The Washington herald., 1907-10-22

World ingenuity and capital shall have
bridge the English Channel with twenty
miles OF steel and put an end 10 the nal
de mer and great loss Of life, the king
ship of steel and the rights of his grand
Viziers, the engineers, will be recognized
without hesitation.
In the Old World bridges follow the
opening Of highways In the United States
they anticipate highways because the rail-
ways are more often the pioneers. The
Indians used no bridges but chance
fallen log. usually preferring to ford a
stream at its mouth, where the slit had
made the water shallow. Pioneers made
temporary affairs. and the railroad bridge
was usually the first permanent one. Cast
Iron bridges came into use when railways
became assured things Italian engineers
had thought of iron as d bridge material
as early as the sixteenth century. and
England built one of iron in III The
first in America was at Frankfort n. Y,
In 1870 though Washington had corre-
spondence on the subject as early as 1926.
Now all Americas bridges, placed end to
end. would more than span the width of
the continent.
Bessemer's experiments made steel
cheaper than wrought iron. and a new era
dawned in bridge-making. a distinctive
type has arisen. in which the architect
viii have TO conspire with the engineer
before a perfect Bit of art is attained.
For, while stone bridge, with its usual
complement Of moss and vines, is always
picturesque and a wooden bridge gathers
gray hue from the weather an iron
or steel structure has to be kept aggres-
sively new in coat Of paint, 10 protect
it from the ravages of wind and rain a
German architect claims that America has
sacrificed beauty 10 utility in bridge-mak-
ing, but the most modern structures are
disprOving this. American bridge-builders
lead the world. When the great GOkteik
viaduct over the Chungzoune River. in
Burma. was projected il was American
skill and American steel that perfected it.
under the spur of English capital
The first use Of steel IN large arches in
America was when Capt Eads bridged the
Mississippi At St Louis. The manufacture
of steel was not then so nearly perfected
as 1t is now, and the task was enormous
This was the first application of the pneu-
matte process on a large scale, and il was
here that physicians began making the
first study of the effect of air pressure,
on the bodies of workmen IN the cais-
sons. marveling over the great pressure,
which they found to be fifteen pounds 10
the square inch, and increasing with
depth. Caissons had by this time super
seeded cofferdams- in pier building, and
marked many centuries of change since
of the Euphrates 10 build her bridge and
raise Babylon 10 the grandeur of Ninevah.
The St. Louis bridge was begun IN 1861 and
finished in seven years, at a cost Of $lO.-
eOO,OOO.
Suspension bridges are very old. Ants
and monkeys. in living chains, gave
the idea TO South American and African
natives, who developed it in vines and
boughs Roeblings famous bridge at
Niagara was the first Of the kind in this
country. Then came one at Pittsburg.
and Cincinnati astounded the world with
one having a span OF 1,035 feet. Then
Roebling's Brooklyn Bridge, the eighth
wonder Of the world" it was called,
marked the climax Of suspension-bridge
work in the United States. 1t swung
clear OF the waterway by l35 feet, with a
central span Of 1856 feet, the largest in
the world. though the projected North
River Bridge will have a span Of nearly
1900 feet.
The new East River Bridge, Of New
York. cost $9,00OO0O. The cables Of steel
are of six times the strength usually re-
quired, and one Of the thickness of a
mans thumb viii support car contain
ing 1900 men. The main cables are as
thick as a barrel. and cost 81 39S. 900 each.
thousands Of fine wires being woven into
cylinders, each Of which can support
100000 pounds The foundations are
laid 100 feet below water level, and the
two-story platform. twice as wide as a
city street. carries six trolley and ele-
waited tracks, two wide carriage tracks
two bicycle paths and two prOmenades.
In 1920 Ithiel Towne patented a wooden
lattice bridge; in 1880 Long patented a
truss bridge. named for him, and in 1S4C
Howe evolved an improved wooden bridge
for railways When the Ohio was
bridged, in 1853, with S20-foot iron span
the beginning OF long spans for railroads
was marked. Since 1870 most railway
bridges have reached a span Of over 50l
feet The Conemaughy Viaduct, on the
Pennsylvania road, and the CarrolltOr
Viaduct on the Baltimore and Washing
ton. famous IN their day, are now sur
passed by more wonderful structures. I'm.
proved facilities have made quick worH
possible. A whole steel span was re-
placed not long ago on the Pennsylvania
road over the Schuylkill at Philadelphis
q IL
ond's delay in trains. Buche replaced
the cables on Niagara Bridge and put il
steel towers, instead Of masonry. with
out interrupting the traffic
The first metallic cantilever in the world
Is said TO have been built by c. Shalel
Smith. over the Kentucky, in 1877, though
this is disputed by Poland, which claim.
to have had one over the Vistula, al
Posen, before this. The longest single
steel cantilever span in the United State,
is over the Mississippi at Memphis The
builder of the great Niagara bridge gave
to the world the greatest steel arch il has
ever known. a clear span of $40 feet 20
feet above the pool. The cantiIever idea
Is very old, and has been developed in z
crude fashion for centuries, ever since
Japan built the Shoguns bridge, at Nikko
before the sixth century.
Distance. height, and depth seem Il
have no terToTs for American bridge
builders, and they are said 10 have over
come more natural difficulties than tn,
engineers of any other nation. The South
ern Pacific crosses the Pecos, in Southern
Texas, on a bridge 800 feet above tn,
river, on a trestle work 2,lS0 feet long. i
was built by sixty-seven men in eighty
seven days and is one Of The four highes
in the world The GOkteik viaduet, II