250. Aqueduct of Segovia. Scale 50 ft. to 1 in.
251. Aqueduct of Tarragona. Scale 50 ft. to 1 in.
The Roman bridges were designed on the same grand scale as their aqueducts, though from their nature they of course could not possess the same grace and lightness. This was, however, more than compensated by their inherent solidity and by the manifestation of strength imparted by the Romans to all these structures. They seem to have been designed to last for ever; and but for the violence of man, it would be hardly possible to set limits to their durability. Many still remain in almost every corner of the Roman Empire; and wherever found are easily recognised by the unmistakable impress of Roman grandeur which is stamped upon them.
One of the most remarkable of these is that which Trajan erected at Alcantara, in Spain, represented in the annexed woodcut. The roadway is perfectly level, as is generally the case in Roman bridges, though the mode by which this is obtained, of springing the arches from different levels, is perhaps not the most pleasing. To us at least it is unfamiliar, and has never, I think, been adopted in modern times. In such a case we should either have made the arches all equal—a mistake, considering their different heights—or have built solidly over the smaller arches to bring up the level, which would have been a far greater error in construction than the other is in taste. The bridge consists of six arches, the whole length of the roadway being 650 ft.; the two central arches are about 100 ft. span; the roadway is 140 ft. above the level of the stream which it crosses. The piers are well proportioned and graceful; and altogether the work is as fine and as tasteful an example of bridge-building as can be found anywhere, even in these days of engineering activity.
252. Bridge of Trajan, at Alcantara, in Spain.
The bridge which the same Emperor erected over the Danube was a far more difficult work in an engineering point of view; but the superstructure being of wood, resting only on stone piers, it would necessarily have possessed much less architectural beauty than this, or indeed than many others.
These examples of this class of Roman works must suffice; they are so typical of the style that it was impossible to omit them altogether, though the subject scarcely belongs in strictness to the objects of this work. The bridges and aqueducts of the Romans richly deserve the attention of the architect, not only because they are in fact the only works which the Romans, either from taste or from social position, were enabled to carry out without affectation, and with all their originality and power, but also because it was in building these works that the Romans acquired that constructive skill and largeness of proportion which enabled them to design and carry out works of such vast dimensions, to vault such spaces, and to give to their buildings generally that size and impress of power which form their chief and frequently their only merit. It was this too that enabled them to originate that new style of vaulted buildings which at one period of the Middle Ages promised to reach a degree of perfection to which no architecture of the world had ever attained. The Gothic style, it is true, perished at a time when it was very far from completed; but it is a point of no small interest to know where and under what circumstances it was invented. We shall subsequently have to trace how far it advanced towards that perfection at which it aimed, but to which it never reached. Strangely enough, it failed solely because of the revival and the pernicious influence of that very parent style to which it owed its birth, and the growth and maturity of which we have just been describing. It was the grandeur of the edifices reared at Rome in the first centuries of the Empire which so impressed the architects of the fifteenth and sixteenth centuries, that they abandoned their own beautiful style to imitate that of the Romans, but with an incongruity which seems inevitably to result from all imitations, as contrasted with true creations, in architectural art.
