The Polish language is spoken at present within a quadrilateral the angles of which are found at the Jablunka pass in the Carpathians,[97] Wissek north of the Netze near the Posen boundary, Suwalki in the eastern Masurian region and Sanok on the San. A northern extension is appended to this linguistic region in the form of a narrow band which detaches itself from the main mass above Bromberg and reaches the Baltic coast west of Danzig. In sum, the valley of the Vistula, from the Carpathians to the Baltic, constitutes the field of Polish humanity and institutions. In spite of the remoteness of the period when they first occupied the land, these children of the plains never attempted to scale mountainous slopes. The solid wall of the western Carpathians, between Jablunka and Sanok, with its abrupt slopes facing the north, forms the southern boundary of the country. This region, in the midst of the diversity of surface of the European continent, has produced a distinct language in the varied stock of European vernaculars. Nevertheless there is no similarity of physical type among individuals speaking Polish. Marked anthropological differences are found between the Poles of Russian Poland and of Galicia.[98] They correspond to the classification of northern Slavs into two main groups, the northernmost of which comprises the Poles of Russian Poland, together with White and Great Russians. Traces of Finnish intermixture can still be detected among them, in spite of the process of Slavicization which they have undergone. The Poles of Galicia, on the other hand, like the Ruthenians and Little Russians, reveal mingling of the autochthonous populations with Asiatic and Mongoloid invaders of Europe.[99] Delimitation of the area of the Polish speech is more easily made in theory than on the field. The transition to alien languages is rarely well defined. Such detailed work as has been undertaken in western Europe, where the predominant language in small villages and hamlets is often determined, does not exist for eastern sections of the continent. The zeal of German and Russian agents of nationalist propaganda aggravates the problem. Within Galicia the boundary line passes west of Sanok and Radymno.[100] Its southern extension skirts the foothills through Rymanow, Dukla, Zmigrod and Grybow. Thence to Jablunka pass it merges with the political boundary. In its western section the physical boundary coincides for all practical purposes with the ethnographic line of division. The Gorales mountaineers have never aspired to cross the divide of the Beskid mountains. The result is that the gentler slopes of the southern side are peopled altogether by Slovaks, while habit and custom have prevented the Podhalians, or Polish shepherds inhabiting the high valley of the Tatra, from leading their flocks to the southern grazing slopes which form part of the Hungarian domain.[101] [Illustration: _Copyright by Brown Bros._