We shall conclude this survey of Siberia with a few observations on the Polar Sea, which constitutes rte northern boundary. Nearly opposite the middle of the cost-line of Siberia, or more precisely, opposite the country between the mouths of the rivers Yana and Indighirks, is a group of Wands, which are called, from their dis coverer, the Liakehoff Islands. They consist of four larger and some smaller isbustle. The larger islands are named Kotelnol, Fadeyefskol, New Siberia, and Liakehoff, and vary in size from 100 mike long by 60 miles broad, to 40 miles long by 20 miles broad. Even the sum mers on these islands are so cold that the snow does not entirely melt, and not a blade of grass grows. They consist of layers of ice, alternating with layers of sand, in which an incredible number of elephants' and other fossil bones are imbedded. The sea between these islands and the continent does not completely freeze before the last days of October, but along the coast of Siberia the ice is formed much earlier in the year, and soon acquires a degree of firmness. On the contrary, in spring, the ice melts much sooner along the coast, which is quite free from it in the month of June, whilst in the open sea it constitutes one unbroken sheet of ice up to the month of July, and the quantity is hardly perceptibly diminished even towards the end of the summer. It floats about in the sea in large masses, which, being impelled by currents and winds, are driven against one another with incredible force. These floating masses render the navigation of the Polar Sea extremely dangerous, and have frustrated attempts made to survey the entire coast; the tract still unsurveyed incloses the most northern cape of Siberia, called the North-East Cape, or Severe Vostostchinii Noss. In endeavouring to reach the American continent by Behring'e Strait, some explorers have made use of nartea, or sledges drawn by dogs. They generally set out in the latter part of the winter, from March to the end of May, when the cold is much less severe than in the earlier part of the winter. It has thus been ascertained that in winter the largo body of the sea is open and free from masses of ice, but this open water occurs in different parts at different distances from the shore. In expeditions of this kind numerous ice-hills have been met with, which sometimes constitute single masses with steep declivities; at other times they form regular groups ; and frequently they form long ridges. They consist of masses of ice irregularly united, but as the hollow places are filled up with snow, they appear to have a regular form. They vary in height from 10 to 70 feet, and are certainly of a different origin from the icebergs of the Greenland Sea. Salt is found on the ice wherever it is not covered with a thick layer of snow. It is iu the form of small shot, and it has a somewhat bitter taste, but may be used. The persona who annually visit the Liakehoff Islands, use it without the least inconvenience. This sea-salt, called rass61, very much retards the progress of the nartes on the ice.
Climate.—Siberia is the coldest country in the northern hemisphere, if we except Greenland and the Arctic Archipelago of North America. It is much colder than any part of Europe situated in the same lati tude. North Cape, in Europe, is near 71 10' N. lat. ' • and Ustyansk, at the mouth of the river Yana, in 70' 55' N. let. The latter place however is nearly 23 degrees colder, as the following table shows : mean annual Mean tem. mean tem. Mean tem. Mean tem. temperature. of Winter. of Spring. of Summer. of Autumn.
North Cape . +32° +24' +30° +42° +32° Ustyarisk . . +439' -24•9' +27'0l° +40.15* -2410* Irkutsk is only about 45' nearer the pole than London, and yet the moan annual temperature is lower than that of North Cape, being 31°; while the mean annual temperature of London 50'. But Irkutsk is 1210 feet above the sea-level.' This elevation however would lower its temperature only three or four degrees. The climate increases in severity as we proceed from west to east. The severity
of the winter in Eastern Siberia is shown by the circumstance that quicksilver freezes every winter in the country near Irkutsk, and in Yakutat It remains in a frozen state for two months together even in mild winters, and in severe seasons for three months. In a large part of Siberia. the ground is frozen to a considerable depth even at the end of the summer. In Western Siberia the winter, although very cold, is much less so than in the eastern districts. The summers in Western Siberia are warm and sultry, chiefly in consequence of its proximity to the Great Caspian Desert, which is subject in summer to excessive best. We may here give the temperature of two places at a considerable distance apart, namely, Bernaul and Nishnei-Kolymsk, of which the former may be considered ouo of the warmest and the latter one of tho coldest places in Siberia. Bernaul is in 53° 20' N. lat., 84' 10' E. long.; and Nishnei-Kolyrnsk in 08° 31' N. let., 160' 56'E. long. Bernaul is 390 feet above the sea; Nishnei-Kolynisk is almost on a level with the sea :— Mean annual Mean tern. Mean tem. Mean tem. Mean tem. temperature, of Winter. of Spring. of Summer. of Autumn.
Bernaul . . . +35.13' +6'61° +42'92° +61.82° +29.18° Niahnei-Kolymsk +12195* +36•15° +44.41° -13.33° Wrangel, who passed three years at Nishnei-Kolymsk, gives a description of tho climate of that place. Tho year is divided into two seasons, the winter and the summer. The river is covered with ice iu the beginning of September, and is not free from It before the begin ning of Juno. In October the cold is diminished by thick fogs and the vapours which rise from the sea, which then begins to freeze. The frost attains its greatest degree of severity in January, when the thermometer sinks to -60'. Respiration then becomes difficult, and the wild reindeer, the truo inhabitant of tho polar regions, hides itself In the thickest parts of the forests, and stands motionless. In February the cold does not decrease much ; in March it begins to decrease more; but the cold which in these months is felt at sunrise is unusually neere to the feelings. The wind which la called the hot wind blow; from eastaouth-east and raises the temperature suddenly from between -45' and -50' to +29' and upwards, but It generally does not last more than 21 hours. A sudden rise of the thermometer takes place during the month of June. It sometimes attains at noon. In July the heat is greatest, and the weather more constant, but there are innumerable swarms of gnats, which torment men and, animals. These gnats compel the numerous herds of reindeer to leave the forests, and to retire to the treeless country on the shores of the sea, when vast numbers of those animals are killed by the natives. In August the heat decreases rapidly, and night-frosts are frequent towards the end of that month.
Firers.—Siberia has a great number of rivers, and as the whole course of most of them, and the greatest part of the course of the remainder, lies through a level and hilly country, nearly all of them are navigable for a great distance. The principal rivers run from south to north, from the agricultural distriota to those where vegeta tion does not supply food to the inhabitants, and hence their great importance for internal intercourse. The tributaries, at least the greater number and the largest of them, run chiefly east and west, and form a water-commonlcation between the agricultural districts themselves, and render it practicable for goods bought from the Chinese at Maimatehin to be transported to European Russia at nearly the same expense as those which are obtained at Canton are carried to Great Britain. Though all these rivers are frozen for more than six months of the year, the advantages arising from them are not thereby materially diminished, as the ice facilitates communication almost as much as the open water. Of the rivers of Siberia the most important are the Oby, the Yenesei, and the Lena.