Jail. 2 1, 1875J 



NA TURE 



231 



that the minimum volume of water passing Nultus during the 

 winter months of any year is not very much less than that which 

 passed the same point on the loth September, 1874. However, 

 it is impossible, in the present state of our information, to state 

 with precision cither the volume of discharge during the winter 

 months, or the quantity of water required to pass during the 

 summer, to scour out the deposits made in the bed of the Ami'i 

 by the winter discharge. But those who are inclined t^ confide 

 in the intelligent arrangements of nature, will have no difficulty 

 in believing that these two volumes were in such a state of pro- 

 portion as corrected the evils induced in the bed of the river by 

 the Ijw velocity of the smaller ol the two volumes, i.e. of the 

 winter discharge of the Ami'i. Under such circumstances, the 

 bed of the river would be undcterioraled, its course would remain 

 constant, and its flow would continue int j the Caspian Sea. 



But immediately the volume and velocity of the summer or 

 flood discharges of the Ami'i Darya were decreased by the action 

 of defluent canals excavated for the irrigation of the lands of 

 Khiv.a, the compensa oiy arrangements of nature, which pre- 

 viously kept the river's bed clear, would be interfered with, and 

 some portion of the silt deposited by the winter stream would 

 remain unremoved. This evil would increase yearly, and the 

 intensity of its action would be greater as the quantity of water 

 div<:r:ed for irrigation purposes becnme greater. A portion of 

 the deposit might occasionally be removed by an accidentally 

 high flood, but, eventually, a state of things would supervene in 

 which the conditions of the Amu would present the precise con- 

 verse of the jtate of adjustment described in Sir Charles Lyell's 

 work ; that is to say, bars and banks of sand would form in the 

 course of the river, would be enlarged yearly, and would prevent 

 it from flowing on to the Caspian. The most westerly point 

 reached by the waters ot the river would continually recede to 

 the east, and they would become erratic while seeking an outlet 

 by a slope steeper than that of their encumbered old bed. 



Such is a tolerably concise description of what I conceive has 

 actually occurred in the case of the Amu, and has caused the 

 change of its flow into the Aral Sea ; and it now remains to exa- 

 mine whether such facts as are known regarding the change and 

 the existent state of things are in harmony with the theory I 

 have ventured to hazard. 



Abulgazee Ivhan, in his history of the Mogols and the Tartars, 

 relates that in the early part of the sixteenth century " all the 

 road from Urgcnj as far as Abul Khan was covered with aouls, 

 i.e. encampments of nomads ; for the Amii Darya, after having 

 passed under the walls of Urgenj, flowed to the foot of the eastern 

 slope of Mount Abul Khan, whence the river turned to the 

 south-west, to turn afterwards to the west, and empty itself at 

 Ogourtcha into the Sea of Mazanderan. The two banks of the 

 river as far as Ogourtcha presented a succession of cultivated 

 lands, of vineyards and of orchards . . . All that country was at 

 that time very populous and in the most flourishing condition." 

 la the early part of the sixteenth century, therefore, the Ami'i 

 Darya fell into the Caspian, and irrigation, by means of its 

 waters, was general along its banks from Urgenj as far as Abul 

 Khan. 



Anthony Jenkinson, the Englishman travelling from the Cas- 

 pian eastwards in A.D. 1559, arrived on the 5th October at what 

 he called a "guile of the Caspian Sea." Here he found " the 

 water very fresh and sweete." He continues: "Note that in 

 times past there did fal into this gulfe the great river Oxus, which 

 hath his springs in the mountains of I'arapomisus, in India, and 

 now Cometh not so far, but falleth into another river called Ardok, 

 which runneth towards the north. . . ." The " very fresh and 

 sweete water" found by Jenkinson could only have been brought 

 by a flood, or have forced its way either by a channel or by 

 filtration through the sand-banks into the old bed of the Oxus to 

 the spot in question. At the date mentioned, therefore, by Jen- 

 kinson, some of the waters of the Amii Darya could still find their 

 way to the Caspian, and the opening of the new course into 

 Ardok, and the closing of the old course, must have been circum- 

 stances of tolerably recent occurrence. 



Jenkinson continues his narrative thus: — "We, having re- 

 freshed ourselves at the forsaid gulfe, departed thence the 4 day 

 of October (either this or his first date, therefore, is a mistake), 

 and the seventh day arrived at a Castle called Sellizure. . . . The 

 Castle of Sellizure is situated upon a high hill. . . . The south 

 part of this Castle is lower land, but very fruitful, where grow 

 many good fruites ... the water that serveth all that country is 

 drawen by ditches out of the river Oxus, unto the great distruction 

 of the said river, for which cause it falleth not into the Caspian 

 Sea as it hath done in times past, and in short time, all that land 



is like to be distroied, and to become a wilderness for want of 

 water, when the river of Oxus shall fail." 



This apprehension was soon to be realised, for Abulgazee 

 relates, in the work already quoted from, that thirty years before 

 his birth, i e. in A.D. 1575, the Amii D.trya found a passage for 

 itsilf into the Sea of Aral ; a circumamce which changed the 

 environs of Urgenj into a desert by depriving them of the water 

 necessary for the irrigation of the soil. 



From the foregoing extracts we learn that, co.nmencing with 

 some year e.irly in the sixteenth century, tTe stream of the Anu'i 

 Darya, year alter year, fell short of reaching as far to the west 

 as it formerly did, until in A.D 1575 fie new channel into the Aral 

 conveyed the whole of t!ie waters which remained after the irri- 

 gation of the lands of the Khanate lying on the course of the river 

 above Urgenj had been provided for. 



As regards the actual condition of the old and present beds of 

 the Amii Darya, the levelling operations carried out in 1S73 and 

 1874 afford the following data : — 



Height of Aral . . above Caspian 250 feet. 

 11 IgJy • • „ Caspian 190 ,, 

 ,, Nukus. . „ Aral . 60 „ 

 ,, Nukus. . „ Caspian 310 „ 

 ,, Bend . . „ Aral . 70 ,, 

 ,, Bend . . „ Caspian 320 ,, 

 ,, Shahbazwali „ Aral . 140 ,, 

 ,, Shahbazwali ,, Caspian 390 ,, 

 Distance along old Amii from Caspian to Igdy . . 200 miles- 

 >■ >> .. Urgenj „ Igdy . . 274 ,, 



>> >i i> Urgenj „ Bend . . 43 ,, 



,, ,, ,, Urgenj ,, Shahbazwali 133 ,, 



>> i> >> Bend . ,, Nukus . 17 ,, 



The foregoing distances are taken along the meanders of the 

 bed. i„.hes. 



Hence the slope per mile from the Caspian . to Igdy . is 11.^ 

 >. .. .. Urgenj . „ Igdy . „ 3;* 



.. .. .. Bend . . „ Urgenj „ 3^ 



I, ,, ,, Shahbazwali,, Urgenj „ b.^ 



)i ,, ,, Shahbazwali,, Bend ,, gj 



>) >) ,, Bend . . „ Nukus „ 7j 



From the foregoing I infer Urgenj to be 56.I ft. above Aral, 



and 306^ ft. above the Caspian. 



The following are the conclusions I draw from the foregoing 

 data : — 



1. That the old bed between Urgenj and Igdy, having the 

 abnormally small slope of 3f in. per mUe, has probably been 

 raised by the deposit of silt carried by the waters of the river. 



2. That the bed of the Kunya Daryalik, which commences 

 opposite Shahbazwali, having a slope of SJ in. per mile above 

 Urgenj, discharged a larger body of water ttian the bed below 

 that place. The difference of the discharges must have been 

 disposed of in irrigation, and the abstraction of water from the 

 Kunya Daryalik was the cause of the silt deposited in the bed 

 of the river below Urgenj, as well as of that in the Kunya 

 Daryalik itself. 



3. The bed of Kunya Daryalik having a slope of 85 in. per 

 mile, while that of the present river, downwards to Bend, from 

 the head of the Kunya Daryalik, has a slope of <)\ in., it 

 follows, that the slope of the old course must have been 

 flattened from something steeper than 9.1 in. per mile to 8.], in. 

 per mile ; otherwise, the waters of the river could have never 

 passed by the Kunya Daryalik towards Urgenj. 



4. The water passing along the old Amii being headed back 

 by the deposition of silt in the old bed of the river, became 

 erratic during floods, and found an outlet by the Ardok channel, 

 which eventually carried all the waters of the Amii Darya towards 

 Nukus. 



5- The small difference of slope per mile of the beds of the 

 Kunya Daryalik, and the present Amii Darya, explains the 

 tenfiency of the flood waters to escape from the river, and the 

 necessity of the dams found along the old course. And since 

 the slope of the bed of the Amii Darya down to Bend is 9| in. 

 per mile, while that from Bend to Nukus is 7|, there must 

 always be a tendency, during Hoods, for the waters to be headed 

 back at Bend, and so to seek an escape by the Loudon channel, 

 across the mouth of which a dam has been constructed to 

 prevent such an occurrence. The condition of the bed of the 

 Amil Darya, from where the irrigation canals commence, down 

 to Bend, fully accords with the theory of the change of the course 

 of the river developed in this note. Descending from the point 

 indicated, the bed of the river is more and more encumbered 



