The above-described features of the physical geography of the empire explain the relative uniformity of this wide territory, in conjunction with the variety of physical features on the outskirts. They explain also the rapidity of the expansion of Sclavonic colonization over these thinly-peopled regions; and they also throw light upon the internal cohesion of the empire, which cannot fail to strike the traveller as he crosses this immense territory, and finds everywhere the same dominating race, the same features of life. In fact, as their advance from the basins of the Volkhoff and Dnieper to the foot of the Altai and Sayan mountains, that is, along nearly a quarter of the earth's circumference, the Russian colonizers could always find the same physical conditions, the same forest and prairies as they had left at home, the same facilities for agriculture, only modified somewhat by minor topographical features. New conditions of climate and soil, and consequently new cultures and civilizations, the Russians met with, in their expansion towards the south and east, only beyond the Caucasus in the Aral-Caspian region, and in the basin of the Usuri on the Pacific coast. Favoured by these conditions, the Russians not only conquered northern Asia--they colonized it. The Russian Empire falls into two great subdivisions, the European and the Asiatic, the latter of which, representing an aggregate of nearly 6,500,000 square miles, with a population of only sixteen million inhabitants may be considered as held by colonies. The European dominions comprise European Russia, Finland, which is, in fact, a separate nationality treated to some extent as an allied state, and Poland, whose very name has been erased from official documents, but which nevertheless continues to pursue its own development. The Asiatic dominions comprise the following great subdivisions:--Caucasia, under a separate governor-general; the Transcaspian region, which is under the governor-general of Caucasus; the Kirghiz Steppes; Turkestan under separate governors-general, Western Siberia and Eastern Siberia; and the Amur region, which last comprises also the Pacific coast region and Kamchatka. _Climate of Russia in Europe_.--Notwithstanding the fact that Russia extends from north to south through twenty-six degrees of latitude, the climate of its different portions, apart from the Crimea and the Caucasus, presents a striking uniformity. The aerial currents--cyclones, anti-cyclones and dry south-east winds--extend over wide surfaces and cross the flat plains freely. Everywhere we find a cold winter and a hot summer, both varying in their duration, but differing little in the extremes of temperature recorded.