[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. [75] The stones laid at full length. [76] There is conflicting evidence on the date of this monument. Pliny attributed the Marcian Aqueduct to Ancus Marcius, whereas Strabo and Frontinus conjecture that the building got its name from Marcius Rex, a pretor, who in the year B.C. 145, or thereabouts, restored some ancient aqueducts whose first construction did not go back beyond the year 272 B.C. Sextus Julius Frontinus, governor of Britain (A.D. 75-78), was the author of two monographs that are still extant--one on the Roman aqueducts, and another on the art of war. He was nominated _Curator Aquarum_, or Superintendent of the Aqueducts, in 97, nine years before his death. Sir William Smith tells us that the earliest aqueduct was not older than the year B.C. 313. In earlier times the Romans had recourse to the Tiber and to wells sunk in the city. During the sixth century of the Christian era there were fourteen aqueducts at Rome. [77] Mr. R. Phené Spiers has written admirably on these technical matters.