The bridges which cross the river form quite a feature of the land, and show considerable engineering skill; though the crossing of them needs a steady head as they are constructed at present. In principle, they are true cantilevers. Piers are built at some convenient place, and a long "bracket" of poplar trees is built out over the stream from each shoreward side. The butts are weighted down with stones, and the projecting ends are perhaps forty feet apart. Two long poplars are then slung side by side between the ends of the converging brackets, and a floor of withy hurdles makes the bridge complete. As the trunks are very elastic, the whole structure swings considerably even if it does remain horizontal. Often, however, it acquires a pronounced tilt to one side or the other; and in any case a three-foot track without any sort of parapet is narrow for a bridge. By old rule, you ought not to look down in crossing such a place, lest the sight of the torrent whirling below should unnerve you. In this case, however, look down you must, and make the best of the vision of the torrent as seen through the withy hurdle floor; for that floor is full of holes and other traps and stumbling blocks, and if you trip, disaster follows! Even natives sometimes condescend to be led across these places, or even to crawl; but animals vary as much as menfolk in their behaviour on such occasions. The writer has known a plains-bred horse walk over one of these bridges as if to the manner born, without even a man to his tail; and has seen a mountain-bred mule jib till he had to be ignominiously towed through the river by a combination of tethering and baggage ropes! One would expect that the useful donkey would be the very best of all possible animals for use in this land; but the Assyrians of Tyari have a prejudice against him. "He that is Lord of Ears"--his name is quite unmentionable,--is _iyba_ for the _ashirets_. _Iyba_ is an institution that needs some explaining. The word means "shame;" but the European presently gets the impression that it can be extended to cover any mortal thing which he orders, and which for any reason the native does not want to do. Anyway, the poor donkey is _iyba_, and no mountaineer will own one. A legendary man of Tyari dared to do so once; but life was made such a burden to him by the jeers of all his kin, that at last he hove the unfortunate jackass into the Zab from one of the bridges we have been describing, and was free of further reproach. A mule is honourable enough, if you are so fortunate as to own one; but it is etiquette to address a hybrid beast like that in Kurdish (which is a second tongue to all mountaineers); whereas your ox, being a proper and biblical sort of animal, is addressed in Syriac, which is a good Christian tongue.