appearing here and there. The mass of solid matter which the rivers deposit is very considerable. The maximum proportion for the Euphrates in the month of January is 1 and at other times 1; for the Tigris the maximum is 1. In general, the northern plains of the interior have a slight but well-defined southerly inclination, with local depressions. The territory undulates in the central districts, and then sinks away into mere marshes and lakes. The clay, of a deep blue colour, abounds with marine shells, and shows a strong efflorescence of natron and sea-salt. When the soil is parched the appearance of the mirage (serab) is very common. As extensive inundations in spring are caused by both the rivers, especially the Tigris, great changes must have taken place in this part of the country in the course of thousands of years. It has been asserted that in former times the alluvial area at the mouth of the river increased 1 m. in the space of thirty years; and from this it has been assumed that about the 6th century B.C. the Persian Gulf must have stretched from 45 to 55 m. farther inland than at resent. The actual rate of increase at the present time is about 72 ft. per annum. While we may be unable to determine accurately the former physical configuration of southern Babylonia, it is at least certain that in Babylonian times the Euphrates and Tigris reached the sea as independent rivers, and Ritter estimates that in the time of Alexander the Great the embouchure's were still separated by a good day's journey. Although they cannot now be traced, great alterations have probably taken place also in the upper portions of the rivers as well as in the country near their mouths. The names of a large number of canals occur in the old Babylonian inscriptions, as in the works of the Arabian geographers, but while some of these have been traced it has not been possible hitherto to identify the greater number of them with actually existing canals or remains of canals. To the west of the Euphrates, on the edge of the Syrian desert from Hit downward to the neighbourhood of Basra and beyond, ran the Sa'ade, now for the most part dry, a very ancient canal, extended or enlarged at different periods. Lower down near Mussaib, the Hindieh canal, at least equal in volume to the present main stream, branches off and after traversing and irrigating an extensive territory rejoins the river at Samawa. Between the Euphrates and the Tigris, there was a large number of great canals, especially in the region northward of Babylon between that city and the northern edge of the alluvial plain, of which the most famous were the 'Isa, the Sarsar, the Malk (“ Royal "), the canal of Kutha, the Sura and the Arakhat (Shatt-en-Nil). Of these only one at present carries water, namely, the Nahr 'Isa, which, leaving the Euphrates at Sakhlawieh (Sakh lawiya), terminates in extensive marshes near Bagdad; but this is now no longer navigable. Southward of Babylon the Daghara canal, which leaves the Euphrates a little below Hillah and empties into the Affech marshes, and the Shatt-el-Kehr, which, leavin that stream a little above Diwanieh, makes a reat curve through the interior of the jezireh, finally losing itself in the Hosainieh (Hosainiya) marshes near the mouth of the Shatt-el-Hai, are the only navigable or partly navigable canals of the Euphrates in the Jezireh. The Tigris canals are not so numerous as those of the Euphrates and were not so famous in history, but eastward of that river the great Nahrawan channel still exists in part, while the Tigris is connected with the Euphrates by a navigable stream, the Shatt-el-Hai, which leaves the former river at Kut-el-'Amara and enters the Euphrates at Nasrieh. Everywhere the country is intersected with ancient canals, some still deep dry beds, other so silted up that their course is represented only by parallel lines of hillocks. Some of these, of great antiquity, like the Shatt-en-Nil, which can be traced through its whole course from Babylon, through or past Nippur, Udnun (Bismya) Gishban (Gis-ukh), Erech and Larsa, to the Hosainieh marshes, were equally as important as the Euphrates itself; and indeed it may be said that in ancient times that stream after reaching the alluvial plain was divided into a large number of channels, partly natural partly artificial, no single one of which, but all together, constituted the Euphrates. By the restoration of these old canals, traces of which are met with at every step, the country might be again raised to that condition of high civilization which it enjoyed not only in antiquity but even as late as the time of the caliphs. The classical writers are unanimous in their admiration of Babylonia, and it is certain that nowhere else in the ancient world was the applicatit of canals to the exigencies of agriculture worked out so successfully as here. The most luxuriant vegetation was diffused over the whole country and three crops were obtainable in the year. In the matter of civilization indeed no country of the ancient world surpassed Babylonia. How densely peopled this country once was ma be gathered from the fact that about 794 B.C., 89 fortified towns and 820 smaller places in the Chaldaean region were captured during one military expedition. And even in the times of the caliphs there stood on the royal canal and its branches, north of Babylon, 360 villages, contributing in gold 225,000 dirhems to the state treasury besides the tax in kind. To-day the whole region from the swamps about Basra northward is dotted with ruin mounds, and at places the plain itself is strewn for miles with fragments of glass and pottery, evidence of earlier occupation, while, as stated, lines of canals of all ossible sizes, from the great triple canals with four rows of parallel hiiiocks, down to the small canals or purposes of irrigation, intersect the country in every direction.
There seem to have been almost from the outset two centres which strove with one another for political supremacy in this region, the south and the north. In the north in the Babylonian time lay Kish, Akkad, Kutha (Tell-Ibrahim), Sippara (Abu Habba), Babylon and Borsippa (Birs-Nimrud). In the south were Eridu and Ur (Mughair)—originally on the shores of the Persian Gulf, now 125 m. inland—Erech (Warka), Larsa (Senkereh), Lagash (Tello) and Gishban (Yokha). Nearly in the centre lay Nippur and Udnun (Bismya). Besides these there were numerous other cities, some of considerable importance, which are known to us at present only by name; and there are in Irak hundreds of ruin mounds, some of them of considerable size, covering ancient Babylonian cities, the greater part of which are still unexplored and unidentified. During the period of Greek domination a Greek city, Seleucia (q.v.), which afterwards attained great prosperity, was founded by Seleucus I. in an extremely favourable situation on the right bank of the Tigris. Greek cities were founded also in the south, at the head of the Persian Gulf, and some of the ancient Babylonian cities of the interior like Lagash, Erech and Nippur, were rebuilt on the old sites. After the conquest of Babylonia by the Parthians (136 B.C.) Ctesiphon (q.v.) was built.on the east bank of the Tigris opposite Seleucia, and became the winter residence of the Persian kings. Later this double city became the imperial capital of the Sassanids, and under the name Madain still continued to flourish after the Arabic conquest, to be finally superseded by the neighbouring Bagdad. That region was called in the time of the Sassanids, Suristan, a translation of the Aramaean designation Beth-Aramaya, “ country of the Syrians,” for the land was mainly occupied by Aramaeans. By a notable substitution the Arabs afterwards gave the name Nabat, i.e. Nabataeans, to these Aramaean tenantry, who it may be added were already found in these parts at the time of the Babylonian empire. Indeed, some small portion of this old Syrian population of Irak still remains distinguished by a special religion (see Mandeans), chiefly on the shores of the lower Euphrates in the neighbourhood of Suk-esh-Sheiukh. Another important city of the Sassanian period was Perisabora, known in the Arabian period as Anbar, the centre also of Babylonian Judaism after the destruction of Pombeditha in A.D. 588, situated on the east bank of the Euphrates in about the same latitude as Bagdad. During the Sassanian period flourished in the south-east the Arabic kingdom of Hira (q.v.). There was also for a time a Jewish kingdom in Babylonia, and Nehardea and Pombeditha are mentioned as centres of Jewish religions and national life during this period.
After the Arabian conquest in the 7th century A.D., Irak entered for a time on a new period of prosperity. Several important new cities were founded, among them Kufa, Basra, Wasit on the Shatt-el-Haï, and Bagdad on the site of an old Babylonian city of the same name, which later became under the Abbasid caliphs not only the capital of Irak but for a time the metropolis of the world (see Caliphate). With the decay of the Abbasid power the system of irrigation began to fall into disrepair, the ancient sites were gradually deserted, and the country finally' returned to a condition of semi-barbarism alternating between inundation and drought, which is its present state.
See Ritter, Die Erdkunde von Asien, 2nd ed., vol. vii., 10th and 11th parts (Berlin, 1843, 1844); W. F. Ainsworth, Researches in Assyria (London, 1838); F. R. Chesney, Expedition for the Survey of the Rivers Euphrates and Tigris (2 vols., London, 1850); W. K. Loftus, Chaldaea and Susiana (1857); F. Delitzsch, Wo lag das Paradies? (Leipzig, 1881); W. F. Ainsworth, The Euphrates Expedition (1888); J. P. Peters, Nippur (1897); E. Sachau, Am Euphrat und Tigris (1900); F. Delitzsch, Im Lande des einstigen Paradieses (1903). Maps: Chesney (1850); Selby, Bewsher and Collingwood (1871); Kiepert, Ruinenfelder (1883). (A. So.; J. P. Pe.)
IRAK-I-AJAMI (i.e. Persian Irak), the name (now obsolete) of the important Persian province which the Arab geographers called Iebel (the mountainous region). It used to be the country bounded N. by Azerbaijan and Gilan, E. by Samnan and the
central Persian desert, S. by Kerman, Fars and Arabistan,