CLIMATE. Europe is the only continent that lies entirely outside of the tropical zone, and only a small part of it is included in the frigid zone. The ameliorating influences of the North Atlantic and the westerly winds That over it are felt far east along the shores of the Arctic so that at Katharine Haven, on the Ilurman Coast, the harbor is practically ice-free the year around. Thus, though the eontinent extends several de grees of latitude north of the Arctic Circle. very little of it is under polar influences. The conti nent lies in the temperate zone; and of all the land-masses in the same latitude it has the mild est and most genial climate. The warm winds from the Atlantic, the prevailing winds, have almost everywhere free access into the interior, sweeping up the arms of the sea and across the low coasts and plains, not only mitigating high and low temperatures, but also giving wide dis tribution to the rainfall. The fact, also, that the mean elevation of the continent above the sea is very much lower than that of any other conti nent excepting Australia (only about 950 feet, according to the results obtained by Supan and De Lapparent), emphasizes the prevailing tem perate influences. In all parts of the continent there is sufficient warmth and rainfall for agri culture except where farm operations are pre vented by cold in the extreme north and in the highest mountain regions, and by dryness on the salt steppes of the Caspian Sea.
The eastern part of Europe, however, is re mote from the influence of the sea, and has the continental rather than the sea climate. The mean annual temperature, therefore, declines not only from south to north, but also, except along the Mediterranean, from west to east. e.g.: Greenwich, 49.7° F.; Berlin, -18.4'; Warsaw, 44.9° ; Saratov (East Russia), 417°—these four places being in nearly the same latitude. But while the yearly mean of temperature is lower in the east than in the west of Europe, the summer temperature is higher in the east than in the west, because the interior land-mass becomes more heated than the regions bordering the sea with their more equable climate. In the south the influence of the Mediterranean is to impart to the countries along its shores a very uniform climate, the Alpine system also contributing to this advantage by warding off the cold northeast winds.
The precipitation decreases with distance from the Atlantic, the eastern part of the continent be ing much drier than the western, and driest along the north coasts of the Black and Caspian seas, where forest gives place to steppe. In no
region, however, is the country so dry as to be come a desert. In the northern half of Europe the precipitation is quite well distributed throughout the year, \011ie winter rains predomi nate in all the Mediterranean countries. In a large part of Spain, for example, irrigation is the basis of agriculture because most of the rain falls after the growing season. Many local con ditions modify both temperature and quantity of precipitation. The Scandinavian mountains, for example, are the cause of the larger precipita tion on the west than on the east side of the peninsula: they also exclude the icy northeast winds of winter from the west harbors of Nor way, which are ice-free.
lion.t. If temperature be taken as the deter minant—perhaps the simplest method in classify ing the flora of Europe—three general regions are observed which more or less overlap one another. In general, the limits of these regions vary with the isotherms and with the eoast-lines, but are modified by mountain ranges and rivers: the summits of the former affording homes to boreal species, the valleys of the latter allowing less hardy plants to extend inland into colder locali ties than they could otherwise reach.
The Arctic region, mainly tundra, which in northwestern Enriqie finds its southern boundary on the polew-ard side of the Arctic Circle, and in the northeastern part of the continent extends considerably to the south of this line. is char acterized on its extreme northern border by lichens and mosses, which gradually give place southward to perennials of wonderful hardiness and longevity, but of small stature, slow growth, and inferior powers of reproduction by seed. The mountains throughout the continent present similar gradations, the vegetation at the highest altitude corresponding more or less closely to that in the highest latitudes and disappearing at lower elevations among species of more tem perate regions, which gradually supplant it as the altitude is reduced and the temperature conse quently increased. Icy far the inost common species of this Arctic flora are the saxifrage, potentilla, poppy, scurvy-grass, crowfoot, all of which bear showy flowers; and stunted, trailing junipers, willows, and birches, which are buried under the snow during the long winters. The species of this region, about seventeen hundred, are of insignificant economic importance when compared with those of the other two regions. See ARCTIC REGION, section Arctic Mints.