“At Loyang, in the Province of Fo-Kien, on an arm of the sea, there is a bridge with three hundred spans; its construction went on for eighteen years and employed twenty-five thousand workmen. Technically it belongs to the same class as the bridges of ancient Babylon, which are said to have been made with long and flat stones laid from pier to pier. If Loyang Bridge be 8800 metres in length, as some writers affirm, then its piers will be 4 metres 87 in thickness, and its spans in width will measure 24.36 metres. The footway is 22.74 metres. The long slabs are 5 metres thick and 3 metres wide. As for the piers, they are 23 metres in height, and bear marble lions carved from blocks 7 metres long.”
Gauthey gives a drawing of this bridge, and his measurements are taken from the Atlas of Martimmart. They have an air of great exaggeration. As Gauthey remarks, “It is difficult to believe that the tabular stones are as large as they are presumed to be: their bulk is more than threefold greater than that of the obelisk at Rome in the Place de Saint-Pierre. Besides, M. Pingeron speaks of them as being fourteen metres long by a metre and a half in thickness and in width, so he diminishes by a full half the length of Loyang Bridge. Even with this reduction it is a wonderful achievement, more than four and a half times longer than the Pont du Saint-Esprit.”[41]
The dimensions given by M. Pingeron may be accurate; they represent a hugely magnified clapper bridge decorated with sculpture and carried on tall piers for a distance of 4400 metres, in a series of three hundred spans. The marble lions, I suppose, ornament the parapets above the piers, like those on the bridge of Pulisangan ([p. 310]). Marco Polo visited the province of Fo-Kien, where Loyang Bridge is said to be, and stayed at the city of Kue-lin-fu, known to-day as Kien-ning-fu. Here he was greatly struck by “three very handsome bridges, upwards of a hundred paces in length, and eight paces in width.”[42] Not a vivid description, yet enough to prove that notable bridges in Fo-Kien have had a long history.
IV
TREE-BRIDGES WITH STONE PIERS
The most famous bridge in this kind is the one built by Trajan over the Danube, just below the rapids of the Iron Gate. Trajan required it for his wars against Dacia, which in A.D. 106 he brought to a successful end, the Dacian leader Decebalus being slain and his people subdued. The bridge had played its part, yet Hadrian, the next Emperor, who began his reign ten years afterwards, looked upon it as a dangerous highway, open to incursions from Dacian revolts, and for this reason he destroyed some piers and the footway. Perhaps Hadrian was jealous of Trajan’s work, for two fortified gates and a handful of Roman troops could have defended the bridge against barbarians.
There has been much controversy over this great structure. Its architect was Apollodorus of Damascus, who designed also the Trajan column placed in the centre of the Forum Trajanum. A bas-relief on this column represents the bridge, but in a manner at odds with the written description given by Dion Cassius, who held important offices under Commodus, Caracalla, and Alexander Severus, A.D. 180-229. Dion Cassius wrote a history of Rome, in eighty books, and a small portion of this work has come down to us entire. His evidence then is worth having, and it states that the bridge had twenty piers of hewn stone, 150 feet high and 60 feet wide, with openings between them of 170 feet, spanned by arches. Doubt has been thrown on the accuracy of this description, because the bridge on the Trajan column is unsuited to a span of 170 feet; “nevertheless thirteen piers are still visible out of the twenty, according to Murray’s ‘Handbook.’ The writer has not been able to find any accurate measurement of the width between these piers, but as the ‘Handbook’ speaks of the length of the bridge as perhaps 3900 feet, and as the Conte Marsigli, writing from personal observation, in a letter to Montfaucon, gives the total length as probably 3010 feet, there can be no doubt that the spans were very considerable and that the representation of the design in the bas-belief is almost wholly conventional. The one point as to which it gives clear information, not supplied elsewhere, is that the superstructure was of wood.”[43]
In other words, this colossal work was a descendant of the earliest tree-bridges, in so far as the footway was concerned. Whether arched timbering was carried from pier to pier to uphold the roadway, as in the bas-relief, is a question of no great moment; the horizontal bearing beams would need support, no doubt, since they had to span openings far wider than the longest trees; and it is useless for us to guess in what way this support was carried to them from the lofty piers, which were built with enormous blocks of stone. The main point is that one phase of bridge-building, whose first models were fallen trees lying astride rivers and chasms, seems to have culminated in the masterpiece of Apollodorus of Damascus. Much inferior work of the same kind, very varied and entertaining, has been common everywhere; some of it belongs to Kurdistan, for example ([p. 73]); and in the Lledr Valley there is a good Welsh specimen called the Pont-y-Pant, whose wooden footway is primitively rustic, and whose piers are fragments of rock gathered from the river-bed and piled together. I have found at Thirlmere a quaint thing which is partly a dam and partly a bridge. The dam, an undulating wall of unmortared stones, has at equal intervals a few angular openings over which wooden hand-bridges are thrown. It would be easy in a shallow river to make a fish-pool by heaping boulders into a dam of this rude sort, and the completed work would rank no higher than the beavers contests against running water. So I tell myself that many a tribe in the great period of prehistoric art, about 50,000 years B.C., ought to have built for itself a bridge as elementary as the Pont-y-Pant and a perforated dam as uncouth as the one at Thirlmere.
From this untutored handicraft we look back again at the great art of Apollodorus, whose vast bridge over the Danube was near the ancient town of Nicopolis. What a long travail in the gestation and birth of infrequent ideas! Even half a million years ago a man of the eagle-beaked tools may have put a boulder under a tree-bridge because the tree was thin and swayed too much on a windy day; half a million years ago, and yet we do not feel ashamed of the Pont-y-Pant!