The Tartars inform you that the word “Aral” implies between, and that that sea or lake is so called from its lying between the Sir and the Amoo, the Jaxartes and the Oxus. It is a popular belief, that the waters of the Aral pass by a subterraneous course into the Caspian. At a spot called Kara Goombuz, between the seas, where the caravans halt, some assert that the water is to be heard rushing beneath. It is said to make a noise like the words “Kara doom,” which mean “I am thirsty;” but the clock strikes what the fool thinks. The necessity of some such subterraneous passage is obvious in the eyes of the people, since the Aral has no outlet for two large rivers, but they do not think of evaporation, which is great beyond belief in this dry country[23], where there is also a perpetual wind. It is a curious fact, however, that at Kara Goombuz, before mentioned, which appears to be a sandy ridge, water is found close to the surface, while further south it is not to be had nearer than 100 fathoms. The water of the Aral is drinkable. It is seldom frozen in winter. In one of its many islands they relate some tales of a colony that passed over the ice with their herds and flocks, and has since had no opportunity of returning. The banks of the Aral are peopled by wandering tribes, who cultivate great quantities of wheat and other grain, which, with fish, that are caught in abundance, form their food. The neighbourhood of the Aral is not frequented by caravans.
Capabilities of the Oxus.
The Oxus is a navigable river throughout the greater portion of its course. Its channel is remarkably straight, and free from rocks, rapids, and whirlpools; nor is it much obstructed by sand-banks: were it not for the marshes which choke its embouchure, it might be ascended from the sea of Aral to near Koondooz, a distance of 600 miles. If we deduct the extent of that delta, commencing some way below Orgunje, which does not exceed fifty miles, we have still an inland line of navigation of 550 miles. The volume of water which this river discharges appears great for the short extent of its course, but it is the only drain of a wide and mountainous country. It is never fordable after it has received the rivers of Koondooz and Talighan, which join it under the name of Aksurai, below Huzrut Imam; these rivers are fed by the melted snow on the northern side of the great Hindoo Koosh. It may then only be so passed below that place (Huzrut Imam) for six months during the year, when the ford is passable for artillery; which has been frequently verified by the ruler of Koondooz. On leaving the hilly ground below Kilef, about sixty miles north-west of Balkh, the channel of the Oxus does not exceed 350 yards; on the plain it is wider spread, and we crossed it at Khoja Salu, thirty miles below that point, with a channel of 823 yards, as determined by the sextant. At Charjooee, 200 miles lower down, within twenty leagues of Bokhara, it had a channel of 650 yards. A detailed account of the river at these points will furnish the best data for a determination of its capabilities in a military and commercial point of view.
Depth, current, and slope of the Oxus.
At Khojusalu, on the 17th of June, a month before the periodical swell had attained its greatest height, the Oxus was divided into three distinct branches, only separated from each other by sand-banks. The width of these arms respectively was 295, 113, and 415 yards; which gives the total breadth of 823 yards. The soundings were irregular, and at the deepest place did not amount to twenty feet. An enumeration of them follows:—6, 9, 12, 6 feet in the first branch; 6 feet throughout the second; and 6, 9, 15, 19, 6, in the third and last. The medium depth of this river will never, therefore, be less than nine feet, since that is the product of 828 yards, divided by 92, the sum total of all the feet in the different soundings. Nor can there be much incorrectness in the approximation, since on the 17th of August, which is precisely two months later, when the river had passed its greatest rise, we had much the same volume of water at Charjooee, near Bokhara. The breadth was less, but the soundings were greater, and five heaves of the lead gave 12, 18, 29, 20, and 18 feet. The Oxus flows with a velocity of 6000 yards, or nearly three and a-half miles an hour; and I discover from the boiling point of water at the two places (Khoja Salu and Charjooee), that there is a difference of one and one third of a degree between them, which will give a slope of 800 feet in a distance of 200 miles. This is a great fall in such a river on so flat at country; and, since the boiling point of water is subject to slight variations even at the same place according to the state of the atmosphere, it must only be received as an approximation to the truth. The smallest change in so rude an instrument, for so nice an operation, produces a great error, but, after every allowance, I cannot rate this fall under 600 feet, or about a yard a mile: the course of the river is not tortuous, which always bespeaks a greater rapidity of descent.
Inundation of the Oxus.
The Oxus is subject to a periodical swell, as are all the great rivers which flow from the south of the same stupendous chain of mountains in which it has its rise. In both cases the causes are similar,—the melting of the snows in elevated regions. The inundation commences in May, and ceases in October; but it is also subject to a second and lesser flood during the rains of spring. It fluctuates in its rise and fall with the state of the weather, rising under the sun of a cloudless sky, and sinking with a denser atmosphere; while on its banks, in June, it subsided a foot and a half in thirty-six hours, and it had not then attained its height. The influence of the waters is rarely felt for half a mile beyond the channel of the river, though its inner banks are low and depressed, but there is a second bank varying in distance from a mile and a half to two miles on either side, and in some places more distant. The valley thus formed is clothed with verdure and moistened, though seldom inundated by the swell. Here it is that the inhabitants cultivate the land, and water it by industry and art. In some instances the aqueducts extend inland for a distance of four miles, and the water must then be raised by the Persian wheel for irrigating the fields. On leaving this tract the scene changes to sterility and desolation: the valley itself is in many places overgrown with a bastard indigo, tamarisk, and rank weeds, and neglected by the inhabitants. In winter, when the river has retired to its bed, it is contracted to a space of 400 yards, but is never fordable. During the swell, the waters of the Oxus are tinged by the soil of the mountains, and assume a reddish hue. I ascertained that one fortieth of their body consisted of silt suspended in the stream; while under the influence of this snowy water, the river had a temperature of 73° at the summer solstice, when the thermometer rose to 103° in the air.
Freezing of the Oxus.
It would not have been suspected that so vast a river, in so low a parallel as 38° north latitude, should be frozen during winter, which is no rare occurrence with the Oxus. The upper part of its course above Koondooz freezes annually, and passengers and beasts of burden cross it on the ice, on their route to Yarkund; but there it flows in an elevated region. In the desert, however, its waters are also congealed in a severe winter. Below Khiva it freezes annually; and at Charjooee, which is about seventy miles from Bokhara, it was frozen last year from bank to bank. The season was remarkably cold, and the caravans passed it on the ice. At Kirkee, half-way to Balkh, it was also frozen; but at the ferry of Kilef, opposite that city, there was a narrow channel in the middle of the stream, which prevented the passage of both boats and caravans for a month. A stone could be thrown from the ice of one bank to that of the other; and it is not doubted that the only hindrance to their junction in this narrow part of the Oxus arose from the rapidity of the current, that was hemmed in by a confined bank. It is an established fact, that the temperature of deserts is both colder and hotter than countries which are more favoured by nature. In the torrid deserts of Toorkistan, there is a cold bleakness during winter, which will account for the congelation of the Oxus; it is nevertheless a curious fact in physical geography, since the Danube, which flows parallel with the Oxus, and in a higher latitude by seven degrees, is not subject to a like phenomenon. In winter, if the Oxus be not frozen, the passage of boats is sometimes endangered by the masses of ice which are floated down from the upper part of its course. These have been known to sink a boat, and require attention on the part of the ferrymen.