Note 123 — Chapter VI · BAGHDÂD TO MÔṢUL April 12—April 28

Mutawakkil began a new canal from the Tigris to the Nahrawân, the latter having silted up by the ninth century, but the labour of cutting through the hard conglomerate was found to be too great and the work was abandoned. I do not know whether the canal I crossed was of his making, but I fancy it was the Nahrawân itself, perhaps cleared and deepened by him. Ross (op. cit., p. 129) speaks of bridge foundations formed of large “artificial stones” (concrete?) “joined together by iron clamps and melted lead.” I saw nothing but brick, but Ross’s bridge may well be, as he conjectured, earlier than the Mohammadan period, since it probably spanned the Sassanian canal. I thought the artificial mound to be pre-Mohammadan.