The Ukrainian river system concentrates in the Black Sea. From northwest, north and east, the rivers of the Ukraine tend toward its sea. Besides, the western boundary lines of the Ukraine lie on the Baltic slope. There, in Podlakhia, in the Kholmshchina, on the San River and in the Lemko country, the Ukrainian people has had its seats since the dawn of its history. In most recent times Ukrainian colonization has gained also parts of the Caspian slope on the Kuma and Terek Rivers. But the region drained by the Black Sea surpasses both the other regions so much in extent and in the size of its rivers, that the Baltic and Caspian region of the Ukraine dwindle in comparison. Nature has, therefore, turned the Ukrainian nation toward the south and southeast to the Black Sea. But, at the same time, she has not denied the Ukraine a convenient connection with the north and south of the globe. The main European river divide is, perhaps, nowhere so flat and so easy to cross as in Ukrainian territory. From the Dniester to the San (bifurcation of the Vishnia creek near Rudki), from the Pripet to the Buh and Niemen the passages are easy. Since ancient times portages have [64]existed here, and in modern times the Pripet has been connected with the Buh and the Niemen by means of canals (King’s Canal and Oginski Canal) which, however, are at present entirely antiquated and almost useless. Besides, the widely branched water system of the Dnieper outside the Ukraine affords easy passage to the Dvina (Beresina Canal), Volga and Neva, in White Russian territory. Over these waterways and the portages lying between them the old path of the Northmen led from Scandinavia to Constantinople. This most important aspect of the Ukrainian water system promises at some future time to bear rich fruit, if the recently-formed plan to build a waterway for navigation on a large scale, from the Baltic to the Black Sea, utilizing the course of the Dnieper, should become a reality. The Baltic watercourses of the Ukraine flow into the Vistula. Several large Carpathian tributaries originate in Ukrainian territory. Here the rapid Poprad carries the melted snow of the Tatra to the Dunayetz. The source of the Visloka also lies in the Ukrainian Lemko country. The last and largest Carpathian tributary of the Vistula belongs, in three-fourths of its extent, to Ukrainian territory, namely, the navigable San. It receives from the Carpathians the Vislok on the left and the Vihor on the right. The other tributaries of the San on the left side, the Vishnia, Sklo, Lubachivka and Tanva, come from the sub-Carpathian country and the Rostoche Plateau.