Victorian genius holds the turbulent Thames in its elegant embrace
PAUL JOHNSON
Last week I did something I had not done since childhood — walked across Tower Bridge. In the 1930s the experience was more spectacular. This wonderful building is a drawbridge, and the giant bascules were designed by the engineer Sir John WolfeBarry to be lifted to let ships through, which often happened up to the second world war. They were raised by throbbing hydraulic engines buried deep under the towers and the whole operation lasted over an hour. So pedestrians climbed to the tops of the towers and walked across footbridges, which gave you a splendid view of what was then called the Pool of London, teeming with boats. Now you just walk across the bridge, but that in itself, especially at night, is an aesthetic thrill of sinewy power, for the floodlights on the Tower, the brilliant light-systems up and down the river, and the consciousness of huge quantities of dark but glittering water rushing underneath make the senses tingle and apocalyptic thoughts mount in the brain.
Of all the great city rivers, the Thames is queen. The Hudson and the East River may deliver a bigger volume of water either side of Manhattan Island, but separately they are no Niagara and you wonder why Brooklyn Bridge was built so high and wide. The Thames looks particularly savage at present, swollen as it is with the longest recorded rains in our history, but it has never been a civilised stream. Before its 19th-century embankment it was much wider, with long flats of stinking mud in summer drought, and cataractal force in winter flooding. When the river was high, only the most skilful boatman could get his craft through the arch-piles of London Bridge, then built over with shops and houses. Indeed, when state prisoners were due to be conveyed east from Westminster Hall, where they were convicted for treason, or attainted in Parliament, to the horrors of the Tower and, as a rule, execution next day, it was sometimes impossible to navigate London Bridge. So the prisoners stayed up-river until the tide fell, and there was always an outside chance, even under the implacable Henry VIII, that a reprieve might be issued. Old Mother Thames saved several lives with her rages, though she also drowned thousands.
The Tiber unites Rome and the Seine flows through the exact middle of Paris, making the Ile de Paris its core and the city one place. The Thames is a different kind of artery, more like a vast moat or a miniature Channel, which cuts London off from Surrey and makes Southwark and the South Bank quite separate places, not entitled to London privileges or subject to London's writ. And that is just as well, for otherwise Shakespeare could not have written his plays: the Globe and other theatres were built in Southwark precisely because it was not controlled by the puritanical City fathers. Another result was that anywhere south of the Thames was never part of the London road network, and it still has no proper system of roads to this day — a good reason for not living there. Have you ever seen a cruising taxi south of the river?
The Thames is so wide and turbulent that we now have no bridge across it which is earlier than the 19th century. Paris still has the Pont Henri Quatre, which links the Ile to both banks and is a splendid piece of early 17th-century masonry; I have painted it often with delight. Rome had eight in its glory and the amazing thing is that six still exist, though four survive only in parts, being incorporated in modern work like the Pons Milvius or a mere ruined arch like the Ponte Sisto. However, the Pons Fabricius, from 62 BC, is still in service, though now known as the Ponte Quattro Capi. The five arches of the Pons Aelius (AD 134) form one of the most important Tiber crossings of the city, and this magnificent structure, called the Ponte San'Angelo in honour of the papal Castello San'Angelo on the far side and the superb white angels Bernini added to its balustrades, carries an immense volume of heavy traffic.
There have never been engineers like the Romans, of the block-and-tackle type who put their trust in weight and sheer strength. By the end of the 2nd century BC they knew everything about how to establish secure foundations in a big, fast-flowing river so they could impose immensely heavy masonry above them. They invented what we call the cofferdam, a temporary enclosure within which complicated and strong foundations could be constructed. They invented concrete, too, which they made by grinding a volcanic rock found in the Bay of Naples and mixing it with water, sand and lime. The Roman Empire, and its communication system in particular, was set in concrete — that is why it lasted so long. Vitruvius, writing just before the birth of Christ, describes exactly
how you made a cofferdam. His book, De Architectura, was eagerly read by Piranesi to discover the secrets of the massive structures he loved to draw. He was particularly fascinated by the Ponte de San'Angelo, and did a magisterial drawing of four of its arches, on their huge spreading piers, seen from ground level on the Trastevere side. This makes an impressive picture and I am going to use the same viewpoint on the next occasion I draw the bridge (1 must have done it a dozen times at least, but usually from the parapet level of the next bridge up-river). Piranesi also did a drawing reconstructing the underwater foundations, showing that the piers rest on blocks of masonry three times their height. Indeed, they constitute half the vertical cross-section of the entire bridge, and themselves rest on wooden piles driven into the river bottom. The foundation is pyramidal and is 230 ft across at its base.
Tower Bridge also had exceptionally deep foundations, not only to carry the enormous towers, which are framed in steel beneath their stone, but all the water-powered machinery. This is now a museumpiece — indeed, the entire bridge, while functioning, is also a museum — for the power to lift the bascules has been provided by electricity since the mid-1970s. A lot of people sneered at this bridge when it was built, 1886-1894, as being Gothic and outof-date. The man responsible for its appearance was Sir Horace Jones, the City Architect, who specialised in vast markets, but who felt that the bridge should match the mediaeval outline of the Tower itself. The sneering continued long after, and in the late 1940s, at a time when it was seriously proposed to pull down the Albert Memorial, there was also a scheme to wrench off the stonework of Tower Bridge and substitute modernistic glass.
There was a third plot by the vandals to root out and replace the enchanting Albert Bridge, an early 1870s construction in wrought iron by R.M. Ordis, which in recent years, repainted and floodlit, has emerged as one of the most beautiful sights in London. Thank God for those gifted Victorians, say I! The Albert and Tower bridges, at either end of London, hold the river in an elegant embrace and are just as salient to its collective image as the Eiffel Tower to Paris or the Dome of St Peter's to Rome. And you can walk across them too and watch the tumultuous river flow beneath your feet.
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