soil—such are the general characters of the northern border region of the great plain of central Poland. The rivers flow across the plain in broad, level valleys, only a few hundred or even only a few dozen feet lower than the watersheds; they separate into many branches, enclosing islands, forming creeks, and drowning wide tracts of land during inundations. Their basins, especially in the west, interpenetrate one another in the most intricate way, the whole bearing unmistakable evidences of having been in recent geological, and partly in historical times the bottom of extensive lakes, whose alluvial deposits now yield heavy crops. The fertility of the soil and the facility of communication by land and by water have made this plain the cradle of the Polish nationality. The very name of Poland is derived from it—Wielkopolska and Wielkopolane being the Slav terms for the great plain and its inhabitants.
Rivers and Canals.—Russian Poland belongs mostly, though not entirely, to the basin of the Vistula—its western parts extending into the upper basin of the Warta, a tributary of the Oder, and its north-east spur (Suwalki) penetrating into the basin of the Memel, of which it occupies the left bank. For many centuries, however, the Poles have been driven back from the mouths of their rivers by the German race, maintaining only the middle parts of their basins. About Jozefow (51° N.) the Vistula enters the great central plain and flows north and west-north-west between low banks, with a breadth of 1000 yds. Its inundations, dangerous even at Cracow, become still more so in the plain, when the accumulations of ice in its lower course obstruct the outflow, or the heavy rains in the Carpathians raise its level. Embankments 20 to 24 ft. high are maintained for 60 m., but they do not always prevent the river from inundating the plains of Opole in Lublin and Kozienice in Radom, the waters sometimes extending for 150 m. to the east. Thousands of rafts and boats of all descriptions descend the stream every year with cargoes of corn, wool, timber and wooden wares, giving occupation to a large number of men. Steamers ply as far as Sandomir. The Wieprz (180 m.), a right-hand tributary of the Vistula, is the chief artery of the Lublin government; it is navigable for small boats and rafts for 105 m. from Krasnystaw. The Bug, another right-hand tributary of the Vistula, describes a wide curve concentric with those of the middle Vistula and the Narew, and separates the Polish governments of Lublin and Siedlce from the Russian governments of Volhynia and Grodno. Only light boats (galary) are floated down this broad, shallow stream, whose flat and open valley is often inundated. Its tributary, the Narew (250 m.), brings the forest-lands of Byelovyezh in Grodno into communication with Poland, timber being floated down from Surazh and light boats from Tykocin in Lomza. The Pilica, which joins the Vistula from the left 30 m. above Warsaw, rises in the south-western corner of Poland, and flows for 200 m. north and east in a broad, flat, sandy and marshy valley, of evil repute for its unhealthiness.
The Warta (450 m.) rises in the Czenstochowa hills, 900 ft. above the sea, and flows north and west past Sieradz and Kolo. Below Czenstochowa it traverses a flat lowland, whose surface rises only 2 to 5 ft. above the level of the river, and the inhabitants have a constant struggle to keep it to its bed; every spring an immense lake is formed by the river at the mouth of the Ner, a little above Kolo.
The Memel flows along the north-east frontier of Poland, from Grodno to Yurburg, separating it from Lithuania. The yellowish sandy plains on its left will grow nothing except oats, buckwheat and some rye. The river often changes its bed, and, notwithstanding repeated attempts to regulate it, offers great difficulties to navigation. Still, large amounts of corn, wool and timber are floated down, especially after its confluence with the Black Hancza.
Though navigable for a few months only, the rivers of Poland have always been of considerable importance for the traffic of the country, and their importance is further increased by several canals connecting them with the Russian and German rivers. The Memel is connected with the Dnieper by the Oginsky canal, situated in the Russian government of Minsk. The Dnieper and Bug canal in Grodno connects the Mukhavets, a tributary of the Bug, with the Pina in the basin of the Pripet, that is, the Dnieper with the Vistula. The Vistula is connected also with the Oder by the Bromberg canal in Prussia, which links the Brahe, in the basin of the Vistula, with the Netze, a tributary of the Warta. All these canals are, however, beyond Russian Poland. In Poland proper, the Augustowo canal connects the Vistula with the Memel, by means of the rivers Black Hancza, Netta, Biebrz and Narew. Another canal, to the west of Lęczyca, connects the Bzura, a tributa of the Vistula, with the Ner and the Warta; and the bed of the Rirmer has been altered so as to obtain regular irrigation of the meadows along its banks.
Lakes.—Lakes are numerous in the government of Suwalki, but are all small and mostly hidden in thick coniferous or birch forests, and their waters penetrate with undefined banks amidst marshes, sandy tracts and accumulations of moss-grown boulders. Another group of small lakes is situated in the basin of the Warta (north part of Kalisz), the largest being Goplo, 18 m. long and 100 ft. deep.
Climate.—With the exception of the Lysa Góra hilly tracts (Kielce and south Radom), which lie within the isotherms of 41° and 42°, Poland is situated between the isotherms of 42° and 46°. The isotherms and isocheims (i.e. lines of equal mean summer and winter temperature respectively) crossing one another at right angles, and the former running east-north-east, Poland is included between the isotherms of 64° and 61° and the isocheims of 35.7° and 39.2°. The prevailing winds are westerly, with north-north-east and south winds in autumn and winter, and east winds in spring. There is an average of 21.7 to 23.6 in. of rainfall in central Poland, and the quantity increases slowly towards the south on account of the proximity of the Carpathians, where it is 30.3 in. Owing to this distribution the snow-sheet in Poland is not very thick, and spring sets in early. Still, frosts of -4° to -22° Fahr. are not uncommon, and the rivers are generally icebound for two and a half to three months—the Warta being under ice for 70 to 80 days, the Vistula at Warsaw for 80 days and (exceptionally) even for 116, and the Memel for 100 (exceptionally for 140).
The following averages will serve to illustrate the climate of Poland:—
| Warsaw. | Vilna (in Russia). | |
| Earliest frost | Oct. 18 | Oct. 17 |
| Latest frost | March 15 | March 25 |
| Absolute maximum temperature | 95.5° | 89.3° |
| Absolute minimum temperature | -37.6° | 39.0° |
| Annual rainfall (total) | 22.8 in. | 7.6 in. |
Flora.—The flora of Poland is more akin to that of Germany than to that of Russia, several middle European species finding their north-east limits in the basin of the Memel or in the marshes of Lithuania. Coniferous forests, consisting mostly of pine (Pinus sylvestris) and birch, cover large tracts in Mazovia in the north, extend across the Baltic lake-ridge southwards as far as the confluence of the Bug with the Narew, and join in the south-east the Polysie of the Pripet. The pine covers the Lysa Góra hills and the hills in the extreme south-west. The larch, which three centuries ago covered large tracts, has almost entirely disappeared. Pinus cembra is only remembered, as also Taxus baccata. Picea obovata is cultivated.
Of deciduous trees, the common beech is the most typical; it extends from the Carpathians to 52° N. and reaches three degrees farther north in small groups or isolated specimens; the confluence of the Bug and the Narew may be regarded as its eastern limit. The white beech (Carpinus betulus), the aspen, and two elms (Ulmus campestris, U. effusa) are found nearly everywhere. The lime appears in groves only in the east (Memel, Pripet, Lublin). It is the most popular tree with the Poles, as the birch with the Russians; judgment of old was pronounced under its shade, and all the folk songs repeat its name. The oak—a highly venerated tree in Poland, though not so much as in Lithuania—grows in forests only on the most fertile land, but it is of common occurrence in conjunction with the beech, elm, &c. The maples (Acer platanoides and A. pseudo platanus) are somewhat rare; the black alder (Alnus glutinosa) lines the banks of the rivers and canals, and the Alnus inana is common. The willow and orchard trees—apple, pear, plum and cherry—are cultivated everywhere.
Fauna.—The fauna of Poland belongs to the middle European zoological group; within the historical period it has lost such species as formerly gave it a subarctic character. The reindeer now occurs only as a fossil; the sable, mentioned in the annals, has migrated eastwards; the wild horse, described by the annals as intermediate between the horse and the ass—probably similar to the Equus przewalskii of central Asia—is reputed to have been met with in the 13th century in the basin of the Warta, and two centuries later in the forests of Lithuania. The wild goat, bison and elk have migrated to the Lithuanian forests. The lynx and beaver have disappeared. The brown bear continues to haunt the forests of the south, but is becoming rarer; the wolf, the wild boar, and the fox are most common throughout the great plain, as also the hare and several species of Arvicola. The mammals in Poland, however, do not exceed fifty species. The avi-fauna, which does not differ from that of central Europe, is represented by some one hundred and twenty species, among which the singing birds (Dentirostrae and Conirostrae) are the most numerous. On the whole, Poland lies to the westward of the most frequented route of the migratory birds, and is less visited by them than the steppes of south-west Russia. Numerous aquatic birds breed on the waters of the Baltic lake-region.
Population.—The population of Poland, 6,193,710 in 1871, reached 7,319,980 in 1881, and 10,500,000 in 1897. The estimated population in 1906 was 10,747,300 Details for 1897 are shown in the subjoined table.
