Autobiography of Sir John Rennie, F.R.S., Past President of the Institute of Civil Engineers. Sir John Rennie
&c., particularly attracted our attention.
On the next morning we started for the scene of the celebrated battle of Waterloo, which had occurred about two months previously. In this place, like every Englishman, I took the greatest possible interest, and pictured to myself the whole of that terrific and stirring scene as being enacted before me. Notwithstanding the lapse of time since which that battle had taken place considerable traces of it were still visible, particularly in the blood-stained walls and ruined, desolate, and half-consumed buildings of the keys of the position, Hougumont and La Haye Sainte, and the remnants of shakos, arms, and military clothing which strewed the field on all sides, and the fresh-made graves, where many thousand gallant fellows lay entombed. The whole field and neighbouring villages were crowded with guides to explain the different particulars of that memorable struggle, and to sell the numerous articles which they had raked up from the field of battle; we bought some of these as mementos, and wandered for hours over every part of this field of desolation, until we fancied that we had mastered every detail of the conflict, and were almost fit to take the command of an army ourselves. We then returned to Brussels, highly gratified and instructed by the excursion.
We left Brussels much pleased with that pretty little industrious capital, and proceeded to Malines, where the fine old cathedral and town rewarded us well during our short visit. From thence we journeyed on to Antwerp, where we stopped at the Grand Labourer, a celebrated old-fashioned hotel. This famous old city, the great emporium of the Belgian trade, interested me much, with its magnificent cathedral and other churches, its fine old Hôtel de Ville, and spacious quays and docks; the Scheldt is here a fine river. There was a good museum of Dutch and Flemish pictures, but the chef-d’œuvres of Rubens and Vandyke had not yet returned from Paris. I was much struck with the extent and strength of the fortifications; also with the costume of the natives, particularly that of the women, which still resembled a good deal that of their former masters, the Spaniards. At the time of our visit everything was in a depressed state. Its trade had not yet recovered from the effects of the great war, and its then silent streets contrasted greatly with their former activity. The Roman Catholic religious ceremonies were conducted with great magnificence, and struck us simple Protestants, who had never witnessed anything of the kind before, with considerable astonishment.
We left Antwerp for Ghent, and took our departure for Bruges in one of the trackschuyts or barges, by means of which the great bulk of the goods and passenger traffic of the kingdom was carried on. These canals are magnificent specimens of the kind, and, being upon a much greater scale than our own, particularly struck me with admiration. The canal was bounded on each side with spacious banks, and was of great width, with a towing path and carriage way for general traffic. These banks were bounded by rows of trees, which serve for shade; at the same time their clippings and timber yield a considerable amount of profit.
We reached Bruges about noon, and had just time to examine the fine cathedral and townhall, as well as the interesting town, its quaint old buildings, quays, mercantile warehouses, all in the architecture of the Middle Ages, during which Bruges attained its greatest prosperity. We left this interesting town in the afternoon by another trackschuyt for Ostend, about 12 miles distant, by a canal of the same dimensions as the one above described. Most of these canals being connected with each other, Brussels, Ghent, Malines, Louvain, and the other large towns, possessed a complete network of water communication with the ports of Antwerp and Ostend, and trade is carried on with the greatest facility.
We reached Ostend in the evening, and learned that a packet was about to sail for Margate, of which we determined to avail ourselves. We had, however, sufficient time to examine this indifferent port, the second in the kingdom, which, in addition to a badly-contrived entrance by two guide piers, has two small docks. It is a mere tidal harbour, with an awkward bar at the entrance, and numerous shoals on the outside. The town possesses nothing remarkable; it was then garrisoned by English troops, and there was constant communication with England.
From this period I devoted my time almost exclusively to the Waterloo and Southwark bridges, but particularly to the latter, which was almost entirely under my direction, subject to the orders of my father. Besides the above works, I was a good deal employed in the drawing office in making drawings and estimates and calculations for a variety of new works upon which my father was engaged. I also occasionally visited the rolling and other machinery of the Royal Mint on Tower Hill, which my father at that time was constructing for the Government, and during the evenings I was employed in learning mathematics under Dr. Bradley and Dr. Firminger, and the Italian, French, and German languages, so that my time from morning to evening was fully employed. I must not omit to say that at this time I attended the lectures of the celebrated Sir Humphry Davy, the Professor of Chemistry at the Royal Institution, who at that day astonished the world by his wonderful discoveries.
The first, second, and third arches of the Waterloo Bridge being completed, Mr. Rennie determined to slacken the centres of the first arch, which was on the Surrey shore, where the bridge commenced. This was when the arches were entirely relieved from the centres, and the total subsiding of this arch was 2½ inches, which is nearly half an inch less than had been allowed; the centres were then removed from the first arch to the fourth arch, only three centres being employed. Each centre consisted of eight ribs, upon the truss principle, resting upon a compound system of wedges, supported upon struts placed upon the offsets of the piers and abutments; all the ribs were well connected together by transverse and diagonal ties, as well as the planking upon which the arch-stones rested. The trestles or bearers of the centre ribs, together with the wedges, having been first fixed in their places upon the offsets of the pier and abutment where the centre was to be fixed, four ribs of the centre were transferred, and fixed upon them in the following manner.
The ribs of the centre having been constructed upon a platform upon the shore near the bridge, a large barge or floating stage, capable of carrying four complete ribs, which weighed 40 tons each, was built to receive them. This floating stage was extremely strong, and transversely across the centre of it there were four strong stages at the same distance from each other as the ribs of the centre were intended to be when fixed in their position, to support the arches whilst building. These stages were supported by double transverse beams, resting upon powerful screws 15 inches diameter, in boxes resting upon the bottom of the vessel. Above each of these stages, yet securely attached to them, was a framework, to which the ribs of the centres were lashed whilst being transported to their places. When the centre ribs were finished and all was ready, the floating stage, at high water, was brought alongside the platform, upon which the ribs of the centre had been constructed, and were lying ready to be transferred to their places. Each rib was then raised by means of powerful sheer-poles, to which were double-purchase crabs, treble blocks, with all the necessary ropes, chains, and other tackle, by which means each rib of the centre was readily raised from the platform where it was built and transferred to its proper stage in the floating barge, and there secured in an upright position, when the ribs had been fixed in their places. The barge was then floated into the opening where the arch was to be constructed, which was generally done about half an hour before high water, so as to allow ample time to adjust and fix the ribs over the corresponding pair of wedges and trestles upon which it was ultimately to rest, which was done as the tide fell, and adjusted to the greatest nicety by the screws before mentioned; when the rib had been fixed in its place, the barge returned to bring another, which was served in the same manner as the first, and thus the fixing of one centre occupied only six days. This system answered most effectually, and was subsequently adopted by Mr. Robert Stephenson for fixing the great tubes for the Menai and Conway bridges.
The Waterloo Bridge, as well known, consists of nine equal semi-elliptical arches, 120 feet span each, with a rise of 34 feet 6 inches, the keystones at the crown being 4 feet 6 inches deep and 10 feet at the spring, and 18 inches thick at the soffit; inverted arches on each pier between the main arches 4 feet 6 inches deep. The piers were 20 feet wide, each having projecting buttresses, supported by two three-quarter Doric columnar pilasters, over each pier, the whole being surmounted by a Doric block cornice and balustrade parapet, level from end to end, the same as the roadway. The roadway above the piers was supported by six brick walls, 2 ft. 3 in. thick, covered with corbel stones. The shores being low on both sides of the river, the approaches are constructed so as to form an inclined plane rising 1 in 30 on the Surrey