In the great desert regions of Gobi, the Caspian and Aral Sea regions, and in Persia, it is below ten inches. In most of Arabia it is below ten inches, except in the higher plateau of the interior, where it reaches twenty inches. In Manchuria the rainfall increases to 30 inches, and in China it increases southward from 30 inches in the north to 40 inches at the mouth of the Hoang, to 70 inches in the southern part, and is 80 inches in Japan. The Malay Peninsula has an excessive rainfall. In the Himalaya region the rainfall on the southern slopes sometimes amounts to over 160 inches, in one limited region to 475 inches, and for much of the southeastern coast region of India it reaches from 120 to 160 inches; but it decreases very rapidly west of Calcutta, and on most of the Deccan Plateau it is only 20 inches, increasing again on the western coast to from 40 to 100 inches. The heaviest annual rainfall in the world occurs in Assam, to the south of the eastern Himalayas, where a precipitation of 800 inches is on record. While the normal rainfall for southern Asia may be estimated at from 40 to 60 inches, yet wherever a mountain range intercepts the moist winds blowing from the Indian Ocean, a rainfall of from 140 to 160 inches occurs on the windward side of the mountains, and usually of from 20 to 40 inches on the leeward side. Northern Asia has rain at all seasons, except in the deserts, where rain seldom falls. Southern Asia, including India and the Malay Peninsula, is subjected to periodic rains, the maximum occurring in summer, the period of the southwest monsoons.
Winds. While southern Asia is in the region of normal winds, the trades, yet these winds are very much, sometimes totally, changed by the monsoons. During the summer season the interior of the Continent becomes intensely heated, and the surface winds blow inward from the south, forming the southwest monsoon; the air thus brought inland is saturated with moisture, which it discharges freely on being cooled in passing over hills or mountain ranges. This monsoon character of the winds has a very marked effect on the rainfall of southern Asia, and it is due to the summer monsoon that the great precipitation occurs on the windward side of the Asiatic highlands bordering the coast.
Flora. Along the Arctic coast there is a barren region from 150 to 500 miles wide, the Tundra, where only dwarf Arctic plants and mosses grow. South of this is an extensive region of forests, mostly coniferous in the north and deciduous trees in the south. To the southward of these are great areas of pasture land which extend to the borders of the deserts. In the greater part of central and western Asia the vegetation is of desert-like character, but wherever the rainfall is sufficient there is the vegetation common to the moister temperate climates. South of the Himalayas the flora is essentially tropical, and mostly occurs with the luxuriance belonging to the well-watered hot zone. The northern part of the continent differs little in general character of its productions from the corresponding parts of Europe and America. Pines, birches, and willows form, as in the other continents, the last forests of the north: but on account of the more severe climate, they do not reach a limit so far northward as in Europe. Some of the common plants of Europe are abundant as far east as Kamchatka; the crowberry (Empetrum nigrum), so plentiful on the moors of Scotland, is still more plentiful throughout Siberia; the same Bilberries (Vaccinium) and Brambles (Rubus) abound in Kamchatka as in Scandinavia. There, are, however, interesting differences. Heathers are comparatively rare in Asia, its flora agreeing in this respect with that of America rather than with that of Europe. The larch extends far northward, at the mouth of the Obi, to the utmost limits of arborescent vegetation. In Kamchatka, a different kind of birch replaces the common birch of Europe as a forest tree, and the Siberian stone pine is different from that of the south of Europe. Siberia in its less frigid and dry regions produces a rich vegetation, of which herbaceous plants, of a size unusually large for a cold or temperate climate, are a characteristic feature: among these may be mentioned species of rhubarb, angelica, and cow-parsnip. In the abundance of currants the warmer parts of Siberia resemble North America, although most of the species are different.
To the south of the Altai Mountains in the Desert of Gobi and the plateau of Tibet the flora is very poor and scanty, owing to the severe climate and the scarcity of rain. The flora of Asia Minor and of the watered parts of Syria has a general resemblance to that of the south of Europe, although exhibiting also features which belong rather to that of India or of Africa. Shrubby members of the Mint family are particularly characteristic of this region. The tropical flora of Arabia abounds in trees which yield fragrant balsams and resins, particularly those of the order Amyridaceæ. Indeed, both the warmer temperate and the tropical regions of Asia excel other parts of the world in the number and variety of the odoriferous drugs which they produce, from myrrh and frankincense to asafœtida. Arabia has long been noted for the production of coffee, which is now also extensively cultivated in other warm parts of Asia. The date-palm is as characteristic of Arabia as it is of Egypt. Acacias and mimosas also abound. The flora of Persia in part resembles that of Arabia, although it is less tropical in character and the altitude of its mountains gives to it in some places a different character. The abundance of Scitamineæ is regarded as particularly characteristic of India; the plants of this order yield ginger, galangal, cardamoms, turmeric, and other articles of commerce, among which not the least important is a kind of arrowroot. Members of the Pea family are also very numerous, both herbaceous and shrubby, or arborescent; many of them exhibiting great beauty of foliage and splendor of flowers, and some producing useful kinds of pulse; others, timber, gum, medicines, etc. The number of valuable medicinal plants which belong to the Indian flora is very great, as is also that of dyewoods; and fine fruits, of which the mango and mangosteen may be particularly noticed. Cucurbitaceæ (gourds) are very numerous; as are also trees of the genus Ficus (fig), some of which produce caoutchouc, and among which are the sacred Peepul and the Banian-tree, so remarkable for the roots which descend from its branches to become new stems, and for the extent of ground which it canopies.
Palms are numerous in the tropical parts of Asia, and particularly in its southeastern re-
