[65] Sir William Smith, in his great “Dictionary of Greek and Roman Geography,” gives a detailed account of the stonework. “The stone of this bridge is a yellowish colour. Seen under the sun from the west side, the bridge has a brightish yellow tint, with patches of dark colour, owing to the weather. The stone in the highest tier is a concretion of shells and sand, and that in the lower tiers appears to be the same. In the stones in the highest tier there are halves of a bivalve shell completely preserved. The stone also contains bits of rough quartzose rock, and many small rounded pebbles. In floods the Gardon rises 30 ft. above its ordinary level, and the water will then pass under all the arches of the lowest tier. The piers of this tier show some marks of being worn by the water. But the bridge is still solid and strong, a magnificent monument of the grandeur of Roman conceptions, and of the boldness of their execution.”
[66] Later we shall see that Perronet, a famous bridge-builder of the eighteenth century, used iron clamps for this purpose.
[67] I believe these measurements to be strictly accurate, unlike those in many books of reference.
[68] Let me add to this account a few details from Sir William Smith’s “Dictionary of Greek and Roman Geography.” “It is generally said that the bridge is entirely built of stones, without mortar or cement. The stones of the two lower tiers are without cement; but the arches of the highest tier, which are built of much smaller stones, are cemented. At the north end of the aqueduct the highest tier of arches and the water channel are higher than the ground on which the aqueduct abuts, and there must have been a continuation of small arches along the top of this hill; but there are no traces of them, at least near the bridge. On the opposite or south side the aqueduct abuts against the hill, which is higher than the level of the channel. There is no trace of the hill having been pierced; and an intelligent man, who lives near the bridge, says that the aqueduct was carried round the hill, and that it pierced another hill further on, where the tunnel still exists....”
[69] See Grangent, Durand et Durant, “Description des Monumens Antiques du Midi de la France,” Paris, 1819, I, p. 113, and Plate XL; see also “Géographie Générale du Département de l’Hérault,” published by the Société Languedocienne, Montpellier, 1905. Vol. III, part II. p. 310.
[70] Two arches over the Salado river, some thirty miles below Seville ([p. 367]).
[71] Between Córdova and Andujar, over a small tributary flowing into the Guadalquivir from the south. This bridge has three arches, one a good deal larger than the others; bays are driven through the spandrils for spate water to pass through. The masonry consists of stone in big blocks, and the craftsmanship has a very peculiar feature: the voussoirs are notched or joggled one into the other, like those in the Elizabethan bridge at Ross-on-Wye, Herefordshire. This technique is a thing to be remembered: it occurs in no other Roman bridge that is known to me. The notching adds much to the endurance of an arch ring, yet it has never entered into the technical routine of bridge-builders. Perhaps the dovetailing of the stones has been looked upon as too costly, for it needs much skill and care and time. Mr. Edgar Wigram drew my attention to this little-known Roman bridge, and to the one at Alcantarilla ([p. 367]).
[72] This bridge is a soldier, and claims masculine pronouns.
[73] “Northern Spain,” by Edgar T. A. Wigram, London, 1906, pp. 231-2.
[74] The stones laid end-foremost.