Tower Bridge

“ In the Tower Bridge there are two of such huge “flaps” or leaves, each about 100 feet long, one rising and falling from each pier and meeting in the centre. Large bascule bridges are usually constructed in this manner, and there is an excellent specimen over the Ouse, for the passage of the North-Eastern railway; one man at each half of the bridge can raise it in less than two minutes. Another fine bascule may be seen at Copenhagen.
The bascules are raised and lowered by chains, which, in the case of the Tower Bridge, are worked by superb hydraulic power from the massive pier towers. ”

“ The bridge was hinged at the third storey of the tower, and fastened with ropes to its extreme top; but, once the ropes were cut, the bridge would fall, and light upon whatever came within its swing, and be held there by the spikes with which it was studded beneath.
I saw, and inwardly felt myself conquered. The cleverness of Phorenice had been too strong for my defence. No war-engine of which we had command could overset the tower. The whole of its massive timbers were hung with the wet new-stripped skins of beasts, so that even the throwing-fire could not destroy it. ”

“ It is risky at the present time to say that a bridge has certain old characters: change is so rapid that no pontist can keep in touch with its vagaries; but I believe the old bridge at Bâle is alive, and that it keeps in use the Gothic tower, a triangular defence of red sandstone erected on the middle pier, and devoted now to a thermometer, a barometer, and a table of weights and measures. ”

“ Nevertheless, even (p. 46) viewed from close by, it is very telling, and dwarfs immeasurably any other building near it; see, for instance, how the little Tower of London, that ancient and most historic fortress, loses its size from its close juxtaposition to those supporting towers! The "bascules," or drawbridges, are worked by hydraulic power, and it is a curious and interesting sight to see them raised to allow tall vessels to pass. Below the Tower Bridge, the broad river seems to extend in a sea of masts, the city to become a world of wharves and docks. ”

“ River during the last hundred years, that have shifted the Port of London from the vicinity of London Bridge and the Upper Pool, and placed it several miles downstream, that have rendered the bascules of that magnificent structure, the Tower Bridge, comparatively useless things, which now require to be raised only a very few times in the course of a day. ”

“ Too soon after this calamity, at a most inauspicious time for commencing, or executing, expensive public works, in 1097, King William Rufus imposed a heavy tax upon his subjects for the re-building of London Bridge,—though that might very well be defended,—the erecting of the palace of West-Minster Hall, and the construction of a wall round the Tower. The ‘Saxon Chronicle’ speaks of these ill-advised undertakings in the blended tones of sorrow and of anger. ”

“ In the centre of the bridge is a little, old, surly tower which forms an arch over the road after the manner of a village Temple Bar. The tower has been converted, with marked unsuccess, into a dwelling house with a bow window and balcony on its less dejected front and with gaudy advertisements on its other sides. Since no one appears to have the courage to live in this impossible dwelling it is empty. As a tower to defend the ford it is a monument of incompetence and as a house on a bridge of the type of those on the Ponte Vecchio at Florence it is a sorry thing. ”

“ It was five months after his torture before the sense of touch was restored to his hands. Arden followed, and both got away safely to the steps beside London Bridge, where they were met by the friends who had cheered them in their captivity, and were taken to a place of safety.
The Cradle Tower is seen best from the Wharf. This broad riverside embankment constructed by Henry III. makes a delightful promenade. It is reached from the level of the Tower Bridge approach by descending a flight of steps on the eastern side of the roadway and passing under the bridge by the archway at the guard-room. ”

“ Old London Bridge escaped the fire, and indeed remained until 1834, although the houses clustering over it had been removed at the close of the reign of George II., and the only prominent building in the panorama which Shakespeare or Raleigh would now be able to recognise, could they look across the rivers Styx and Thames, would be the great White Tower with its surrounding lesser towers and battlements. All the rest, like “the baseless fabric of a vision,” has passed away for ever. ”

“ As soon as the B and C frames were set up on one side of the tower, another pair of B and C frames was set up on the other side of the same tower. A cantilever bridge must always be built out on both sides of the tower at the same time, otherwise it will be overbalanced on one side and topple over. After the B and C frames were in place we took two D frames, with oppositely cut ends, and rested their tie sticks on the top of the tower, just under the ends of the C frames. ”

“ From this there ran a ferry, which was in use long after the bridge was built, for the narrowness of the street and the continual blocks made a passage by the bridge a [211] process of time. Gower, the poet, was a benefactor to the priory, and is buried in the church.
DUTCH BARGES NEAR THE TOWER
As the Tower Bridge can swing open, ships of all sizes can get up as far as London Bridge, when the tide allows them sufficient water-way, and a busy scene, watched by a never-failing crowd of idlers, is always to be witnessed in the reach below. ”

“ I have often wondered how and where people crossed the Vltava previous to 1167 when Judith, Queen of Vladislav II, built a bridge very near the site of the present Charles Bridge. Judith's bridge was eventually carried away by floods, but the Mala Strana bridgehead tower remains; you see it with its squat tower and broad chisel-shaped steeple, rising up beside the more graceful and ornate tower of the present bridge, which was new in the early years of the fourteenth century. The stout tower built by Judith is a very interesting study of architecture ”

“ As it is, emphasis seems to have been studiously avoided. The offsets are merely long batterings of the wall, which do nothing to separate the piers into related parts with definite transitions, and so to refine the crudity of the masses. To see the difference between a mechanical and a monumental conception of a great structure, compare these towers with the front of Amiens, or of Strasburg, or of Notre Dame of Paris. Of course the designer of a modern bridge must not attempt to reproduce in his work “those misty masses of {79}multitudinous pinnacle and diademed tower.” ”

“ In the roof of the building are three sets of windows; and an open stage, or floor, appears a short distance below it. At the North end, also, of this most interesting prospect, against the first sterling, is a high square building, like a tower, having a low wooden gallery in front of it; and a single water-wheel turning beneath it; which are, most probably, intended for the Waterworks and Tower at London Bridge. ”

“ A prominent feature in its outline is the graceful, tapering spire of Trinity Church, while higher still rises the clock-tower of the Tribune building. Other towers, spires and domes, break the monotony of roofs and walls. Approaching the mouth of the East River, the most striking objects are the massive towers of the Suspension Bridge, one on either shore, while between them is the bridge, swung upon what seem at a distance like the merest cobwebs.
At the extreme southern end of Manhattan Island is the Battery, already referred to, a park of several acres, protected by a granite sea wall. ”

“ Wheeling sharp round to the left, for the Walls here take a direction southward, we cross a second Railway Bridge, and then turn to regale ourselves with an immediate foreground of startling interest. We are looking upon a Tower erected in 1322, by one Helpstone, a mason, who contracted to build it for 100l., a high price in those days, when workmen for their day’s wage, “received but every man his penny.” ”

“ At each abutment he put up a silly tower pierced with arrow-slits and armed with battlements, advertising a farce of warlike make-believe which scores of foolish engineers would copy and adapt, while leaving their bridges entirely unfortified.
A bridge here and there is supposed to be all right. [Pg 350] Take, for instance, the Forth Bridge, with his 51,000 tons of steel, and his amazing cost, about £3,000,000; he is looked upon as a “safe” bridge, and safe he is if we forget what bombs and shells can do in a few seconds. ”

“ Within the triangle a central tower rises to a still greater height, and commands the whole. The entrance passage is broad and vaulted, and provided with gates and a portcullis. Within, it opens upon the level of the outer ward; without, it terminates abruptly upon the scarp of the ditch, there about 50 feet deep. From this gateway a bridge communicates with the opposite bank. A single lofty pier rises from the centre of the ditch, and from it an arch springs to the outer abutment, carrying a regular roadway and parapets. ”

“ The Tower, wharf, and river before them, occupy the whole foreground of the painting; and in the back appears the East side of London Bridge, with numerous houses standing upon it, the Chapel of St. Thomas reaching down to the sterlings, and the violent fall of the river through the different arches; whilst, beyond it, rise the spires of several Churches, especially the very high one of old St. Paul’s, and the other buildings of London erected along the banks of the Thames. ”

“ Beyond the bridge are an outer and inner gateway, with their defences. The large gateway forms one angle of the square enclosure of the fortress, and at the other landward angle is built a large round tower. There are vestiges of similar towers occupying the angles of the precipice overhanging the sea. These towers were connected by a curtain, on which artillery seems to have been mounted. Within this circuit are the ruins of an establishment of feudal grandeur on the large scale. ”

“ In the exterior wall are some cylindrical holes about 2 feet deep and 2 inches diameter. Their use is not clear. There were gurgoyles below the embrasures of the parapet. It is well to rebuild the bridge to the Water Tower, but to vault the ground-floor would be a mistake. The lower floor covering was always timber, and of a curious pattern. It should be replaced.
The Bloody Tower is the gatehouse of the inner ward. It stands in the south front, west of the centre, opposite to the earlier Traitor’s Gate, and it abuts against the also earlier Wakefield Tower. ”

“ Tremor and vibration caused by a passing load, tend to pull the towers into the river. The section for weight only might be very small. From the practice of the best builders, a mean section of one fifth of the height seems to give the best results; thus, if a tower is sixty feet high, the mean thickness should be twelve feet; or the top being 8 × 8 feet, the bottom should be 16 × 16 feet.
If the bridge is so little braced laterally as to swing, a dangerous momentum will be generated which would very much increase the strain, both upon the masonry and upon the cables. ”

“ The towers, however, were designed to sustain a heavy train and locomotive and to withstand the terrific wind of the monsoon. The pressure of such a wind on a 320-foot tower is tremendous. The bridge was completed within the specified time and bore without flinching all the severe tests to which it was put. Heavy trains—much heavier than would ordinarily be run over the viaduct—steamed slowly across the great steel trestle while the railroad engineers examined with utmost care every section that would be likely to show weakness. ”

“ Among many other examples may be quoted the beautiful fourteenth-century bridge at Warkworth, Northumberland,58 which also deserves notice for another characteristic much more rarely to be met with, that is, the preservation of the tower built at one end for its defence. Most of the bridges of any importance were protected in this way, which, as the country became quieter, was found useless; the consideration that they were ornamental rarely sufficed to prevent their being pulled down. ”

“ There is, however, another point to be noticed in this bridge of Turner's. Not only does it slope away unequally at its sides, but it slopes in a gradual though very subtle curve. And if you substitute a straight line for this curve (drawing one with a rule from the base of the tower on each side to the ends of the bridge, in Fig. 34., and effacing the curve) , you will instantly see that the design has suffered grievously. ”

“ Brooklyn Bridge.—The suspension bridge between New York and Brooklyn is the largest bridge of its kind in existence, and, until the construction of the “Forth” bridge, was the longest clear span ever built. Every one is so familiar with this stupendous structure that only a few statements will be made, which may give a better idea of the unprecedented problem which confronted the great engineer, John A. Roebling. When looking at the exceedingly graceful design of the towers,342 one is apt to forget that a large part of the structure of each tower is hidden from view. ”

“ In 1437, at noon of January, 14th, the great stone gate, with the tower upon it next to Southwark, fell down, and two of the farthest arches of the same bridge, yet no men perished in body, which was a great work of God. ”

“ Two door jambs then reduce the opening by a foot, and between them, in the vault, is a hole 9 inches diameter, apparently intended for a chain which passed out over the rib of the further door, and worked, still within the tower, a light bridge, the recess for which is seen outside the door. The chamber here widens by 3 feet, to allow space for those defending the east wall. When this bridge was down, a way was opened to a door in the west wall, outside which is a platform, whence a second bridge dropped southwards across the ditch. ”