl
was composed OF 5000 strands, which is S
splice1 rs 10 become one continuous wire
1850 milrs in length. Each strand wa
laid with a tension of 1900 pounds. A
each cable contains 1850 miles of wire. tn
four contain 5000 miles. The who'll
weight of wire is over 500 tons. giving
safe working capacity Of 10000 tons,
is estimated, however, that the cable
would easily bear strain of $4,000 tons
Connecting these cables with the brdg
are go suspenders, each of thirty tens ca
pacty, with fifty guys fastening the bridg
to the river banks, extending from til
center to the rocks in such manner rs t
prevent n lateral Or lifting movement b
the winds. A single train extendn
from one end of the bridge to the Other
with an engine and tender Weighing ffl
tons, would weigh 1926 tons, 30 that, (;
their mean hearing capacity of 10000 ton
it would take forty trains, one piled on to
of the other, to snap the cables.-Chicag
Tribune.
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