the Mare Hyrcanum of the ancients, derives its name from the Caspi, a tribe who settled on its shores. Among the Orientals it is known under a variety of names; by the Russians it is called the Sea of Astracan, and by the Turks Bahri-Ghong. It is situated between 36. 35. and 47. 25. N. Lat., and 46. 15. and 55. 10. E. Long., is the largest inland lake in the world, and has no outlet to the ocean. It is surrounded by the Russian governments of Astracan and Orenburg, the Caucasian countries, Persia, and Tartary; its greatest length is about 760 miles, and its greatest breadth about 400 from east to west; generally, however, only half that breadth, and where narrowest, not more than 120 miles across. Its estimated area is from 120,000 to 140,000 square miles.

The eastern coast of the Caspian Sea, with the exception of the projecting promontory of Tuk-karagan and a few gulfs, extends nearly in a direct line more than 10° in length from north to south, between the parallels of 37 and 47. The small gulf of Aster-shid forms its southern limit, whilst its northern boundary is marked by a very large bight at its N.E. extremity, which receives the waters of the Emba. The principal branch of this river expands, before it reaches the sea, into a great many shallow basins like lakes, the northern branch of it being nearly choked up with sand. All this part of the coast, as well as that adjoining to the N. and N.W., is extremely flat and shallow, as the large rivers, namely, the Aral, the Volga, and the Tuck, which here empty themselves into the sea, are constantly bringing along with them a quantity of sand which accumulates on the shores. The whole of the northern part of the Caspian Sea, which, like the adjoining eastern coast, is exceedingly low, is thus rendered so shallow, that for the distance of several miles from the shore the water is only a few feet in depth; and an immense number of small sand-hills and banks of sand, make it difficult to land on any part of it. Similar sand-hills occupy also the shore itself, and extend to a considerable distance inland among the steppes; but it cannot be said that they form a continuous ridge. At the very commencement of this Sinus Mortuus (Mertooi Kultuk) there rises a small chain of calcareous hills, called the Chink, which forms, as it were, the rampart of a remarkable high level, named Ustirt, which extends under the 45th parallel, between the Aral and Caspian Seas, with a breadth of about 160 miles. This high plain is so steep towards both those seas, that it rises above the Caspian 639 English feet; and its fall towards the side of the Aral is not less. The elevation of this plain is never less than 550 feet, and is in some places more than 727 feet above the level of the Caspian; it extends nearly in a direct line between the two seas; and it sinks so insensibly, that there is nowhere to be observed anything like a continuous chain of hillocks, and it can only be considered in the light of one elevated plain. The extreme headlands of this high plain, namely, the Aksakil, the Sarak, the Karâ-chî, and the Karâ-tau, form so many small connected hill-tops round the height of Tuk-kara-sû, which is the southern branch of the Sinus Mortius. This continuous range of hills incloses the whole coast from this spot to Alexander's Bay, and extends nearly straight from north to south, with the exception of a small divergence to the east. They consist throughout of a recent tertiary calcareous formation. The depth of this coast is very remarkable; it is seldom so little as 6 fathoms, generally between 10 and 18. This gulf, as in Alexander's Bay, is connected with a large height, the entrance of which is formed by a precipitous rocky bank, from which the height widens considerably, and receives several rivers descending from the high plateau, namely, the Sirbîsh, the Kichik and the Kumbenska. Further east, and a little to the south, where we come upon the gulf of Kenderlui, the land shelves off, but as it is entirely surrounded by hillocks, it seems to receive no stream. Here, however, the hills of Kenderlui form again small chains connected with the larger hilly chain of the Kankhatch; and further inland, they are quite lost in the elevated plateau. A coast stream, the Turakhli, here empties itself into the sea, between the Kenderlui and Karâ-highi gulfs. The narrow entrance into this supposed very deep gulf is confined by a number of rocks, forming some dangerous eddies, and is surrounded in all directions by a steep bank; along the whole of its coast there is but one inconsiderable stream, the Makranda. To the east it is bounded by some small hilly knolls, which extend from north to south; but these are less remarkable for their height than for the great number of salt lakes, most of them very small, which are in the lower valleys. Finally, under N. Lat. 40., the gulf of Balkán is bounded by the extreme points of this elevated plateau; here also the hills rise steep and precipitous from the bank, and present at the top porphyritic formations, which in remote times have broken through beds of granite which occur also round the gulf of Krasnovodsk, at the entrance of the bay of Balkán, and in some of the islands in the bay. Here, likewise, this plateau consists of a tertiary calcareous formation which, towards the Balkán, crops out in single protuberances. The Bélán mountain, which shuts in to the east the bay of Balkán, so that the Amu-darya, whose old bed Dr Eichwald followed up for 5½ miles, could only fall into the bay between the great and little Balkán, whilst it wound round the southern point of the great Balkán and thus emptied itself into the bay in a direction from south to north. In consequence of the confined outlet of this old river, the bay is continually more and more choked up with sand, and has scarcely a depth of a few feet. Indeed, all this part of the coast is very much sanded up, and is very flat.

On the west shore the whole space between this sea and the Euxine is filled by the immense masses of the Caucasus. From this region the Caspian receives rivers which have their sources nearly 300 miles distant, the principal of which are the Rouma, the Terek, and the Kur; and it is remarkable, that between the Volga and the Terek, a distance of nearly 200 miles, there is only one river mouth, that of the Rouma, in consequence of the land at a little distance from the sea being so elevated as either to leave the running water to be absorbed in the soil, or to direct it towards the Don or the Euxine. The rivers that fall into the basin of the Euxine, Baltic, and Arctic oceans have their sources in this region at so small a distance from each other that a short canal has been cut uniting the Tvertza and Schlama, and connecting the Caspian with the Baltic through the Volga. Much of the timber used in the imperial yard at Petersburg is cut in the woods of Kazan and conveyed by this route up the Volga to its destination. This canal was the work of Peter the Great; and the same prince projected the union of the Caspian and Euxine Seas by connecting two small streams, affluents of the Volga and Don, which in the neighbourhood of Tzaratzen approach each other within two miles.

There are no tides in this sea, nor are there any regular currents; but the high winds which occasionally blow over its large surface cause considerable and irregular agitations in its motions.

The mean depth of the Caspian Sea is from 400 to 600 feet, and in some places is found to be 2700 feet; but its waters are everywhere very shallow near the shore, especially towards the west. Vessels drawing 9 or 10 feet water are thus compelled to unload far from the shore, excepting near Bakou and some other parts of the lake. Navigation is, in general, dangerous, owing to the frequency and violence of the east and west winds; and the contracted space forces the navigator to beat about in order to avoid the sand-banks concealed near its shores. The waters of the Caspian have a slightly bitter taste, communicated by the naphtha which abounds in the surrounding countries, and is carried into it by the streams which it receives; but they are not so salt as those of the ocean, in consequence of the great volume of water poured into it by the Volga and its other tributaries. Horses do not refuse to drink along the shores and near the mouths of the rivers.

Colonel Monteith says, "while in the habit of bathing in the Caspian, I found along the whole of the coast that for 100 yards the sea was not more than three feet deep, which increased like a step to 6, and at a short distance to 10, the intermediate space being perfectly level and the sand hard."

This sea is distinguished by a remarkable phenomenon. It appears to increase and decrease in actual bulk—in periods, according to native report, of about thirty years each. It is difficult to assign any cause for this phenomenon proportionate to the effect.

Monteith found the extra pressure of the atmosphere to be equivalent to a column of 390 feet in height; Burnes, some four or five years later, to one of 800 feet. It is therefore not improbable that the varying level depends in some degree on the varying pressure of the atmosphere. But whatever may be the variations in the surface of this lake, there can be little doubt that it was formerly much more extensive on three sides, north, west, and east, and it seems to be still diminishing. The fact that it never increases nearly in the ratio of the water poured into it, combined with its want of outlet to discharge that water, has led to the most extravagant hypotheses to account for a phenomenon apparently so paradoxical. But the diminution of the waters of this sea may be most reasonably accounted for by the evaporation, which is incredibly great in these regions; not from the temperature, which is lower than might be expected in these latitudes, but from the extreme dryness of the atmosphere. On the E. and N.W. shores the land rises in terraces like the present bed of the lake, and presents incontestible proofs of having been formerly covered with sea-water. The surface abounds in sea-salt, sea-weed, marshes, and salt-pits, together with innumerable shells exactly resembling those of the Caspian Sea, and which are not found in any of the rivers. Towards the east the whole country has the same appearance of a deserted sea-bed. Hence it is inferred that at no distant period the Black Sea, the Caspian, and the Aral formed one body of water. This conclusion is strengthened by the presence of the same species of fish, seals, &c., in the three seas.

It has always been evident that the bed of the Caspian was very low; and in the beginning of the present century Messrs Englebert and Parrot, with the view of ascertaining the fact, performed a series of barometric levelings between its shores and those of the Baltic, the result of which gave a depression of 333 feet for the surface of the Caspian. The accuracy of this measurement was however suspected by Humboldt and others; and to determine the question, the Russian government despatched an expedition, which after two years' labour, completed in 1838 a series of trigonometrical levellings, which were commenced on the 31st October 1836 by Messrs G. Fuss, Sailler, and Sawitsch, at the town of Kaganik, a little to the south of Azov, at the mouth of the Kagalnka, which falls into the Sea of Azov, between Lat. 47° 4° 26′ 3″ N., and Long. 2° 27′ 59″ E. from Paris. Thence they were continued by Stawropol (where the expedition passed the winter), Georgijewsk, Motlock, and Kisiljar, to the town of Tschemoi Rynok, on the shore of the Caspian, a little to the north of the mouth of the Terek, where the operations were terminated. The whole extent of this line is about 800 versts (about 600 English miles).

The measurements were of two kinds—trigonometrical and barometrical; the results obtained from six different measurements varied from 78 feet 1 inch to 83 feet 3 inches. The discrepancies in these results arise from the way in which the observers have calculated the measurements for the purpose of removing the effect of terrestrial refraction. We cannot decide as to which of these results is most probably the correct one; but it is evident, that as the uncertainty amounts only to a few feet, we shall not be very far wrong in assuming, as the number most nearly approaching the truth, the mean of the last four (which are those that agree the best with one another), viz., 81′3 English feet. Even should this number not be regarded as a definitive result, yet, at all events, by means of this first trigonometrical survey of the Caucasian isthmus, the fact is established that the surface of the Caspian Sea is actually at a lower level than that of the ocean, an opinion which has been lately disputed; and it is likewise ascertained, that the depression is only about one quarter so great as the older measurements led us to believe.

Considering the latitude, the temperature of this sea is extremely low. The northern part is frequently frozen, and the ice at the mouth of the Volga does not generally break up till April. The following table shows the temperature at Leukoran, on the west shore of the Caspian (in 38° 44′), Palermo, and Trèves.

| Seasons | Leukoran. | Palermo. | Trèves. | |---------|-----------|----------|--------| | Winter | 38° 16′ | 52° 5 | 36° 1 | | Spring | 55° 9 | 59° 0 | 50° | | Summer | 76° 8 | 74° 3 | 64° | | Harvest | 62° 1 | 66° 2 | 50° 1 | | Mean | 57° 2 | 62° 9 | 50° |

The surrounding country abounds with forests of fine trees, many of them covered with vines and hops, which frequently extend over three and four trees; almost every kind of fruit grows wild in abundance, and this is perhaps the country from which the greater part were originally brought. The largest class of vessels that navigate the Caspian vary in burden from 90 to 100, and sometimes 150 tons burden. Small fisheries are established on most of the rivers, and salmon are taken in large quantities. This fish is found in great abundance in all the clear mountain streams, but never in those proceeding from the swamps. Herrings, although taken in considerable quantities in the Terek and Aras, are never found to the south of the last-mentioned river. The fishermen do not ply their vocation in the open sea, nor have they nets fit for the purpose. Steamboats have been introduced into the Caspian, and the trade of the sea is entirely in the hands of Russia. (Hanway's Travels; MacCulloch's Geograph. Dict.; Edinburgh Philosophical Journal; Journal of the Royal Geograph. Society; Humboldt's Central Asia; Pallas's Travels; Eichwald.)