Brangwyn’swater-colour of the Pont HenriIVat Châtellerault, over the Vienne, represents a bridge built and fortified by an architect of the Renaissance, Charles Androuet du Cerceau. Here is a fact to be remembered, for Androuet du Cerceau was perhaps the latest European bridge-builder who tried to fit his work into a nation’s policy of defence. From his time onward to our own no high road conducted over a river has been made in any respect a military way, safeguarded from the dangers of war, at least as much as possible.
If Androuet du Cerceau had been asked to foretell the development of bridge-building, his answer could not have been less militant than the Pont HenriIV; he would have said that bridges, like battleships and fortified places, would continue to oppose the science of military attack, because their safety would be affected by all improvements in the methods and materials employed by armies. His view of life and art, as we see it in his work, has been the view of all thoughtful craftsmen. He believed that the genius of invention, age after age, set up her home in the ablest minds, and passed through an ordered growth, till at last she attained her culmination. As long as improvements could be made in the action of aggressive war, counter improvementscould be made in the reaction of defence, for the art of inventing each new weapon would suggest a means by which its utility in war might be thwarted, and perhaps nullified.
But I do not think that Androuet du Cerceau realised to the full what competent bridges ought to have been to his generation. He was too mediæval in his attitude to strife, and this defect was perhaps inevitable. You see, the Pont HenriIVwas erected between the years 1564 and 1609; and during these forty-five years the spirit of the times was dead against an efficient strategy both in defence and in attack. Soldiers of every rank were passing through a transition, unaided by much enthusiasm. Indeed, new methods were hated rather than liked, because they seemed to be less chivalric, or what the French called less “heroic,” than were the ancient methods, though many of these had grown obsolescent. Alexandre Dumas wrote several delightful books on this period in the evolution of fighting, when gunpowder was a war-god that no brave man was at all eager to worship before an altar of unwieldy firearms. Soldiers liked a battle to be a duel at very close quarters, so they were not amused when they fired through a fog of suffocating smoke, and coughed and sneezed in a chorus, while tears dripped from their eyes. Here and there, of course, while Androuet du Cerceau was engaged upon his bastille bridge, “villainous saltpetre” had some ardent followers. Turn to the military writers of Queen Elizabeth’s reign, for instance, and read the long dispute that went on between the old school and the new. Some experts had a firm belief in the old archery statutes, while others put their trust in ponderous firearms that went off after much coaxing and never carried straight for a hundred yards.
Title or descriptionPONT HENRIIVOVER THE VIENNE AT CHÂTELLERAULT IN FRANCE BUILT BY CHARLES ANDROUET DU CERCEAU, 1504-1609. TILL 1624 THE TWO GREAT TOWERS WERE UNITED BY A PAVILION FORMING A GATEWAY. ONE OF THE LATEST OF THE BASTILLE BRIDGES
PONT HENRIIVOVER THE VIENNE AT CHÂTELLERAULT IN FRANCE BUILT BY CHARLES ANDROUET DU CERCEAU, 1504-1609. TILL 1624 THE TWO GREAT TOWERS WERE UNITED BY A PAVILION FORMING A GATEWAY. ONE OF THE LATEST OF THE BASTILLE BRIDGES
In those days there were two handguns, both rather old, and their improvement baffled the ingenuity of gunsmiths. One was the petronel or arquebuse, which had come into vogue in 1480; the other was the musket, which in 1521, or thereabouts, was brought into use by the Emperor CharlesV, who believed in it because he had never tried to hold the “kicking demon” through a battle. For a long time petronels were discharged by a lighted match, but at the beginning of the sixteenth century a wheel-lock was invented, to be superseded at last—about the year 1692—by the flint-lock. Progress was exceedingly halt-footed; but one day a pious clergyman, theRev.Mr. Forsythe, happened to be startled by a very profane idea; it seemed to him that gunpowder in a musket might be ignited by a percussion cap. Good Forsythe! Being very practical as well as pious (these two qualities go together like body and soul, as a rule), he patented his mother-idea,A.D.1807; and in less than thirty years the principle of the percussion cap was accepted by the War Office, though public opinion in England cooed over Peace, believing that henceforth mankind would be satisfied with continual wars between Capital and Labour. There is no need to sketch the equally slow improvements in the manufacture of cannon. Enough to say that amongWellington’s siege artillery in Spain there were Spanish guns dating from the Armada period.
Briefly, then, from Androuet du Cerceau’s time onward to the year 1857, when the old musketBrown Besswas put aside for ever, the dilatory progress of attack in war gave bridge-builders every opportunity of keeping pace with it and of making their defence as thorough as possible. Yet nothing was done. Not even a single effort was made to evolve the old war-bridge into a modernised protection; and it is very far from easy to explain this quite sudden departure from a very old routine of defensive forethought. Several reasons have been given, of course, but they have no backbone and no brain. It was argued, for example, that bridges were as advantageous to an attack as to a defence, so the whole strategy of war would protect them quite enough. Even in our own time this very queer argument has been advocated, as if to prove that minds as well as eyes often suffer from astigmatism. What successful army is not hindered and harassed by guarding many hundreds of defenceless bridges? And what modern army in retreat has ever failed to leave behind it an extra rearguard of broken bridges?
Let me give but one example. Sir John Moore could never have made his terrible march from Sahagun to Coruña, but for his good fortune in the matter of rivers and bridges. When Napoleon himself got within striking reach, near Benavente, on the torrent Esla, Moore’s rearguard blew up three spans of the old bridge of CastroGonzalo; and when the cavalry of the Imperial Guard found a deep crossing and forded the river into a wide poplared plain, Paget and the 10th Hussars galloped through their broken ranks, destroying half of them, and capturing their general Lefebvre Desnouettes. Much later, when the narrow and snowbound Pass of Piedrafita was littered with dead British troops, all killed by hunger and cold and exhaustion, Moore was befriended by the great Roman bridge of Constantino, and by the noble viaduct of Corcul between Nogales and Becerrea. Paget was left behind with the rearguard, and in brilliant actions at the bridges he checked the pursuit, while Moore marched on toward Lugo. If a French spy had blown up the bridge of Constantino and the viaduct, after hearing of Moore’s approach, the British would have been brought to a standstill, and from a desperate position there would have been little chance of escape. So the viaduct and the Roman bridge stood between victory and defeat; they saved the British and baffled the French. In fact, Moore reached Lugo without much further harrying.
Not only is there a bridge of Constantino in all campaigns, but we may be sure that as no country will ever wish to be invaded the airmen scouts of the future will try to destroy all bridges beyond their own frontiers, so as to cripple the enemy’s prearranged movements. Defeat in the near future may be nothing more than a paralysis of communications, caused by bridge-wrecking airships and aeroplanes. Try to imagine what we should suffer, if welost in a single night eight or ten of the bridges that help to unite London to Edinburgh and Glasgow. To lose the Forth Bridge alone would be a bad defeat; and yet, as I have said, there are people still who argue that bridges need no protection because their utility in war is invaluable to bothsides.[136]
This hollow argument was very active during the ferment of the Renaissance, which became to architecture what a political party spirit is to an army. In fact, it was the Renaissance that produced the disintegrating party strife of rival “styles,” and soon the followers of classic forms and ceremonies were more powerful than their opponents, who believed in the native genius of Gothic art. The aim of our classic men was to renew under our Northern sky an alien inspiration born and bred in the ardent climates of Greece and of Rome. In other words, they wished to repeat, by plodding and self-conscious effort, what Rome had done in architecture with the patient and slow methods of her colonisation. In this way they appealed to everybody who tried to seem erudite, and their endeavours entered that world of educated fashion where a false quantity was a greater sin than intemperance. Just as the chatty, delightful Montaigne wanted to hide his genius among profusegleanings from ancient writers, so most architects believed that they could do no good in life unless they tried to be Greek or Roman. Progress was no longer an organic growth, it was a copied fashion, an inconvenient mode. Not even a church could be built without help from pagan temples. Not an equestrian statue could be modelled unless a Christian of sorts, either king or warrior, put on the costume of a Cæsar, and then straddled ill at ease across the back of a reasonable horse, which alone merited the long life of bronze. Amid this ferment of comic priggishness and pedantry young men served their apprenticeship, and became artists and craftsmen. Inevitably, bridge-builders were affected, and as prigs most of them did their work as public servants.
One remarkable thing was the fussy interest that their projects excited. During the eighteenth century, for instance, a ridiculous ado was made about bridge-building. Voluntary guidance came from mathematicians, and chatter and hesitation implied that at last, for the first time in the history of the world, a reputable bridge would be erected. As for the results of all this flutter and fuss, they were usually out of joint with the public interests that bridges ought to have served efficiently. No attention was paid to military defence, and some famous men blundered like amateurs. Perronet was regarded as the most expert bridge-builder of his time; his knowledge was prodigious, and yet he made astounding mistakes, which would have shamed such mediæval masters as Bénézet and Isembert. As anexample I will mention his Pont de Neuilly-sur-Seine, which was finished in 1772.[137]The delicate operation of striking the centres, by freeing the arches from their supports, was begun only eighteen days after the keystones were put in their places, when the mortar was not yet hard enough to resist new pressure. In one great arch the crown sank twenty-three inches—truly a historic mishap, and for several reasons. The upper part of this arch in Perronet’s plan was an arc of a circle 320ft.in diameter; after the mishap it became an arc of a circle whose diameter would be 518ft., hence a stone arch of this size—518ft.on the chord line—might be constructed! No wonder that writers have been astounded by the Pont de Neuilly-sur-Seine, for it passed safely through a most dangerous experience. Perronet was saved, not by his good design, nor by his mathematical calculations, but by a rare stroke of good luck. Indeed, there are a good many technical faults in his work at Neuilly. The piers are only fourteen feet broad, too small to be in scale with the wide arches, and all lateral pressure travels along the bridge to the abutments. If one arch were cut the others would be endangered. In later years Perronet became wise, and told the French Government that two or three arches in every long bridge should have abutment piers, as a safeguard against mishaps inwar.[138]
Several famous engineers had to learn by experience, like Perronet, that a self-conscious desire to be “scientific” had dangers of its own in bridge-building. Smeaton’s bridge over the Tyne at Hexham was a tragic failure; Labelye produced a very perishable bridge on the Thames at Westminster; and learned engineering did not save the Tay Bridge from catastrophe, though science welcomed it with a din of confident approval.
The Tay Bridge was a railway track to connect the town of Dundee and the North British Railway System in Fife; it crossed the Firth of Tay about a mile and a half to the West of Dundee. Its length exceeded two miles, and journalists with rapture bragged about it as the longest iron bridge in the world. Even the responsible engineers, Thomas Bouch and A. D. Stewart, did not keep their heads while their work was being done, for they published in the “Encyclopædia Britannica” a long article on their unfinished bridge—a fine example of modern vanity. Soon afterwards, on February 4th, 1877, the building work was badly injured by a gale, yet in a few months—on September 25th, in fact—the over-confident engineers had the bridgetested from end to end, and on the 31st of May, 1878, it was opened to train service.
Thomas Bouch became Sir Thomas. No one suspected that a “scientific bridge” might be a trap for railway carriages. The structure was superlatively modern: huge, ugly, vulgar, meretricious, mechanical, and charmed also with a small cost of production, which included twenty human lives and £350,000. At this price, you will understand, the longest metal bridge in the world seemed very cheap and fascinating. Newspapers were overjoyed, of course, and declared that the Tay Bridge was admirably fitted for the rushing enterprise of a commercial time. Yet every part of it was ill with the cancer of cheapness, and in 1879 the disaster came, on a Sunday evening, three days after Christmas. At about seven o’clock a terrific gale struck the eighty-four spans of the bridge, making a gap of about three thousand feet: and a few minutes later a North British mail-train drew near. Into the gap carriage after carriage dived: about eighty passengers perished, down below in the raging waters. It was a lofty bridge, in some places 92ft.above high tide, so the falling carriages turned more than one somersault before they plunged into the Firth of Tay.
The Board of Trade held an enquiry and issued a report, affirming “that the bridge had been badly designed, badly constructed, and badly maintained.” True: but the verdict was without pity. Some excuse should have been made for the engineers’ modernity. The Tay Bridge was no worsethan the popular spirit that liked screaming newspapers, and fevered excitements, and wild adventures in the quicksands of jerried workmanship. The Board of Trade published its report on the 3rd of July, 1880; and a few months later, on October 30th, Sir Thomas Bouch died of a broken heart. Perhaps the most humbling trial in his adversity was the foolish article written by his second in command, Mr. A. D. Stewart, who wanted to be quite contemporary with the flying minutes. The “Encyclopædia Britannica” deleted the article from its next edition, and printed ... some tame remarks on the disaster....
No public calamity has much effect on the modern mind. Tay Bridges and Titanics are like strong acts in a tragic play, whose influence we forget very soon. It is a thousand pities, for the next war may teach us, by frequent disasters, that machine-worship has been a mad gambler everywhere. Bridges suffered much from the priggishness of the Renaissance, but they have suffered infinitely more from the obsessions that ruined Sir Thomas Bouch. Poor Bouch! Not only did he wish to astonish the world by constructing an unparalleled bridge, wonderfully long, curved at both ends, and with a varying gradient. He desired also to prove to his employers that he could be a pattern of unusual economy. Worse still, he was so wrapped up in his calculations that he looked upon Nature with little respect. In other words, he tried to achieve “a great feat of engineering”—not often a fortunate enterprise.
From the founding of his piers he ought to have learntthat his work would be endangered partly by the repercussion of railway traffic, and partly by the varied way in which the piers would feel the scour of tidal waters during bad weather. Fourteen piers on the southern side were built on rock, then for six piers the bed was a layer of hard material resting on silt, and from the twenty-second pier northward there was sand, with occasional beds of gravel mixed with boulders. Here was a site to inspire as much awed patience and care as the Bridge Friars gave untiringly to the Pont Saint-Esprit over the Rhône. Yet in Mr. Stewart’s description there is but one emotion—a quiet self-confidence, as if the forces of Nature were as easy to manage as well-trained poodle dogs.