Encyclopædia americana. A popular dictionary of arts, sciences, literature, history, politics and biography, a new ed.; including a copious collection of original articles in American biography; on the basis of the 7th ed. of the German Conversations-lexicon. Ed. by Francis Lieber, assisted by E. Wigglesworth ...

BRIDGE. 267
ties of banditti. The object of this soci- fectly understood. The first bridge of
ety was, to put a stop to these outrages, cast-iron ever erected is that over the
by forming fraternities for the purpose of Severn, about two miles below Colebrookbuilding bridges and establishing ferries dale, in Shropshire. It is an arch comrnand caravansaries on their banks. The posed of five ribs, forming the segment
bridge of Avignon was commenced in of a circle. Its chord is 100 feet long,
1176, and completed in 1178. It was and its height 45 feet. It was erected in
composed of 18 arches. The length of 1777. The second cast-iron bridge was
the chord of the largest was 110 feet 9 designed by Thomas Paine, the fakmous
inches, and its height 45 feet 10 inches. political writer, and was intended to have
France can boast of many fine bridges, been taken to America; but, the speculabuilt during the last two centuries.-ln tor failing in his payments, the materials
Great Britain, the art of building bridges were afterwards used in constructing tile
appears to have been diligently studied beautiful bridge over the river Wear at
from early times. The most ancient Bishop's Wearmouth, in the county of
bridge in England is the Gothic triangu- Durham. The chord of the arch is 240
laL bridge at Croyland in Lincolnshire, feet long; the height, 30 feet. The Southsaid to have been built in 860. The as- wark or Trafalgar bridge over the Thames
cent is so steep that none but foot-passen- at London is, at present, the finest iron
gels can go over it. The longest bridge bridge in the world. It consists of three
in England is that over the Trent at Bur- arches. The chord of the middle arch is
ton in Staffordshire, built in the 12th 240 feet long, and its height 24 feet.
century, of squared free-stone. It con- There are several other fine bridges of this
sists of 34 arches, and is 1545 feet long. kind in England. Mr. Telford proposed
London bridge was commenced in 1176, an iron arch of much larger dimensions
and was incumbered with houses for than any now existing, to take the place
many years. These were removed be- of London bridge. The length of the
tween 1756 and 1758. The other bridges chord was to be 600 feet, and its height
over the Thames are highly ornamental, 65. The plan has not been executed.
as well as necessary, to the metropolis. Timber bridges. Timber is the most
Blackfriars bridge is both novel and hand- ready, and perhaps the most ancient nmasome in design, and its elliptical arches terial used for the construction of bridges.
are well suited to its situation, but its ma- The earliest timber bridge on record is
terial is bad and perishing. This bridge that thrown by Julius Caesar over the
was designed and erected by Robert Rhine, and described in his ComlnmentaMilne, an able Scotch architect. It was ries. Germany is the school for wooden
commenced in 1760, and completed in bridges, as England is for those of iron.
1771. It is 995 feet long, and 43 feet 6 The most celebrated wooden bridge was
inches broad between the parapets. The that over the Rhine at Schaffhausen.
centre arch is 100 feet in span, and 41 This was 364 feet in length, and 18 feet
feet 6 inches in height. Waterloo bridge broad. The plan of the architect was,
is one of the greatest architectural works that the bridge should consist of a single
of our times. It is the only bridge over arch. The magistrates of the place, howthe Thames which has a flat surface in ever, required that he should make it of
its whole course. Its length is 1250 feet. two, and use the middle pier of a stone
It consists of 9 elliptical arches, each of bridge, which had previously stood there.
120 feet span, and 32 feet in height. He did so, but contrived to leave it doubtWestminster bridge is one of the hand- ful whether the bridge was at all supportsomest as well as most scientifically con- ed by the middle pier. It was destroyed
structed bridges in Europe, and forms an by the French, in April, 1799. The
era in English bridge architecture, from same architect and his brother have also
the success of the method employed in erected several other fine arched wooden
laying the foundations in deep water and bridges. Several others have been erecta rapid current. It was commenced in ed, in Germany, by Wiebeking, perhaps
1740, and completed in 1750. It is 1220 the most ingenious carpenter of our
feet long, and 44 feet between the para- times.-In the United States, the Trenton
pets, has 13 large and 2 small arches, all bridge over the Delaware, erected by
semicircular. The middle arch is 76 feet Burr in 1804, is the segment of a circle
in span. 345 feet in diameter. Its chord measures
MJIetal bridges are the invention of 200 feet; its height, or versed sine, is 32
British artists. The true elements of feet, and the height of the timber flaming
their construction are as yet but imper- of the arch, at its rertex, is no more than