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Geographical. western parts of Asia and the northern parts of Africa being intimately connected by their geological structure with the southern part of Europe; and 3d, the North American realm, which extends as far s. as the table-land of Mexico.

The temperate zone is not characterized, like the arctic, by one and the same same fauna. Not only are the animals different in the eastern and western hemispheres, but there are differences in the various regions of the same hemisphere: as we before remarked, the species resemble, but are not identical with one another. Thus, in Europe, we have the brown bear; in North America, the black bear; and in Asia, the bear of Tibet; the common stag or red deer of Europe is represented in North America by the Canadian stag or wapiti and the American deer, and in eastern Asia by the muskdeer; the North American buffalo is represented in Europe by the wild aurochs of Lithu ania, and in Mongolia by the yak; and numerous other examples might readily be given. The marked changes of temperature between the different seasons occasion migrations of animals more in this zone than any other, and this point must not be overlooked by the naturalist in determining the fauna of a locality within it. Many of the birds of northern Europe and America, in their instinctive search for a warmer winter climate, proceed as far southward as the shores of the Mediterranean and of the gulf of Mexico. See MIGRATIONS OF ANIMALS.

Amongst the most characteristic of the animals of the Asiatic realm, we may mention the bear of Tibet, the musk-deer, the tzeiran (Antilope gutturosa), the Mongolian goat, the argali, the yak, the Bactrian or double-hunched camel, the wild horse, the wild ass, and other equine species, the dtschigetai (equus hemionus). The nations of men inhabiting these realms all belong to the so-called Mongolian race.

That the European is a distinct zoological realm, seems to be established, says Agassiz, "by the range of its mammalia, and by the limits of the migrations of its birds, as well as by the physical features of its whole extent. Thus we find its deer or stag, its bear, its hare, its squirrel, its wolf and wild cat, its fox and jackal, its otter, its weasel and marten, its badger, its bear, its mole, its hedgehogs, its bats, etc. Like the eastern realm, the European world may be subdivided into a number of distinct faunas, characterized each by a variety of peculiar animals. In western Asia, we find, for instance, the common camel instead of the Bactrian; whilst Mount Sinai, Mounts Taurus and Caucasus have goats and wild sheep which differ as much from those of Asia as from those of Greece, the Alps, the Atlas, or of Egypt." There is no reason for our referring, as many writers have done, our chief domesticated animals to an Asiatic origin. A wild horse, different in species from the Asiatic breeds, once inhabited Spain and Germany, and a wild bull existed over the whole range of central Europe. The domesticated cat, whether we trace it to felis maniculata of Egypt or to felis catus (the wild cat) of central Europe, belongs to this realm; and whatever theory be adopted regarding the origin of the dog, the European realm forms its natural range. The merino sheep is still represented in the wild state by the mouflon of Sardinia, and formerly ranged over all the mountains in Spain. The hog is descended from the common boar, still found wild over most of the temperate zone of the old world. Ducks, geese, and pigeons have their wild representatives in Europe. The common fowl and the turkey are, on the other hand, not indigenous, the former being of e. Asiatic, and the latter of American origin. The reader will observe that the European zoological realm is circumscribed within exactly the same limits as the so called white race of man.

The American realm contains many animals not found in Europe or Asia, amongst which we may mention the opossum; several species of insectivora, as, for example, the shrew-mole (scalops aquaticus) and the star-nosed mole (condylura cristata), several species of rodents (especially the musk-rat), the Canadian elk, etc., in the northern portion; and the prairie-wolf, the fox-squirrel, etc., in the southern portion of the fauna. Amongst other types characteristic of this zone must be reckoned the snapping-turtle among the tortoises; the menobranchus and menopoma among the salamanders; and the rattlesnake among the serpents; and the lepidosteus and the amia, important representatives of two almost extinct families, among the fishes.

The faunas of the southern temperate region differ from one another more than those of the corresponding northern region. Each of the three continental peninsulas jutting out southerly into the ocean, represents, in some sense, a separate world. The animals of South America beyond the tropic of Capricorn are in all respects different from those at the southern extremity of Africa. The hyenas, wild boars, and rhinoceroses of the cape of Good Hope have no analogies on the American continent; and the difference is equally great between the birds, reptiles, fishes, insects, and molluscs. New Holland, with its marsupial mammals, with which are associated insects and molluscs no less singular, furnishes a fauna still more peculiar, and which has no similarity to those of any of the adjacent countries. In the seas of that continent, we find the curi ous shark, with paved teeth and spines on the back (cestracion Phillippii), the only living representative of a family so numerous in former zoological ages."

TROPICAL FAUNAS are distinguished in all the continents by the immense variety of animals which they contain, and in many cases by the brilliancy of their color. Not only are all the principal types of animals represented, but genera, species, and individuals occur in abundant profusion. The tropical is the region of the apes and monkeys (which seem to be naturally associated with the distribution of the palms, which

furnish to a great extent the food of the monkeys on both continents), of herbivorous bats, of the great pachyderms, such as the elephant, the hippopotamus, and the tapir, and of the whole family of edentata. Here, too, are the largest of the cats, the lion and the tiger. Among birds, the parrots and toucans are essentially tropical: amongst the reptiles, the largest serpents, crocodiles, and tortoises belong to this zone, as also do the most gorgeous insects. The marine fauna is also superior in beauty, size, and number to those of other regions. The tropical fauna of cach continent furnishes new and peculiar forms. Sometimes whole types are restricted to one continent, as the sloths, the toucans, and the humming-birds to America; the gibbons, the red orang, the royal tiger, and numerous peculiar birds to Asia; and the giraffe and hippopotamus to Africa; while sometimes animals of the same group present different characteristics on different continents. Thus, for example, the American monkeys have flat and widely separated nostrils, 36 teeth, and generally a long prehensile tail; while the monkeys of the old world have their nostrils close together, only 32 teeth, and non-prehensile tails.

The island of Madagascar has its peculiar fauna. A large number of species of quadrumana, cheiroptera, insectivora, etc., are found only in this island; and of 112 species of birds that have been described, 65, or more than half, are found nowhere else. We have already referred to the still more exclusive fauna of the Galapagos islands, which has been specially studied by Darwin.

The multiplicity of facts in zoological distribution, which cannot be accounted for by climate, or any other external existing cause, has given rise to various explanations. Until recently, the received theory was that the several species of animals had been originally created in certain spots named specific centers, whence they migrated more or less widely, and that they had existed unchanged throughout the longest succession of generations. This theory was felt from the first to be unscientific; and increasing knowledge of the facts rendered it less and less satisfactory. Other schemes of distribution, into which the consideration of the Distribution of Life in Past Ages and the Doctrine of Evolution largely enter, are accordingly now in favor. Mr. Sclater, followed by Mr. Wallace, divides the earth into six main zoological regions. In one of these, the Palæarctic, consisting of the northern portion of the old world, it is held that animal life originated—at least in its higher forms. Each of the other regions, it is argued, has been at one time or another in connection with this original seat of life, and has received its supply of animals from it by migration. Geological revolutions have gradually produced the present state of the earth's surface, and the new conditions of life met by the migrated animals have, in accordance with the theory of evolution, so modified them as to produce the varying fauna of the globe. In those countries which have been longest and most completely separated from each other the difference of animal life will be found greatest.

See the various works of Agassiz; Vogt's Zoologische Briefe, vol. ii.; Mrs. Somerville's Physical Geography, vol. ii.; Maury's La Terre et l'Homme; Klöden's Handbuch der Physischen Geographie; Schmarda's great work, Die Geographische Verbreitung der Thiere; and especially The Geographical Distribution of Animals, by A. R. Wallace (1876). GEOGRAPHICAL DISTRIBUTION OF PLANTS, usually known as GEOGRAPHICAL BOTANY, treats of the distribution of vegetable organisms in time and space. The distribution of plants in time belongs properly to Fossil Botany (q. v.), and hence stands in close relation to Geology. The distribution of plants in space, i. e., the way in which living plants are arranged upon the earth's surface, was first studied by Clusius (L'Écluse, b. 1526) who is said to have made the first botanical excursion. It is the province of Geographical Botany to determine not only the localities in which a plant species occurs, but also to find its origin, and to note the various conditions under which it exists.

Temperature and moisture are very important factors in fixing the range of a species, although it has been found that plants are capable to a very marked degree of adapting themselves to climatic conditions. In general, however, the flora of the frigid zone will not flourish in the tropics, nor will the plants of the tropics withstand the cold of the frigid zone. This has led to numerous efforts to divide the earth's surface into vegetable zones, based upon latitude, with but little success, however, except in a general way, for the reason that the plants of one zone gradually become adapted to climatic conditions and pass over into the adjacent zones. Thus the zones come to overlap, and no definite boundary can be fixed. It has been observed that the range of a species is much narrower than that of a genus, and the range of a genus much more limited than that of an order. This arises from the fact that the different species which make up a genus are variable in their ability to resist climatic differences. Again, botanists have endeavored to divide the surface of the earth into so-called botanical regions regardless of latitude, but based upon the different species found in different localities, e. g., the Rocky Mountain region, the Australian region, etc. While this is in a measure advantageous in the study of flora, it is not to be understood that the plants which belong to a certain region are necessarily confined to that region alone. This last division into botanical regions is based largely upon moisture, which exerts a very marked influence upon the nature of the flora of different regions even in the same latitude. Here again adaptation to circumstances is noticeable in the differences both in species and in the

nature of the tissues of the vegetation of arid regions from that of moist regions. In arid regions the surface of the plant is reduced and otherwise modified in order to retard the amount of evaporation, while in moist regions the surface of the plant is greatly increased in order to augment the amount of evaporation. It should also be noted that certain plants require moisture to perform the process of fertilization; hence, if moisture is continually absent during the season of reproduction, the species must sooner or later become extinct in that region.

Another important consideration in the distribution of plants is the division of the earth's surface into land and water, leading to the general division of vegetation into land plants and water plants. The latter include many of the lower forms of vegetable life which are as a rule more widely distributed than the higher plant species. The temperature of the water plays an important part in plant distribution, some plants being confined to the waters of the tropics, while others are found only in the waters of colder regions. Numerous plant species live only in fresh water, while others require salt water; some require shallow water while others flourish better if the water is deep; and, again, some species live only where the water is still, while others need either running water or the beating of the waves. The nature and condition of soil as well as the nature and condition of water greatly influence plant distribution, many plants being found only in very moist soils, while others flourish best in soils that are comparatively dry. Again, a loose soil is better adapted for certain plants, especially those with fine roots, than is a firm, heavy soil. The chemical composition of soil also modifies plant distribution to a marked degree. All green plants must obtain from the soil sulphur, phosphorus, potassium, calcium, magnesium, and iron in larger or smaller quantities. Since these necessary elements are not uniformly mingled with soil in all parts of the earth's surface, plants must accordingly vary in different regions. It is not to be understood, however, that plants will not grow where they are not indigenous.

The agencies of dispersion which are instrumental in distributing plants over the surface of the earth are numerous and varied. Prominent among natural agencies are wind, water, glaciers and animals, which, combined with the adaptation of seeds and other plant parts to transportation have been largely instrumental in the distribution of certain species. Seeds like those of Taraxacum (dandelion) with pappus, enabling the seed to float in the air, may be carried many miles. Other seeds like those of Bidens (beggar-ticks) are provided with hooks, prongs, or barbs, which enable them to cling to the coverings of animals, and thus be distributed over large areas. Seeds which birds use for food are sometimes carried long distances, and often dropped in some place favorable to growth. Or seeds may cling to the toes of birds by means of mud, and thus be widely distributed, as Darwin has shown in his Origin of Species. Again, seeds may float long distances. upon the water, which undoubtedly accounts in a measure for the vegetation on many of the coral islands. Seeds that are resistent to the cold may be transported by means of moving ice and snow. This probably explains the presence of species of arctic plants found on the mountain-tops in lower latitudes. Here again botany and geology touch, for it was during the geological period known as the Glacial Epoch that these species were carried southward by the movement of glaciers and as the latter receded under the influence of heat, the arctic plants were left stranded upon the mountain top. Other plants were at the same time left in the valleys and lowlands, but, being unable to adapt themselves to the climatic changes, they perished. Man has acted as an important agent in plant distribution, both intentionally and unintentionally. With the seeds of plants that are useful for food and other economic purposes he has frequently transported, quite without intent, the seeds of many noxious weeds. Both useful and useless plants thus distributed often flourish better in the new locality than in their native haunts.

For further information concerning the flora of different regions see articles AMERICA, ASIA, AUSTRALIA, etc., and also the articles on the orders and genera of plants. For the distribution of the higher plants of North America see Illustrated Flora of Northern United States, Canada and British Possessions by Britton and Brown.

GEOGRAPHY (Gr. ge, the earth, graph-, to write or describe) is, as its name implies, a description of the earth. This science is best considered under the three distinct heads of Mathematical or Astronomical geography, Physical geography, and Political geography, which all admit of further subdivision into numerous subsidiary branches. Mathematical or Astronomical geography describes the earth in its planetary relations as a member of the solar system, influencing and influenced by other cosmical bodies. It treats of the figure, magnitude, and density of the earth; its motion, and the laws by which that motion is governed; together with the phenomena of the movements of other cosmical bodies, on which depend the alternation of day and night, and of the seasons of the year, and the eclipses and occultations of the sun, moon, and planets; it determines position and estimates distances on the earth's surface, and teaches methods for the solution of astronomical problems, and the construction of the instruments necessary for such operations, together with the modes of representing the surface of the earth by means of globes, charts, and maps. The numerous subjects comprised in this portion of geographical science will be found in other parts of the present work, and we therefore refer our readers for further particulars to the several articles in which they are more fully treated, as, for instance, ASTRONOMY, LATITUDE AND LONGITUDE, MATHEMATICAL INSTRUMENTS, OBSERVATORY, etc.

Physical geography, as the name indicates, considers the earth in its relation to nature and natural or physical laws only. It describes the earth, air, and water, and the organized beings, whether animal or vegetable, by which those elements are occupied, and considers the history, extent, mode, and causes of the distribution of these beings. This may be regarded as the most important branch of geographical science, since it involves the consideration and study of phenomena, which not only tend to further the material interests of man, by teaching him how best to promote the develop. ment of the products of nature, but also conduce in no inconsiderable degree to general intellectual advance, by stimulating the faculties of observation, and exercising the powers of thought. The vast sphere of inquiry included in physical geography necessarily embraces the consideration of all the natural sciences generally, and we can here, therefore, merely refer our readers for more special information regarding the details of the subject to such articles as CLIMATE, HEAT, LAKE, RIVER, MOUNTAINS, OCEAN, WIND, RAIN, CLOUDS; ETHNOLOGY, GEOGRAPHICAL DISTRIBUTION OF ANIMALS AND PLANTS, etc.

Political geography has been well defined as "including all those facts which are the immediate consequences of the operations of man, exercised either on the raw materials of the earth, or on the means of his intercourse with his fellow-creatures." Thus considered, it embraces, primarily, the description of the political or arbitrary divisions and limits of empires, kingdoms, and states; and, secondarily, that of the laws, modes of government, and social organization which prevail in the several countries. The details of this branch of geography will be found under the names of countries, cities, etc., while more general information in regard to the subject must be sought from historical, political, and statistical sources.

Before proceeding to sketch the progress and history of geographical discovery, we will indicate a few of the leading works that afford the best aid in studying the three main branches of geography to which we have referred. Thus, for instance, in mathematical geography, we would specially instance: Manual of Geographical Science (Part I. Mathematical Geography, by Mr. O'Brien); Herschel's Outlines of Astronomy; Klöden's Erdkunde (Part I.): in physical geography, Ritter's Erdkunde; Klöden's; A. Maury's La Terre et l'Homme; Mrs. Somerville's Physical Geography; Mr. F. Maury's Physical Geography of the Sea, etc.: while in regard to political geography, information may be sought from the great works of Ritter, Berghaus, Stein, Wappäus, and Klöden, and from the ordinary geographical manual and maps.

Geographical Discovery.-The earliest idea formed of the earth by nations in a primeval condition seems to have been that it was a flat circular disk, surrounded on all sides by water, and covered by the heavens as with a canopy, in the center of which their own land was supposed to be situated. The Phoenicians were the first people who communicated to other nations a knowledge of distant lands; and although little is known as to the exact period and extent of their various discoveries, they had, before the age of Homer, navigated all parts of the Euxine, and penetrated beyond the limits of the Mediterranean into the Western ocean, and they thus form the first link of the great chain of discovery which, 2,500 years after their foundation of the cities of Tartessus and Utica, was carried by Columbus to the remote shores of America. Besides various settlements nearer home, these bold adventurers had founded colonies in Asia Minor about 1200 B.C., and a century later they laid the foundation of Gades, Utica, and several other cities, which was followed, in the course of the 9th c. by that of Carthage, from whence new streams of colonization continued for several centuries to flow to hitherto unknown parts of the world. The Phoenicians, although less highly gifted than the Egyptians, rank next to them in regard to the influence which they exerted on the progress of human thought and civilization, for their knowledge of mechanics, their early use of weights and measures, and what was of still greater importance, their employment of an alphabetical form of writing, facilitated and confirmed commercial intercourse among their own numerous colonies, and formed a bond of union which speedily embraced all the civilized nations of Semitic and Hellenic origin. So rapid was the advance of geographical knowledge between the age of the Homeric poems (which may be regarded as representing the ideas entertained at the commencement of the 9th c. B.C.) and the time of Hesiod (800 B.C.), that while in the former the earth is supposed to resemble a circular shield, surrounded by a rim of water, spoken of as the parent of all other streams, and the names of Asia and Europe applied only, the former to the upper valley of the Caïster, and the latter to Greece n. of Peloponnesus, Hesiod mentions parts of Italy, Sicily, Gaul, and Spain, and is acquainted with the Scythians, and with the Ethiopians of Southern Africa. During the 7th c. B.C., certain Phoenicians, under the patronage of Neku or Necho II. king of Egypt, undertook a voyage of discovery, and are supposed to have circumnavigated Africa. This expedition is recorded by Herodotus, who relates that it entered the Southern ocean by way of the Red sea, and after 3 years' absence, returned to Egypt by the Pillars of Hercules. The fact of an actual circumnavigation of the African continent has been doubted, but the most convincing proof of its reality is afforded by the observation which seemed incredible to Herodotus, viz., "that the mariners who sailed round Libya (from e. to w.) had the sun on their right hand." The 7th and 6th centuries B.C. were memorable for the great advance made in

regard to the knowledge of the form and extent of the earth. Thaies, and his pupil Anaximander, reputed to have been the first to draw maps, exploded many errors, and paved the way, by their observations, for the attainment of a sounder knowledge. The logographers contributed at this period to the same end by the descriptions which they gave of various parts of the earth; of these, perhaps the most interesting to us is the narrative of the Carthaginian Himilco, who discovered the British islands, including the Estrymnides, which he described as being a four months' voyage from Tar

tessus.

With Herodotus of Halicarnassus (born 485 B.C.), who may be regarded as the father of geography as well as of history, a new era began in regard to geographical knowl edge, for although his chief object was to record the struggles of the Greeks and Persians, he has so minutely described the countries which he visited in his extensive travels (which covered an area of more thrn 31° or 1700 m. from e. to w., and 24° or 1660 m. from n. to s.), that his history gives us a complete representation of all that was known of the earth's surface in his age. This knowledge, which was extremely scanty, consisted in believing that the world was bounded to the s. by the Red sea or Indian ocean, and to the w. by the Atlantic, while its eastern boundaries, although admitted to be undefined, were conjectured to be nearly identical with the limits of the Persian empire, and its northern termination somewhere in the region of the amberlands of the Baltic, which had been visited by Phoenician mariners, and with which the people of Massilia (the modern Marseilles) kept up constant intercourse by way of Gaul and Germany. In the next century, the achievements of Alexander the Great tended materially to enlarge the bounds of human knowledge, for while he carried his arms to the banks of the Indus and Oxus, and extended his conquests to northern and eastern Asia, he at the same time promoted science, by sending expeditions to explore and survey the various provinces which he subdued, and to make collections of all that was curious in regard to the organic and inorganic products of the newly visited districts; and hence the victories of the Macedonian conqueror formed a new era in physical inquiry generally, as well as in geographical discovery specially. While Alexander was opening the east to the knowledge of western nations, Pytheas, an adventurous navigator of Massilia, conducted an expedition past Spain and Gaul through the channel, round the e. of England into the Northern ocean, where, after six days' sailing, he reached Thule (conjectured to be Iceland). and returning, passed into the Baltic, where he heard of the Teutones and Goths. Discovery was thus being extended both in the n. and e. into regions whose very existence had never been suspected, or which had hitherto been regarded as mere chaotic wastes. An important advance in geography was made by Eratosthenes (born 276 B.C.), who first used parallels of longitude and latitude, and constructed maps on mathematical principles. Although his work on geography is lost, we learn from Strabo that he considered the world to be a sphere revolving with its surrounding atmosphere on one and the same axis, and having one center. He believed that only about one-eighth of the earth's surface was inhabited, while the extreme points of his habitable world were Thule in the n., China in the e., the Cinnamon coast of Africa in the s., and the Prom. Sacrum (cape St. Vincent) in the west. During the interval between the ages of Eratosthenes and Strabo (born 66 B.C.), many voluminous words on geography were compiled, which have been either wholly lost to us, or only very partially preserved in the records of later writers. Strabo's great work on geography, which is said to have been composed when he was 80 years of age, has been considered as a model of what such works should be in regard to the methods of treating the subject; but while his descriptions of all the places he has himself visited are interesting and instructive, he seems unduly to have discarded the authority of preceding writers.

The wars and conquests of the Romans had a most important bearing upon geogra phy, since the practical genius of the Roman people led them to the study of the material resources of every province and state brought under their sway, and the greatest service was done to geographical knowledge by the survey of the empire, which was begun by Julius Cæsar, and completed by Augustus. This work comprised a description and measurement of every province by the most celebrated geometricians of the day. Pliny (born 23 A.D.), who had traveled in Spain, Gaul, Germany, and Africa, has left us a compendium of the geographical and physical science of his age in the four books of his Historia Naturalis which he devotes to the subject. He collected with indefatigable industry the information contained in the works of Sallust, Cæsar, Tacitus, and others, to which he added the results of his own observations, without, however, discriminating between fact and fiction. The progress that had been made since Cæsar's time in geographical knowledge is evinced by Pliny's notice of arctic regions and of the Scandinavian lands, and the accounts which he gives of Mt. Atlas, the course of the Niger, and of various settlements in different parts of Africa, while his knowledge of Asia is more correct than that of his predecessors, for he correctly affirms that Ceylon is an island, and not the commencement of a new continent, as has been generally supposed. The study of geography in ancient times may be said to have terminated with C. Ptolemy, who flourished in the middle of the 2d c. of our new era. His work on geography, in eight books, which continued to be regarded as the most perfect system of the science through the dark middle ages down to the 16th