The general sterility of Media arises from the scantiness of the water supply. It has but few rivers, and the streams that it possesses run for the most part in deep and narrow valleys sunk below the general level of the country, so that they cannot be applied at all widely to purposes of irrigation. Moreover, some of them are, unfortunately, impregnated with salt to such an extent that they are altogether useless for this purpose; and indeed, instead of fertilizing, spread around them desolation and barrenness. The only Median streams which are of sufficient importance to require description are the Aras, the Kizil-Uzen, the Jaghetu, the Aji-Su and the Zenderud, or river of Isfahan. The Aras is only very partially a Median stream. It rises from several sources in the mountain tract between Kars and Erzeroum, and runs with a generally eastern direction through Armenia to the longitude of Mount Ararat, where it crosses the fortieth parallel and begins to trend southward, flowing along the eastern side of Ararat in a south-easterly direction, nearly to the Julfa ferry on the high road from Erivan to Tabriz. From this point it runs only a little south of east to long. 46° 30’ E. from Greenwich, when it makes almost a right angle and runs directly north-east to its junction with the Kur at Djavat. Soon after this it curves to the south, and enters the Caspian by several mouths in lat. 39° 10’ nearly. The Aras is a considerable stream almost from its source. At Hassan-Kaleh, less than twenty miles from Erzeroum, where the river is forded in several branches, the water reaches to the saddle-girths. At Keupri-Kieui, not much lower, the stream is crossed by a bridge of seven arches. At the Julfa ferry it is fifty yards wide, and runs with a strong current. At Megree, thirty miles further down, its width is eighty yards. In spring and early summer the stream receives enormous accessions from the spring rains and the melting of the snows, which produce floods that often cause great damage to the lands and villages along the valley. Hence the difficulty of maintaining bridges over the Aras, which was noted as early as the time of Augustus, and is attested by the ruins of many such structures remaining along its course. Still, there are at the present day at least three bridges over the stream--one, which has been already mentioned, at Keupri-Kieui, another a little above Nakshivan, and the third at Khudoperinski, a little below Megree. The length of the Aras, including only main windings, is 500 miles.