But a more memorable historical bridge is admirably described in another military episode of this favorite historian,—that which Alexander of Parma built across the Scheldt, whereby Antwerp was finally won for Philip of Spain. Its construction was a miracle of science and courage; and it became the scene of one of the most terrible tragedies and the most fantastic festivals which signalize the history of that age, and illustrate the extraordinary and momentous struggle for religious liberty in the Netherlands. Its piers extended five hundred feet into the stream,—connected with the shore by boats, defended by palisades, fortified parapets, and spiked rafts; cleft and partially destroyed by the volcanic fireship of Gianebelli, a Mantuan chemist and engineer, whereby a thousand of the best troops of the Spanish army were instantly killed, and their brave chief stunned,—when the hour of victory came to the besiegers, it was the scene of a floral procession and Arcadian banquet, and "the whole extent of its surface from the Flemish to the Brabant shore" was alive with "war-bronzed figures crowned with flowers." "This magnificent undertaking has been favorably compared with the celebrated Rhine bridge of Julius Cæsar. When it is remembered, however, that the Roman work was performed in summer, across a river only half as broad as the Scheldt, free from the disturbing action of the tides, and flowing through an unresisting country, while the whole character of the structure, intended only to serve for the single passage of an army, was far inferior to the massive solidity of Parma's bridge, it seems not unreasonable to assign the superiority to the general who had surmounted all the obstacles of a northern winter, vehement ebb and flow from the sea, and enterprising and desperate enemies at every point."[G]
Even the fragile bridges of our own country, during the Revolution, have an historical importance in the story of war: the "Great Bridge" across the Elizabeth River, nine miles from Norfolk in Virginia, the floating bridge at Ticonderoga, that which spanned Stony Brook in New Jersey, and many others, are identified with strife or stratagem: King's Bridge was a formidable barrier to the invasion of New York by land. Indeed, from Trenton to Lodi, military annals have few more fierce conflicts than those wherein the bridge of the battle-ground is disputed; to cross one is often a declaration of war, and Rubicons abound in history.
There is probably no single problem, wherein the laws of science and mechanical skill combine, which has so won the attention and challenged the powers of inventive minds as the construction of bridges. The various exigencies to be met, the possible triumphs to be achieved, the experiments as to form, material, security, and grace, have been prolific causes of inspiration and disappointment. In this branch of economy, the mechanic and the mathematician fairly meet; and it requires a rare union of ability in both vocations to arrive at original results in this sphere. To invent a bridge, through the application of a scientific principle by a novel method, is one of those projects which seem to fascinate philosophical minds; in few have theory and practice been more completely tested; and the history of bridges, scientifically written, would exhibit as remarkable conflicts of opinion, trials of inventive skill, decision of character, genius, folly, and fame, as any other chapter in the annals of progress. How to unite security with the least inconvenience, permanence with availability, strength with beauty,—how to adapt the structure to the location, climate, use, and risks,—are questions which often invoke all the science and skill of the architect, and which have increased in difficulty with the advance of other resources and requisitions of civilization. Whether a bridge is to cross a brook, a river, a strait, an inlet, an arm of the sea, a canal, or a valley, are so many diverse contingencies which modify the calculations and plans of the engineer. Here liability to sudden freshets, there to overwhelming tides, now to the enormous weight of railway-trains, and again to the corrosive influence of the elements, must be taken into consideration; the navigation of waters, the exigencies of war, the needs of a population, the respective uses of viaduct, aqueduct, and roadway, have often to be included in the problem. These considerations influence not only the method of construction, but the form adopted and the material, and have given birth to bridges of wood, brick, stone, iron, wire, and chain,—to bridges supported by piers, to floating, suspension, and tubular structures, many of which are among the remarkable trophies of modern science and the noblest fruits of the arts of peace. Railways have created an entirely new species of bridge, to enable a train to intersect a road, to cross canals in slanting directions, to turn amid jagged precipices, and to cross arms of the sea at a sufficient elevation not to interfere with the passage of ships,—objects not to be accomplished by suspension-bridges because of their oscillation, nor girder for lack of support, the desiderata being extensive span with rigid strength, so triumphantly realized in the tubular bridge. The day when the great Holyrood train passed over the Strait of Menai by this grand expedient established the superiority of this principle of construction, and became a memorable occasion in the annals of mechanical science, and immortalized the name of Stephenson.
We find great national significance in the history of bridges in different countries. Their costly and substantial grandeur in Britain accords with the solid qualities of the race, and their elegance on the Continent with the pervasive influence of Art in Europe. It is a curious illustration of the inferior economical and high intellectual development of Greece, that the "Athenians waded, when their temples were the most perfect models of architecture"; and equally an evidence of the practical energy of the old Romans, that their stone bridges often remain to this hour intact. Our own incomplete civilization is manifest in the marvellous number of bridges that annually break down, from negligent or unscientific construction; while the indomitable enterprise of the people is no less apparent in some of the longest, loftiest, most wonderfully constructed and sustained bridges in the world. We have only to cross the Suspension Bridge at Niagara, or gaze up to its aërial tracery from the river, or look forth upon wooded ravines and down precipitous and umbrageous glens from the Erie Railway, to feel that in this, as in all other branches of mechanical enterprise, our nation is as boldly dexterous as culpably reckless. As an instance of ingenuity in this sphere, the bridge which crosses the Potomac Creek, near Washington, deserves notice. The hollow iron arches which support this bridge also serve as conduits to the aqueduct which supplies the city with water.
Amid the mass of prosaic structures in London, what a grand exception to the architectural monotony are her bridges! how effectually they have promoted her suburban growth! Canova thought the Waterloo Bridge the finest in Europe, and, by a strangely tragic coincidence, this noble and costly structure is the favorite scene of suicidal despair, wherewith the catastrophes of modern novels and the most pathetic of city lyrics are indissolably associated. Westminster Bridge is as truly the Swiss Laboyle's monument of architectural genius, fortitude, and patience, as St. Paul's is that of Wren; and our own Remington's bridge-enthusiasm involves a pathetic story. At Cordova, the bridge over the Guadalquivir is a grand relic of Moorish supremacy. The oldest bridge in England is that of Croyland in Lincolnshire; the largest crosses the Trent in Staffordshire. Tom Paine designed a cast-iron bridge, but the speculation failed, and the materials were subsequently used in the beautiful bridge over the River Wear in Durham County. There is a segment of a circle six hundred feet in diameter in Palmer's bridge which spans our own Piscataqua. It is said that the first edifice of the kind which the Romans built of stone was the Ponte Rotto, begun by the Censor Fulvius and finished by Scipio Africanus and Lucius Mummius. Popes Julius III. and Gregory XIV. repaired it; so that the fragment now so valued as a picturesque ruin symbolizes both Imperial and Ecclesiastical rule. In striking contrast with the reminiscences of valor, hinted by ancient Roman bridges, are the ostentatious Papal inscriptions which everywhere in the States of the Church, in elaborate Latin, announce that this Pontiff built or that Pontiff repaired these structures.
The mediæval castle moat and drawbridge have, indeed, been transferred from the actual world to that of fiction, history, and art, except where preserved as memorials of antiquity; but the civil importance which from the dawn of civilization attached to the bridge is as patent to-day as when a Roman emperor, a feudal lord, or a monastic procession went forth to celebrate or consecrate its advent or completion; in evidence whereof, we have the appropriate function which made permanently memorable the late visit of Victoria's son to her American realms, in his inauguration of the magnificent bridge bearing her name, which is thrown across the St. Lawrence for a distance of only sixty yards less than two English miles,—the greatest tubular bridge in the world. When Prince Albert, amid the cheers of a multitude and the grand cadence of the national anthem, finished the Victoria Bridge by giving three blows with a mallet to the last rivet in the central tube, he celebrated one of the oldest, though vastly advanced, triumphs of the arts of peace, which ally the rights of the people and the good of human society to the representatives of law and polity.
One may recoil with a painful sense of material incongruity, as did Hawthorne, when contemplating the noisome suburban street where Burns lived; but all the humane and poetical associations connected with the long struggle sustained by him, of "the highest in man's soul against the lowest in man's destiny," recur in sight of the Bridge of Doon, and the two "briggs of Ayr," whose "imaginary conversations" he caught and recorded, or that other bridge which spans a glen on the Auchinleck estate, where the rustic bard first saw the Lass of Ballochmyle. The tender admiration which embalms the name of Keats is also blent with the idea of a bridge. The poem which commences his earliest published volume was suggested, according to Milnes, as he "loitered by the gate that leads from the battery on Hampstead Heath to the field by Camwood"; and the young poet told his friend Clarke that the sweet passage, "Awhile upon some bending planks," came to him as he hung "over the rail of a foot-bridge that spanned a little brook in the last field upon entering Edmonton." To the meditative pedestrian, indeed, such places lure to quietude; the genial Country Parson, whose "Recreations" we have recently shared, unconsciously illustrates this, when he speaks of the privilege men like him enjoy, when free "to saunter forth with a delightful sense of leisure, and know that nothing will go wrong, although he should sit down on the mossy parapet of the little one-arched bridge that spans the brawling mountain-stream." On that Indian-summer day when Irving was buried, no object of the familiar landscape, through which, without formality, and in quiet grief, so many of the renowned and the humble followed his remains from the village-church to the rural graveyard, wore so pensive a fitness to the eye as the simple bridge over Sleepy-Hollow Creek, near to which Ichabod Crane encountered the headless horseman,—not only as typical of his genius, which thus gave a local charm to the scene, but because the country-people, in their heartfelt wish to do him honor, had hung wreaths of laurel upon the rude planks.
Fragments, as well as entire roadways and arches of natural bridges, are more numerous in rocky, mountainous, and volcanic regions than is generally supposed; the action of the water in excavating cliffs, the segments of caverns, the, accidental shapes of geological formations, often result in structures so adapted for the use and like the shape of bridges as to appear of artificial origin. In the States of Alabama and Kentucky, especially, we have notable instances of these remarkable freaks of Nature: there is one in Walker County, of the former State, which, as a local curiosity, is unsurpassed; and one in the romantic County of Christian, in the latter State, makes a span of seventy feet with an altitude of thirty; while the vicinity of the famous Alabaster Mountain of Arkansas boasts a very curious and interesting formation of this species. Two of these natural bridges are of such vast proportions and symmetrical structure that they rank among the wonders of the world, and have long been the goals of pilgrimage, the shrines of travel. Their structure would hint the requisites, and their forms the lines of beauty, desirable in architectural prototypes. Across Cedar Creek, in Rockbridge County, Virginia, a beautiful and gigantic arch, thrown by elemental forces and shaped by time, extends. It is a stratified arch, whence you gaze down two hundred feet upon the flowing water; its sides are rock, nearly perpendicular. Popular conjecture reasonably deems it the fragmentary arch of an immense limestone cave; its loftiness imparts an aspect of lightness, although at the centre it is nearly fifty feet thick, and so massive is the whole that over it passes a public road, so that by keeping in the middle one might cross unaware of the marvel. To realize its height it must be viewed from beneath; from the side of the creek it has a Gothic aspect; its immense walls, clad with forest-trees, its dizzy elevation, buttress-like masses, and aërial symmetry make this sublime arch one of those objects which impress the imagination with grace and grandeur all the more impressive because the mysterious work of Nature,—eloquent of the ages, and instinct with the latent forces of the universe. Equally remarkable, but in a diverse style, is the Giant's Causeway, whose innumerable black stone columns rise from two to four hundred feet above the water's edge in the County of Antrim, on the north coast of Ireland. These basaltic pillars are for the most part pentagonal, whose five sides are closely united, not in one conglomerate mass, but, articulated so aptly that to be traced the ball and socket must be disjointed.
The effect of statuary upon bridges is memorable: the Imperial statues which line that of Berlin form an impressive array; and whoever has seen the figures on the Bridge of Sant' Angelo at Home, when illuminated on a Carnival night, or the statues upon Santa Trinità at Florence, bathed in moonlight, and their outline distinctly revealed against sky and water, cannot but realize how harmoniously sculpture may illustrate and heighten the architecture of the bridge. More quaint than appropriate is pictorial embellishment; a beautiful Madonna or local saint placed midway or at either end of a bridge, especially one of mediæval form and fashion, seems appropriate; but elaborate painting, such as one sees at Lucerne, strikes us as more curious than desirable. The bridge which divides the town and crosses the Reuss is covered, yet most of the pictures are weather-stained; as no vehicles are allowed, foot-passengers can examine them at ease. They are in triangular frames, ten feet apart, but few have any technical merit. One series illustrates Swiss history; and the Kapellbrücke has the pictorial life of the Saint of the town; while the Mile Bridge exhibits a quaint and rough copy of the famous "Dance of Death."
In Switzerland what fearful ravines and foaming cascades do bridges cross! sometimes so aërial, and overhanging such precipices, as to justify to the imagination the name superstitiously bestowed on more than one, of the Devil's Bridge; while from few is a more lovely effect of near water seen than the "arrowy Rhone," as we gaze down upon its "blue rushing" beneath the bridge at Geneva. Perhaps the varied pictorial effects of bridges, at least in a city, are nowhere more striking than at Venice, whose five hundred, with their mellow tint and association with palatial architecture and streets of water, especially when revealed by the soft and radiant hues of an Italian sunset, present outlines, shapes, colors, and contrasts so harmonious and beautiful as to warm and haunt the imagination while they charm the eye. It is remarkable, as an artistic fact, how graciously these structures adapt themselves to such diverse scenes,—equally, though variously, picturesque amid the sturdy foliage and wild gorges of the Alps, the bustle, fog, and mast-forest of the Thames, and the crystal atmosphere, Byzantine edifices, and silent canals of Venice.