Frostburg mining journal. [volume] (Frostburg, Md.) 1871-1913, 1881-08-13

ICMe or ths Great Bridges.

TCMe or the Great Bridges.
Robert Stephenson, great engineer as
hewas, reported that suspension bridges
would never do for steam. John A.
Rosbling answered with the Niagara
suspension bridge, the cheapest structure
and one Of the best ever built for such
necessity.
In Menai strait, which divides an
island from the northwestern corner Of
Wales, the tide rises to the height of
thirty feet sometimes, and generally
twelve feet. The British government
erected bridge on the great high road
from England to Irelan d over this strai
In 1896. It is suspension bridge built
By Telford on chains, and cost $500, 900
(gold) at that time. 1t Is 100 feet above
water. Twenty years afterwArd George
Stephenson began to build tho tubular
bridge three miles above, spanning the
samo strait It took five years, and
trains crossed 1t in 1850. It has four
spans, the two In the middle being 400
fest vide each, and the whole bridge il
about 1,840 feet long. It is 1913 feet
above high-water mark, and cost
$4,000
Tho Niagara suspension bridge. built
BY Roebling in 1852, cost only $780,
600, is 800 feet long, $50 feet above the
river, and its towers are about eighty
four feet high. The Niagara foot
bridge, built in 1869, cost 8175. 900. and
was said to be. when opened, the longest
suspension bridge in the world. or
1898 feet between towers.
The Cincinnati suspension bridge, by
Roebling, stands next to the East river
bridge, and is 1,057 feet between tow
srs and 2,252 between the ends; the
bride is 103 feet above low water, the
towers are 230 feet high, and each ID
taller and larger than the Bunker Hill
monument, and the structure cost
$1,000, 900; it was built by a company,
and charges three cents toll per man.
This bridge has been in most useful
operation since about 1867; it was
eleven years between its commence
ment and opening.
Roebling, the protector Of the Brook
lyn bridge, was the greatest bridge
builder in the world. He started the
making Of wire cordage in America, and
built suspension bridges to carry the
acqueducts Of canals across rivers, and
engineered the Pennsylvania railroad
across the mountains. The Brooklyn
bridge, between towers, is 1895 feet
long. Behind the towers there are $40
feet each side, back to the anchorages.
The whole length of the bridge and ap.
proaches is 5000 feet. 1t is one of the
widest bridges in the world, eighty-five
feet, with O promenade thirteen feet
wide, two railroad tracks and four car
Yisge and two horse-car tracks. 1t is
1876 feet in the center above the water.
The rock on which the towers rest is
about ninety feet below the surface OF
the water on the New York side, and
half that depth on the Brooklyn side
the most stupendous thing about the
structure. Each tower is 1874 feet long
by ffty-six wide, and at the top these
dimensions are reduced to 100 feet by
forty, or the size of very large house.
Each tower is 268 feet above high water.
II is 1886 feet from the beginning Of
the causeway on Chatham street out to
the anchorage on the New York shore.
The architect Of the bridge received his
death wound almost at its inception
Baldviw's Monthly