The reduction of Khiva marks a new era in the history of the Russian advance. The last semblance of organised opposition to the movement had disappeared, and the Tsar saw himself the unquestioned suzerain of the great Khānates. Westwards, his base was planted securely on the Caspian, where the port of Krasnovodsk, founded in 1869 by General Stolietoff,[560] was connected with the Russian colonies in the Mangishlāk peninsula by a chain of strong places. The Amū Daryā, that ancient boundary of nations, marked the limits of the new empire in the west. But the vast tract between sea and river was still unsubdued, and Russia’s boundary marched with that of no organised state. Here lay the habitat of the Turkomans, a race with whom no peace or truce was possible, and the story of their subjection forms the final chapter in the history of the heart of Asia. The haunt of these untamed tribes may be described as a triangle, with Khiva as its apex; its sides the Caspian and the Amū Daryā; and its base formed by a line drawn from the city of Balkh in Afghanistān to the south-eastern corner of the Caspian Sea. The area thus enclosed is not far short of 240,000 square miles, more than twice as great as that of the United Kingdom. The north portion is a trackless waste; but it is by no means a desert of the Sahara type, made familiar to us by so many records of African travel. Variety is its most salient characteristic. In some parts so firm is the surface that a horse’s hoof rings on it as on a macadamised road. In others, again, the loose sand forms ridges like petrified waves.[561] After the spring rains the expanse of dull white is carpeted, as if by miracle, with gorgeous lilies, tulips, and other bulbous plants, long grass and tufts of reed. Water is, indeed, required to clothe the arid sand with perennial verdure, and render it a breeding-ground for countless flocks and herds. It is found at depths rarely exceeding thirty feet below the surface, and wells are of frequent recurrence.[562] The only rivers of importance are the Murghāb and the Tajand, which rise in the mountains of Afghanistān and lose themselves in the sand; but streams innumerable descend their flanks. In times beyond the range of history the western portion of the Turkoman Desert was watered by the Amū Daryā, which discharged itself into the Caspian at the head of the Bay of Michaelovsk. Owing to some convulsion of nature, or to interference with its course by an attempt to employ it for irrigation, the bed of the mighty stream shifted and now discharges into the Sea of Aral. Vegetation is scanty, except during the brief spring-time. The soil is covered, in some parts, with the camel’s thorn, a forbidding plant which can be masticated only by the “ship of the desert.” The perennial flora are completed by the stunted tamarisk, a root like the stem of a rose called takh, and a shrub termed saxaul (_haloxylon ammodendron_). The latter is full of knots, and has a grain most difficult to cut or split, but it is precious as fuel, and still more valuable as a means of binding the billowy sands. These steppes contain few traces of animal life. Herds of beautiful wild asses are sometimes seen in the distance, and a species of antelope is oftener met with.[563] Wells are beset with a variety of birds, which fly down to their depths in search of water. But the stillness of the waste is intense, and the boundless horizon is seen through the clear pure air shimmering with the heat or broken only by a mirage. The climate of the Turkoman Desert is one of extremes. In December and January the cold is intense. Moser, who traversed the Kārakūm in the depth of winter, encountered a temperature of 15 degrees below freezing-point, with squalls, snow, and glacial cold.[564] In the summer months the heat is equally trying, and it is sometimes accompanied by sand-storms which render respiration almost impossible. But the Turkomans are not confined to regions so inhospitable. They have long been established in the south-east of the Caspian, a tract watered by the rivers Gargan and Atrak, which is swampy towards the embouchure, but farther inland is broken by valleys as rich and full of charm as any on the flanks of the Pyrenees.[565] The streams descending from the Kopet Dāgh, a mountain range which separates Persia from the Turkoman Desert, has produced a fertile belt of fifteen to twenty-five miles wide, extending from Kizil Arvat to Giaour, a distance of 187 miles. This is the Akkal oasis. Where the Murghāb enters the desert it forms the great Merv oasis, a land which, even in its decadence, is one of the most fertile in the world.