Suspension bridges go back to the beginnings of human
culture, but stiffened suspension bridges were not introduced until the
early 19th century, by an American, James Finley. Thomas
Telford, one of the great civil engineers of England, showed the potential
of the suspension bridge when he successfully crossed the Menai Straits,
which lie between Wales and Anglesea, on the route of the London-Dublin
mail. The bridge was begun in 1819 and opened for traffic in 1826. The
roadbed is suspended from sixteen chains, in sets of four; each chain is
made up of flat wrought iron eyebar links that are eight feet long. The
links were made under Telfords supervision in the Shropshire iron works
of William Hazeldine. Each link was dipped in hot linseed oil after
forging, to prevent rusting.
With a central span of 580 feet, the Menai bridge was the
longest clear span in the world when it was completed.