that Gyalpo used ropes from twisted willows or yak skins. He may have also used tightly bound cloth. Chain bridges The first iron chain suspension bridge in the Western world was the Jacob's Creek Bridge (1801) in Westmoreland County, Pennsylvania, designed by inventor James Finley. Finley's bridge was the first to incorporate all of the necessary components of a modern suspension bridge, including a suspended deck which hung by trusses. Finley patented his design in 1808, and published it in the Philadelphia journal, The Port Folio, in 1810. Early British chain bridges included the Dryburgh Abbey Bridge (1817) and 137 m Union Bridge (1820), with spans rapidly increasing to 176 m with the Menai Bridge (1826), "the first important modern suspension bridge". The first chain bridge on the German speaking territories was the Chain Bridge in Nuremberg. The Sagar Iron Suspension Bridge with a 200 feet span (also termed Beose Bridge) was constructed near Sagar, India during 1828-1830 by Duncan Presgrave, Mint and Assay Master. The Clifton Suspension Bridge (designed in 1831, completed in 1864 with a 214 m central span), is similar to the Sagar bridge. It is one of the longest of the parabolic arc chain type. The current Marlow suspension bridge was designed by William Tierney Clark and was built between 1829 and 1832, replacing a wooden bridge further downstream which collapsed in 1828. It is the only suspension bridge across the non-tidal Thames. The Széchenyi Chain Bridge, (designed in 1840, opened in 1849), spanning the River Danube in Budapest, was also designed by William Clark and it is a larger-scale version of Marlow Bridge. An interesting variation is Thornewill and Warham's Ferry Bridge in Burton-on-Trent, Staffordshire (1889), where the chains are not attached to abutments as is usual, but instead are attached to the main girders, which are thus in compression. Here, the chains are made from flat wrought iron plates, eight inches (203 mm) wide by an inch and a half (38 mm) thick, rivetted together. Wire-cable The first wire-cable suspension bridge was the Spider Bridge at Falls of Schuylkill (1816), a modest and temporary footbridge built following the collapse of James Finley's nearby Chain Bridge at Falls of Schuylkill (1808). The footbridge's span was 124 m, although its deck was only 0.45 m wide. Development of wire-cable suspension bridges dates to the temporary simple suspension bridge at Annonay built by Marc Seguin and his