century the Lower Town fenced itself off with these walls from the Upper Town because of the permanent contradictions between the noblemen of Toompea and the citizens of Down Town. At the end of the street there used to be a wooden gate, in place of this a gate-tower was built at the end of the 14th century. At present Pikk Jalg Street is only for pedestrians. There still exists another gate to Toompea Short Leg. It was laid in the 15th century. The massive wooden gate with ironworks dates from the 17th century. Long Leg was used by vehicles. Until the 20th century there was no way down form the western side of Toompea except for a foot-path. The stairs were built in 1903 and are called Patkul Stairs. The name Patkul itself comes from Johann Patkul. He had worked against the Swede, so Patkul was remembered by Russians. In the Middle Ages that part of Toompea where the castle stands was called the Small Fortress
5in (6cm) diameter wrought-iron rods and five vertical iron posts cast integrally with the wrought-iron chord members. In the last 20 years an older bridge has been discovered in South Wales (UK) at Merthyr Tydfil, a major early 19th century iron- producing centre. Pont-y-Cafnau (Bridge of Troughs) is a unique cast-iron combined aqueduct tramroad bridge below the confluence of the Taff and Taff Fechan, built in January-June 1793 by Watkin George, Chief Engineer of the Cyfarthfa Ironworks, to carry an edge railway and water channel. An iron trough-like girder is carried in an A-frame truss of cast iron spanning 47ft (14.2m), held together by mortise-and-tenon and dovetail joints. The next extant iron railway bridge seems to be another recently discovered at Aberdare (1811), followed by Gaunless. The oldest still in service is Hall's Station Bridge, a Howe truss designed in 1846 by Richard Osborne, a London-born
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