SB- ■■■■ «2ES£*.fl w . 'BEHICEIHY LIBRARY UN1VHWITY OP .CAUI'CWNIA :WCJaiOS urn, J* / I .-; / » * •5 \ i'f i ■ . -ft. *-. <*» -/ * ! 1 w * 4 ¥ K j f • * GUTOT'S GEOGRAPHICAL SERIES. Physical js GEOGRAPHY / BY / ARNOLD GUYOT, of "Earth and Man. ( NEW YORK: Charles Scribner's Sons, 19 X m- * Sntared according to Act of Congress, in the year 1S73, by SORIBNER, ARMSTRONG, & CO., In the Office of the Librarian ot Congress, at Washington. £jue*kib« RIVERSIDE, CAMBRIDGE . SLECTROTYPED AND PRINTED BI H. O. HOUGHTON AND COMPANY. Kuan: GIFT §. a ess I ?73 PREFACE. t-tst^oC , Physical Geogeaphy, in the highest sense of the term, is the Science of the Earth as a great individual organization. In this science the material body of the globe, wi^h its atmosphere, the myriads of plants and animal forms living upon it, and man himself, as a part of the life-system, are not only considered in themselves but in their mutual relations, as working together towards a common end. Though entirely resting upon the solid basis of observed phenomena, it does not stop there. Its aim is preeminently the discovery of the laws which govern these phenomena, and of the grand chain of causes and effects which explains the mode of their occurrence. Such a study requires an extensive knowledge of facts drawn from the domain of all the natural and physical sciences, which cannot be expected of the youthful student, and a habit of generalization which does not belong to the early stages of mental development. A full treatment of Physical Geography and its intricate problems is, therefore, more in place in the highest institutions of learning than in our general school system. But by far the greater number of the youth in our schools will never enter the walls of a college or university. A glance, however, at the subjects treated in the present work, will convince every thoughtful mind that, in this age of universal education, it woidd be a grievous mistake to send this multitude into the wide world of active life, without some knowledge of the laws of these natural phenom- ena, in the midst of which we live and move. The mariner on the stormy sea, the agriculturist at home, the merchant embracing the world in his commercial ventures, the far-see- ing statesman — all have a direct interest in knowing the course of. the winds, the laws of the distribution of heat and rains, which regu- late the abundance or scarcity of crops, determine the special nature of the useful productions in every part of the inhabitable globe, and, in consequence, the resources and the intercourse of the civilized nations. The problem to be solved in preparing the work was to furnish to the pupils of higher grades a general outline of Physical Geog- raphy which, by its simplicity and conciseness, would be suited both to the amount of general information they are expected to possess, and tho limited time available for this study in the school course. This task the author has attempted to perform without sacrificing the special character of the science. All parts of the subject are presented in their true relations, as the writer conceives them, and in their proper subordination. They form a body of facts strongly connected together by ties of mutual dependence, which, once well understood and thoroughly mastered, in the spirit of the book, cannot fail to be easily and forever remembered, while, at the same time, they estab- lish a sound basis for future progress. In every part of the work a strict geographical point of view has been preserved. From the kindred sciences — geology, natural philosophy, meteorology — only such facts and principles have been borrowed as were necessary to illustrate geographical phenomena. In the exposition of the life-system the associations of plants, animals, aud races of men in geographical groups, characterizing the great natural divisions of the globe, have been defined, and not the botanical, zoological, or ethnological classifications. To enliven the presentation of the subject by vivid descriptions of remarkable phenomena, or countries, would have been a pleasant and easy task, but the prescribed space forbade any such indulgence. A text-book can be but little more than a skeleton designed to give solidity, and to put order and method in the structure to be erected. To the intelligent teacher belongs the privilege of clothing these dry bones with forms of life and beauty. But the teacher and the pupil will find an invaluable help in the analyses placed at the end of the sections, and it is hoped that the latter will be thus induced to perform that mental process without which a real acquisition of knowl- edge is simply impossible. The numerous maps constitute in themselves a work as laborious as it is indispensable. They have been prepared with great care, and are thought to embody the results obtained to the present day in this domain of scientific inquiry. The illustrations have been selected strictly with a view to instruct the pupil, and not simply to adorn the pages of the volume ; and the execution of the work gives ample evidence that the publishers have spared neither pains nor expense to do justice to the subject and extend the usefulness of this manual. This volume closes the series, now complete, of the geographical text-books which the author had engaged to prepare for our public schools. It represents the highest of the three normal stages of study, alluded to and fully defined hi the preface of the lower books, and in the accompanying manual of geographical teaching. Experience has shown that, in. the hands of the proper teacher, — and we ought not to have any others, — these manuals carry the pupil to the aim with ease, and by gradual and sure steps. It is a most gratifying fact that the method on which they are based has received the full indorsement of the best educators both in this country and abroad. To those who, having used the first books of this series, have patiently waited for this work, the author begs to express his sincere regret that an unexpected interruption in his usual health, which rendered a prolonged absence necessary, should have retarded, for more than two years, the issue of this volume. With this last offering the author takes leave of the youth of our schools, and their teachers, with an already well-grounded assur- ance that more than a half score of his best years, earnestly devoted to the introduction of a method of instruction more rational than that of mechanical memorizing, — which is still the bane o'f too many of our schools, and the strongest barrier to all progress, — have not been spent in vain for the cause of public education. Whether a manual of a higher kind, for the mature student and the scientific public at large, can be prepared, remains in the hands of Providence rather than in the writer's will and desires. ^ ARNOLD GUYOT Pkinceton, New Jeksev, b^U BMr Pro f essor f Physical Geography ami April 25, 1873. Geology, College of New Jersey. -.-■■! ANALYSIS OF THE VOLUME. PART J. — THE EARTH. I. Introduction. Nature of Physical Geography. Subdivisions. II. The Earth in the Universe. III. The Earth in the Solar System. IV. The Globe, — its Form, Volume, and Mass. V. The Globe, — its Circles and Surface Measurements. VI. The Globe as a Magnet. VII. Temperature of the Globe, independently of the Sun's Rays. VIII. Results of Internal Heat. Volcanic Phenomena. IX. Results Continued. Distribution and Cause of Volcanoes. X. Results Continued. Earthquakes. XI. Review of Part I. PART II. — THE LAND. I. General Arrangement of the Land Masses. II. Horizontal Forms of the Continents. III. Relief Forms classified. Plains Described. IV. Reliefs Continued. Plateaus. Mountains. Valleys. V. Structure of the New World Described. VI. Structure of Asia. VII. Structure of Europe. VIII. Structure of Africa and Australia. IX. General Laws of Continental Reliefs. X. Islands classified. Formation of Coral and Volcanic Islands. XI. Review of Pasts I. and II. PART III. — THE WATERS. I. Water as a Geographical Element. II. Continental Waters. 1. Rivers, — their Formation and their Agency. 2. Lakes, — their Formation and Distribution. 3. Drainage of North America described. 4. Drainage of South America. 5. Drainage of Asia and Europe. 6. Drainage of Africa and Australia. HI. The Sea. 1. Introduction. Composition of Water. Temperature. Bottom. 2. The Oceans. Their Forms, Sizes, Depths, etc. 3. Oceanic Movements. Waves and Tides. 4. Marine Currents. IV. Review of Part HI. Marine Life. Sea PART IV. — THE ATMOSPHERE. I. The Atmosphere as a Geographical Element. Climate. II. Astronomical Climate. Law of Distribution of Heat. Influence of Earth's Motion. HL Physical Climate. Deviations from Astronomical Climate, Classifi- cation and Cause. IV. The Winds. General Circulation of Atmosphere. Trade Winds. V. Winds Continued. Periodical Winds. Variable Winds. VI. Revolving Storms. Character and Cause. VIL Distribution of Vapor in the Atmosphere. VIII. Time and Character of Rains in Different Latitudes. IX. Rainfall of the Different Continents. X. Snow, Horizontal and Vertical Distribution. XI. Glaciers, Formation and Geographical Distribution. XII. Optical and Luminous Phenomena of the Atmosphere. XIII. Review of Part IV. PART V— LIFE UPON THE EARTH. 1. Life in Nature. 1. Introduction. 2. Vegetation in the Different Latitudes. 3. Distribution of Vegetation in the Northern Continents. 4. Vertical Distribution of Vegetation. 5. Vegetation of the Southern Continents. 6. Aspects of Nature in Different Zones. 7. Animals of the three Northern Continents. 8. Animals of the Southern Continents. H. Provision for Human Life and Social Progress. 1- Materials for Sustenance, Raiment, and Shelter. 2. Minerals Employed in the Arts. HI. The Human Family. 1. The Geographical Races, their Locations and Characteristics. 2. Law of Variation of Types. 3. Historical Importance of the several Races. IV. Conclusion. 1. The great Terrestrial Contrasts. a. Continental and Oceanic Worlds b. Eastern and Western Worlds. c. Northern and Southern Worlds. 2. The Continents of History. a. Historical Function of Asia. b. Historical Function of Europe. c. Historical Function of North America. V. Reviews, etc. 1. Review of Part V. 2. General Review. 3. Vocabulary. 4. Tables of Mean Temperature and Rainfall. 1. The Solar System 2. Lines of Equal Magnetic Declination 3. Distribution of Volcanoes and Earthquakes Page 4 . 9 18 4. Physical Map of the World (Mercator) • . 28 5. Structure of North America (Diagram) 31 6. Structure of South America (Diagram) 32 7. Structure of Asia (Diagram) 34 8. Structure of Europe (Diagram) 36 9. Structure of Central Europe (Diagram) 37 10. Structure of Africa (Diagram) 38 11. Structure of Australia (Diagram) 39 12. Tide Waves and River Basins of the Globe 63 LIST OF MAPS. Page 13. Tidal Wave of the British Isles 64 14. Marine Currents 66 15. Isothermal Lines 74 16. Winds 80 17. Rains 86 18. Distribution of Vegetation on the Globe 98 19. Vertical Distribution of Vegetation 102 20. Aspects of Nature in Different Latitudes 1° 6 21. Distribution of Useful Minerals and Precious Metals . 113 22. The Races of Men 117 23. The United States. River Basins • 120 24. The United States. Vegetation 12 ° PHYSICAL GEOGRAPHY. PART I. ' THE EARTH. ALEXANDER VON HUMBOLDT. (From the portrait by Schroder, in possession of Albert Bavemeyer, Esq., New York.) I. — NATURE OF PHYSICAL GEOGRAPHY. I. Subject of Geographical Science. Thb Eabth, as an individual organization with a definite struc- ture, character, and purpose, is the subject of geographical science. The globe as a whole, the three great geographical elements which it comprises, — the land, the water, and the atmosphere, — and the organic life which it supports, each presents peculiar classes of phe- nomena which it is the province of the scientific geographer to investigate, both in their individual character and their mutual rela- tions. - II. Points of View in which the Earth may be studied. The Eartti, as the subject of geographical science, may be re- garded in two different points of view : — 1. In itself, as a master-piece of Divine workmanship, perfect in all its parts and conditions. 2. In its PURPOSE, as the abode of Man, the scene of his activity, and the means of his development. The first gives rise to the Geography of Nature, the second to the Geography of Man. THE EARTH IN THE UNIVERSE. III. Geography of Nature. The MODE OF treatment in the geography of nature may be either simply descriptive, or scientific. 1. Descriptive natural geography, or Physiography, 1 is a simple description of the surface of the globe — of the position, ex- tent and character of the lands ; the distribution and extent of the waters ; and the nature of the climate and productions in different parts of the Earth. It forms the basis of scientific geography. 2. Scientific natural geography, or Physical Geography proper, not only describes the various phenomena exhibited by the Earth as an individual organization, but seeks to discover the laws which govern them, and investigates their relations, causes and consequences. This department of geography is frequently, and very properly, called Terrestrial Physics. 2 IV. Problems of Physical Geography. Among the problems which physical geography aims to solve are the following : — 1. What laws govern the situation, extent, outlines, and relief 3 of the land masses ? 2. What is the influence of the relief of the continents upon the formation of their systems of rivers and lakes ? 3. What is the cause, the extent, the connection, and the influence of the great oceanic currents ? 4. What is the fundamental law of the distribution of heat upon the surface of the globe ; what modifications of this law are observ- able ; and how are those modifications produced ? 5. What general atmospheric movements have been observed, and what is their cause, course and influence ? 6. What laws control the periods, distribution, and amount of rain upon different portions of the globe ; and how is the existence of vast rainless regions in certain latitudes to be accounted for ? 7. What general laws govern the distribution of vegetable and animal life upon the globe, and how are these laws related to the character and well-being of the human family ? V. Results of a Study of Physical Geography. A careful study of physical geography tends to lead the mind to the conclusion that the great geographical constituents of our planet — the solid land, the ocean, and the atmosphere - — are mutually de- pendent and connected by incessant action and reaction upon one another ; and hence, that the Earth is really a wonderful mechan- ism, all parts of which work together harmoniously to accomplish the purpose assigned to it by an All-wise Creator. VI. Physical Geography distinguished from Geology. 1. Geology, sometimes wrongly included in physical geography, is the study of the Earth under quite another aspect. It describes, in their succession, the past ages of the globe, before the creation of man, and seeks to give a true history of the long periods of gradual formation by which it was made ready for the reception of mankind. Like all other bodies in nature, the Earth had its periods of slow, gradual forma- tion, preceding its completed state. The rocks composing the solid mass of the land were long ages in forming ; the continents emerged by slow successive steps from beneath the sea, system after system of mountains contributing to their final 1 From two Greek words, phusis, nature, and grapho, to write. 2 From the Greek phutikos, pertaining to nature. Terrestrial, belonging to the Earth. 3 Elevatien of the surface. figu.-e and relief ; tribes of animals and plants, differing from existing species, ap- peared successively in vast numbers, during untold periods of time. These suc- cessive stages of progress form the materials for the science of geology. 2. Physical Geography, on the contrary, concerns itself only with the present completed condition of the globe ; thus it begins where geology ends. Its natural subdivisions are as follows : — 1. The Earth as a whole. 2. The Land. 3. The Water. 4. The Atmosphere. 5. The Life upon the globe. ANALYSIS OF SECTION I. I. Subject of Geographical Science. II. Points of View in Geographical Study. 1 Earth considered in itself. 2. Earth considered in its purpose. 3. Results. III. Geography of Nature. 1 . Modes of treatment distinguished. 2. Physiography. a. Definition. b. Derivation of name. c. Relation to higher study. 3. Physical Geography. a. Definition. b. Other name, derivation of. IT. Problems Investigated by Physical Geography. 1. Relief, etc., op Land Masses. 2- Influence of Relief on Drainage. 3. Ocean Currents. 4. Distribution of Heat. 5. Atmospheric Currents. 6. Laws of Rain-fall. 7- Distribution of Life on Globe. V. Results of Geographical Study. 1. Geographical Constituents connected and mutually depf,xdent. 2. The Earth a Mechanism designed for a Definite Purpose. VI. Distinction between Geology and Physical Geography. 1. Geology studies Past Conditions 2. Physical Geography studies Present Conditions. 8 Subdivision of Physical Geographt. II. — THE EARTH IN THE UNIVERSE. I. The Universe. The Universe is a general term used to represent the entire ma- terial creation. Our knowledge of it, however, is confined to a par- tial acquaintance with the Earth and its sister planets ; and some general ideas in regard to the more distant heavenly bodies, whose existence is revealed to us only by the light they shed upon the Earth. II. The Starry Heavens. 1. The Heavenly Bodies, which occupy the immensity of space, appear to be arranged in groups, or systems, sweeping through immeasurable circuits. Our Sun is the self-luminous centre of a group of small non-lumi- nous bodies called Planets,* which reflect his light, and revolving around him accompany him through space. Our Earth is one of these planets. These solid bodies, together with a few apparently gaseous and partially self-luminous bodies called Comets, form the Solar System. The fixed stars, which adorn the heavens in countless numbers, are suns — many of them of vastly greater magnitude than our Sun - — some revolving around one another, while others, possibly, are — — — 1 4 Planet, from the Greek planao, to wander. THE EARTH IN THE SOLAR SYSTEM. the centres of planetary systems like ours. They are at such vast distances from us that their light alone is within the reach of our observation. 2. The Magnitude of the Starry Heaven is such that our entire solar system, extending over an area 5,550 millions of miles in diameter, is only a point in the boundless space. A ray of light from the Sun, travelling 185,600 miles in a second of time, reaches Neptune, the most distant known planet, in a little more than four hours ; but it requires more than three years to reach the nearest fixed star, and three years more to reach the next. It may travel on, from system to system, for two or three thousand years before reaching the limits of the starry heavens visible to the naked Bye. III. IVebulie. Separated from our starry heavens by empty abysses of inconceiv- able magnitude, are other heavenly bodies called nebula?, of which more than 6,000 have been observed. Some of these, seen through the most powerful telescopes yet pro- duced, appear only as small shining clouds, whence their name. 1 Others have been found to be composed of multitudes of stars, apparently clustered together, but, doubtless, as widely separated as tlie stars above us. Thus there may be other starry heavens, pos- sibly yet more extensive than that which gladdens our eyes. IV. Insignificance of the Earth. Tin; Earth, therefore, vast as it seems to the feeble mind of man, is only one of the smaller members of a little family of planets. The Sun, the all-controlling centre of this family, with a multitude of other suns, forms one group of stars in the immensity of the visible heavens ; while the measureless firmament itself is filled with myriads of star clusters, which "declare the glory oi God" and •• show forth his handiwork." ANALYSIS OF SECTION H. I. The Universe. 1. Significance of tf.rm. 2. Extent of our knowledge of it. II. The Starry Heavens. 1. Heavenly Bodies grouped. (Sun. a. Solar System, -i Planets. | COHietS. ! Character. Distance. 2. Magnitude of Starry Heavens. a. Exteut of Solar System. b. Distance of nearest fixed stars. c. Distance of bounds of visible stars b. Fixed Stars. • III. Nebulae. 1. Their Position. 2. Their Number. 3. Their Appearance. 4. Their Probable Character. IV. Comparative Insignincauce of the Earth. 1. The Earth in Solar System. 2. Solar System in Srv Si 3. Sun Groups in Visible Hi. , 4. Star Clusters in Firm i III. — THE EARTH IN THE SOLAR SYSTEM. I. Bodies Composing the Solar System. The Solar System consists of the Sun — the central and controlling body — eight primary planets, and twenty secondary planets or satel- lites revolving around their several primaries ; more than one hun- dred and twenty asteroids, 2 which are small planets visible only through the telescope ; and an indefinite number of comets. The primary planets are separated by the asteroids into two groups of four each, one between the asteroids and the Sun, the other beyond them. Recent observations render probable the ex- istence of another planet between the Sun and Mercury. II. Primary Planets. 1. Relative Position. The primary planets, in the order of their position, are Mercury, — the nearest to the Sun, — Venus, the Earth, and Mars, composing the first group ; Jupiter, Saturn, Uranus, and Neptune, composing the second. 2. Comparative Size. The size of the planets, in general, in- creases with their distance from the Sun. The four composing the first group are all comparatively small, the Earth being the largest. Those of the second group are all of great size. Jupiter, the largest, is not less than 1,390 times as large as the Earth ; but as it is much less dense, the amount of matter it contains is only a trifle more than 337 times that of the Earth. All the planets together equal but 7-Jjj part of the mass of the Sun. 3. Comparative Density. The density of the planets decreases with their distance from the Sun. Mercury, the most dense, has a specific gravity 3 of 8^, a little greater than that of iron ; the Earth, of, and Venus and Mars about the same ; Jupiter, lj ; and Saturn, the least dense of all the planets, but §, or about the same as cork. 4. The Distance bet w ken the Primary Planets increases with their increasing distance from the Sun. Reckoning the asteroids as one place, and excepting Neptune, the distances of the successive orbits from the orbit of Mercury increase in very nearly a twofold ratio. Thus from Mercury to Venus is 31 millions of miles; to the Earth, 56 millions ; to Mars, 105 millions, etc. The four smaller planets are all comparatively near the Sun, their several distances from it being only 36, 67, 92, and 141 millions of miles ; Avhile Jupiter, the nearest of the great planets, is 481 millions of miles distant. 5. The Satellites, except our Moon, belong wholly to the second group of planets. Jupiter has four ; Saturn eight, and sev- eral revolving rings ; Uranus has four, and possibly more ; while Neptune, so far as known with certainty, has but one. III. Movements Within the Solar System. 1. Rotary Motion. The Sun, all the primary planets, and their satellites, as far as known, rotate from west to east. Each rotation constitutes a day for the rotating body. The central line of rotary motion is called the axis of rotation, and the extremities of the axis are called the Poles. 2. Revolution around the Sun. All the primary planets and asteroids revolve around the Sun in the direction of their rota- tion, that is from west to east ; and the planes 4 of the orbits in which 1 From the Latin nebula, a little cloud. - These may be fragments of a former great planet occupying the same place ill the sysMn. 8 Weight as compared with an equal bulk of pure water. 4 The ideal plane in which their circular path is conceived to lie. ^fc SOLAR BTstxjit i*r T *E ABOVE DlAG^ AlJt THE RELATIVE SIZES OP" THE SUN & PLANETS ARE PRESERVED THE SIZE OF THE SUN BEING BEPBESENTED BY THE OBBIT OF NEPTUNE . flt *~«Nr •»* Asteroids JupiU-r Saturn Uranus t % ^ >», 7 * *30 881 1.772 COMPARATIVE DISTANCES OF THE PLANETS FROM THE SUN Neptune HSmnlox P.) hlti hi noli iter THE EARTH IN THE SOLAR SYSTEM. they revolve coincide very nearly with the plane of the Sun's equator. 1 One revolution around the Sun constitutes the year of a planet. All the satellites except those of Uranus and perhaps Neptune, also revolve from west to east. Most of the comets revolve around the Sun in very irregular and elongated orbits, only a few having their entire orbit within the planetary system. Some so move that after having entered our system and made their circuit around the Sun, they seem to leave it never to return. 3. Velocity op Planetary Movements. The velocity of the planets in their annual revolutions decreases as their distance from the Sun increases. Mercury moves at the rate of nearly 2£ millions of miles per day, and the Earth 1| millions ; while Neptune advances at the slower pace of little more than £ of a million. The velocity of rotation, on the contrary, is least in the smaller planets which are near the Sun, while it is greatest in the larger and more distant ones. The former require from 23£ to 24^ hours of our time for one rotation ; while the latter, except Neptune, whose rotary velocity is not known, accomplish an entire rotation in from 9^ to 10| hours. 4. Time of Revo- lution. As the or- bits of the planets in- crease in circumference with their distance from the Sun, and their ve- locity at the same time diminishes, the time of revolution, or length of the year, increases cor- respondingly. Mercury performs a revolution in about 88 days of our time ; and the Earth, in 365£ ; while Jupiter re- quires 4,332, and Nep- tune 60,126 days. 5. The axes of all the planets, so far as known, are more or less inclined towards the planes of their orbits. This inclination causes an apparent passing of the Sun from one hemisphere to the other during the course of the annual revolution, thereby producing variation in the relative length of day and night, and change of seasons. The greater the inclination of the axis, the greater is the variation in the length of day and night, and the more extreme the contrasts in temperature during the year at any given point. The Earth seems to present a happy medium in this respect. Its axis is inclined about 23£° , 2 sufficient to give the larger part of its surface four seasons of nearly equal length — Summer, Winter, and two transition seasons of medium temperature — with day and night varying from 9 or 10 to 14 or 15 hours ; while but a small area, ex- tending 23^ degrees from each pole, is ever entirely deprived of the Sun's rays during one or more rotations of the Earth. The two polar regions combined occupy but 16£ millions of square miles, out of 197 millions, the entire surface of the Earth. If the axis of the planet Venus be, as is supposed, inclined 72°, then in the course of its annual revolution the Sun must be vertical on every part of its surface except a little area extending 15° from the poles, where it is so nearly vertical as to produce scarcely less heat than if it were so. Thus every part of its surface must alternate between excessive heat during one half the year, and in- tense cold, from an almost entire absence of the Sun's rays, durin<* the other half. 6. Eccentricity of Planetary Orbits. The planetary orbits are not exact circles, but are more or less elliptical, the Sun being situated not at the centre, but at one of the foci of the ellipse. The distance of either focus from the centre is called the eccentricity of the ellipse. On account of this eccentricity the distance of a planet from the Sun, and its velocity of revolution, vary in different parts of its orbit. Some of the planets are so much nearer the Sun in one portion of their orbit than in another, that the degree of heat received varies greatly in different seasons of the year. Thus Mercury receives, when nearest the Sun, about 2j times as much heat as when most distant from it, a difference equal to the variation in temperature between summer and winter in the middle latitudes of our globe. The Earth, on the contrary, revolves in an orbit but slightly eccen- tric. Its nearest ap- proach to the Sun oc- curs in the winter of the northern hemisphere, where the larger part of the land is concentrated. Hence, if this slight ec- centricity of the orbit has any appreciable ef- fect upon climate, it must be to moderate the cold of winter, and the heat of summer, in the most populous .zone of the globe. THE ORBIT OF THE EARTH. IV. Advantages in Con- ditions of the Earth. 1 A great circle the plane of which cuts the axis of rotation at right angles. 1 In more exact terms, 23° 27'. The Earth is thus subject to physical conditions intermediate between the extremes presented by the other planets. It is the largest of the smaller planets, and occupies a middle position in the group. This frees it alike from the blinding glare and burning heat to which Mercury is exposed, and the dimness of light and the cold which must prevail on distant Jupiter and Neptune. The comparative velocities of its diurnal and annual motions, the trifling eccentricity of its orbit, and the slight inclination of its axis, establish a harmony in the relative length of its days, years, and seasons, and its alternations of temperature and of light and dark- ness, such as cannot exist in most of the other planets. Thus the Earth appears better fitted than any other member of the solar system for sustaining that great wealth of organic life — vege- table, animal, and human — with which it is endowed, and which constitutes its greatest glory. Indeed, whatever may have been the the past, or may be the future of the other planets, it is doubtful whether, at the present time, any one of them possesses those physi- cal conditions under which alone a life-system at all similar to ours is possible. THE TERRESTRIAL GLOBE. .-> ANALYSIS OF SECTION HI. I. Bodies Composing the Solar System. 1. Sun, its Bank. 2. Primary - Planets, their Number. 3. Satellites, Number and Relation to Primaries. 4. Asteroids, Number and Size. 6. Comets. 6. Grouping op Planets. II. Primary Planets. 1. Relative Position. 2. Comparative Size. a. Law of increase. b. Size of first group. c. Size of second group. (1. Total mass compared with Sun. 3. Comparative Density. a. Law of decrease. b. Specific gravity of small planets. c. Specific gravity of Jupiter and Saturn. 4. Planetary Distances. a. Law of increase. b. Distance of small planets from Sun. c. Distance of great planets from Sun. 6. Satellites. a. To which group belonging. b. Number accompanying each great planet. III. Movements within Solar System. 1. Rotary Motion. a. Direction. b. Resulting measure of time. c. Centre. 2. Revolution around the Sun. ( Primary planets. a. Direction of motion. \ Asteroids. [ Satellites. b. Measure of time. c. Revolution of comets. 3. Velocities of Planetary Motions. a. Law of variation in revolution. Examples. b. Law of variation in rotation. Examples. 4. Time op Revolution. a. Law of variation. Example. 6. Axis op Rotation. a. Law of position. b. General effect of inclination. o. Earth, degree of Inclination. Results. d. Venus. Supposed degree of inclination. Results. 6. Eccentricity of Orbits. Definition. a. Mercury, Comparative Eccentricity. Results. b. Earth, Comparative Eccentricity. Results. IV. Advantages In Physical Condition of Earth. 1. Of Position in Solar System. 2. Of Velocity op Motions, Eccentricity op Orbit, and Inclination op Axis. IV. — THE TERRESTRIAL CxLOBE. ITS FORM ; VOLUME ; MASS. I. Form of the Earth. 1. The Earth, as ascertained by mathematical measurements, is an oblate spheroid, being slightly compressed about the poles, and slightly bulging in the equatorial regions. The difference between the polar and the equatorial radius is only 13£ miles. 2. This deviation from a perfectly spherical figure is such as would be pro- duced by the rotation of a slightly plastic 1 globe upon its axis. It indicates that the Earth, in some period of its existence, must have been in a semi-fluid condition. II. Volume or Bulk of the Terrestrial Globe. 1. The term volume, as applied to the Earth, signifies its size or dimensions, as shown by measurements, irrespective of the amount of matter contained in it. 1 Capable of being moulded or shaped. 2. The dimensions of the Earth according to Herschel are : — Equatorial diameter 7,925.65 miles. Polar » 7,899.17 " Mean " 7,916 " Circumference at equator . . . 24,899 " Extent of surface .... 196,900,278 square miles. Solid contents .... 260,000,000,000 cubic miles. 3. The APPROXIMATE DIMENSIONS, expressed in round numbers for convenience in remembering them, are — diameter, 8,000 miles ; circumference, 25,000 miles ; extent of surface, 197 millions of square miles ; solid contents, 260 thousand millions of cubic miles. « III. Mass of the Globe. 1. The term mass, as applied to the Earth, signifies the amount of matter it contains irrespective of its volume. Material substances differ greatly in the mass of matter contained in a given volume. Thus a cubic foot of stone weighs 2£ times as much as a cubic foot of water, that is, contains 2£ times as much matter ; in other words, its specific grav- ity is 2J. The specific gravity of iron is 7£, that of lead 11|, of gold 19. 3. The SPECIFIC GRAVITY of the terrestrial globe is found to be about 5§ ; that is, it would require 5| globes of water, of the same size, to balance the weight of the Earth. 4. The matter composing the surface of the globe is much less dense, having a specific gravity of but 2| ; consequently the in- terior must be correspondingly denser. Hence we conclude, either that metallic substances predominate in the interior of the globe, or that the matter therein is very greatly compressed. 5. The absolute WEIGHT of the globe is computed at not less than 5,852,000,000,000,000 of tons, a weight of which our minds can form no conception. ANALYSIS OF SECTION TV. I. Form of the Earth. 1. Figure of the Earth. 2. Deviation from Perfect Sphere. a. How produced. b. Proves what. II. Volume of Terrestrial Globe. 1. Signification of term Volume. 2. Exact Dimensions of Globe. a. Equatorial Diameter. b. Polar Diameter. c. Mean Diameter. d. Equatorial Circumference. e. Extent of Surface. f. Solid Contents. 8. Approximate Dimensions. a. Diameter. b. Circumference. c. Surface and solid contents. III. Mass of Terrestrial Globe. 1. Signification op term Mass. Examples. 2. Specific Gravity of Globe. 3. Specific Gravity of Surface Regions. Conclusion. 4. Absolute Weight op Globe. V. — THE TERRESTRIAL GLOBE. ITS CIRCLES, AND SURFACE MEASUREMENTS. I. Circles of Position. 1. The term Circle, in geographical science, is used in a special sense. The geographical circles are not planes cutting the terres- THE TERRESTRIAL GLOBE. trial globe, but simply lines encircling it. Those which bisect the surface of the sphere are called great circles ; all others small circles. 2. Great Circles. The Equator is a great circle encompassing the globe from east to west, midway between the poles. Meridians are great circles encompassing the globe from north to south, inter- secting at the poles, and crossing the equator at right angles. 3. The Parallels are small circles parallel to the equator. 4. Use. The parallels and meridians, which are conceived as in- tersecting at every point on the Earth's surface, are employed in de- termining the geographical position of places. II. Climatic Circles. 1. Climatic Parallels. Four parallels serve not only to deter- mine position, but also to mark certain important climatic bounda- ries, hence they may be distinguished as climatic parallels. The Tropics, situated 23^° from the equator, mark the highest latitude which receives the vertical rays of the Sun. Their position is fixed by the inclination of the Earth's axis 23^ degrees towards the plane of its orbit. On the 21st of June the vertical Sun, in its diurnal course, passes over every point on the northern tropic ; on the 22d of December, over every point- on the southern. Twice in the year it passes, in succession, over every parallel between the tropics ; from June to December ad- vancing southward, from December to June, northward. (See page 70, Positions of the Vertical Sun.) The Polar Circles, situated 23^° from the poles, mark the limits of illumination when the Sun is ver- tical at the tropics. Each is 90° distant from the tropic on the op- posite side of the equator. 2. The Ecliptic is a great cir- cle whose plane coincides with that of the Earth's orbit, and consequently intersects the plane of the equator at an angle of 23^°. It marks the apparent path of the vertical Sun from tropic to tropic during the annual revolution of the Earth. The ecliptic bisects the equator, and touches the two tropics in opposite latitudes, and on opposite meridians. III. Surface Measurements. 1. Latitude is the distance of a place from the equator, measured upon the meridians. It is reckoned from the equator to each pole ; hence there are 90° of north latitude and 90° of south latitude. The length of a degree of latitude is 69£ miles, or 3 J ff part of the circumference of the Earth. Near the poles the degrees are slightly longer, owing to the oblateness of the sphere. 2. Longitude is the distance of a place east or west from some given meridian, called the prime meridian, measured on the equator. It is reckoned half way round the globe in each direction ; thus there arcs 180° of east longitude and 180° of west longitude. The length of a degree of longitude at the equator is 69£ miles. As the parallels constantly diminish in circumference from the equa- tor to the poles, the length of a degree of longitude — ^ part of each parallel — must decrease in like manner. At the poles, where all the meridians meet, longitude ceases. One minute of longitude at the equator constitutes the geographical or nautical mile used in reckoning distances at sea. table showing the circumference of every fifth paral- lel, AND THE LENGTH OF ITS DEGREES IN ENGLISH MILES. Circumference Length of degree Circumference Length of degree of Parallel. of Longitude. 45° of Parallel. of Longitude. Equator 0° 24,899 69.164 17,636 48.988 5 24,805 68.909. 50 16,036 44.545 10 24,523 68.120 55 14,314 39.760 15 24,056 66.829 60 12,481 34.669 20 23,406 65.018 65 10,552 29.310 25 22,580 62.721 70 8,541 23.726 30 21.581 59.948 75 6,465 17.957 35 20,418 56.718 80 4,338 12.049 40 19,100 53.055 85 2477 6.048 4.", 17,636 48.988 Pole 90 0,000 0.000 The prime meridian commonly employed by the English and the Americans, is that of the National Observatory at Greenwich, near London. The French and German geographers also use the merid- ian of the observatory at Paris, and the Americans often employ that of the National Observatory at Washington. Paris is the most easterly, Greenwich being 2° 20' 22" west of Paris, and Washington 77° 02' 47" west of Greenwich. The meridian of 20° west from Paris, falling somewhat beyond Ferro, the most westerly of the Canary Islands, is also employed as NOR7V; MERIDIANS AND PARALLELS. CLIMATIC CIRCLES. prime meridian ; and, lying at the west of all the lands of the Old World, it has been generally adopted as the most appropriate boundary between the eastern and the western hemisphere. IV. Relation of Longitude to Time. 1. Computation of Longi- tude by Time. Since any given point on the Earth's surface passes through 360° of longitude — one entire rotation — in 24 hours, it must pass through =\ 8 ,°-°, or 15°, in one hour ; and 1° in T V of one hour, or 4 minutes. Hence if the difference in time marked at two places be known, their difference in longitude can at once be ascertained, and vice versa. Suppose, for example, an accurate time-keeper, marking New York time, be taken to London; it will be found four hours and fifty-six minutes, or 296 minutes, slower than London time. Hence the difference in longitude, expressed in degrees, must be one fourth this number, or 2 $& = 74°. 2. Difference of Time marked at the same Moment. The moment at which the Sun crosses the meridian of a given place, is noon or mid-day at that place. The meridian which is 90°, or a quartet of a rotation, to the eastward has six hours later time at the same moment ; and one which is 180° east, twelve hours later. Meridians at corresponding distances to the westward have a corres- ponding number of hours earlier time ; so, in proportion, of less dis- tances. The diagram below illustrates the different time marked in different longitudes at the same moment : — West. 180° 0° East. 90° 180° 12 A. M. Monday, or mid- night of Sunday. 6 A. M. Monday. Noon of Monday. 6 P. M. Monday. 12 P. M. Midnight of Monday. Thus it happens that mariners, starting from a given point and sailing around THE TERRESTRIAL GLOBE A MAGNET. the world to the west, lose a day in making the circumnavigation ; while in sailing eastward they gain a day. To correct this error in the former case they must, at some point, add one day to their reckoning of time, making the date 24 hours later, and in the latter case drop a day. ANALYSIS OF SECTION V. I. Circlet* of Position. ■ 1. Geographical Use of the term Circle. 2. Great Circles. a- Equator, b. Meridians. 3. Parallels. 4. Use. II. Climatic Circles. 1. Parallels. ( Definition of. ' ) Position to what due. u t» . n- , ( Definition of. b. Polar Circles, i „ ... . . . / Position in reference to tropics. 2. Ecliptic. a. Definition. b. What it marks. c. Relation to tropics and equator. III. Surface Measurements. 1. Latitude. a. Definition. b. Number of degrees. c Length of degrees. Exception. 2. Longitude. a. Definition. b. Number of degrees. c. Length of degrees at the equator. How varying. ( Locations of. d. Prime meridians. / Relative situation. IV. Relation of Longitude to Time. 1. Computation op Longitude prom Difference op Time. a. Basis of computation. b. To convert difference of time to difference of longitude. c. To convert difference of longitude to difference of time. 2 Differences op Time marked at same Moment. a. Variation eastward. b. Variation westward. c Variations in circumnavigating the globe. How corrected. VI. — THE TERRESTRIAL GLOBE A MAGNET. I. Magnetism. 1. A Magnet is a body which, has the property of attracting iron ; and the term Magnetism is applied to the cause of this attraction and the resulting phenomena. Magnetism was known to the ancients, having been first ob- served in the loadstone, a species of iron ore found in abundance near the city of Magnesia, in Asia Minor, whence the magnet takes its name. 2. Abtificial* Magnets may be readily produced by friction. A bar of steel rubbed with a natural, or other, magnet ac- . mariner's compass. quires permanent magnetic prop- erties. The magnetic needle is an artificial magnet suspended upon a pivot, so as to move freely in any direction. The Chinese availed themselves of it, in traversing the trackless deserts of central Asia, long before the use of the compass was known in Europe. The mariner's compass is a magnetic needle attached to the lower side of a leaf of mica, on which is traced a star with 32 points, marking the eight rhumbs, the semi-rhumbs, and the quarters of the wind. The compass is suspended in a box »o as to preserve a horizontal position in spite of the motion of the ship. II. Properties of Magnets. 1. The magnetic force is not equally distributed throughout the magnet, but is greatest at the extremities, diminishing towards the centre, where it ceases. Every magnet, therefore, has two poles, at opposite extremities — one positive, the other negative — with a neutral line in the centre. They are distinguished as the north pole and the south pole. Poles of the same name repel, and those of contrary name attract each other. When a magnet is broken, each half becomes itself a complete magnet. The illustration below represents a magnet which has been plunged into a basin of iron filings. These cluster in great numbers around the ends, each piece in contact with' trie magnet attracting others ; but they are absent from the centre, where the opposite poles neutralize each other. A MAGNET. 2. The Earth a Magnet. The terrestrial globe exhibits the properties of a magnet in the directing power it exerts upon the magnetic needle. Whether on sea or land, on mountains or in deep valleys, a magnetic needle, if free to move, always so adjusts itself that its poles point in a definite direction, along a line which is vir- tually north and south. That pole of the needle which is attracted by the north mag- netic pole of the Earth, must be in an opposite magnetic condition. Hence it is the proper south pole of the magnet, but since it points toward the geographical north, it is designated the north "pole. 3. The Magnetic Poles op the Earth do not coincide with the poles of rotation, but are found about 20° from them. Neither do the magnetic meridians, which pass through the magnetic poles of the Earth and those of the needle, generally coincide with the geographical meridians, for the needle rarely points due north. III. Magnetic Variation or Declination. 1. Magnetic variation, or declination, is the difference be- tween the true north and the direction indicated by the mag- netic needle. The declination is said to be east or ivest, according as the north pole of the needle is east or west of the geographical meridian. By connecting all points which have equal declination, we obtain a system of lines which show at a glance, as in the map on page 9, the extent to which the needle deviates from the true north, in all parts of the world. The eastern declination is distinguished on this map by dotted Jines and a light brown color ; the western by solid lines in a blue ground. The degree of variation is shown by figures attached to the lines. The lines of equal declination, at all points on any one of which the needle pre- serves one unvarying direction, must not be confounded with magnetic meridians which, passing through the poles of the needle, would show what that direction actually is. In certain parts of the globe the magnetic and geographical me- ridians coincide. These places are connected by an irregularly POCKET COMPASS. 10 TEMPERATURE OF THE TERRESTRIAL GLOBE. parture from a horizontal position, of a needle suspended so as to move freely in a vertical plane, and adjusted in the magnetic meridian. In the northern hemi- sphere the north pole of the needle dips, in the southern the south pole. 2. Degree of Dip. The magnetic inclination is greatest at the magnetic pole, where the needle assumes a vertical position. Passing towards the equator the inclination becomes less and less, until a line is reached in which the needle is horizontal. The line of no inclination constitutes a magnetic equator, and the lines of equal inclination, magnetic parallels. They coincide in a remarkable manner with the isolhermals, or lines of equal mean temperature on the globe, thus indicating a close connection between the distribution of magnetism and of solar heat. 2. Variations. Magnetic inclination, like declination, is subject to both pe- riodical and secular variations. The later is shown by the following table : — INCLINATION OBSERVED AT PARIS. 1371 75° W 1780 71° 48' 1798 69° 51' Year. Inclination 1806 69° 12/ 1814 68° W 1820 68° 20' Year. Inclination. 1825 68° OCC 1831 67° 40' 1853 66° 28' Since the year 1G71, it appears, the inclination of the needle at Paris has stead- ily decreased from three to five minutes per year. ANALYSIS OF SECTION VI. I Magnetism. 1. Phenomena exhibited. a. Where first observed. b. Origin of name magnet. 2. Artificial Magnet. a. How produced. b. Magnetic needle. c. Mariner's compass. II. Properties of Magnets. 1. Polarity. a. How exhibited. b. Poles of magnet. c. Subdivision of magnet. 2. The Earth a Magnet. a. Property of magnet exhibited by it. b. Position of magnetic needle. c. Relative position of poles of needle and of Karth 3. Magnetic Poles op Earth. a. Their geographical position. b. Magnetic meridians. c. Direction of magnetic needle. ill. Magnetic Declination. 1. Definition. a. Lines of no declination. b. Direction of declination. Definition. Number Position. East hemisphere. West hemisphere 2. Secular Variation. a. Definition. b Results of observation in Paris. (1.) Extent of variation. (2.) Minimum and maximum. (3.) Direction of change before 1814. (4.) Direction of change since 1814. (5.) Rate of change. 8 Minor Variations. IV. Magnetic Inclination. 1- Definition. 2. Degree of Dip. a. How varying. b, Magnetic equator and parallels. 3. Variation of Inclination. a. Kinds of variation. h. Results of observation in Paris. VII. — TEMPERATURE OF THE TERRESTRIAL GLOBE. I. Evidences of Internal Heat. That the interior of the terrestrial globe maintains a high temper- ature, independently of the influence of the Sun upon the surface, is proved by a variety of phenomena. 1. Waem Springs are numerous in nearly all parts of the Earth, varying in heat from a degree but slightly above the mean annual temperature of the place where they occur, to the boiling point. The temperature of ordinary springs and wells does not differ materially from the mean annual temperature of the ground and the air above it, and is compara- tively uniform throughout the year. Thus in winter the water is warmer than the air ; in summer, colder. Explanation of the cat. The geysers seem to be due to the unequal heating of a column of water in an open vertical shaft, traversing hot volcanic strata. Steam escapes when the tem- perature of the water enables its expansive force to overcome the pressure of the atmosphere, viz., at 212° Fahr., at sea level. But at the bottom of a shaft of <>8 feet, for instance, the press- ure being equal to three atmos- pheres, a much higher degree of heat is required. When this is reached, steam is formed, which, in ascending, partially expels the water from the shaft. The pressure being thus re- lieved, new masses of steam de- velop rapidly, and the explo- sions become so frequent, and the successive jets so powerful, as to form a continuous column of boiling water and vapor rising in the air. When the explosions cease, the water, now cooled, falls back into the shaft, and after a time of rest the process recommences. The correctness of this view is confirmed by the fact that the temperature within the shaft increases towards the bottom. In the Great Geyser of Iceland. Bunsen found the temperature at the surface of the water to be from 169° to 192° Fahr. ; but at the depth of 72 feet it was 261° before an eruption, and 2.") 2° after, or from 40° to 50° higher than boiling water. TUB GIANTESS GEYSER. (See page 11.) Springs, of whatever temperature, are simply the return of water to the surface, after circulating among the Earth's strata 1 at a greater or less depth. When it entered the ground it could not have been warmer than the surrounding atmosphere ; hence the higher temperature of warm, or thermal, springs must have been imparted to the water by the strata among which it has circulated. 2. Active Volcanoes are found in all latitudes, ejecting, from time to time, streams of red hot lava ; hence it is evident that at i Beds of earth or rock, formed by natural causes, and usually consisting of a series of layers. TEMPERATURE OF THE TERRESTRIAL GLOBE. 11 some place within the Earth there exists a degree of heat sufficient to melt even the solid rock. 3. Artesian Wells and Mines permit the actual observation of the internal temperature of the Earth to the depth of about 3,000 feet, and the results corroborate the inference drawn from ther- mal springs and active volcanoes. II. Thermal Springs. 1. Thermal springs are most numerous in mountainous or volcanic regions, where the strata are most dis- turbed, broken, and creviced. Europe is proba- bly the richest of the continents in warm springs. Over 800 have been de- scribed in France, 400 in Spain, and a still greater number in Ger- many, Bohemia, Switzerland, Italy, and England, some of which have a temperature as high as 180° Fahr. 2. Intermittent spouting springs, or Geysers^ — whose tempera- ture reaches or even somewhat exceeds 212° Fahr. — are found in Iceland, also near tile head waters of the Yellowstone River in the Rocky Mountains, and in New Zealand. They are all in volcanic districts. The Great Geyser of Iceland is the most famous of these intermittent springs. It ejicts at intervals, from a vertical chimney, a column of water sometimes ten feet in diameter and nearly a hundred feet in height. Even more remarkable are the Giantess, throwing a column of water over two hundred feet high, the Grand Geyser, and other springs in the extensive geyser basin of the upper Yellowstone, in Montana Territory. (See explanation, page 10.) The so called geysers of California, near Mount St. Helena, north of San Francisco Bay, are simple boiling springs, neither spouting nor intermit- tent. Boiling springs also occur in Venezuela and the Andes of Peru, South America ; in Japan, and in va- rious other regions both in the New World and the Old. 3. Thermal springs usually are highly impregnated with mineral substances, a condition facilitated by the increased solvent power of warm water. Mineral springs are classified according to the gaseous or the mineral substances THE GREAT GEYSER BASIN OF THE UPPER YELLOWSTONE. 1 From an Icelandic word which signifies raging or spouting. It is applied to intermittent boiiing springs whose waters burst out at intervals with great force. they contain. The principal classes are — (1.) The acidulous, containing large quantities of carbonic acid gas, as the waters of Pyrmont and Seltz in Germany Spa in Belgium, and Vichy in France. (2.) The sulphurous, as the White Sul- phur springs in West Virginia, and the Saratoga springs in New York. (3.) Saline springs, abounding in common salt, numerous in all parts of the world. (4.) Chal- ybeate springs, containing salts of iron, abundant in all countries rich in iron mines. (5.) Complex springs, containing a variety of salts without the special preponderance of any one. III. Artesian Wells and Mines. 1. Formation of Artesian Wells. The commonly received theory supposes a geographical basin, of greater or less extent, in which two impermeable 2 strata, like clay, inclose between them a permeable stratum, like sand or gravel. The rain water, falling on the latter where it reaches the sur- face of the ground, filters through it, following the inch- nation and accu- mulating in the lower levels, where it is retained by the impermeable strata above and below. (Such a formation is shown in the small cut below, of a well in the London basin.) If the drill, in boring a well, reaches such a water-bearing bed be- low its highest level, the water rises in the well to that level ; or if the highest level of the bed be above that of the mouth of the well, the water spouts out like a fountain. The artesian well is so called from the province of Artois, in France, where such wells have long been in use. 2. Observations in Wells. (1.) How Made. Observations on temperature are made with self-reg- istering thermometers, lowered to different depths. They furnish the means of ascertaining the rate of in- crease in the internal temperature of the globe, starting from the mean an- nual — or invariable — temperature of the ground, which is found at a greater or less distance below the surface. The surface layers of the soil are affected by the varying heat of the seasons, being colder in winter and warmer in summer ; but the variations gradually diminish below the surface, to a point at which the temperature is constant throughout the year. This point gives the mean annual temperature of the ground, which is equal to that of the air above. In the equatorial regions, where the seasons are nearly uniform in temperature, it is found a few feet below the 2 Not permitting the passage of a fluid through its substance. F ARTESIAN WELLS. 12 RESULTS OF INTERNAL HEAT. — VOLCANIC PHENOMENA. surface ; but it descends, with increasing latitude, as the difference between the summer and winter temperature of the air increases. In middle latitudes it is found about sixty or eighty feet below the surface. (2.) Where Made. Among the wells in which valuable observa- tions have been made are the following: one at Columbus, Ohio, 2,775 feet deep; at Louisville, Kentucky, 2,086 feet; at St. Louis, Missouri, 2,199.> feet ; at Q-renelle, near Paris, 2,021 feet deep ; at Neu-Salziverh, in Germany, 2,288 feet; and at. Mouillelonge, in cen- tral France, 2,677 feet. (3.) Result of Observations. The following table, giving the result of observations in the above named wells, shows that the tem- perature invariably increases with increasing depth, but the rate of increase is different in different wells. Well Depth of observation. Temp. Fahr. Rate of Increase. Columbus, 2,775 88.0° 1° for 73 feet. Louisville, 2,086 82.5° loi< 72 " St. Louis, 2,199 8O.40 1°" 88 " Mouillelonge, 2,677 101.0° 1°" 51 " Neu-Salzwerk, 2,288 92.5° 1°" 55 " Grenelle, 1,798 82.4° 1°" 58 " 3. Observations in Mines exhibit similar results. The increase of heat downward is constant, but the rate of increase often differs widely even in mines not very far apart, owing probably to differ- ence in the nature of the rocks. In the Prussian mines, where observations have been made with the greatest care, the most rapid rate observed is 1 ° Fahr. for 2 7 feet of descent ; and the slowest, 1° for 197 feet, the average being 1° for 92 feet. In the mines of Saxony the ave- rage increase is 1° for 72 feet; in six of the largest mines in England, 1° for 44 feet; and in the coal mines of Virginia, 1° for 60 feet. Even the frozen soil of Siberia, having a tempemture near the surface of but 10°, shows a steady in- crease downward at a rate which would free the soil from frost at the depth of 600 feet. 4. The average of all known observations, whether in artesian wells or mines, shows an increase of heat towards the interior of the Earth, at the very rapid rate of about 1° Fahr. for every 55 feet. 5. Conclusion. If this ave- rage rate continues without in- terruption, the temperature of boiling water must be reached at the depth of 9,000 feet, or less than two miles from the surface ; and at the depth of thirty miles the heat would be sufficient to melt the most refractory sub- stances. analysis of section vii. I. Evidences of Internal Heat of Globe. 1. Warm or Thermal Springs. a. Distribution and temperature. b. Source of waters. c. Source of warmth. 2. Active Volcanoes — conclusion prom. 3. Artesian Wells and Mines. a. Depth of observations. b. Result of observations. II. Thermal Springs. 1. Situation and Temperature. a. Where most numerous. b. European springs. i Number. ' I Temperature. 2. Geysers, how explained. a. Temperature. b. Where found. c. Great geyser described. d. Other remarkable geysers. Geyser* of California. 3. Waters of Thermal Springs. a. Character. b. To what due. c. Classification. III. Artesian Wells and Alines. a a Strata not volcanic. d d Crater. There is, however, some rea- son to believe that the rate of increase becomes slower at greater depths ; and that the solid crust of the Earth, inclosing the melted mass, has a thickness varying from 50 to 100 miles. The active volcanoes, pouring out torrents of fiery lava, demon- strate that the conclusion drawn from observations of the Earth's in- ternal temperature is not a fanciful one ; for the volcanic phenom- ena are too general and too closely connected with the great frac- tures of the Earth's crust to be accounted for, as has been attempted, by merely local chemical causes. FORMATION AND STRUCTURE OF VOLCANIC CONES. mouth of the shaft 1. Formation of Wells described. a. Supposed conditions b. Effect of drilling. c. Origin of name. 3- Observations in Wells. a. How made. b. Temperature of ground. c. Mean annual temperature found where. d. Observations. Where made. e. Results. a. Observations in Mines. Examples. 4. Average Result of all Observations. 5. Conclusion from all Observations. a. Temperature at 9,000 feet. b. Temperature at thirty miles. c. Probable thickness of Earth's crust. d. Conclusion how sustained. VIII. — RESULTS OF INTERNAL HEAT — VOLCANIC PHENOMENA. I. Nature and Formation of Volcanoes. 1. A volcanic mountain is usually of conical form, with a circular basin or depression, called a crater, at its summit. In the centre of the crater is the mouth of a perpendicular shaft or chim- ney, which emits clouds of hot vapor and gases ; and in periods of greater activity, ejects ashes, fragments of heated rock, and streams of fiery lava. 2. The volcanic cone is FORMED by the accumulation of the ejected materials, in a series of concentric layers, around the These layers are distinctly visible on the inner walls of the crater, and in every part of the mass which is open to observation through crevices. This mode of formation not only explains the conical form of vol- canoes, but distinguishes them from the mountains and mountain chains which are the result of the folding or uplifting of the solid crust of the Earth, and which form the skeletons of the continents and islands. c c Lava and ashes. e Cone of eruption. // Lateral eruptions, parasitic cones. Chimney. RESULTS OF INTERNAL HEAT. — VOLCANIC PHENOMENA. 13 «3. The form of VOLCANIC cones appears to depend upon the ative fluidity of the ejected materials by which they were built up. In general the more liquid the lava, and the smaller the quantity of solid materials, the broader and flatter are the cones. The vol- canoes of the Sandwich Islands, noted for the liquidity of their lavas and an almost entire absence of ashes, are remarkable for their flattened form and the slight inclination of their slopes. Dana estimates tlie average slope of Mauna Loa to be only from six to eight degrees. A horizontal section 1,800 feet below the summit, would be nearly twenty miles broad; and the top, in which the crater is sunk, though nearly 1 1,000 feet in elevation, is a plain so level that the surrounding ocean cannot be perceived from it. In volcanoes where the lavas are less liquid and ashes abound, as in Vesuvius and Etna, the form is more conical and the slopes are more steep, being from twenty to thirty-five degrees. Volcanoes which eject only ashes and fragments of rock, as those of the Andes, art; still more steep and pointed in form ; as shown in the cones of Cotopaxi and Arequipa. In the volcanoes of Iceland, where the lava is viscous and alter- nates with ashes, the form resembles a dome. 4. Volcanic Pboducts. Volcanic ashes, when ex- amined under a micro- scope, are found to be simply pulverized lava, frequently in minute crystals, and bear no re- semblance to ashes in the ordinary sense of the term. They occasionally form a line powder which is car- ried by the wind to a dis- tance id' hundreds of miles. Coarser materials take the name of volcanic sand. Irregular fragments of view of solidified lava, of all sizes, including large pieces of the walls of the erat.r, are at times ejected with great violence. Humboldt speaks of a mass of several tons weight which was thrown to the distance of seven miles from the crater, in an eruption of Cotopaxi. The lava stream, when flowing white hot from the crater, is not unlike a jet of melted iron escaping from a furnace, and moves at first with considerable rapidity. It soon cools on the surface, and becomes covered with a hard, black, porous crust, while the interior remains melted and continues to flow. If the stream is thick the lava may be found still warm after ten or even twenty years. 5. The amount of matter ejected by volcanoes is very great. The whole island of Hawaii, the largest of the Sandwich Islands, seems to be only an accumulation f lava thrown out by its four craters. All high oceanic islands are of the same character. Iceland, with an area of 40,000 square miles, is a vast table land from 3,000 to 5,000 feet in elevation, composed of volcanic rock sim- ilar to the lavas still ejected by its numerous volcanoes. Tb» formation of a new volcano which occurred in Mexico in 1 759, and has been described by Humboldt, exhibits the magnitude of volcanic eruptions. In a fertile and highly cultivated plain, with an elevation of 2,000 feet, the ground was rent ; and at points along the fissure were ejected an immense amount of lava and frag- ments of rock, which accumulated in six distinct volcanoes. The central one, iorvllo, rises 1,G00 feet above the plain; and all rest on a bed of volcanic rock studded with small steaming cones, and gently rising towards the centre where it is 500 feet thick. This region, covering an area of four square miles, now bears the name of the Malpays, or " bad lands." 6. The number of volcanoes, active and extinct, is variously estimated. Dr. Fuchs enumerates 672, of which 270 are active. Of the active volcanoes 175 are on islands, and 95 on the continents near the sea shores. 7. The height of volcanoes varies from submarine cones to an elevation 23,000 feet above the level of the sea. If such volca- noes as Mauna Loa, 14,000 feet high, have their base at the bottom of the deep waters which surround them, the total elevation of such a structure may reach that of the highest mountains on the globe. II. Volcanic Activity — Vesuvius. Nearly all active volcanoes have intervals of comparative repose, in- terrupted by periods of increased activity which terminate in a violent ejection of matter from the interior, during which the volcano is said to be in a state of erup- tion. The phenomena which characterize these differ- ing phases of volcanic ac- tivity may be best made clear by describing them as actually observed in Vesuvius, one of the most carefully studied and most active volcanoes of mod- ern times. This remarkable moun- tain may be considered as typical, for the phenomena exhibited by it are more or less common to all ac- tive volcanoes. Each volcano may dif- jorcllo. f er from this in the rela- tive amount of ashes and broken fragments compared to the liquid lava ; in the violence and frequency of the eruptions ; the form and size of the crater ; the greater or less steepness of the cone ; the composition of the lavas, and other secondary circumstances : but the general course and character of the phenomena show a remarkable similarity. Even submarine volcanoes do not seem to differ materially from others, though the arrangement of the ejected materials, in the for- mation of a submarine cone, is no doubt modified to a certain extent. III. Vesuvius, the Typical Volcano. 1. Situation and Form. Vesuvius is a solitary mountain rising to the height of nearly 4,000 feet, from the midst of a highly cultivated plain which bor- ders upon the shores of the Bay of Naples. Though the mountain has a regular conical form, two summits, very nearly equal in height, are visible from Naples — Monte Somma, on the north, and Vesuvius proper on the south. Monte Somma is only the northern half of the crater-rim of the old Vesuvius, the southern half of which was destroyed in the year 79 a. d., in which occurred the first eruption of that volcano in historical times. Vesuvius proper, is the new cone which has gradually grown out of the old crater, by the ejection of materials in subsequent eruptions. After an eruption the energies of the volcano seem to be exhausted, and it enters into a state of relative repose. 2. State of Repose. At the close of the great eruption of 1822, the orater was emptied to the depth of 700 or 800 feet ; its rim was broken on the south and sunk several hundred feet ; and the lava, deeply sunk in the chimney, had almost disappeared from sight. Only a few jets of vapor and gases, called fumaroles, es- caped from fissures in the walls and at the bottom of the crater. Gradually the fumaroles become more numerous, and their united vapors form a column constantly ascending from the crater. The lava reappears in the chimney, and on its surface there is formed a crust which, bursting under the pressure of imprisoned steam, sends fragments of red-hot lava into the air. These falling back accumulate around the mouth of the chimney, and build up a cone of erup- limi within the crater of the main volcanic cone, as Vesuvius proper within the crater of the old Monte Somma. A smaller cone of this description could be seen within the crater of Vesuvius in 1828. This cone grows constantly in dimensions, occasional overflows of lava and the materials which fall from the crumbling walls of the crater contributing to its in- crease, until the crater is full to the brim, or the cone of eruption rises even higher, as was the case in 1 756. When the cra- ter is thus full and its mouth choked up, the expansive forces below rapidly ac- cumulate, and soon there are indications of an approaching eruption. 3. Premonitions of an Eruption. In Vesuvius among the indications of the approach of a great eruption is the drying up of the wells and springs, probably due to the increasing heat of the ground, causing internal evaporar tion, and to the formation of numerous fissures in which the underground wa- ters disappear. Loud subterranean noises like the reports of distant artil- lery, shocks of earthquake which shake the neighborhood of the volcano, and a large increase of the volume of vapors which escape from the boiling lava im- prisoned in the chimney, indicate the struggle going on within the mountain. 4. The eruption begins generally with a tremendous explosion which seems to shake the mountain to its very foundations, and hurls into the air dense clouds of vapor and ashes. Other explosions succeed rapidly, and with increasing violence, each sending up a white, globular cloud of steam, or aque- ous vapor. This long array of clouds, accompanied by dark ashes, volcanic sand, and fragments of red-hot lava of all sizes, soon forms a stupendous column. When checked in its ascending mo- tion by the action of gravity, the col- umn expands at the top, its form resem- bling an immense umbrella, or the Italian pine, to which it has often been com- pared. In the eruption of 1822, remarkable for its violence and the abundance of ashes, the height of the umbrella was estimated at 7,000 feet, and in that of 1779, at 10,000 feet. Finally the boiling lava overflows the rim of the crater and descends in fiery torrents down the slopes ; or, bursting the mountain by its weight, finds a vent through some fissure far below the summit. After the expulsion of the lava the eruption is generally near its end, though it does not necessarily terminate at once. Alternate phases of outbursting steam, ashes, and lava, may continue with more or less violence for weeks or even months. 5. Atmospheric Phenomena. The sudden condensation of the enormous accumulation of hot vapor thrown into the air by the eruption, gives rise to strik- ing atmospheric phenomena. Vivid flashes of lightning start from all parts of the column, and play about the clouds above ; and often a local thunder-storm, formed in the midst of a clear sky, pours a heavy rain of warm water and ashes upon the slopes of the mountain. The hot, destructive mud torrents, created by these rains, have often been mistaken for lava streams. The majesty of the spectacle is still greater at night. Though flames of burn- ing gases are of rare occurrence, the clouds and column of vapor are strongly illu- VESUTIUS IN ERUPTION, minated by the reflection of the white-hot lava within the crater ; and fragments of this lava constantly thrown into the air give the column all the brilliancy of a gigantic piece of fire-work. The sky itself, far and wide, partakes of the same vivid coloring and the whole scene resembles a vast conflagration. 6. Periods of Eruption. A series of eruptions, separated by intervals of but few years during which indications of activity are still numerous, constitutes a, period of eruption. The history of Vesuvius shows a number of such periods separated by centuries of almost absolute repose, in which the volcano seemed to be extinct. At the birth of Christ, Vesuvius was described by the Roman geographer, Strabo, as a burnt mountain, but it had never been known to show any activity. Its crater, nearly full, was covered with a dense forest, and its slopes adorned with cultivated fields, villages and cities. In the year 63 several shocks of earthquake startled the inhabitants of its de- lightful slopes, and sixteen years later, in 79 a. d., the first eruption occurred, af- ter which the northern half of the mountain alone remained. The south- ern half was ground to powder, and the rain of hot, wet ashes was so abundant as to cover the whole neighborhood with a deep layer of volcanic materials, burying the flourishing cities of Hercu- laneum and Pompeii, which have been recently exhumed from beneath several yards' depth of volcanic tufa. No lava, however, is mentioned in the descrip- tions of this eruption. From that time to the year lo.ii; only seven eruptions are recorded, and lava streams are noticed for the first ,time. After two others, occurring in 1049 and 1138, the mountain entered into a period of repose which, inter- rupted only by slight eruptions in 1306 and 1500, lasted nearly 500 years. In 1631, when the volcano had been SO long dormant that its slopes were cultivated to the foot of the cone of eruption, and the walls of the crater covered with forests, an eruption took place surpassing in destructiveness all others on record. The umbrella shaped mass of vapors and ashes extended above the clouds and, spreading in every direction, cov- ered a large extent of country with a thick layer of volcanic materials, de- stroying all vegetation. The rain of ashes extended eastward even beyond the Adriatic Sea. Torrents of hot mud, an 1 seven streams of fiery lava, flowing with unusual rapidity down the moun- tain slopes to the sea, completed the work of destruction. The eruption continued nearly three months, and a number of beautiful cities and villages were almost or entirely destroyed. This great eruption was followed by a rest of thirty years ; but from 1660 to the present time, eruptions have occurred at intervals not exceeding ten years. That of 1794 was the most imposing and destructive which has occurred since 1631. The recent eruption of 1872 is described as remarkable both for the immense quantity of lava ejtcted and the exceeding brilliancy of the spectacle presented. 7. Some important contrasts to Vesuvius are presented by other noted volcanoes, occasioned probably by differences in height and in the size of the cra- ter. In Stromboli, a volcano less than 3,000 feet in elevation, situated on one of the Lipari Islands, the eruptions are continuous and all from the crater. In Vetumvs, 4,000 feet high, the eruptions occur at irregular intervals, and the number from the crater is about equal to that from fissures in the sides. In Etna, a volcano nearly 11,000 feet high, situated on the island of Sicily, the eruptions are less frequent than those of Vesuvius, and are mainly from the sides. It seems that the pressure of the column of lava in the lofty chimney, combined RESULTS OF INTERNAL HEAT. — VOLCANIC PHENOMENA. 15 with the expansive force of the Imprisoned vapors, is sufficient to burst its walls and cause deep fissures through which both liquid lava and ashes escape. The great cone is studded with more than 200 smaller or parasitic cones, formed by the lateral eruptions and arranged mainly on straight lines radiating from the great crater. The inference is, therefore, that the lower the volcano the more easy and frequent are i r s eruptions, and the greater the proportion from the top ; the higher the vol- cano and the inclosed column of lava, the greater is the pressure on the walls of the chimney, the more frequent the bursting of the mountain and the lateral erup- tions, and the more numerous are the parasitic cones. The volcanoes of the Andes form an apparent exception to this law. Many of them have an altitude of more than 20,000 feet, yet the eruptions are wholly from the top. This is accounted for by the fact that the volcanic peaks rest upon a vast and elevated mountain system which is too massive to be rent by the inter- nal pressure. The inclosed column of lava, unable to reach the elevated crater, is tn> rd about in the chimney and escapes in the form of ashes and coarser frag- ments, but scarcely ever in a fluid condition. The volcanoes of the Sandwich Islands, remarkable for their exceedingly flattened form and the vast size of their craters, are distinguished by the absence of ashes and the usually quiet flow of their lavas from the crater. Extensive lateral erup- tions are, however, frequent in Mauna Loa. ANALYSIS OF SECTION VIII. I. Nature and Formation of Volcanoes. 1. Volcano Described. 2. Volcanic Cone. a. Mode of formation. b. Evidences of this formation. c. Effect of formation. 8. Form of Volcanic Cones. a. Governed by what. ( Volcanoes of Sandwich Islauds. b. Examples. Vesuvius and Etna. Volcanoes of Andes. Volcanoes of Iceland. Volcanic Products. a. Ashes. b. Sand. c. Lava fragments. d. Lava stream ( Appearance. | Process of cooling. 6. Ejected Matter. a. Relative amount of. [ Hawaii. b. Examples. \ Iceland. { Jorullo. 6. Number op Volcanoes. Active. Extinct. Position. 7. Height op Volcanoes. H. Volcanic Activity. a. Activity how varying. b. Typical volcano. c. How volcanoes differ. d. In what respects similar. TTI. Vesuvius. 1. Position and Form. Why two Summits. 2. State op Repose. a. Early condition after 1822. b. Later condition. c. Cone of eruption. How formed. Size attained. 3. Premonitions op Eruption. a. By wells and springs. b. Noises. c. Earthquakes. 4. Eruption. a. Ejection of vapors and solid matter. Description. Amount. b. Ejection of liquid lava. c. Subsequent conditions. 6. Atmospheric Phenomena accompanying Eruptions. a. Observed by day. b. Observed by night. 6. Periods op Eruption. a. What constitutes a period. b. Examples in history. <•. Kesults of eruption in 79 A. D. d. Results of eruption of 1631. e. Condition since 1631. 7. Contrasts to Vesuvius. a. Contrasts due to what. b. Eruptions of Stromboli. c. Eruptions of Vesuvius. d. Eruptions of Etna. «. Inference drawn. f. Apparent exception. Where occurring. How explained. IX. — RESULTS OF INTERNAL HEAT {Continued-). I. Relative Positions of Volcanoes. 1. Lines of Volcanoes. Volcanoes, though they are but local and apparently independent accumulations of materials, ordinarily occur in lines more or less irregular. The six volcanoes of Mexico, among which Orizaba and Popocatepetl are the greatest, are on a line which, when prolonged into the Pacific, strikes the vol- canic island of Socorro. The volcanoes of South America are all on the line of the Andes; and those of North America on the line of the Sierra Nevada and Cascade Mountains. Numerous examples are also found in other quarters of the globe. An apparent exception to this rule is seen where volcanoes seem isolated, or form groups consisting of a central volcano surrounded by secondary cones. But even in this case the linear arrangement is apparent, since the groups themselves form long bands, as in the Polynesian islands ; and in the larger groups the disposition of the individual volcanoes in parallel lines is obvious, as in Iceland and the Sandwich Islands. 2. General Distribution op Volcanoes. Nearly all the vol- canoes on the Earth's surface are situated along the mountain ran- ges and belts of islands which skirt the shores of the continents, while the interior is almost destitute of them. Omitting a few extinct craters, the only well authenticated exception to this rule is found in the few volcanoes around the Thian-Shan Mountains, in the heart of the great Asiatic continent, nearly 2,000 miles from the sea. II. Volcanic Zones. 1. Two great terrestrial zones include nearly all the known volcanoes of the globe, arranged in long bands or series, or in isolated groups. The first zone includes the vast array of mountain chains, penin- sulas, and bands of islands which encircle the Pacific Ocean with a belt of burning mountains. Within it occur, in the New World, (1) the Andes Mountains, with three of the most remarkable series of volcanoes — those of Chili, Bolivia, and Ecuador — separated by hun- dreds of miles ; (2) the volcanic group of Central America ; (3) the series of Mexico ; (4) the series of the Sierra Nevada and Cascade Mountains ; (5) the group of Alaska ; and (6) the long series of the Aleutian Islands. In the Old World are (1) the series of Kamchatka and the Kurile Islands ; (2) the group of Japan ; (3) the series south of Japan, in- cluding Formosa, the Philippine and the Molucca Islands ; and (4) the Australian series, including New Guinea, New Britain, New He- brides, and New Zealai/1. In this vast zone there are not less than 400 volcanoes, 170 of which are still active. The second zone, though less continuous, is hardly less remarkable. It is the belt of broken lands and inland seas, which, extending round the globe, separates the northern from the southern continents, and intersects the first zone, in the equatorial regions, nearly at right angles. RESULTS OF INTERNAL HEAT. — VOLCANIC PHENOMENA. This zone includes (1) the volcanic regions of Central America and Mexico, and the series of the Lesser Antilles ; (2) the groups of the Azores and Canary Islands ; (3) the Mediterranean ifilands and penin- sulas, including all the active volcanoes of Europe ; (4) Asia Minor with numerous extinct volcanoes ; (5) the shores of the Red Sea and Persian Gulf, and the two Indias, rich in traces of volcanic action ; (6) the East Indian Archipelago with hundreds of burning moun- tains ; and (7) the Friendly Islands and other volcanic groups of the central Pacific. In this zone there are no less than 160 volcanoes, so that the two volcanic zones together contain 560, or five sixths of all known. The volcanic forces display the greatest intensity at the intersections of the two volcanic zones, in Central America and the East Indian Archipelago, nearly one third of all known volcanoes occurring in these two regions. Central America, Mexico and the Antilles include 85 volcanoes, while the East Indian Archipelago possesses 117. The volcanoes not included in these two great zones are isolated, in the midst of the oceans, or .in the broken polar lands. The most noted are the Sandwich Island group, in the Pacific ; Bourbon and Mauritius, in the Indian Ocean ; Cape Verd Islands, Ascension, St. Helena, and Tristan da Cunha, in the Atlantic ; Iceland and Jan Mayen, in the Arctic Ocean ; and Erebus and Terror, in the Antarctic. III. Causes of Volcanic Action. 1. The peculiar distribution of volcanoes suggests the nature and causes of volcanic action, which must not be confounded Avith that more general force which has uplifted the continents and de- pressed the basins of the oceans. Three facts are obvious and significant, namely: (1.) Nearly all volcanoes are either along the highest border of the continents, or in the great central zone of fracture. (2.) Most of the volcanic groups exhibit a linear arrangement. (3.) The agent at work in these mighty engines is mainly vapor of* water, or steam power. 2. The primary source of volcanic action is the heated condi- tion of the Earth's interior, of which we have evidence so conclusive. The effect of this condition will necessarily be most intense along the deep fissures which establish a ready communication between the interior and the surface of the globe. Nowhere are the Earth's strata more deeply broken than on the very edge of the continents ; and it is along the mighty chasms caused by the upheaval of these vast land masses, that mountain chains, such as encircle the sunken basin of the Pacific, have been raised. There, also, volcanic vents abound in long lines, following either the top or the foot of the mountain chains. Similar condi- tions exist in the zone of fracture. The folding and breaking up of the solid crust of the Earth, and the formation of those great surface features which adorn it, must not be ascribed to the heat of the interior mass, but to its slow cool- ing and the consequent contraction of its bulk. Volcanic action, therefore, is not the cause but a consequence of the upheaval of mountain chains and continents ; and the proximity of volcanoes to the sea does not imply the necessity of sea water to their formation, but is due to the deep fissures in the Earth's crust, along the line of contact of the depressed ocean basin and the up- lifted continent. The rain water which, having entered the ground, instead of reappearing in the form of springs or artesian wells, penetrates deep into these subterranean cavities, may become so heated, under the high pressure to which it is subject, as to pro- duce the usual volcanic phenomena. X.— ANALYSIS OF SECTION IX. I. Relative Position of Volcanoes. 1. Lines op Volcanoes. a. Ordinary arrangement. b. Examples. c. Apparent exception. 2. General Distribution. a. Ordinary situation. b. Exceptions. II. Volcanic Zones. a. Number of zones. b. Pacific zone Volcanic regions included. c. Transverse zone Volcanic regions included d. Greatest intensity of volcanic forces. e. Volcanoes not included in zones. III. Volcanic Action. 1. Nature and Causes — how suggested. Prominent facts of distribution. 2. Primary Source op Volcanic Action. a. Effects, where most intense. b Strata, where most deeply broken. c. Folding of Earth's crust ascribed to what. d. Volcanic action, how related to upheaval of mountain chain. RESULTS OF INTERNAL HEAT. {Continued.) EARTHQUAKES. I. Earthquake Defined. 1. Earthquakes are movements of the Earth's crust, varying in intensity from a hardly perceptible vibration to violent convulsions, which change the face of the ground and overthrow the mos v sub- stantial works of man. 2. Example. The earthquake at Lisbon, Portugal, on the morning of November I, 1755, one of the most appalling in its results, exhibits the nature of these commo- tions of the Earth's crust, and the phenomena attending them. The day was the festival of All-Saints, and the churches of the city were full to overflowing; when, at forty minutes past nine, a rumbling noise was heard like distant thunder, gradually increasing until it resembled the sound of heavy artillery. A faint shock was followed by a heavier one, and within six minutes 30,000 persons were buried under the ruins of the churches and other edifices ; and 30,000 more perished before the end of the catastrophe. The ground seemed to undulate like the waves of the sea, the surrounding mountains were seen rocking violently on their base, and broad chasms opened in the earth and closed again. More than 3,000 persons had taken refuge from the falling edifices on a broad marble quay just built on the banks of the Tagus, when the sea, which had before receded, came back in a furious wave forty feel high and swallowed up the entire multitude ; then rushing upon the city it continued the work of devastation. Similar oscillations of the sea were repeated several times; and when the commotion ceased several hundred feet of water covered the spot which the quay had occupied. Fires, kindled in the fallen dwellings, spread over the scene of desolation, creat- ing a vast conflagration which completed the work of destruction. The ground continued to be agitated for several weeks afterwards, and another severe shock occurred in December following. One of the most remarkable features of this earthquake was the extent of country over which it was felt. All western Europe was agitated ; the northern coast of Africa suffered considerably; nearly all the cities of Marocco were de- stroyed, and fissures whence streams of water issued, were opened in many places. On some of the West India Islands the sea rose twenty feet, and a similar rise was observed in the harbors of New York and Boston. The entire surface disturbed by this earthquake amounts, according to Humboldt, to four times the area of Europe. II. Kinds of Earthquake Movement. Three kinds of motion are observed in earthquakes. 1. The wave-like or undulatory motion is most common and least destructive. It appears to be the normal one, and it is pos- sible that the others may be simply the result of various systems of waves intersecting one another. The waves either advance in one RESULTS OF INTERNAL HEAT. — EARTHQUAKES. 17 direction, like waves of the sea, or spread from a central point, like ripples produced by dropping a pebble into still water. The earthquakes of the Andes are chiefly linear, being propa- gated along the mountains, with the undulations perpendicular to the direction of the ranges. The earthquake at Lisbon, described above, was a central one, the concentric waves gradually diminish- ing in intensity with increasing distance from the place of origin. 2. The VERTICAL motion acts from beneath like the explosion of a mine, and when violent nothing can resist its force. The earth- quake at Calcutta, in September, 1828, owed its great destructive- ness to the fact that the main shock was vertical ; and one in Murcia, Spain, in 1829, destroyed or injured more than 3,500 houses. 3. The rotary or whirling motion, is the most dangerous, but happily the rarest of all. In the gr.eat earthquake of Jamaica, in 1692, the surface of the ground was so disturbed that fields changed places, or were found twisted into each other. 4. The velocity with which the earthquake wave moves is vari- able. Humboldt estimates the ave- ft rage rate at from j twenty-three to \ thirty-two miles ] per minute. III. Duration of Earthquakes. Great earth- quakes usually consist of a series of successive shocks, some of which are of ex- traordinary v i o - lence. They may be repeated at longer or shorter intervals, during a period of several days and weeks, or even of several months and years, before the earthquake is at an end. During the earthquake on the coast of Venezuela, which began on the 21st of October, 1766, and destroyed the city of Cumana in ' a few minutes, the earth continued to be shaken almost every hour for a period of fourteen months. After the destruction of the beautiful city of Messina, on the island of Sicily, in 1783, the ground continued to be agitated almost daily for ten years. IV. Distribution of Earthquakes. 1. General pacts : — (1.) No part of the globe is absolutely free from earthquakes. (2.) There are circumscribed regions in which the surface is liable to be shaken simultaneously, such a region being called an earth- quake area. (3.) The most extensive earthquake areas, and those in which the convulsions are most numerous and violent, are situated within the two great volcanic zones — that is, the coast regions of the Pacific EARTHQUAKE AT LISBON. Ocean, and the transverse zone separating the northern from the southern continents. 2. Th» analogy IN THE distribution of earthquakes and volca- noes is evident, yet the former occupy a far more extensive domain than the latter. Both are most intense in their action along the great fractures of the Earth's crust ; yet we are not, on that account, to conclude that the one is the cause of the other ; they only require similar conditions for their manifestation. The immediate connection of earthquakes with, volcanic eruptions is evident in many instances, yet these are of a special kind. Volcanic eruptions often take place without earthquakes, as in the Sandwich Islands ; and many severe earth- quakes occur in regions far removedljfrpm any active volcano, and destitute of volcanic rocks. Even in volcanic districts the most extensive earthquakes bear apparently no relation to the surrounding volcanoes. The two sets of phenomena may have a common cause, but they must not be confounded or considered as necessarily belonging to the same class. V. Relation to Atmospheric and Astronomical Conditions. Within the trop- ics, especially, earthquakes are most frequent in that part of the year in which the greatest atmos- pheric disturban- ces take place. They are most dreaded at the be- ginning of the rainy season, when the monsoons 1 are changing their di- rection. In the Molucca islands the inhabitants, at this period, for- sake their houses for greater safety, and shelter them- selves under tents or the lightest bamboo structures until the danger is past. 3. Perrey, by comparing 7,000 observations, found the number of earthquakes occurring at the syzygies — when the attraction of the Sun and Moon is com- bined and the Moon is nearest the Earth — greater than at the time of the quad- ratures, when the Moon is most distant ; also that, during an earthquake, the shocks are more frequent where the Moon is on the meridian. Wolf finds a co- incidence with the periodicity of the Sun's spots, the years in which these are most numerous being those in which earthquakes are most frequent. VI. Theory of Earthquakes. 1. A General Cause Necessary. No satisfactory explana- tion of the phenomenon of earthquakes has as yet been proposed. Local earthquakes, preceding or accompanying a volcanic eruption, are doubtless due to the action of the volcano ; but all which take place outside of volcanic districts, and especially those general con- vulsions, disturbing areas hundreds of thousands of miles in extent, must be assigned to some more general cause. This cause may possi- bly be found in the constantly increasing tension produced in the i See page 78, 1. O Longitude 20 East from 40 Greenwich. 60 E. Sandoz.Sc J . Krumholz , -del . Entered according toAct of Cona^ess in the Year 1872 . 6, k Ml H E xp 1 a 11 a t i o n - Volcanoes are marked by black dots. ( • ) and the Regions visited by Earthquakes are distinguished by shading, which, is darker in proportion to the force and frequency of the shocks . Coral reefs and Islands are marked by a blue shading . In the Profiles the black peaks are the Volcanoes, and the limit is indie t , „ ., , EARTHQUAKES JHlaja T i^Bro ^ Rat ter | L ySh-to ; Pop.catepet l^ pe, the atmosphere, mutually acting upon one another, form the hree great geographical elements which, under the influence of the >un, support life in all its varied forms. The extent, form, and relative position of the land masses, materi- ully modify climate, and regulate the distribution and development >f organic life. Hence the htrimary importance. The proportion of land to rater upon the globe is as IE : 72, the land covering 53,- ©0,000 square miles, the sea 44.000,000. I. The Land Masses. 1. Division. The land is either concentrated into one ast mass, nor uniformly dis- ributed over the globe. It consists of six great bodies ullcd continents, widely differ- lg in size and form ; and a niltitude of small fragments died islands, which skirt the lores of the continents or dot te broad expanse of the sea. from which there results, in each, a belt of broken lands — peninsulas and islands. Within this belt are the great archipelagoes of the East and West Indies, and the peninsulas of southern Asia and Europe. These regions form part of a broad transverse zone which may properly be designated the central zone of fracture. Its position can be traced by describing a circumference upon the globe, from Behring Strait as a centre, with a meridian arc of 80° as a radius. Figure 1 exhibits the divergent arrangement of the land masses, and the zone of fracture. The latter passes over the Caribbean Sea, in the New World ; and the Mediterranean Sea and East Indian Archipelago, in the Old. III. Grand trasts. Terrestrial Con- This division of the land lto diverse bodies produces a diversity of climate, and promotes a tiler and more perfect development of every order of life. 2. Position on the Globe. The land masses are crowded kether around the north pole, their northern limits being about te 70th parallel. Thence they extend towards the south, in three ast divergent tracts, terminating in points widely separated one •om another, and very distant from the south pole. The sea encircles the south pole, and sends three great arms north- 'ard, between the divergent land masses, forming the Pacific, the itlantic, and the Indian Ocean. 8. ZONE of Fracture. Each of the three divergent tracts of md is invaded nearly midway by the ocean, or by great inland seas, 1. Northern and South- ern Worlds. The trans- verse zone of fracture divides each of the divergent tracts of land into two continental mas- ses, or a pair of continents. Hence there are three northern and three southern continents, forming two groups which pre- sent marked contrasts. The northern continents lie near together, and almost whol- ly within temperate latitudes ; the southern continents, on the contrary, ara isolated one from another, and lie chiefly in trop- ical latitudes. 2. Eastern and Western Worlds. Two of the three di- vergent pairs of continents are crowded together upon one side of the globe, while the third is isolated upon the opposite side ; the eastern, or Old World, thus contains more than twice as much land as the western or New World. This difference in area, together with the concentration of the lands in the former, and their greater separation in the latter, con- stitutes a second terrestrial contrast of great importance, whose influence is felt, through climate, upon every order of life. 3. Continental and Oceanic Worlds. A third great con- trast is produced by the combined concentration of the lands upon the northern and eastern regions of the globe. This gives rise to a northeastern or Land Hemisphere, and a southwestern or Wa- FIG 1. DIVERGENCE OF LAND MASSES, AND ZONE OF FRACTURE. 22 HORIZONTAL FORMS OF THE CONTINENTS. tir Hemisphere, first traced by Carl Ritter, and properly designated the Continental and Oceanic Worlds. The former contains over six sevenths of the land surface of the globe. The latter includes only Australia and the southern extremi- ties of Asia and South America, which, with numerous islands, make less than one seventh of the solid surface of the Earth. IV. Relative Areas and Position of Laud Masses. The western pair of conti- nents is the longest ; and the two Americas are nearly of the same size. Europe-Africa is the shortest pair, and the smaller continent is at the north, the larger at the south. In Asia-Australia the larger is at the north, the smaller at the south. Thus the greatest variety is obtained, both in size and in relative situation, by the slanting direction of the zone of fracture. The relative areas of the three pairs of continents, as well as that of the conti- nents individually, is represented to the eye by Figure 3. The numbers within the several rectangular spaces give the areas of the continents in square miles. ANALYSIS OF SECTION I. I. Geographical Elements. a. Elements enumerated. b. Importance of the arrangement of land masses. c. Proportion of laud and water on globe. II. The Land Masses. 1. Division op Land. a. Extent of division. b. Importance of division. 2. Position op Lands on Globe. a. Northward position of land masses. b. Converse position of sea. 3. Central Zone of Fracture. a. Kelation to diverging lands. b. Position of zone. III. Terrestrial Contrasts. 1. Northern and Southern Worlds. a. Number and arrangement of continents. b. Position of northern group. c. Position of southern group. 2. Eastern and Western Worlds. a. Relative position of pairs of continents. b. Relative extent of Old and New World. c- Results of difference in area and compactness. 8 Continental and Oceanic Worlds. a. Basis of third series of contrasts. b. Relative amount of land in each hemisphere. IV. Areas of Continents. a. Relative areas and positions. b. Absolute areas in English square miles. II. — HORIZONTAL FORMS OF THE CONTINENTS. I. Twofold Aspect of Continen- tal Forms. Every continent presents it- self to the observer in a two- fold aspect — as a surface, with peculiarities of horizontal form and outline, given by the line of contact of land and water ; and as a solid, with peculiari- ties of vertical form, given by the elevation of its surface above the level of the sea. FIG. 2. LAND AND WATER HEMISPHERES EUROPE. NORTH AMERICA. 8,261,000. 3,565,200. ASIA. AFRICA. 11,314,300. 16,216,600. 80UTH AMERICA. 8,889,500. AUSTRALIA. 2,948,300. FIG. 3. RELATIVE AREAS OF THE CONTINENTS. The former, though the more obvious, is not the fundamental char- acter, since it is the result of the latter. II. General Figure of Continents. 1. Common Fundamental Figuee. Every great conti- nental mass has a figure more or less triangular. The two Americas are each triangular ; the double continent, Asia- Europe, forms a triangle ; and the main body of Africa has a similar figure. Australia alone approaches a quadrilateral form ; and even this, including the island of Tasmania, which is properly a part of the continental figure, approximates to a triangular outline. This remarkable coincidence in the fundamental form of the continents, evidently indicates a common law of structure, which it is the province of geology to discover. 2. Direction op Greatest Prolongation. In the two Amer- icas, the sharpest angle of the continental figure is turned towards the south, and the greatest elongation is in the direction of the me- ridians. In Asia-Europe, on the contrary, the sharpest angle is towards the west, and the greatest elongation of the double continent is in the direction of the parallels. In Africa and Australia, while the continents narrow towards the south, their greatest extent from east to west is approximately equal to that from north to south. The difference in the direction of elongation in America and Asia- Europe, causes marked differences in other respects. The former, extending over 9,000 miles from north to south, traverses all tin- climatic zones, exhibiting, as a result, great variety in the character of its plants and animals. Asia-Europe, having a length of i 7,000 miles, has, from the Pacific shores to the Atlantic, a general similarity of climate, vegetation, and animals. III. Continental Outlines. 1. Differences in Outline. The outlines of the continents display striking differences. Some are deeply indented with gulfs and inland seas, or have projecting peninsulas ; while others pre- sent a massive form with simpler outlines, without indentations or projections worthy of notice. 2. Importance of Articu- lation of Coasts. These irregularities, or articulations of outline, are of vast impor- tance to the civilization of the continent. They greatly increase the length of the coast line, and the contact of land and water ;. they favor the formation of con- venient harbors, and open the interior of the continents to commerce by sea, facilitating HORIZONTAL FORMS OF THE CONTINENTS. 23 BTTB.OPE. 19,800. 3,565,200 Sq. miles ASIA. 85,500. 16,216,600 Sq. miles. ' AFRICA. 16,200. 11,314,300 Sq. miles. AUSTBALIA. 8,760. 8,948,800 Sq. niiks. communication with other parts of the world ; and the sea, penetrat- ing into the land, moderates the extremes of temperature, and in- creases the moisture of the atmosphere, and the fertility. Again, the subdivision of the continents into peninsulas, form- ing diverse physical regions, gpcurea a higher development of human society by assisting in the formation of distinct nationalities ; like those cre- ated in the great peninsulas of India and Arabia, Greece, Italy, and Spain. It is a remarkable fact that the deeply indented, well articulated continents, are, and have always been, the abode of the most highly civilized nations. The unindented (uus, shut up within themselves and less accessible from without, have played no important part in the drama of history. It should be re- membered, however, that variety of contours is but the expression of a complicated inner structure, which, together with the climatic situation of the northern continents, has had a large share in this result. 3. Gradation in Artic- i i.ation. A significant gradation is exhibited by the several continents in regard to irregularities of outline. Europe surpasses all the others in the relative magnitude of its indentations find projections; the proportion of its penin- sulas to its entire area being as 1 : 4. Three great peninsulas — the Hellenic peninsula, Italy, and Spain — project into the Medi- terranean ; while Bretagne, Denmark, and Scandinavia enrich the shores of the Atlantic. Even the British Isles are scarcely more than a projection of the continent. (See page 38, British Isles.~) Asia is second in the relative extent of its peninsulas, the pro- jecting lands being to the entire area of the continent as 1 : 5.5. Asia Minor on the west, Arabia, India, and Indo-China on the south, and China, Manchuria with Corea, and Kamchatka, advancing into the waters of the Pacific, form a wide border of projecting lands, con- taining the richest regions of the continent. North America, though considerably less indented, still has penin- sulas bearing to its entire area the proportion of 1 : 14. Flor- ida, Nova Scotia, and Labrador are the most prominent on the At- lantic coast ; Boothia Felix and Melville Peninsula on the Arctic ; and California Peninsula and Alaska on the Pacific. The southern continents, on the contrary, are nowhere deeply penetrated by the waters of the ocean. The Gulf of Arica, in South America, the Gulf of Guinea, in Africa, and the Great Aus- tralian Bight, are merely gentle bends in the coast line. The slight projections of the Atlas Mountain region and Somali in Africa, and Fork Peninsula in Australia, are scarcely to be reckoned among true peninsulas. These three continents are aptly styled by Ritter, trunks without branches, or bodies without members; while the, three northern continents are beautiful trees with abundant spreading branches, or bodies richly articulated with useful mem- bers. 4. The Amount of Indentation in each continent is shown in Figure 4. The inner squares represent the area of the continents, and their contours show the length of coast required to inclose that area without indentations or projections. The contours of the outer squares represent, on the same scale, the actual length of coast line inclosing the same area as it exists in the continents. The difference between the contours of the outer and inner squares," is the true measure of the amount of indentation. A NORTHERN CONTINENTS. NOKTH AMERICA. 27,700. 8,261,000 Sq. miles. glance reveals the difference be- tween the northern and the south- ern continents in this respect. The following TABLE gives the length of the coast line in each continent, and the area without islands, in English miles. SOUTHERN CONTINENTS. Europe, Asia, North America, Africa, Australia, South America, 3,£65,200 sq. m. 1G,216 600 " 8,261,010 " 11,314,300 k * 2,948,300 " 6,889 ,50 J " Length of Co;i.-t. 19,800 m. 35,500 " 27,700 " 16,200 « 8,760 " 15.700 " SOUTH AMERICA. 16,700. FIG. 4. LENGTH OF THE COAST-LINK IN EACH CONTINENT, COMPARED WITH THE LINE ENCLOSING ITS CONSOLIDATED AREA. This table shows that Eu- rope has 3,600 miles more of coast than Africa, though the latter has more than three times the area of the former. North America, but little larger than South America, has 12,000 miles more of coast. Australia, nearly the size of Europe, has less than half its length of coast. ANALYSIS OF SECTION II. I. Twofold Aspect of Continental I onus a. Continent as a surface b. Continent as a solid. c. Relative importance of the two. II. General Figure of Continents. 1. Common Fundamental Figure. a. Figure belonging to alt great masses. b. Examples. c. Figure of Australia. d. Inference from coincidence in fundamental form. 2. Direction of Greatest Elongation. a. The Americas. b. Asia-Europe. c. Africa and Australia. d. Effect of difference in direction of elongation. III. Continental Outlines. 1. Differences exhibited by Continents. 2. Importance of Irregularities. a. Influence on extent of coast and communication. b Influence on climate. c. Influence oo development of society. d. Coincidence between articulation of outlines and historical importance. 3- Gradation of Continents in Articulation of <\m-ts. ;i. Kurope. b. Asia. c. North America. <1. Southern continents. Figure used by Ritter. i. Amount of Indentation of Continents. a. How exhibited by diagram. b. How exhibited by table. o. Comparison of coast lines. 24 VERTICAL FORMS OF THE CONTINENTS. III. — VERTICAL FORMS OF CONTINENTS. I. General Relief Forms. 1. Relief Defined. The vertical configuration of a continent or island — that is, its elevation as a whole, varied by plains, table- lands, mountains, and valleys — is called its relief. The elevation of any given point, reckoned from the level of the sea as a common base, is called its altitude. The height of a hill, moun- tain, or plateau,above the surrounding country, is its relative elevation. 2. Classes of Relief Forms. Although the forms of relief are exceedingly varied, they may all be referred to two great classes, namely : elevations in mass, and linear elevations. Elevations in mass, or great areas of nearly uniform altitude, are called plains or lowlands, when their altitude is less than 1,000 feet ; and plateaus or table-lands, when it reaches or exceeds 1,000 feet. Linear elevations are those whose breadth is slight compared with their length. In this class are included chains of mountains and hills, and the intervening valleys. The term hills is applied to ridges less than 2,000 feet in elevation. 3. Importance of a Study of Relief Forms. The loftiest mountains, when compared with the diameter of the Earth, are but as grains of sand upon a globe several feet in diameter ; yet the element of altitude so powerfully affects climate, and organic life, that a knoAv ledge of the reliefs of the several continents is of the utmost importance. A difference in altitude of no more than 330 feet, is sufficient to produce a difference in temper- ature of 1° Fahrenheit, being equivalent to a difference of sev- enty miles in latitude. An in- crease in altitude of but a few thousand feet, therefore, changes en- tirely the character of a region, like a removal of it from torrid to temperate latitudes, or from temperate to frigid. Again, the relief of a continent controls its drainage, shaping the river basins, and directing the course of its flowing waters ; and in- fluences, to a certain extent, the direction and character of the winds, and the distribution of rain. II. Plains. 1. Extent of Plains. Plains occupy nearly one half of the surface of the continents. They are most extensive and unbroken on the Arctic slopes of the Old World, and in the interior of the two Americas. The great Siberian plain extends from the northeastern extrem- ity of Asia to the Ural Mountains and Caspian Sea ; and the Euro- pean plain stretches from the Ural westward, through Russia and North Germany, to the lowlands of Holland. In North America the great central plain extends, with but slight interruptions, from the Arctic shores to the Gulf of Mexico. In South America the plains of the Orinoco basin, the Selvas of the Amazon, and the Pampas of the La Plata, form an uninterrupted series of low lands which, continued by the plains of Patagonia to the southern extremity of the continent, extend over a distance of 3,500 miles from north to south. The interior of Australia is also a plain of great extent. The KORTH AMERICA. Highland. EUROPE. Highland. ASIA. Highland. Lowland. AFRICA. Highland. Lowland. Lowland. S. AMEMCA. Highland. Lowland. Lowland. AUSTRALIA. Lowland. FIG. 5. RELATIVE AREA OF HIGHLAND AND LOWLAND IN EACH CONTINENT. plains of China, Hindoostan, and the Euphrates basin, in Asia, justly celebrated as the seats of mighty civilized nations, are smaller and of a more local character. 2. Surface. On account of differences in the character of their surface, plains may be divided into three general classes, namely : alluvial, marine, and undulating plains. Alluvial plains are almost absolutely level, their surface often being unbroken by any elevation deserving even the name of a hill. They are formed of materials deposited by rivers upon overflowed lands along their courses, or in shallow waters about their mouths, the deposits gradually converting the shallows into flat moist lands. The most marked examples of alluvial plains are the delta of the Mississippi and the flat bottom land, from thirty to eighty miles in width, lying between its bluffs; the great plains of the Amazon, the Orinoco, and the La Plata; the low plains of China, Hindoostan, and the lower Euphrates ; the delta and valley of the Nile ; and the plains of the Po and of the lower Rhine. Marine plainsare&o called because they seem to have been formed under sea water, and resemble the sandy bottom of an ancient ocean. Theyshow but slight inequalities of surface, due to local accumula- tions of sand drifted by the currents, or to other accidental causes ; and where there is a scarcity of rain the soil is frequently im- pregnated with salt, soda, and other substances remaining alter the evaporation of sea water. Plains of this class are situated, chiefly, on the shores of the con- tinents, or around great salt hikes and inland seas ; like the sandy plains of our Atlantic slope, and those adjacent to the Baltic, the Caspian, and the Aral Sea. Undulating plainx have the surface varied by swells of greater or less elevation, but rarely much above the general level. They occupy an intermediate position be- tween the highlands of the continents and the low alluvial and ma- rine plains. Of this class are the larger part of the plains in the Mississippi basin, and the uplands at the eastern foot of the Appalachian Moun- tains ; the central and southern plains of Russia, and the eastern half of the Siberian plain. 3. The productiveness and general aspect of plains varies as widely as their surface. Treeless plains, whose vegetation consists of grasses and other her- baceous plants, or stunted shrubs, occur in every continent, and are designated by a variety of terms. In ^North America the fertile treeless plains are termed "prairie* " (meadows), while the sterile ones, east of the Rocky Mountains, are known as " the plains." In South America the Spanish term "llano" (plain), and the Peruvian " pampa," designate the treeless plains of the Orinoco and La Plata basins. Those of eastern Euro])e and Asia are denom- inated " steppes ; " while more limited treeless regions in western Europe are called " landes " and "heaths." Wherever treeless plains are subject to periodical rains, they lose their verdure in the season of drought, and assume the aspect of a desert ; but they resume their freshness on the return of the rain, and many are adorned with a great variety of beautiful flowers. VERTICAL FORMS OF THE CONTINENTS. 25 The marine plains being chiefly sandy, are the least fertile ; but the more favored ones produce forests of pine and excellent pasturage ; like the Baltic plains of Europe, and the sandy plains on the Atlan- tic coast of North America. The plains of the Caspian Sea and western Siberia are dreary steppes, covered with coarse grasses, often growing in tufts, alter- nating with patches of heather, furze, dwarf birch, and other stunted shrubs ; or old sea bottom, covered with salt efflorescence. Immense reaches of flat country, near the Arctic shores of Asia and Europe, consist of frozen marshes, called tundras, where mosses and lichens are almost the only vegetation. The undulating plains produce the most extensive forests of tem- .perate latitudes ; but where subject to long summer droughts, — as in the western half of the Mississippi basin, in southern Russia, and in many other localities, — these plains are often treeless. The alluvial plains are among the most valuable portions of the globe. There the waters, descending the slopes of the continents, meet, bringing with them the spoils of the upland, and accumulating that rich soil upon which, in all periods of history, men have gathered by millions. On the alluvial plains of the Old World civilization began and developed ; and their inexhaustible fertility supplied the wants of the most populous nations of antiquity. The great centres of an- cient civilization in Egypt, China, India, and Babylonia, all had their growth in alluvial plains, built up and fertilized by the mighty rivers which traverse those countries. In the New World are the cane fields and forests of the lower Mis- sissippi ; the Llanos of the Orinoco, during one half of the year cov- ered by the richest pasturage, bright with flowers, but during the other half a parched waste ; the Selvas of the Amazon, a luxuriant forest covering more than a million square miles ; and the treeless Pampas, with their tall grasses and thickets of clover and thistles : all illustrating the endless richness and variety of nature. 4. Altitude. Alluvial and marine plains generally have but a slight altitude, while the undulating plains are sometimes consider- ably elevated. The Mississippi valley, at St. Louis, 1000 miles from the ocean, is hardly 400 feet above the sea level ; and the Amazon, at an equal distance from the sea, does not reach 250 feet. The marine plains adjacent to the Caspian and Aral Seas are still lower, the larger portion being below the sea level. 5. The area covered by low lands in eacli continent is shown, approximately, in the following table, which gives their extent in English square miles, and their proportion to the entire area of the continent. A^ia, Europe, North America, Area of Lowlands. 7,116,000 sq. miles. 2,541,000 " 3,840,000 " Propor- tion. Africa, South America, Australia, Area of Lowlands. 1,000,000 sq. miles. 5,417,000 " 2,500,000 " Propor- tion. ANALYSIS OF SECTION III. I. General Relief Forms. 1 Relief Defined. Relief distinguished from altitude. 2. Classes op Relief Forms. a. Elevations in mass. Plains. Plateaus. b. Linear elevations. Mountains. Hills. 3. Importance op Study op Reliefs. a. Greatest elevations compared with diameter of Earth. b. Effect of elevation on climate. c. Effect of relief on drainage of continent?. II. Plains. 1. Extent op Plains. a. Proportion to entire area of continents. b. Geographical position of great plains. c. Examples. Siberian Plain. European Plain. Plains of North America. Plains of South America. Plains of Australia. d. Less extensive plains. 2. Surface of Plains. a. Alluvial plains. Surface. Formation. Examples of alluvial plains. b. Marine plains. Their nature. Surface and soil. Geographical situation. Examples. c. Undulating plains. Surface. Examples. 3 Productiveness op Plains. a. Treeless plains how designated. In North America. In South America. In Eastern Europe and Asia. In Western Europe. Treeless plains under periodical rains. Q. Marine plains. c. Undulating plains. General character. Exceptional regions. d. Alluvial Plains. General Character. Alluvial plains of Old World. Alluvial plains of New World. 4 Altitude of Plains. a. Altitude of different classes. b. Examples. 6. Area of Plains. IV.— VERTICAL FORMS OF THE CONTINENTS Con- tinued'). I. Plateaus. 1. Plateaus are situated either between two lofty mountain chains, which form their margins, or descend by successive terraces to the nearest seas ; or they pass, by insensible gradations, from the base of high mountains to the low plains in the interior of the conti- nents. The Great American Basin, between the Rocky and Sierra Ne- vada Mountains, and the plateau of Thibet, between the Hima- laya and Kuenlun Mountains, are examples of the first position ; and the table-land of Mexico, of the second. The third is seen in the high plains at, the eastern foot of the Rocky Mountains, which de- scend from an altitude of 5,000 or 6,000 feet, at the foot of the mountains, to the low plains in the centre of the Mississippi basin. 2. The surface of plateaus varies as widely as that of plains, some, like the Great American Basin, being even quite mountainous; but in all cases the lowest part of the plateau has still a considerable elevation. Although in the sloping plateaus, such as the one east of the Rocky Mountains, there may be no well defined limit at which the name of plateau must be exchanged for that of plain, yet striking differences in climate, as well as in vegetable and animal life, dis- tinguish the plateaus in general as one of the most strongly marked geographical forms. 3. Elevation of Plateaus. The plateaus most remarkable for their elevation are, — Thibet, from 10,000 to 18,000 feet above the sea ; and the elongated valley-like highlands, from 10,000 to 13,000 feet high, between the two chains of the Andes, in South America. These, with some smaller regions, also situated between lofty mountain ranges, may be denominated plateaus of the first order. Plateaus of the second order, averaging from 4,000 to 8,000 feet, are the most extensive. East Turkestan and Mongolia, in central Asia ; the plateau of Iran, in western Asia ; Abyssinia, and the vast plateau which occupies all the southern part of Africa ; and the broad table-land which m fills the western half of North America with a continuous mass of high land : are examples of this order. Plateaus of the third order, from 1,000 to 4,000 feet in altitude, occupy the gre^t peninsu- las ; as the Deccan, Arabia, Asia-Mi- nor, and Spain. The central plateau of France, and those of Switzerland, Ba- varia, and Transyl- vania, are oi the same order. 4. Importance of Plateaus . Great plateaus of the first and second orders, together with their accompanying mountain ranges, form the nucleus or back-bone of almost every continent ; determining its general form, and, to a great extent, the direction and combination of its water courses. 5. The nature of the soil and climate of great plateaus is in gene- ral such as to render them the least useful portions of the continents. Sahara — with an average altitude of 1,500 feet — and the higher plateaus of Mongolia, Iran, and the Great American Basin, may serve as types. Their surface consists of hardened sand and rock ; of hillocks and plains of loose sand con- stantly shifting by the wind; upheaving force. and of immense tracts, as in Mongolia, covered with pebbles varying from the size of a wal- nut, or even less, to a foot in diameter : all indicating the original transporting, grinding, and de- positing of these materials by water. Salt lakes without outlet occur in each, and salt efflorescence often covers the ground. A lack of rain to wash from the soil substances injurious to vegetation, and furnish the water necessary for the growth of plants, leaves these plateaus generally sterile, and some of the most exten- sive are in part, if not wholly, deserts. II. Mountains. 1. Appearance of Mountains. Mountains rise in long and comparatively narrow lines or ridges, the tops of which are often deeply indented, presenting to the eye the appearance of a series of THE GREAT WESTERN PLATEAU OF NORTH AMERICA, NEAR FOB BBIDGER. FIG. 6. MOUNTAINS UY FOLDING. A TRANSVERSE SECTION OF THE JURA. peaks detached one from another. As each of these peaks or dis- tinct elevations is called a mountain and often receives a sepai'ate name, the common designation chain or range of mountains is nat- urally applied to the whole. 2. A mountain CHAIN therefore, is not a series of isolated peaks touching each other only at the base ; but has the form of a prism with a broad base and two oppo- site slopes. The upper edge of some is nearly even — as in the Appa- lachian Mountains, — of others deeply indented, as in the Rocky Mountains and the Alps. These indenta- tions, even in ex- treme cases, do not extend more than half way to the base, leaving the lower part of the mountain chain an unbroken or continuous mass. The top of the ridge, from which the waters descend on opposite sides, is called the crest; and the notches between the peaks, from which transverse valleys often stretch like deep furrows down the slopes of the chain, are called passes. 3. Mountain System. Mountain chains are seldom isolated, but are usually combined into systems, consisting of several more or less parallel and connected chains, with their intervening vail — as the Appalachian system, the Alps, and the Andes. These systems often form great mountain zones, thousands of miles in length and several hundred miles broad ; hence their gene- ral slope averages but few degrees. In many cases one side of the system is flanked by a pla- teau descending very gradual- ly towards the distant plains; while on the other side an ab- rupt descent terminates in low plains lying at the base of the mountains. This formation is apparent both in the Alps and the Himalaya Mountains. 4. Formation of Mountains. Most mountain chains seem to have been produced by tremendous lateral pressure in portions of the Earth's crust, causing either long folds, or deep fissures with upturned edges rising into high ridges, the broken strata forming ragged peaks. There are, accordingly, two distinct types of mountain chains — mountains by folding, which are generally of moderate eleva- tion ; and mountains by fracture, to which belong the highest chains of the globe. The Appalachian Mountains, in North America, and the Jura, in Europe, are examples of the first ; the Rocky Moun- tains, Andes, Alps, and Himalayas, of the second. (See Figs. 6 and 7.) VERTICAL FORMS OF THE CONTINENTS. 27 5. Mo l.MNG are curved into long arches, either en- tire or broken at the summit ; forming a system of long, parallel ridges, c al height, separated, by trough-like valleys. The crest* of the ridges, seen against the horizon, present a nearly uniform outline, with neither sharp peaks nor deep passes. Here and there, however, deep gaps, or gorges, cut the chains trans- versely to their base, allowing the rivers to escape from one valley to another. Direction of upheaving force. These gaps are numerous in the Appalachian Mountains, entering the Atlantic north of the Roanoke, rise in or beyond the westernmost range, and cross the other ranges eastward through such breaks. South of the Roanoke similar gaps permit the streams rising in the east- ernmost range to cross the system westward, and enter the Misssis- sippi. All the long rivers TRANSVERSE SECTION OF THE CENTRAL ALPS Mont Blanc. Direction of upheaving force. FIG. 7. CHAIN OF MOUNTAINS BY FRACTURE. 6. Mountains by Fracture. In systems of mountains pro- duced by fracture, there is usually one main central chain, with several subordinate ranges. They have, however, less regularity and similarity among themselves than the parallel chains of moun- tains by folding. The crests are deeply indented, cut down one third or one half the height of the range, forming isolated peaks and passes which present to the eye the appearance of a saw, called in Spanish, Sierra ; in Por- tuguese, Serra. Such ranges are frequently distinguished by these terms, as the Sierra Ne- vada, in North America ; and the Serra do Mar, in Brazil. III. Valleys. 1. Valleys occur both in mountain sys- tems and in the more uniform surface of pla- teaus and plains. 2. Valleys among MOUNTAIN RANGES Owe their existence primarily to folds or fissures in the Earth's crust, produced in the upheaving of the ran- ges ; but they are subse- quently deepened, wid- ened, and otherwise changed in form and ex- tent, by the action of rains and frosts, and the streams to which they furnish a pathway. Mountain valleys are distinguished as longitudinal and transverse, the former lying parallel with, and the latter crossing, the ranges. In mountains by folds the longitudinal valleys are numerous and ex- tensive, the transverse comparatively few. In mountains by fracture, though the main valleys are longitudi- nal, the transverse valleys are the most numerous and strongly marked. They usuallv consist of a series of basins between the ranges, connected by narrow denies or clefts with precipitous sides. THE GREAT CANON AND LOWER FALLS OF THE YELLOWSTONE, The basins become successively lower, as they recede from the origin of the valley, the connecting defiles usually having a considerable slope. Most of the Alpine lakes, celebrated for their picturesque beauty, occupy deep basins at the outlet of transverse valleys. 3. Valleys in plains and plateaus are mainly, if not entirely, the result of the erosion, or wear of the surface, by running water. Little rills, formed by the rains or issuing from springs, set out on their course down the slope of the groimd, each wearing its small furrow in the surface. Uniting they form a rivulet which wears a broader and deeper channel ; and the rivulets in turn com- bining, form rivers which pro- duce still greater effects. Thus the entire surface of plains is furrowed by valleys descending from the higher to the lower levels. In the lower course of the screams the val- ley is usually wider and less deep than in the upper. In the great basin of the Mississippi, for example, is one grand central valley, cut by the main stream in the line of lowest level, towards which the valleys of the Missouri, the Arkansas, the Ohio, and a multitude of smaller streams, all converge. The central valley, in the upper course of the stream, is from 300 to 500 feet deep, its boundaries consisting of abrupt bluffs from whose top stretches away the sur- rounding plain ; and the breadth of the valley does not much exceed that of the stream in time of high water. In the middle course, below the Missouri, it attains a width of ten miles, while the height of the bluffs, or more properly the depth of the valley, is only about 200 feet. Farther down the stream the valley is from 60 to 80 miles wide, while the depth gradually decreases. (Seepage 48, Section of the Mississippi Valley.) The most remarkable examples of valleys by erosion occur in the pla- teaus adjacent to the Rocky Mountains. The Grand Canon of the Col- orado, 300 miles long, has a depth of from 3,000 to 6,000 feet below the sur- rounding country. The sides of this tremendous gorge, which are nearly or quite precipitous, ex- hibit the successive geo- logical strata down to the oldest rocks. A similar formation exists in the upper course of the Yellowstone, one of the main tributaries of the Missouri, and to a less extent in all the streams flowing through the high barren plateaus. The term valley is frequently, but very improperly, applied to the entire basin of a river, whence great misconceptions result in discussing the character and forma- tion of valleys. Thus the basin of the Mississippi, — that is, the entire ana drained by the stream, stretching from the Rocky to the Appalachian Mountains, — is frequently called the " great Mississippi Valley "; but the latter term prop- erly applies only to the depression within which the course of the river lies. This was excavated by running water ; but the basin, or the great trough between the Physical THE IN MERCA &*^- [•:■ TfyL,' ;"_' : ■„.. . j; Islands ; T R.P.PJ. C . •**. L__ ; ]*i "*- *** J ; Marianne - t > -Wft^. /^e^ . -4 . C a r o 1 1 ne I.jA , .■ . ,; ;MilJ , shi 3 ail i«lm\d» f ;:.G iii)wt ''*'«r : tkl C a r r i lit lU atDri?.;; Counter C i| r Palmira- I.J^jung -Ellice crux /.•' : " 2! 'V/ V -"- '■-■ .Mar-ipies ai day "T; ^foil^sssv^r? H North* ">; ■; T HMUS*>Jn i.rl'al UUBBK.4N SEA-. jet own L CaledoalaVf J ■■ r. \ ■■."«! f,i, .- ■• * 1 ,V^ ^ „ S •^'" Pin- TROPIC OF CAPRICOR: Earner r? O U r H PACIFIC O C K A N vaiparaisot SanUaedl ■ iivi n K y vJ 7J °5 drift T A ■i .lu-r„,i,- Kui-tl,.; ,,/• /,,„,( bel.nv WOO feel Altitude. .■■■■-■■■ ' above W.000 feel Altitude o c Soul: H C X V MOUNTAINS lypRTE T O SOUTH. -J.-T aincui :*° .ZV Shetland****' _. • i GrahsniXani A... COMPARATIVE ALTITUDE or THE PRIN1 i£WhttD.ev i FBrowit I ongsPeak| Pike 8 Peak A H D E S Jfevadode S or al a A M D E S Aconea V.Orizaoa Chimborazo, VAremiipa MShaeta V. Popocatepetl >f.S ?Helen8 J. -" v Spa nish ALAS K A I So ,:.'..■ ;.-,l- .! Ki-un.holz dtl. B K I T I 8 H XTEt T T r D AMERICA STATES I 11 U ^ Peaks Mexico »■ VdelFuego T Chihtialraa ' CE\"E\L Bogota Quito PLATEAU of BOLIVIA MEXICO AMERICA OOLfMBIA PEKC B OLIVIA CHILI PATAGO.V1A ORLD PROJECTION. byAfiuyot . 120 longitude HO last from 160 Greenwich 180 WScA.-K.Joh nston.Edinhuroh Se 30 VERTICAL FORMS OF THE CONTINENTS. two mountain systems, was the work of those general forces which uplifted the continents. 4. Valleys descending the slopes of mountains are formed in the same manner. In the language of Dana : — " The gathering drops make the rill, and the rill its little furrow ; rills combine into rivulets, and rivulets make a gully down the hill-side ; rivulets unite to form torrents, and these work with accumulating force, and excavate deep gorges in the declivities. Other torrents form in the same manner about the mountain ridge, and pursue the same work of erosion until the slopes are a series of valleys and ridges, and the summit a bold crest overlooking the eroding waters The larger part of the valleys of the world are formed entirely by running water." IV. < (mimon Features of Continental Relief. 1. Structure of Continents. Although there is in each con- tinent a peculiar combination of mountain systems, plateaus, and plains, giving it a distinctive character, yet there are certain grand features common to all. Each continent has upon one side of the centre a great mass of elevated lands, usually extending throughout its entire length, and constituting the primary feature of its structure. On the opposite side is found a similar, though smaller and less elevated mass, extending through but a part of the continent, and constituting the secondary feature of the continental structure. Between the primary and secondary elevations is a central depres- sion, which forms the third feature common to all the continents. 2. Continental Axes. The great dividing ridges, from which the continent, as a whole, slopes in opposite directions, may be called the main axis of the continent. The less highlands, sepa- rating into opposite slopes the part of the continent in which they are situated, form a secondary axis. The converging directions of their fundamental axes give to the continents their common tendency towards a triangular form ; while the peculiar combination of mountain chains, plateaus, and plains in each continent, determines its individual figure and contours. ANALYSIS OF SECTION IV. I. Plateaus. 1. Situation of Plateaus. a. Situation described. b. Examples. 2. Surface of Plateaus, a. General character. b. How plateaus differ from plains. 3- Elevation of Plateaus. a. Plateaus of first order. b. Plateaus of second order. c. Plateaus of third order. 4. Importance of Plateaus in Structure of Continent*. 5- Character of Plateaus. a. General character stated. b. Examples in great plateaus. Their surface. Their soil II. Mountains. 1. Appearance of Mountains. 2. Mountain Chain Described. a. General form and character. b. Crest. c. Passes. 3 Mountain System. a. Consists of what. b. Breadth and slope. c. Adjacent regions. 4. Formation of Mountains. a. Upheaval how produced. b. Main types of mountain chains. Names and difference in height. Examples. 5. Mountains by Folding. a. General character,*, b. Crests. c. Gaps. Example In Appalachian Mountains. 6. Mountains by Fracture. a- Ranges. b. Crests. III. Valleys. 1. Valleys Occur where. 2. Valleys among Mountain Ranges. a. Origin due to what. b Subsequent modifications. c. How distinguished. d. Valleys in mountains by folding. e. Valleys in mountains by fracture. 3 Valleys in Plains. a. Cause. b. Mode of formation described. c. Examples in Mississippi basin. Grand Canon of the Colorado. Similar formations where e Erroneous use of term valley. Example. 4. Valleys Descending Mountain Slopes. a. Dana's description of formation. b. Dana's statement of origin of valleys. IV. Common Features of Continents. 1. Structure op Continents. a. Existence of features common to all. b. Primary highlands. c. Secondary highlands. d. Central depression. 8. Continental Axes. a Main Axis. b. Secondary All*. c. Effect of convergence. d. Effect of combination of relief forms MAP STUDIES ON RELIEF FORMS. Xutk. — The plains are represented on the map, pages 28 and 29, by preen ; plateaus of tbe second and third orders by brown, and those of the first order by white. The light shading, in the representations of mountains, indicates the lower ranges, and heavy shading the higher. The profile at the bottom of tbe map shows the comparative elevation of the principal plateaus and moun- tains of the globe. Their altitude can be ascertained by means of the scale, which is separated into parts of5,00D feet each. In what part of North America are the great plains? In wliat part of the continent is the greatest highland region? What mountain system included in this region? What mountain system near the Atlantic coast? How do the Rocky and Appalachian Mountains compare in direction? How do they compare in height and extent? What great mountain system on the western coast of South America? What form of relief prevails in the eastern part of the continent ? How do the mountains on the plateau of Brazil compare with the Andes in direction? How do they .compare with the Andes in elevation and extent ? In what part of South America are the great plains? How (see profile) do the Kocky Mountains compare with the Andes in height? How do the western plateaus of North America compare in elevation with those in the Andes ? In what part of Asia are the most extensive plains? In what part of the continent is the plateau of Thibet? What two mountain systems border this plateau? What mountain chains immediately south of the great northern plains of Asia? What mountain chain and plateau between the Altai and the Kuenlun Mountains? How (see profile) does the plateau of Mongolia compare in elevation with Thibet? What form of relief predominates in the western part of Asia? What forms of relief predominate in the great peninsulas of Asia? In what part of Europe are the great plains? What mountains separate the European plains from the Asiatic? In what direction do the Ural Mountains extend? What form of relief predominates in the southwestern part of Europe? What relief form predominates in the peninsula of Norway and Sweden? How (see profile) do the plateaus and mountains of Europe compare in height with those of Asia ? What is the dominant relief form in Africa? In what part of the continent are the longest and highest mountain ranges? Where are the largest plains of Africa ? What relief form occupies the Island of Madagascar? What form of relief is most extensive in Australia? Ill what part of the continent are the great plains ? In what part of the continent is the principal elevated region? How do the mountain ranges in the Islands of New Zealand compare with those on the east- ern coast of Australia ? How do the mountain ranges in the Asiatic islands compare in direction with the chains on the adjacent coasts? STRUCTURE OF THE NEW WORLD. 31 lo.ooc Englft- V. — STRUCTURE OF THE NEW WORLD. Introduction. The New World as a whole shows a marked unity of structure, one common flan pervading the two Americas. In each the main axis, which extends unbroken through the entire length of the continent, lies near the western shore ; the secondary axis near the eastern. Vast low plains occupy the interior, but the plains on the seaward slopes of the axes are only of limited extent. North and South America, however, differ greatly in the details of their structure, as well as in their climatic situa- tion, each possessing peculiar characteristics which show it to have been constructed for the performance of a distinct part, both in the realm of nature and in the history of human progress. I. North America. Notk. Figure 8 represents to the eye a section of North America along a line connecting Delaware and San Francisco Bays. The horizontal base of the drawing represents the level of the sea. The irregular lop line indicates the successive ele- vations and depressions of the surface, along the line specified, the altitude of which can be ascertained by means of the scale at the margin. The map exhibits the relative posi- tion of the great features of continental relief, and the altitudes of mass eleva- tions. The mountains are represented by straight or broken lines, the heavier lines indicating the higher ranges. The dotted lines represent swells of land but slightly above the general level. 1. The Pacific Highlands, which form the primary feature of North America, occupy al- most all the western half of the continent, extending from the Arctic Ocean to the Isthmus of Panama. This region consists of a vast plateau, surmounted by two lofty mountain systems — the Rocky Mountains and the system of the Sierra Nevada — with nu- merous shorter parallel ranges lying between them. The breadth of the plateau, between the Sierra Nevada and Rocky Mountains, is not* lest than 600 miles, and the more northern and southern portions have an average breadth of about 300 miles. The elevation increases, through a succession of swells and depressions, from 800 feet near the Arctic shores to 8,000 in the table-land of Mexico, whence it decreases rapidly southward. Two remarkable depressions occur in the plateaus east and south- east of the Sierra Nevada. Death Valley, into which the Amargoza Rivet flows, is situated east of the highest part of the Sierra Nevada. It J is about forty miles long ; and its centre is, in winter, a salt marsh whose surface is more than 100 feet below the sea level. Appalachian Mts. Great Central Plains. Atlantic Ocean . FIG. 8. NORTH AMERICA FROM WEST TO EAST. The Colorado Desert is the dry bed of an old salt lake, situated west of the lower Colorado, and near the head of the Gulf of California. The lowest part of its surface is about 300 feet below the sea level. The Rocky Mountain system, which forms the main axis of the continent, is composed of several distinct chains, approximately parallel, and bound together by numerous cross ranges. Although these mountains, in the highest part of the system, be- tween 35° and 40° north lati- tude, rise no more than 6,000 or 8,000 feet above the surround- ing country, they are from 12,000 to 15,000 feet above the sea level. The crests in this part of the system, are gener- ally high ; but farther north they are often deeply indented, and the peaks bold and quite irregular. The Sierra Nevada and Cascade Mountains form the western border of the great plateau. Their eastern slope is short and ab- rupt, their base resting upon the plateau, which is from 2,000 to 4,000 feet in elevation. The western slope is long and gentle, descending into extensive valleys which are but little above the level of the sea. The Sierra Nevada chain is lofty and continuous, but the Cascade is lower, and is studded with Atlantic Highlands. NORTH AMERICA. The figures incUcaie areraqe Altitudes af Sut£xjc& m English. Teet . numerous volcanic cones, some of which are still active. The highest peaks are from 10,000 to 15,000 feet in elevation. Low mountains, called the Coast Ranges, lie between these border chains and the Pacific Ocean. Both, the border and the coast chains, appear to con- tinue northward to the western projection of the continent ; but the Coast Ranges, north of Cape Flattery, are broken into a se- ries of islands. 2. The Atlantic Highlands, which form the secondary fea- ture of the continent, extend from the northern coast of Lab- rador nearly to the Gulf of Mexico ; approaching, but not meeting, the western highlands on the south. This region consists of the plateau of Labrador, with the Laurentide Mountains, on the north of the St. Lawrence ; and the Appalachian Mountain sys- tem and adjacent low plateaus, on the south. The Labrador plateau is only about 2,000 feet in elevation ; and its mountains, which are generally parallel with the St. Lawrence, are rarely above 4,000 feet. The Appalachian region is composed of a succession of low, par- allel mountain ranges, separated by long, trough-like valleys ; and a plateau about 2,000 feet high, which descends gently from the crest of the westernmost range, towards the interior of the continent. The average height of the mountain chains is but 3,000 feet. They 32 STRUCTURE OF THE NEW WORLD. Andes. Plains of El Gran Chaco. Pacific Highlands. FIG. 9. are lowest near the centre of the system, in northern New Jersey, and thence rise gradually to the north and the south, attaining their greatest altitude near their southern terminus. The system is broken transversely through its entire breadth by a deep cleft, from the centre of which the Hudson flows southward to the SBa, and the waters of Lake Champlain northward to the St. Lawrence. East of the Appalachian Mountains a rolling plain descends gradually, terminating in a flat tide-water region adjacent to the ocean. 4. The Central Region of the continent is a great plain, which, with but slight variations of level, stretches from the Arctic shores to the Gulf of Mexico. A slight swell near the centre, designated the Height of Land, separates it into two parts, one descending north- ward to the Arctic Ocean ; the other, southward to the Gulf. This swell, which connects the Atlantic with the Pacific highlands, is only from 1,000 to 2,000 feet above the sea level. The central plain is formed by the long gentle slope descending eastward from the base of the Rocky Mountains, and the western slope from the Atlantic highlands. On the south their intersection is marked by the position of the Mis- sissippi River. On the north a broad low swell, approximately parallel with the Rocky Mountains, extends from Lake Superior to the Arctic shores, separating the northern plain into two vast basins. The western basin, which is narrow and elongated, is connected with the eastern by a break in the dividing swell, through which the Nelson River flows to Hudson Bay. The eastern basin, which is more expanded, is partly below the level of the sea and covered by the waters of Hud- son Bay. A series of remarkable depressions, oc- cupied by the great lakes of the Macken- zie and Saskatchewan river systems, — Great Bear, Great Slave, Athabasca, and Winnepeg — marks the intersection of the northern swell with the slope from the Rocky Mountains. On the Height of Land, near its junc- tion with the northern swell, are three vast depressions, diverging from a com- mon centre, with a depth reaching con- siderably below the level of the sea. These are filled by the waters of the great lakes — Superior, Michigan, and Huron. Similar, though less extensive, basins in the St. Lawrence valley are occupied by lakes Erie and Ontario. II. South America. 1. Distinguishing Featuees. This continent has, like North America, the greater highland parallel with the western shore, and the less, with the eastern ; while a vast central region of low plains stretches between them. Atlantic Highlands. SOUTH AMEKICA FROM WEST TO EAST. But the western highland of South America, the Andes Moun- tains, is a single narrow system, composed of two main chains and an intervening valley, all of great height ; while that of North America is a vast plateau, surmounted by two great systems of mountains, hundreds of miles apart and of medium height. The eastern highland is a low plateau, occupying, at its greatest extension, two thirds of the breadth of the continent, while that of North America is a narrow moun- tain region. Again the central plain of North Serrade America is divided, by distinctly Mantiqueira. . Plateau of Brazil. Atiantic mai '' ie d water-sheds, into separate 0coaQ - basins and slopes ; and is character- ized by numerous great depressions, in which are formed the most re- markable belt of lakes on the globe ; but the great plains of South America are exceedingly flat, have scarcely distinguishable water-sheds, and are destitute of great lakes. 2. Primary Highland. The Andes Mountain system, in the larger part of its extent, consists of two parallel chains whose crests are separated by broad, plateau- like valleys, from 20 to 60 miles wide, and from 8,000 to 13,000 feet high. Near the northern ter- minus there are three diverging chains instead of two, and near the southern there is but one. Numerous cross swells, or moun- tain knots, connect the ranges, separating the high intervening valley into a number of distinct basins. The broadest and highest of these is the Plateau of Bolivia, opposite the Gulf of Arica, the great indentation of the Pacific coast. The altitude of the Andes in- creases from the Isthmus of Pan- ama southward to the Plateau of Bolivia, where the crests rise to 16,000 feet, and the highest peaks are from 20,000 to 25,000 feet in elevation. The breadth of the sys- tem is only from 200 to 300 miles. The slopes are abrupt and deep- ly cut by transverse valleys. No longitudinal valleys occur on the western slope, and but few on the eastern slope of the central Andes. The summit of the ranges is not a narrow, sharp ridge, but is often a plateau-like expansion, sometimes several miles broad, from which numerous volcanic peaks rise abruptly. 2. The Secondary Highland, called the Plateau of Brazil, has an average elevation of only 2500 feet, and is comparative!} level. It is, however, surmounted at intervals by ranges of 1«\> mountains, which are approximately parallel, but are connected a the south by cross ranges and swells of land, forming a transvevse water-shed, called the Serra dos Vertentes. SOUTH AMERICA The fi$u.T-c£ tnd-Cccute average Altitude* of Su. r£a£e in. E^y lt,%hs fee t" ■ The highest and most continuous ranges, forming the secondary axis of the continent, extend along the eastern coast, reaching their greatest elevation west of Rio Janeiro. Their average altitude is from 4,000 to 6,000 feet, the highest peaks reaching nearly 10,000 ft. A subordinate highland region, called the Mountain-land of Guiana, lies in the northern part of the continent. It is a low plateau covered with short ranges of medium height, extending in an east and west direction, and increasing in eleva- tion towards the southwest, where Maravaca peak reaches 8,000 feet. 3. The Central region is chiefly a vast alluvial plain, but few hundred feet above the level of the sea, and almost devoid even of such slight swells as divide the great interior plain of North America. On the east the plains of the Amazon are separated from those of the Orinoco and La Plata by the secondary highland regions ; but farther west the three plains are blended into one, with only very slight water-sheds between them. ANALYSIS OF SECTION V. Introduction. ». Common plan of structure. b. Differences in North and South America. I. North Ameriea. 1. Primary Highlands. a. Position and extent. b. Structure. c. Breadth of plateau. Elevation. d. Depressions. e Rocky Mountain system. Consists of what. Elevation of highest part- Crests and peaks. f. Sierra Nevada and Cascade Mountains. East slope and base. West ditto. Continuity of chains. Coast mountains. Northward prolongation. 2. Secondary Highlands. a. Position and extent. b. Structure. c. Labrador plateau aud mountains. d. Appalachian region. Structure. Elevation. Breaks. e. Eastern slope. Central Region. a. Character. Dividing swell. b. Formation by slopes. Intersection on tbe south. Separation on tbe north. c. Depressions. In west basin. In height of land. In St. Lawrence valley. II. South America. 1. Distinguishing Features. a. Position of highlands. b. Highlands compared with North America. c. Central Plain ditto. 2. Primary Highland. a. Structure in the larger part. b. Structure of extremities. c. Divisions of valley. d. Altitude. e. Breadth. f. Slopes. g. Summit. 3. Secondary Highland. a. Elevation and surface. b. Mountains surmounting it. Character and direction. Highest ranges, c Subordinate mountain region. 4. Central Region. a. Character. b. Elevation. c. Surface. VI. — STRUCTURE OF ASIA. I. Introduction. 1. The Double Continent, Asia-Europe. Asia and Europe have, like the%wo Americas, a remarkable similarity in their general plan of structure, and are so closely connected as to form but one great continental mass, analogous to the New World. Yet each possesses striking physical peculiarities which secure to it a marked individu- ality, and constitute it a distinct continent. Asia is the main body of the double continent, Europe the pe- ninsular portion. A natural separation between them is formed by the belt of low, marine plains, east of the Ural Mountains and river, and the vast depressions occupied by the Caspian and Black Seas. 2. Common Features. In both Asia and Europe the primary and secondary highland regions extend east and west ; each includes several separate mountain systems or plateaus ; and the secondary highlands are near the centre of the continent. The central depression in each consists largely of plateaus, and is small compared with the extent of the continent, the great plains lying between the secondary highlands and the sea. A series of subordinate elevations lies between the primary high- lands and the sea, forming the great peninsulas which mark the southern shores of both continents. 3. Asia is characterized by the division of its mass into two parts — Eastern and Western Asia — each of which has a certain individuality of character. The former includes the great body of the continent ; but all the peculiarities of its structure are repeated, on a smaller scale, and in a somewhat modified form, in the latter. Each has its primary and secondary highlands crowded towards the centre, the intervening region being a plateau ; large low plains form the northern slope, and smaller plains and peninsular high- lands, the southern. II. Eastern Asia. 1. The Interior of Eastern Asia is a vast square mass of ele- vated land, where the primary and secondary highlands, and the in- tervening lower plateaus, are all crowded within one third of the breadth of the continent. From its margins the land descends on every side — on the north to the Arctic ocean, on the east to the Pacific, on the south towards the Indian Ocean, and on the west to the low basin of the Caspian and Aral Seas. 2. The Primary Highland region, which is situated south of the centre, is a vast swell of land including the highest mountains and plateaus of the globe. It consists mainly of the Himalaya and Kuenlun chains, and the intervening mountainous plateau of Thibet ; but the lower plateaus and mountains of southern China continue this feature of the continent to the Pacific shores. Mount Everest, in the Himalayas, is the highest mountain known, its altitude being over 29,000 feet. Many peaks in this and the ad- jacent ranges are above 25,000 feet. The plateau of Thibet, which is surmounted by the Karakorum Mountains, scarcely inferior to the Himalayas in altitude, is highest in the western part, reaching in some places nearly 19,000 feet. Its average height is 16,000 feet. 3. The Secondary Highland is a broad expanse of plateaus and mountains, having the Thian Shan chain on its southern mar- gin, and the triple chain of the Altais on the northern. The high- lands are prolonged, by the Yablonoi and lower ranges, to the north- eastern angle of the continent. Plains of Siberia. V> A Jt The greatest altitude is attained in the western part of the Thian Shan, where the highest peaks are from 15,000 to 20,000 feet high. The primary and secondary highlands converge on the west, and are connected, at the terminus of the Himalayas, by the high pla- teau of Pamir. Both are continued westward, beyond the connect- ing plateau, by lower ranges which extend nearly to the meridian of the Ural Moun- tains. On the east the Great Khin- gan, and other ranges having a general north and south di- rection, partially connect the Yablonoi with the Himalaya Moim tains. 4. The Central Depression consists of the great low plateau of eastern Turkestan and Mongolia, between the primary and secondary swells, which stretches without interruption from the pla- teau of Pamir on the southwest, to the Great Khingan Mountains on the northeast. Though this vast basin is from 2,000 to 4,000 feet above the sea level, yet it lies from 6,000 to 12,000 feet below the neighboring plateau of Thibet. Near the mountains the soil is fertile and supports a large population. In the interior the surface is generally cov- ered with sand and pebbles, forming the so-called des- erts of Gobi and Shamo, yet many portions producea scanty vegetation. The open valleys separat- ing the Thian Shan and Altai Mountains, form the main connection between this bar- ren plateau and the more fertile and populous regions of western and southern Asia. 5. The Slopes. The long northern dope of east- ern Asia forms the vast Si- berian plain. The eastern half is elevated and its sur- face is rugged or hilly ; but the western part, including the steppes of the Obi ba- sin, is more level, and only about 250 feet in average elevation. The eastern slope, extending from the Khingan and more south- erly ranges to the Pacific, is extremely varied in surface. It in- cludes the projections of China and Manchuria, formed by the east- ward prolongation of the great continental swells, and an interven- ing region of low alluvial plains which prolong the central depres- sion. China is elevated and mountainous in the south and west, many of the ranges being of great height ; but extensive low plains form the northern and eastern portions. Manchuria consists chiefly of plateaus, with alluvial plains adjacent to the Amoor River and its tributaries, and ranges of low mountains skirting the coast. The southern slope of eastern Asia comprises the low plains of Hindostan, at the foot of the Himalaya Mountains ; and two great peninsulas which prolong the continent far into the equatorial regions. Celltr Depress. Karakorum. Himalaya. E. Turkestan Thian Shan FIG. 10. SECTION OF ASIA FROM NORTH TO SOUTH C T X" C O C E A xr ^fj*^ ASIA The ilgiuts tnxUxaJjL outrage AUitujltJt ol £u.r/ixcfc ui» K^luh Tte£ The descent, through suc- cessive ranges, from the sum- mit of the Himalayas to the low plains of the Ganges and Indus, which are but little above the sea level, is short and abrupt. The contrast presented by the lands on opposite sides of this great mountain system — cold, sterile plateaus on one side, and, on the other, low plains covered with luxuriant tropical vege- tation — is not equaled elsewhere on the globe. The plains of the Ganges and upper Indus basins are chiefly un- dulating or alluvial. East of the lower Indus is an extensive bar- ren marine plain, forming the Indian Desert. The peninsula of India is formed by the triangular table-land of Deccan, south of the Himalayas, bordered on each side by moun- tain ranges — the Ghauts on the east and the west, and the Vindhya Moun- tains on the north. The surface is comparatively uniform, though the eleva- tion gradually increases from north to south. The peninsula of Indo- China is formed by a num- ber of mountain ranges di- verging from the southeast- ern angle of Thibet, and decreasing in elevation to- wards the south. The cen- tral range, much longer than the others, forms the secondary Malay peninsula. The western slope con- sists of low mountains and fertile plains, gradually de- scending from the western terminations of the Thian Shan and Altai Mountains and the Plateau of Pamir, to the low, barren steppes of Turan, adjacent to the Aral and Caspian seas. III. Western Asia, 1. Highlands. Western Asia has its primary and secondary highlands in the lofty and mountainous borders of the Plateau of Iran, which extend from the low plains of the Indus to the western extremity of the continent. These two marginal swells, which are from 500 to 700 miles apart in the east, converge towards the west, meeting in the mountain- land of Armenia, south of the Caucasus ; and, being prolonged be- STRUCTURE OF EUROPE. 35 tween the Mediterranean and the Black Sea, they form the penin- sula of Asia Minor. The altitude of the plateau increases from 2,500 feet in Asia Mi- nor, to 4,000 south of the Caspian Sea, and 6,000 or 8,000 at the eastern terminus. The mountains rise to 10,000 or 15,000 feet. Armenia, a volcanic region, is considerably higher than the adjacent portions of the plateau ; and Mount Ararat, its highest peak, has an elevation of 16,900 feet. As in Eastern Asia, the main axis lies on the south, the secondary on the north. Both, however, are pushed far to the south of the corresponding regions of Eastern Asia, the secondary highland of the one continuing the primary of the other. 2. Central Region. In the eastern half of the plateau of Iran is a very marked central depression, lying from 3,000 to 5,000 feet below the general level. This region is similar in character to Mon- golia, the surface consisting mainly of salt steppes and deserts. The altitude, both of the marginal swells and the central depres- sion, is least in the region directly south of the Aral Sea. There the northern swell is but 2,000, the interior 1,500, and the southern swell 5,000 feet in elevation. The plateau terminates on the east with the Suliman and other ranges of mountains, which rise abruptly from the low plains of the Indus to a height varying from 8,000 to 10,000 feet. Occasional passes in this high, mountainous border, form the only practicable routes of travel between the interior of Western Asia and India. The most important are the Bolan pass, near the centre, and the Cabool or Peschawer pass, near the northern terminus. 3. Slopes. North of Iran is a depressed region including the low steppes south of the Aral Sea ; the small plains of Georgia, south of the Caucasus Mountains ; the submerged basins of the Black and Caspian seas ; and the low plains of the Amoo Daria. South of the plateau is a corresponding depression, including the low plains of the Euphrates and Tigris rivers, and the submerged basin of the Persian Gulf. The plains which are undulating or alluvial, were, in ancient times, the seat of mighty nations ; and, being irrigated with cai*e, they were surpassingly fertile. Now, de- prived of moisture other than the winter rains afford, they are, dur- ing the larger part of the year, a parched and barren waste, except on the borders of the rivers. The peninsula of Arabia is an immense plateau, separated from the table land of Iran by the Persian Gulf and the low plains of the Tigris and Euphrates, and connected with the mountain region of Asia Minor by the plateau and mountains of Syria. The surface in the interior is varied by ranges of hills and moun- tains, which, however, do not rise much above the general level. The elevation gradually increases from north to south, being great- est in the southeastern part. A large portion of Arabia, is nearly rainless, and consequently a desert ; but the mountainous regions on the southern coast receive copious rains, and are more productive. The valley of the Dead Sea and the Jordan, amidst the highlands of Syria, is one of the most remarkable depressions known. (See page 51, Topic III., 3.) ANALYSIS OP SECTION VI. I. Introduction. 1. Individuality of Asia and Europe. a. Structure and connection. b. Division. 2. Common Features. a. Highlands. b. Central regions.. c. Great plains. d. Subordinate elevations. Asia how Characterized. a. Division of mass. b. Resemblance in structure. 11 Eastern Asia. 1. Interior. a. Character. b. Slopes. 2. Peimart Highland. a. Situation and comparative elevation. b. Consists of what. c. Altitude of mountains and plateau. 3. Secondary Highland. a. Structure. b. Altitude. c. Convergence and connection of highlands. d. Westward prolongation. e. Eastern connecting ranges. 4. Central Depression. a. Character and extent. b. Altitude. c. Surface. d. Connections westward. 6. Slopes. a. Northern slope, extent and character. b. Eastern slope, consists of what. Manchuria, China. c. Southern slope, consists of what. Contrasts presented. Plains of Ganges and Indus. Peninsula of India. Peninsula of Indo China. d. Western slope. III. Western Asia. 1. Highlands. a. Where situated. b. Convergence and prolongation. c. Altitude. d. Position of axes. 2. Central Region. a. Position and relative elevation. b. Altitude, where least. c. Eastern terminus. d. Routes of travel between plateau and plains 3. Slopes. a. Northern slope, consists of what. b. Southern slope, consists of what. c. Plains. Peninsula of Arabia. VII. — STRUCTURE OF EUROPE. I. Characteristic Structure. 1. Eueope is characterized by its small size, the extreme irregularity of its outline, and the extent to which it is penetrated by arms of the sea. Nearly one fourth of the entire area of the continent consists of peninsulas, yet all these peninsulas together do not equal Arabia in area. Europe resembles Asia in the position and direction of its axes, the limited extent of the region between them, and the subdivision of each of its principal features into a number of distinct regions. 2. The Primary Highland region of Europe is even more broken and irregular than that of Asia. The Alps form the central and highest portion. The Pyrenees and Cantabrian Mountains, on the northern border of Spain, prolong the main axis to the Atlantic shores ; and the Balkan, south of the Danube, continue it to the Black Sea. All these mountain systems have numerous practicable passes, and are separated one from another by low valleys or small plains. The Alps, an exceedingly broken mountain system, have an aver- age elevation of 10,000 to 12,000 feet, about equal to that of the Rocky Mountains and the Sierra Nevada. The loftiest peak is Mont Blanc, 15,780 feet high. The passes range from 5,000 to 11,- 000 feet in elevation. 36 STRUCTURE OF EUROPE. SAXONY. Harz Mts. Thuringiar. Northern Plains. Forest. 1 1 The Pyrenees are also rugged and broken, but are considerably less elevated than the Alps. The crest, in the highest portion, is about 8,000 feet high;. the highest peak, 11,168 feet. The Canta- brian Mountains are somewhat lower than the Pyrenees. The Balkan Mountains, connected with the Alps by the high- lands on the south of the middle Danube, are still lower, their average elevation being only about 5,000 feet. 3. The Secondary Highlands consist of the Carpathian, the Sudetic, and Riesen Mountains, and lower ranges extending nearly to the shores of the North Sea. This series of mountain ranges forms a dividing line between Northeastern, or Low Europe, and Southwestern, or High Europe ; the former being a great low plain, while the latter is, in general, elevated and mountainous. 4. The central region, lying between the primary and the sec- ondary highlands, consists of low plateaus and mountain ranges, and small plains. Its structure is rendered extremely complex by the prevalence of two widely differing directions in the trend of the mountains. Those east and northeast of the Alps continue the direction of the Asiatic systems, from southeast to northwest, converging and diminishing in elevation towards the west. The Alps and the more westerly chains extend from southwest to northeast, diverging eastward. The two series intersect north of the Alps, forming a great number of small inclosed basins, which give to Cen- tral Europe its peculiar character. (This peculiar- ity of structure is shown by the Structure Map of Cen- tral Europe, page 37.) II. Contrasting Divisions. 1. High Europe as a whole, including the pri- mary and secondary high- lands and the central re- gion, is separated into three main divisions by the val- leys of the Rhone, the Sa- one, and the Middle Rhine, on the west, and the plains of Moravia, at the eastern extremity of the Alps. The middle section is the most characteristic of the continent. It has for its base the main body of the Alps ; at the north is a low plateau gently sloping in terraces to the maritime plains of the North Sea and the Baltic ; at the south, the low plains of the Po. The surface is greatly diversified by the numerous ranges of moun- tains intersecting each other north of the Alps. The most marked of its subdivisions are the plateaus of Switzerland and Bavaria, the broad valley of the Middle Rhine, and the basin of Bohemia. The western section has the Cevennes Mountains and adjacent Plat, of Bavaria. FIG. 11. SECTION OF EUROPE FROM NORTH TO SOUTH. plateaus for its central mass, with the valley of the Rhone on the east, and the Atlantic plains on the west and north. The eastern section has for its centre the TransyWanian Alps and Plateau, with the Carpathian Mountains on the north, the low plains of Roumania on the east, and the Hungarian plains on the west. The barriers between these regions, sufficient to give each a dis- tinctive character, are not sufficient to isolate them one from another, or to render intercommunication so difficult as between the different regions of central Asia. Each of the main divisions of High Europe is prolonged southward by a great peninsula. The Hellenic peninsula, between the Black and Adriatic Seas, prolongs the eastern section ; Italy, the middle section ; and the Spanish peninsula, the western. These peninsulas present a marked contrast to those of Asia in regard to size, but an equally marked similarity in general struc- ture, position, and character. The Hellenic peninsula, formed by mountain ranges diverging from the east end of the Alps, corresponds to the Asiatic peninsula >f Indo-China ; but its mountains are lower, and many transverse chains in the eastern part, complicate its structure, and render its outline much more irregular. The Italian peninsula corresponds in position to the peninsula of the Deccan, in Asia, but differs from the latter in having for its centre an elongated moun- tain chain instead of a pla- teau. It consists of the Apennine range and its slopes, the range being forked near the southern terminus. The Apennines are connected with the Alps only at their north- western extremity. Between this chain and the Alps are the low plains of the Po, corresponding in position and character to those of the Ganges in A sia, yet presenting a much less striking contrast to the pla- teaus north of the Alps than is exhibited by the cor- responding regions of Asia. The Spanish peninsula corresponds to Arabia in position, in general form, in regularity of outline, and in the elevation of its entire mass. It is a great plateau, highest in the northeast, with the southwestern portion broken by parallel ranges of mountains. 2. Low Europe. The great European plain extends, with scarcely varying elevation, from the secondary axis, northward to the Arctic shores, and eastward to the Ural Mountains. This plain is slightly elevated in the centre, the highest part being the Valdai Hills, only 1,100 feet above the sea level. They rest upon a slight swell of land which separates the streams enter- 38 AFRICA AND AUSTRALIA. ing the Baltic and White Seas from those flowing into the Black Sea and the Caspian. This swell continues westward, through the plains south of the Baltic, to the peninsula of Denmark, but forms only a slight obstacle in the path of streams. Low Europe is bordered on every side by mountain regions. On the east are the Urals, on the south the Caucasus, on the southwest the secondary highlands of the continent, and on the northwest the Scandinavian highlands. Depressions occupied by inland seas, — namely, the Caspian, the Black, the Baltic, and the White Sea, — separate these elevated regions one from another, forming so many doorways of communication with the outer world. The Scandinavian Alps form a large part of the peninsula west of the Baltic. They rise abruptly from the Atlantic shores, and are deeply cut by transverse valleys, with perpendicular walls often several thousand feet high. Partially submerged, and admitting the sea to the heart of the mountain mass, these valleys give rise to those deep, narrow bays, called fiords, which are so characteris- tic of the Norwegian -coast. Atlantic Ocean. Mozamba Ridge. The British Isles form properly a part of the continental plain, sepa- rated from the main land by the sub- mergence of a portion of its surface. i. Central Region. a. Consists of what Structure, how complicated. b. Direction of ranges. Intersection of ranges. Slopes. II. Contrasting Divisions. 1. High Europe. Main Divisions. a. Middle section. Structure. Surface. b. Western section. Structure. c. Eastern section. Structure. Barriers between sections. d. Peninsulas. Comparison with Asiatic peninsulas. Hellenic peninsula. Italy. Plains of Po. Spanish peninsula. 2. Low Europe a. Extent. Highest part. Dividing swell. b. Borders. Scandinavian peninsula. Fiords. c. British Isles. 8. SUMMARY. a Subdivisions compared with those of Asia. b. Low and High Europe compared. VIII. — AFRICA AND AUSTRALIA. I. Africa. 1. Africa is characterized, in its structure, by the combina- tion of the plan of the Old World (Asia-Europe) with that of the New. In the northern half of the Western Swell. FIG. 12. These submarine plains which form the base of the islands, are, in the North Sea, only from 200 to 300 feet below the sur- face. They extend westward, from 40 to 60 miles beyond the British Isles, to a well defined line, where an ab- rupt descent marks the termination of the European continent and the commencement of the deep basin of the ocean. 3. Summary. The subdivis- ions of this continent, no less numerous than those of Asia, differ from the latter in their smaller area, in the milder contrasts between adjacent re- gions, and in the facility of communication between them. Low and High Europe, how- ever, present a much greater contrast in structure than East- ern and Western Asia. Low Europe is one vast plain, sur- rounded by mountain chains, but nearly uniform in surface and character, and without marked natural subdivisions ; while High Europe is separated into a great number of distinct physical regions, diverse in structure and character. East- ern and Western Asia, on the contrary, differ little except in the magnitude of features of structure common to both. analysis of section vii. I. Characteristic Structure. 1. Characteristics op Europe. a. Characteristics enumerated. b. Extent of peninsulas. Resemblance to Asia. 2. Primary Highlands. a. General character. Mountain chains included. b. Passes and separation of chains. c. Elevation of Alps. Average. Highest peak. Passes. d. Elevation of Pyrenees. Elevation of Balkan Mountains. 3. Secondary Highlands. a. Consists of what. Division formed by these chains. SECTION OF AFRICA FROM WEST TO EAST. Indian Ocean. 10.000 Engl.ft continent, the highlands extend east and west, causing the great westward projection into the Atlantic. In the southern half, as in the New World, the highlands, both primary and secondary, extend north and south ; but the former is on the eastern shore (see map), the latter on the western, while in the two Americas the re- verse is true. The two halves of the conti- nent are bound together by a northward extension of the primary highland of the south- ern division, which, continuing nearly to the Mediterranean, becomes the main axis of Af- rica as a whole. The central regions, occupy- ing the larger part of the con- tinent, though considerably lower than the border swells, are yet, in general, much above the sea level. Hence the en- tire continent is really a vast plateau without extensive low- lands. (See Fig. 12.) II, South Africa. The ftgwrea tndtuiat* a*wq^» ALtUMxles o£ Sttrfctce. in English Feet? . 1. The primary highland lies near the eastern coast, and extends from the southern ex- tremity of the continent nearly to the Mediterranean. It consists of abroad belt of land somewhat above the general level, surmounted, in various portions, by irregular ranges and groups of mountains. The highest part, including the plateaus of Abyssinia and Kaffa, and an adjacent mountainous region, lies north of the equator. The plateaus have an average elevation of 6,000 to 7,000 feet ; while the highest mountains rise to 15,000 feet. Immediately south of the equator, on the same line, are the volcanoes of Kenia, Kilima-Njaro, and Ngai, the highest peaks in Africa, which reach an elevation of nearly 19,000 feet above the sea level. AFRICA AND AUSTRALIA. 39 In the southern part of the great eastern swell, deep breaks occur through which the Zambesi and Limpopo Rivers pass eastward to the sea. Beyond these breaks southward, a nearly continuous moun- tain region, including the Quathlamba, Sneeuw, and Nieuweveld .Mountains, extends to the Cape of Good Kope on the Atlantic coast. Tlie secondary highland is similar in character to the primary, but is less elevated and less mountainous. The highest mountains are the Cameroons, an isolated group of volcanic peaks north of the equator, 13,000 feet high. The primary and secondary high- lands meet on the south, form- ing a continuous plateau, 5,000 Indian Ocean. Western Highlands Eastern Highlands. Central Depression. Engl. ft r-^— ^ -- — --—: -- feet in elevation, which fills all that part of the continent lying south of the Tropic of Capricorn. The central region, though a plateau, is from 2,000 to 3,000 feet lower than the marginal swells. It extends from Lake Nganfi northward, expanding and decreasing in elevation as the highlands diverge ; and is separated, by a transverse swell, into two basins, the northern of which contains a great number of lakes. III. North Africa. 1. Highlands. Northern Africa has its two border highlands, in the Atlas Mountains and plateau on the north, and the Kong Mountains on the south, both FIG. 13. AUSTRALIA FROM WEST TO EAST. "* — ^3^3. of which are continued east- ward, by minor elevations, to the main continental axis. The average elevation of the Great Atlas plateau is about 3,000 feet, the mountains being from 5,000 to 7,000 feet. In the High Atlas of Marocco some peaks reach 13,000 feet. The Kong Mountains aver- age 3,000 feet, while the high- est peaks may reach 10,000. The greatest altitudes of the continent, exclusive of volcanic peaks, occur where the eleva- tions which prolong the Kong highlands, meet the main con- tinental axis, in the plateau of Abyssinia. At the southern foot of the Atlas Mountains, and of the more easterly elevations on the Mediterranean shores, on a line with the Gulfs of Cabes and Sidra, is a remarkable belt of depres- sions, some of which are more than 300 feet below the sea level. The temporary Lake Melrir, south of the eastern part of the Atlas region, is 280 feet, and the great valley south of the plateau of Barca, 340 feet below the level of the sea. On the same line, to- wards the Nile, are several of the best known oases of northern Africa, — including Aujila, Siwa, and the Natron Lakes, — all of which lie from 100 to 200 feet below the sea level. On the eastern margin of the Abyssinian plateau are the low val- leys of Lake Assal and the Ha wash River, both of which are below the sea level. The valley of Assal, or the salt plain, 35 miles long by 15 wide, is not less than 200 feet below the level of the Mediterranean. 2. The central region is the broad plateau of the Sahara, stretching, with little variation of level, from the Nile valley to the Atlantic shores. Its average elevation is 1,500 feet, but the northern and southern margins are considerably lower than the inte- rior. The surface of the Sahara is varied by occasional higher plateaus, from 4,000 to 5,000 feet in altitude, and groups or short ranges of mountains sometimes reaching 6,000 feet. It consists almost wholly of sand and rocks, and forms the most extensive and com- plete desert upon the face 'of the earth. Fertility is con- fined to oases, situated in the depressions on its borders and around the mountains of the interior. IV. Australia. 1. General Plan. Australia greatly resembles Southern Africa in its general plan of structure, but differs in consisting principally of low plains, and in the surface of the northern portion being gen- erally the more elevated. Its great features of structure are no less distinctly marked than those of the larger continents. (Fig. 13.) 2. The Primary Highlands, as in Africa, lie near the eastern coast of the continent, extending through its entire length ; and are prolonged on the north, forming AU8THALIA 2ne figure* md.iN THE KIII.NK. 3. Low Europe. The European plain, unlike the great interior plains of the New World, is highest in the centre, where the Valdai Plateau is about 800 feet in altitude, with hills of 1,100 feet. Hence its streams, instead of being combined into a few great systems, are dispersed in separate courses, descending the slopes from the interior, towards the four cardinal points. These diver- gent streams, al enter the four in- land seas, which border upon thi great European plain and fori its only outlets. Low Europe, with more e x ■ tended plains, has on the whol( longer rivers thai: H igh Europe. But here, also, the central swell suf- fices to prevent combination of the fl o w i n g waters into one great system like that of the Mississippi It is worthy o remark, that th< longest streams o Europe, and those draining the largest areas, are nearly all di- rected towards the vast depression which separates that continent from Asia. 4. The PENINSULAS have only subordinate streams. The longest are those of Spain which descend from the northeastern highlands, near the Mediterranean shores, to the Atlantic Ocean. In the Scandinavian Peninsula the streams mainly enter the Bal- tic, the fiords, due to the submergence of the valleys, taking the place of rivers on the Atlantic slope. In the transverse valleys, or the eastern slope of the mountains, are many beautiful Alpine lakes, some of which are of considerable size. IV. Tables of Rivers and Lakes of Asia-Europe. Rivers of Asia. Obi . . . . Yenisei . . . Yang-tse kiang Lena . . . . Amoor . . - Uoang-bo . Brahmapootra . Ganges . . . Area of Ba- Length of sin in Eng Course in sq. miles. Eng. miles. 1,250,000 3,000 1,040,000 3,400 960,000 3,320 800,000 2,700 786,000 2,650 714,000 2,800 450,000 2,300 416,000 1,600 <0 Rivers of Asia. Rivers of High Europe. Danube Rhine . Vistula Elbe . Loire . Rhone Po . . 311,000 1,800 90,000 880 68,900 650 59,600 800 52,000 660 37,400 550 31,200 460 Indus Mekong Euphrates .... Tarim Amoo Daria .... Irawaddy Sir Daria Helmund Rivers of Low Europe. Volga Dnieper Don Dwina Ural Petchora Duna Area of Ba> sin in Hi i!'" sq. Miles. 402,000 400,000 255,000 235,000 220,000 140,000 100,000 80,000 Length of Course in Eng. miles. 600,000 180,000 170,000 130,000 106,000 100,000 44,000 1,850 2,500 1,750 1,160 1,260 1,200 1,200 800 2,000 1,120 1,100 1,000 970 1,000 flOO Lakes of Asia. Caspian Sea . . . i Aral Sea Baikal Lake, E. Siberia Balkhash, W. Siberia Tengri-nor, Thibet . Tong-ting, China . Koko-nor, Mongolia Urumia, Armenia . Kossogol , Mongolia . Van, Armenia . ■ Dead Sea, Palestine . Sir-i-kol, Pamir . . Area iu Altitude Depth. sq. miles in feet. 132,000 -83 2,700 26,400 36 200 15,200 1,280 3,000 6,400 600 60 3,500 — — 2,300 — — 2,000 — — 1,700 4,350 60 1,500 5,520 — 1,414 5,470 — 500 -1,286 1,300 40 15,600 — Lakes of Europe. Ladoga, Russia Ouega " Wener, Sweden Wetter " Maelar " Balaton, Hungary . Hielmar, Sweden . Leman, Geneva, Switz'd Constance, Switzerland Qarda Maggiore, Italy . . . Como, Italy .... Area in Altitude sq. miles in feet. 6,900 50 4,900 237 2,300 143 800 289 320 6 265 469 202 76 240 1,226 190 1,263 140 237 70 686 59 697 ANALYSIS OF SECTION V. I. Eastern Asia. 1. Influence or Continental Structurs. a. Position of axes. b. Waters of central depression. c. Waters of exterior slopes. Depth. 400 38 DRAINAGE OF AFRICA AND AUSTRALIA. 57 Principal Streams. a. Of northern, eastern, and southeastern slopes. b. Of southern and western slopes. c. Of central depression. H. Western Asia. a. Principal system. Stream of central depression. III. Europe. 1. Separate Hydrographical Centres. 2. High Europe. • a. Four Alpine systems. b. Secondary systems of High Europe. c. Truth illustrated by course of these streams. Effect of mountain ranges and swells. d. Course of Danube. Rhine. Rhone. e. Course of secondary streams. 3. Low Europe a. Hydrographical centre. Result. Course of rivers. b. Streams compared with those of High Europe. IV. Tables of Rivers and Lakes. VI. — DRAINAGE OF AFRICA AND AUSTRALIA. I. Africa. 1. Influence op Structure. Africa having, like the Ameri- can continents, its axes near opposite shores, has its flowing waters combined in the interior of the continent. Five principal systems — the Nile, the Niger, the Congo, the Zamhesi, and the Orange — embrace nearly all the flowing waters of the continent ; and all but the. last derive their water wholly from the tropical region, between 20° south and 16° north latitude. Each is especially connected with one of the primary regions of the continental structure. 2. The Nile, draining the west slope of the main axis, is the most characteristic as well as the most celebrated of African streams. Its main sources are in great lakes, near the equator, from 3,000 to 4,000 feet above the level of the sea ; but, in its mid- dle course, it receives the waters of eastern Soudan and Abyssinia. This part of the course is characterized by the famous " Cataracts of the Nile," the last of which occurs at Assuan, at the entrance of the stream into Egypt. Below the Atbara the Nile traverses a rainless district 900 miles in breadth, within which, in a course of 1,700 miles from the Mediterranean, it does not receive a single tributary ; and its valley is a narrow belt of verdure in the midst of a burning desert. The fertility of this narrow valley is due to alluvial soil accumulated during the periodic overflows of the river. This wonderful inundation in a rainless region, so mysterious to the ancient world, is explained by the fact that, though its lower course is in temperate latitudes, all the sources of the Nile lie within the region of abundant periodical rains. These fall copiously on the sources of the White Nile about the time of the equinoxes, and in Abyssinia a little later. The Abyssinian rains, being nearer the mouth, cause a first rise, which reaches Egypt about the middle of June. This is soon followed, and increased to the maxi- mum, by the rising waters of the White Nile ; and in August and September the flood is at its height. By the middle of October it begins to abate ; in November the water has receded sufficiently to permit the sowing of the seed in the fresh Baud. In December all the valley is green with growing crops, and the harvests follow iii quick succession. 3. Other Systems. The Niger drains the Kong plateau. Starting in the west, from the highest portion, it descends successive terraces to the interior depression ; then turning southward, and reaching the sea through a break in the mountains, it forms a delta far surpassing in extent the famous delta of the Nile. The Congo, draining the equatorial portion of the central depres- sion, is the Amazon of Africa. It discharges, into the Atlantic, a volume of water fully three times that of the Mississippi ; and its powerful current is perceptible in the sea, scores of miles from the mouth. The Zambesi drains the southern part of the central depression, and enters the Indian Ocean. In its middle course is the celebrated Victoria Fall, discovered by Dr. Livingstone, and said to rival in majesty and beauty the cataract of Niagara. The Orange River drains the extreme southern plateau, in which the continental axes meet. Nearly its entire course lies through a table land from 4,000 to 5,000 feet in altitude. II. Australia. No continent has so few rivers as Australia. The Murray, with its great tributaries, the Darling and the Lachlan, forms the only river system worthy of the name. Owing to the great irregularity of the rains, most other rivers have no permanent existence ; but are transformed, in seasons of drought, into a series of disconnected, shallow pools or lakes. III. Table of African and Australian Rivers and Lakes. Rivers. Basin in Course in Lakes. Area in Altitude Lakes. Area in Altitude Eng. sq. m. Kug. m. sq. miles in feet. sq miles in feet. Nile 1,425,000 4,000 Victoria, Africa 28,000 4,300 iMoero, Africa 3,000 3,000 Niger 800,000 3,000 Albert, " 26,000 2,700 iTzana, " 1,000 6,000 Congo 800,000 — Tchad, " 15,000 800 Ngami, " 300 2,800 Zambesi 900,0C0 1,600 Tanganyika" 13,000 2.800 Eyre, Aust'a 3,000 70 Orange 446,000 1.000 Xyassa, " 8,000 1,300 Gairdner " 2,400 366 Murray, Aust. 500,000 1,500 Bangweolo, " 5,000 4,000 Torrens, u 2,600 — IV. Conclusion. The distribution of river systems shows how closely, in each con- tinent, the drainage depends upon the general plan of structure. Farther, we observe that the Atlantic and Arctic Oceans, toward which all the long continental slopes are turned (see page 42, IX., and Map, page 63), receive, either directly or through inland seas, three fourths of all the continental waters, including the greatest streams of the globe. The Pacific and Indian Oceans, covering nearly half of the Earth's surface, receive but the remaining fourth ; and among these only the three streams of Eastern Asia hold the first rank in regard to length of course and extent of basin. ANALYSIS OF SECTION VI. I. Africa. 1. Influence op Structure. a. Position of axes. b. Source and connections of systems. 2. Nile System. a. Region drained by it. b. Main sources. Accessions in middle course. c. Peculiarities of lower course. d. Valley, source^fertility. e. Inundations. Cause. Progresi 3. Other African Systems. ' # a. Niger. Region drained by it. Course b. Congo. Zambesi. c. Orange. Termination. II. Australia. a. Comparative number of streams. Principal system. b. Character of other streams. III. Tabic of IMvers. IV. Conclusion. 58 THE SEA. THE SEA. L — INTRODUCTION. I. Sea Water. 1. Its Composition. The water of the sea contains in solution a large amount of common salt (chloride of sodium), and smaller proportions of sulphate and carbonate of lime, magnesia, pot- ash, iodine, and some other substances. It is estimated that they constitute about one-thirtieth of the entire weight of sea water. In the open ocean the composition of the water is nearly uniform, though about 20° north latitude, and 16° south, there is a slightly greater proportion of saline matter than elsewhere. Some inclosed arms of the sea, in or near tropical regions — like the Mediterranean and the Red Sea — evaporating more water than they receive by rivers, and having i n consequence a constant influx of sea water, are more salt than the ocean. Others, like the Black and Baltic Seas, receiving more water by r i v ers than they evaporate, and dis- charging the excess into the sea, are less salt than the ocean. 2. The tempe- EATUKE of the ocean, at and near the surface, varies with the latitude, from an average of 80° Fahr. within the tropics, to near the freezing point in the polar re- gions, where ice is to be found in the sea at all seasons of the year. Below a certain depth, which varies with the latitude, the tempe- rature is nearly uniform, at from 33|° to 35° Fahr., about equal to the average temperature of the surface waters in latitude 60°. In lower latitudes, as the climate becomes warmer, this low tem- perature is found at constantly increasing depths ; until, at the equator, it is reached only about 10,000 feet below the surface. Towards the poles, also, where the climate is colder, the line of uni- form temperature rapidly sinks ; and in latitude 70° it is found at the depth of about 4,000 feet. Thus it appears that within 60° of the equator the deep waters are colder than the surface, while beyond that latitude they are warmer. The salt of the ocean tends to preserve its liquid condition at low temperatures. Sea water freezes only when the temperature is re- duced to 26£°, while the freezing point of fresh water is 32° Fahr. II. Marine Life. The ocean supports an inconceivable variety of animal life. Its iUBMAKINE LIFE LN THE NORTHERN SEAS. inhabitants vary in size, from the gigantic whale to animals too small to be perceived by the unaided eye ; and in organization, from the mammal to the formless, jelly-like mass, floating upon the sur- face of the water. It is, perhaps, not equally rich in vegetable life ; but plants in great variety, some of which are exceedingly beautiful in form and color, are found, both attached to rocks in the shallow waters adja- cent to the shores, and floating in mid ocean. Immense fields of sea weed, covering thousands of square miles, occur in those portions of the ocean not disturbed by the general currents. The most remark- able of these is the Sargasso Sea, near the Tropic of Cancer, in the Atlantic Ocean. III. Bottom of the Sea. The bottom of the sea, as far as known, is less irregular than the surface of the continents, but its | variations of level are on a much grander scale. It is convex, like ! the surface of the sea, being a vast j area of the Earth's j crust slightly de- j pressed below the 1 regular curve of the sphere ; while the continents are] smaller areas, ele-J v a t e d somewhat above this curve. On these depres- sions, the waters, \ originally covering \ the entire, surface of the sphere, have j collected, in obe- dience to the law of gravity, filling up the irregularities in the spherical outline, and forming the oceans. This convexity of the sea bottom is clearly illustrated by the Sections of the Atlantic Basin, page 60. ANALYSIS OF SECTION I. I. Sea Water. 1. Its Composition. a. Substances in solution. b. Waters in open ocean. c. Waters in inclosed seas. 2. Tempeeatube. a. At and near the surface. b. Temperature of deep waters. c. Temperature of depths towards the equator. d. Temperature of depths towards the poles. e. Deep waters compared with surface. f. Freezing point of sea water. II. Marine life. a. Animal life. b. Vegetable life. c. Examples of mariue vegetation- IJT. Rottom of Sea. a. Nature of its surface. b. Relation to spherical outline. c. Why covered with waters of globe. THE OCEANS. 59 II. — THE OCEANS. The Basins of the Oceans. 1. Their Sepabation. The waters of the sea are separated by (foe lands into three great oceans, which are the counterparts of the land masses. The Pacific, the Atlantic, ancLthe Indian Ocean, cor- respond to the three pairs of continents in which the lands are grouped (See p. 21, II.), and separate them one from another. The Atlantic and the Pacific are subdivided, each having a north- ern and a southern basin, corresponding to the northern and the southern continents. The Indian Ocean has only a southern basin ; but the vast depression between Asia and Europe, in the bottom of which lie the Caspian and Aral Seas, may be considered as, in a cer- tain sense, its complement. The Arctic Ocean is properly a continuation of the Atlantic ; but, surrounded as it is by the coasts of the three northern continents, it has a physiognomy of its own. The Antarctic, also, is not properly a separate ocean, but is the common centre from which the three great basins radiate. 2. Their Forms and Sizes. Each of the three great oceans is broadest at the south, and gradually narrows towards the north ; hence their general figure is the opposite of that of the continental masses. The Pacific is oval in outline, and broadly open at the south ; but it is nearly closed at the north, the opposite shores converging so that only the narrow passage of Behring Straits connects this ocean with the Arctic. This vast basin contains more than half of the waters of the entire sea. Its extent, its compact form, and the direction of its greatest elongation from southeast to northwest, makes it the counterpart of Asia-Europe, the dominant mass of the Old World. The Atlantic basin, which has only about one half the area of the Pacific, has been likened by Humboldt to a long valley, with approx- imately parallel sides. This is the only basin widely open at the north ; and, stretching from pole to pole, it forms the only complete channel for the interchange of polar and equatorial waters. By its narrow, slender form, and its direction from north to south, it forms the counterpart of the New World. The Indian Ocean, which has a triangular outline, has no commu- nication with the northern waters. It finds its counterpart in Africa, like itself compact in outline, and almost destitute of projecting members. 3. Their Branches. The three great ocean basins differ in regard to the position and character of the branches, by which the coasts of the continents are indented, each being distinguished by a particular class of coast waters. Coast waters may be classified, according to their form and their position in respect to the adjacent lands, as inland seas, border seas, and gulfs or bays. The first lie within the general figure of the continent, being en- closed by peninsulas, as the Baltic Sea; or between adjacent conti- nents, as the Mediterranean and Red Seas. (See Map, pages 28, 29.) The second lie without the continental figure, and are separated from the main ocean by islands, as the Caribbean Sea. The third are simple bends in the coast line, without separation from the ocean basin, as the Gulf of Bengal. The Atlantic is the most branching of the oceans. It has all the forms of coast waters just described, but is especially distinguished by the number and great size of its inland seas. Two of these, the Mediterranean Sea and the Gulf of Mexico, lie in the warm regions ; and two, Hudson Bay and the Baltic Sea, in colder latitudes. The border seas are represented by the Caribbean Sea, within the tropics, and the Gulf of St. Lawrence and the North Sea, in tem- perate latitudes. The Gulf of Guinea, and the Bay of Biscay, are examples of the third class of coast waters, in the Atlantic. The Pacific is particularly rich in vast border seas, a continuous series of which lines the Asiatic and Australian coasts. Among these are the Behring Sea, inclosed by the peninsula of Alaska and the Aleutian Islands ; Okhotsk Sea, inclosed by Kamchatka and the Kurile Islands ; the Sea of Japan, and the North and South China Seas ; and the Arafura, Coral, and New Zealand Seas, on the Australian coast. Only two inland seas of considerable size — the Gulf of Califor- nia, in North America, and the Yellow Sea, in Asia — mark this entire basin. The Indian Ocean is characterized by gulfs, two of which form the entire northern extension of the basin, namely : the Gulf of Ben- gal, and the Arabian Sea. It has also two inland seas of consider- able extent, the Red Sea and the Persian Gulf, isolating the penin- sula of Arabia from the adjacent continents ; but border seas are wholly wanting in the Indian Ocean. 4. Their Islands. The Pacific is far richer than the other oceans in both continental and oceanic islands. The most extensive continental archipelago on the globe, is formed by the multitude of islands lying between Asia and Australia. Successive series of conti- nental islands skirt the entire eastern coast of Asia and Aus- tralia ; and nowhere is found a parallel to the multitude of oceanic islands which are spread over the central portions of this basin. (See Map, page 18.) The Atlantic possesses — in the Antilles, the British Isles, and the islands of the Mediterranean — continental archipelagoes of great importance ; but its oceanic islands are limited to the groups of the Bermuda, Azores, Madeira, Canary, and Cape Verd Islands, with St. Helena and a few other isolated volcanic islands. The Indian Ocean has comparatively few islands of either class. Madagascar, Ceylon, and Socotora, represent the continental islands ; the Laccadives and Maldives, with here and there a few volcanic islands, as Bourbon and Mauritius, make up the oceanic. II. Tlie Beds of the Ocean. 1. Extent of our Knowledge. Little is known, in detail, in regard to the conformation of the bottom of the sea. But numerous soundings, both in shallow shore waters and in the deep sea, have given us an approximate idea of the nature of the beds of the Atlan- tic Ocean, the Mediterranean Sea, the Indian Ocean, and the Red Sea. 2. The Atlantic Bed. The Atlantic basin is, in general, deeper on the side of the New World. The deepest portions, so far as known, form a great trough, in three parts, which are severally parallel to the eastern shore of North America and the northern and eastern shores of South America. The bed of the North Atlantic seems to consist of two parallel valleys — the western about 18,000 feet in average depth, the east- ern about 13,000 — separated by a swell less than 10,000 feet deep. (See Fig. 25.) Both valleys become less deep towards the north, but are still distinguishable in the so called " Telegraph Plateau," between Newfoundland and Ireland. (See Fig. 26.) 60 THE OCEANS. FIG. 25. SECTION OF THE ATLANTIC BASIN FROM CAPE ST. ROQUE, BRAZIL, TO CAPE PALMAS, WESTERN AFRICA. In the latitude of Iceland, whose volcanic mass rises from the northern terminus of the dividing swell, the eastern valley is oblit- erated, the depth of the sea between this island and the European shore scarcely averaging 1,500 feet. The western valley pre- serves a depth of 8,000 or 9,000 feet as far as Greenland, where it divides, its two branches extending to the Arctic, on opposite sides of Greenland. The accompanying profiles show, in fathoms, the depths of the Atlantic in equa- torial regions (Fig. 25), where the dividing swell is distinctly perceptible ; and along the line of the survey for the first Atlantic cable (Fig. 26), where, though less apparent, it still exists. Near the continents the sea is often shallow, the bottom seeming to be only an extension, by gentle slopes, of the adjacent lands. Along the American shores, in the latitude of New York, the depth, for a distance of more ,, 1 AA *1 ' 1 Cape St. Roque. Length, 1760 nautical miles. than 600 feet ; then suddenly the bed de- scends, by a steep slope, to the depth of 6,000 or 9,000 feet. After a comparatively narrow interval, a second terrace descends to the main basin, from 15,000 to 18,000 feet deep. These regular variations of level, and the absence of any oceanic islands other than the volcanic and coral islands, disprove the idea, often advanced, that the bed of the oceans is like the surface of a submerged continent, covered with mountain chains and valleys. It seems far more uniform, extensive plains and huge table lands being its predominating features. Mountain chains are found only near the continents, as parts. of the continental structure; and when reaching above the surface of the sea they form chains of continental islands. 3. The Pacific and Indian Oceans. The Indian Ocean, — according to soundings made in laying telegraphic cables, from Aden to Bombay, and from Madras to the Malay peninsula, — is quite similar to the Atlan- tic in the general fea- tures of its bed. A regular valley, having an average depth of 12,000 feet, lies between Africa and India, its eastern margin being about 200 miles from Bombay, whence a submarine plateau, but a few hun- dred feet deep, extends to the peninsula. East of India is a similar valley from 12,000 to 14,000 feet deep. It terminates, near the shores of Sumatra, in a submarine plateau, less than 250 feet below the surface, which forms the base of the isl- ands in the great Indian Archipelago, between Asia and Australia. The chain of coral islands, — the Laccadives, the Maldives, and the Chagos Archipelago (See map, page 18), — extending south- ward through the central part of the Indian Ocean, seems to indi- cate the presence of a submarine dividing ridge in this basin, similar to that separating the two valleys of the Atlantic. Occasional soundings in the southwestern part of this ocean, in- dicate depths equal to the maximum in the Atlantic basin. The bed of the Pacific is much less known than that of the At- lantic and Indian Oceans. In the absence of soundings, of which Cape Palmas. Newfoundland. FIG. 26. few have been made, its average depth has been calculated from the velocity of the tide-wave and earthquake waves crossing it, which depends upon the depth of the basin in which the waves move. Prof. Bache, late Superintendent of the United States Coast Sur-j vey, estimates, in this way, the depth between Japan and California at from 12,000 to 14,000 feet. A calculation by Prof. HochstetterJ based on the movement of the waves raised by the great earthquake! of 1868, gives 11,500 feet as the depth of the sea between the Soutli American coast and the Chatham Islands, east of New Zealand! The central part of the South Pacific basin, however, is probably 1 much deeper than this. 4. Inland and Bokdek Seas. These inclosed basins belong to the structure of the continents, rather than to the oceans. All are of slight depth, ex-j cept those lying with-] in the transverse zone: of fracture 1 ; and even these are shal- low in comparison 1 with the great basins, with which they ard connected, as is apparent from the depths given.below. The Gulf of Mexico is from 5,000 to 1000 feet in depth. The deepest pari of the Caribbean Sea, on a line connecting Porto Rico and Costa Rica, average! 7,000 feet ; and near the latter it reaches a depth of 14,000 ; but the ocean, imme- diately outside of the Lesser Antilles, is more than 18,000 feet deep. The Mediterranean is divided into two basins, by a rocky isthmus, from 50 to] 500 feet below the surface, lying between Sicily and Cape Bon, in Africa. The] western basin is over 9,000 feet in depth, and comparatively uniform ; while thej eastern is more irregular, varying from 6,000, near the centre, to 13,000 feet, soutli of the Ionian Islands. The Red Sea has an irregular bottom, with an averagJ depth of 3,000 feet, but in some places it reaches 6,000. The Baltic Sea, being a simple depression in the great European plain, is bufl a few hundred feet deep. In the North Sea, the depth averages 300 feet, and rarely exceeds 600. The continent is here prolonged in the form of a submarini plain, whose highest portions form the British Isles. (See page 38.) The Border Seas oM Length, 1670 nautical miles. Valentia, Ireland. ,4 gja, lying within the chain of continental isl- j ands, are only a few hunfl dred feet in depth, whilfl immediately without thosJ islands, abrupt slopes dca scend to the great depths of the Pacific basin. 5. The greatest depths thus far found in the ocean basins, have been reported from] the South Atlantic. Captain James Ross reports a sounding, wesB of St. Helena, of 27,000 feet, without touching bottom. Captai™ Denham and Captain Parker report, severally, 46,000 and 50,00^ feet, west of the island of Tristan da Cuiiha ; but owing to the din ficulty of obtaining accurate soundings in great depths, these figured can hardly be accepted as conclusive. Observations thus far made justify the conclusion that the greatS est depths of the sea are from 25,000 to 30,000 feet, about equivaf lent to the greatest heights upon the continents. But rightly to understand the magnitude of these features of rej lief, it must be remembered that mountain tops are but isolated! points, much above the general level of the mass of the emerged] lands ; while the greatest depths of the oceans are, doubtless, com mo: »*o SECTION OF THE ATLANTIC BASIN FROM NEWFOUNDLAND TO VALENTIA ISLAND, ON THE LINE OF THE TELEGRAPH CABLES. 1 See page 21, Topic II., 3. WAVES AND TIDES. 61 to extensive surfaces, which are the counterparts of the continental plains and table lands. ANALYSIS OP SECTION II. I. Ocean Basiim. 1. Their Sep.* RATION. :i Three great basins. Pacific, Atlantic, Indian. b Arctic basin. c. Antarctic basin. 2. Form and Size. a. Common feature. b Pacific basin. Form. Amount of water. * Resemblance to Old World. c. Atlantic basin. Form. Extent. Resemblance to New World. d Basin of Indian Ocean. i. Extensions on Continental Coasts. a. How classified- Inland seas. Border seas. Gulfs and bays. b Atlantic. Characteristic coast basins. Other forms of coast basins. c. Pacific. d Indian. 4 Islands a. Pacific. Relative number. Examples. b. Atlantic. Relative number. Examples. c. Indian. Relative number. Examples. Hm Ocean Beds. 1. Extent OP our Knowledge op them. 2 Atlantic Bed. a. Of what consisting. Depth of valleys and dividing swell Change of level northward. b Depth of shores and successive terraces. c Conclusion from observed variations of bed. 3. Beds OF Indian and Pacific Oceans. a, Indian Ocean.- Resemblance to Atlantic bed. Bed between Africa and India. Bed east of India Other parte of bed. b Pacific bed. Mode of ascertaining its depth- Results of calculations. 4. Inland urn Border Seas. a. General character as to depth. b. Gulf of Mexico and Caribbean Sea. c. Mediterranean. Red Sea. d. Baltic e. North Sea. f. Border seas of Asia. 5. Greatest Ocean Depths. a. Where supposed to be. b. Depths reported. a, Reported figures to be regarded how. III. — WAVES AND TIDES. I. Oceanic Movements. The waters of the :;ea are subject to various kinds of motion, due both to atmospheric and astronomical causes. Chief among them are waves, tides, and marine currents. II. Waves. Waves are the alternate rise and fall of successive ridges of water. They result from a disturbance of the equilibrium of the surface waters, by the action of the wind, and affect the sea only to a mod- rate depth. • Waves vary in height, extent, and rapidity of progress, according ;o the force of the wind, the depth of the water, and the extent of the basin in which they occur. They are much larger, and advance more rapidly, in the open sea than in inland basins. The advance of the wave is the communication of the wave move- ment to successive portions of the sea ; and not, to any considerable extent, except in shallows, an onward movement of the water itself. Thus a body floating upon the surface of the sea may be seen repeat- edly rising and falling with the waves, with but a slight change of position. When waves, advancing towards the shore, reach the shallows, the motion is retarded at the bottom by friction ; and the top, moving on without support, curls over and breaks in foam upon the beach ; or, in very shallow seas, it may break at a considerable distance from the shore. After the wind, which disturbed the surface, has subsided, the wa- ter continues to undulate with a gentle motion, called the swell. This seldom ceases entirely before a fresh storm arouses the waves anew. III. Tides. 1. Tides are movements similar in character to waves, but differ- ing in their cause, extent, and the regularity of their occurrence. Tides are caused by the action of the Sun and Moon upon the Earth ; they affect, therefore, the ocean to its greatest depths, and throughout its entire extent ; and they occur with unvarying regu- larity, the water, in every part of the ocean, rising and falling alter- nately through periods of about six hours each. Each period is fol- lowed by an interval of a few moments, during which the water remains at the level it has just attained. LOW WATER. MOON. o LOW WATER. FIG. 27. PRODUCTION OF TIDAL WAVE. The period of rising water is called flood tide, that of receding water, ebb tide. The level attained at the close of flood tide is called high water, or high tide ; and that at the close of ebb tide, low wa- ter. The interval between two consecutive high tides or low tides is twelve hours and twenty-six minutes ; hence high water, or low wa- ter, occurs about fifty-two minutes later each successive day. 2. Mode of Production of Tides. The Moon, notwithstand- ing its smaller mass, has, on account of its greater nearness to the Earth, an influence in the production of the tides which is more than double that of the Sun (as 100 to 30). The solar tides, being so much less marked, and chiefly merged in or overpowered by the lunar tides, are of secondary importance. The phenomena of the tides must, therefore, be explained mainly by reference to the latter. Tidal Waves. The Moon attracts both the land and the sea ; but the particles of the latter being free to move, the waters are drawn towards the attracting body ; and, where its influence is most power- ful, are lifted up above the normal curve of the surface of the sea. Thus is formed a vast swell, or tide wave, upon the hemisphere turned towards the Moon. The flowing of the more distant waters towards the crest of this wave, causes, on each side of it, a depres- 62 WAVES AND TIDES. FIG. 28. sion of the surface, or low water, which occurs about 90° from the line of high water. (See Fig. 27.) On the opposite side of the Earth the equilibrium of the sea is equally disturbed, and the same cause produces a second wave, the formation of which is explained as follows : The waters most distant from the attracting body being least affected by it, their weight is somewhat lessened, and they are less attracted towards the centre of the Earth than those on the sides. To restore the equilib- rium, the waters on the sides, which exert a greater pressure, tend to move towards the region of least attraction and their accumulation there raises the surface of the sea slightly above its normal level, producing the second, or counter wave. Two area* of high water, therefore, occur simultaneously upon the Earth, 180° distant from each other, the one under the Moon, and the other on the opposite side of the globe. Two areas of low water occur at the same time, midway between those of high water. Owing to the rotation of the Earth upon its axis, bringing all longitudes successively under and opposite the Moon, this permanent system of waves and troughs travels from east to west over every part of the sea. This occasions the regular succession of rising and falling waters, at equal intervals of time, occurring along all coasts, and known to us as the tides. 3. Spring Tides. The attraction of the Sun causes a similar, though less strongly marked, system of four daily tides. As the relative positions of the Earth, the Sun, and the Moon are constantly changing, the solar and lunar tides do not usu- ally coincide. Twice a month, however, at new and full Moon, the three bodies are in a line (as shown in figure 28). At these periods, the Sun and Moon act to- gether ; and an unusually high water is produced which is the sum of the solar and the lunar high tide. This is called the spring tide. Low water at this period is correspondingly lower than at any other, as high water is higher. At the first and third quarters of the Moon, the three bodies are so situated relatively to one another (see Fig. 29), that the attractive power of the Sun upon the Earth is exerted at right an- gles to that of the Moon, thus diminishing the effect of the latter. High -water is then below, and low water above, its ordinary level. These are the neap tides. The highest tides occur when the luminaries are nearest, and pass most nearly vertically on the place of observation. The highest of the spring tides occur in March, some time before the vernal, and in September, some time after the autumnal equinox, when the Sun, being vertical at the Equator, and the Moon nearest to the Earth, the equatorial, parent wave is highest. Thus the tides have daily, monthly, and annual periods. IV. Course of Tidal Waves. 1. Introduction. If the ocean covered the whole Earth with a uniform depth of water, the tidal waves, with their long crests ex- tending from north to south, would follow the apparent course of the Moon, passing from east to west entirely around the globe. They would be highest in the equatorial regions, and would there move with the velocity of more than 1,000 miles an hour. The continents, which divide the sea into three great basins, op- pose the passage of the tidal wave, and it is subjected to great modi- fications in each ocean. The velocity with whi :h the wave advances depends upon the size and form of the ocean in which it moves, the depth of the water, and the absence of obstacles to its progress. The southern half of the Pacific presents the most favorable conditions ; and there is fori led what might be called the parent tidal wave, which, entering the In- dian and Atlantic Oceans, seems to control their tides. The Map of Co-tidal Lines, or simultaneous tides, on page 63, shows the succes- sive positions and directions of the crest of the tidal wave, at intervals of one hour. Each line passes through places having high water at the same hour, the hours being marked on the lines in Roman numerals. The more rapidly and regularly the wave ad- vances, the further apart and more nearly parallel are the co-tidal lines which exhibit its position at sueces- spring tides. sive hours. 2. Tidal Wave of the Pacific. The Parent wave, which originates in the central and southern Pacific, moves on most swiftly in the broad, deep, and unobstructed basin lying south of the Tropic ' of Capricorn. There, also, it preserves its normal direction west- ward, and its crest extends nearly north and south. In the equatorial Pacific its progress is obstructed by the nume- ' rous oceanic islands ; and, reaching the shallow seas of the great Indian Archipelago (see page 60, Topic III.), it becomes exceedingly j slow and irregular. (See Map of Co-tidal Lines.~) In the northeastern portion of this basin, the tidal wave is deflectec northward and eastward. The deflected wave strikes the American shores, be-l tween California and Alaska, at the same hours at which the direct wave strikes the Asiatic shores, between Kamchatka and Japan. A reflected wave also starts in the longitude of the Galapagos Islands ; ' and, advancing eastward and southward] along the South American coasts, it meetsl the tide wave from the south Atlantic at] Cape Horn. NEAP TIDE ! NEAP TIDES. QUESTIONS ON THE MAP OF -CO-TIDAL LINES. Note. — The co-tidal lines are numbered from I. to XII. in J elusive, corresponding with the divisions of the dial. By observ- ing the numbers on- the lines, at given places, one learns the n um- ber of hours required for the wave to pass from the one to the other. For example, the line at the Sandwich Islands is num- t bered II., while that at Sitka, on the American coast, is X. This 6hows that the latter place has high tide eight houn later than I the former. What part of the North American coast has high water at the same hour with the Sandwich Islands ? How many hours between high water at the Sandwich Islands and at New Zealand?! (See note above.) How much of the American coast has high water at (he same hour with! San Francisco ? How long is the tidal wave in passing from the southern point of Kamchatka to the souther point of the Japan Islands? How long is the tidal wave in passing from the Galapagos Islands, across the Pacific, to Kamchatka and New Zealand ? How long from the Galapagos Islands to the southern extremity of South America? Hovrj long from the Sandwich Islands northward to the southern coast of Alaska ? In what direction does the tidal wave advance through the middle and northern part on the Atlantic Ocean? What places have high tide at the same hour with Rio Janeiro? How long is the tidal wave in passing from Rio Janeiro to Cape Race ? What portions of the North American coast have high tide at the same hour with Newl York? How long is the tidal wave in passing from New Zealand, through the Indian and Atlantic! Oceans, to Iceland? How long in passing from New Zealand to Muscat, in Arabia? What direction does the tidal wave take in the eastern half of the Indian Ocean? i H 1 B o 5 3} H m > W o u H H g a — <* > i i < rn 3) > | c i § > > r | >> — CO H < ^ w > Z H 1 pi B M 64 WAVES AND TIDES. 3. Tides of the Indian and Atlantic Oceans. The tides of the Indian and Atlantic Oceans seem to be either overpowered by, or merged into, the great wave generated in the south Pacific. This wave advances rapidly through the deep waters of these ba- sins ; but it is greatly retarded in the northern portions of the In- dian Ocean. Muscat, near the northern extremity of the Arabian Sea, has high water at the same hour as Rio Janeiro on the west- ern shores of the Atlantic. In the middle and south Atlantic the tide wave advances north- westward ; in the northern part it moves towards the northeast, following, in both cases, thj direction of the narrow ocean basin. The course of the tidal wave on the coast of the British Isles, illus- trates forcibly its retardation in shallow and narrow arms of the sea. The main wave of the north At- lantic advances from Brest, on the western coast of France, to Ber- gen, on the coast of Norway, in four hours. The branch entering the English Channel has, during the same time, only reached South- ampton, and that in the Irish Sea has arrived at Dublin. The main wave, entering the North Sea from the north, descends slowly along the coasts of Scotland and England ; and finally meets the branch from the Channel, which, having passed the Strait of Dover, advances along the coasts of Hol- land and Germany. (See Fig. 30.) V. Height of Tides. FIG. 30. 1. Variations in Level. The height of the tide depends. on local circumstances. In the midst of the Pacific it is scarcely more than two feet, which may be considered its normal level. But when dashing against the land, or forced into deep gulfs and estuaries, the accumulating tide waters sometimes reach a great height. On the eastern coast of North America, the average rise of the tido is from nine to twelve feet. At the entrance to the Bay of Fundy, however, it rises eighteen feet, while at the head of that bay it reached 60, and in the highest spring tides, even 70 feet. At Bristol, in England, the spring tides rise to 40 feet ; and at St. Malo, on the south coast of the English Channel, they reach 50 feet. 2. Effects. Differences in level, produced by high tides, cause currents which vary in force and direction with the condition of the tide, producing, in some cases, dangerous whirlpools. The famous Maelstrom, off the coast of Norway, is but a tidal cur- rent, which rushes with great violence between two of the Lofoden Islands, causing a whirling motion in the water which is reversed at each ebb and flow of the tide. Such is, also, the famous whirlpool of Charybdis, in the Strait of Messina, and many others of less note. The powerful currents of Hell Crate, in the passage from Long Island Sound to New York Bay, are due to a similar cause, high water oc- curring at different hours in the bay and in the west end . of the sound. 1. Bore. In estuaries into which great rivers flow, the resistance offered by the current of the stream to the entrance of the tide, produces a huge wave called the Bore, which, like a moving wall of water, advan- ces with great rapidity and a deep roaring noise up the stream to the limit of tide water. The Hoogly, a mouth of the Ganges, the Tsien-tang in China, and the Amazon, afford the most remark- able examples of this phenomenon. The bore of the Tsien-tang rises thirty feet in height, and travels at the rate of twenty-five miles an hour. In the Amazon five bores, each about fifteen feet in height, may sometimes be seen rushing up the river one after the other within the space of 200 miles. CO-TIDAL LINES OF liHITISH ISLES ANALYSIS OF SECTION IU. I. Oceanic Movements. a. Causes of movement in sea water b. Classes of movements. II. Waves. a. Description of wave movement. b. Cause. Variation in waves. c. Advance of waves. Swell. III. Tides. 1. Phenomenon Described. a. Kind of motion. b. Difference between tides and waves. c. Periods of tide. Flood. Ebb. High water. Low water d. Interval between two consecutive high tides. e. Hour of high water on successive days. 2. Mode op Production of Tides. a. Comparative influence of Moon and Sun. b. Production of tidal wave under Moon. c. Production of tidal wave on opposite side of globe. d. Areas of simultaneous high water. e. Areas of simultaneous low water. f. Advance of tidal system around globe. 3. Spring Tides and Neap Tides. a. Want of coincidence in lunar and solar tides. b. Spring tides, when and how formed, high water, low water. c. Neap tides, when, how formed, high water, low water. d. Highest spring tides. Lowest ueap tides. IV. Course of Tidal Wave. 1. Introduction. a. Course in case a uniform ocean covered the globe. b. Influence of continents on course. c. Regularity and velocity of motion. d. Explanation of map of co-tidal lines. 2. Tidal Wave of Pacific. a. Course of parent or primary tide wave. b. Tidal wave iu equatorial Pacific. 3. Tidal Wave op Indian and Atlantic Oceans. a. Relation to Pacific tide wave. b. Progress in deep waters. c. Retardation. d. Course around British Isles. V. Height of Tide. 1. Variations of Level. a. Height depends on what. b. Normal level. c. High water on North American coast. Exceptions. d. Spring tides in Bristol and English Channel 2. Results of Differences of Level. 3. Bore — how formed. Examples. IV. — MARINE CURRENTS. I. General Circulation. 1. The Ocean Currents are vast rivers in the sea, which move on steadily through water comparatively at rest, and are often differ- ent from the latter in color and temperature. Some are hundreds n ilcs broad, thousands of feet deep, and have a course embrac- ing the larger part of the ocean in which they move. Currents ex- ist not only at the surface but in the deep waters, where their course is frequently in a different direction from, sometimes even opposite to, that of the surface currents. 2. Equatorial Currents. Within and near the tropics the waters, under the influence of the constant trade winds (see page 77, Topic III.), advance westward around the globe, forming a vast Equatorial Current, 50° or more in breadth. Reaching the eastern shores of the continents, in each ocean, this great current separates, one part turning northward and the other southward. Advancing towards the poles these branches swerve gradually eastward ; and, reaching the middle latitudes, they cross the ocean, striking the western shores of the continents. Finally, a part at least of the water returns to the equatorial regions, while the remainder continues its course towards the poles. Thus is formed, on each side of the equator, a vast elliptical circuit of moving waters, occupying the entire breadth of the ocean basins, and extending over the tropical and middle latitudes. In the centre is a broad expanse of quiet water, which is covered, to a large ex- tent, with sea weed, forming the so called Sargasso Seas. The main causes of these vast movements in the ocean are found in the winds, the excessive evaporation within the tropics which tends to lower the level of the water there, and the differing temperatures of polar and equatorial regions. The cold waters of the higher lat- itudes, being heavier, tend constantly to flow into the warmer wa- ters of the equatorial seas ; and the latter, being displaced by the for- mer, flow away as surface currents towards the poles. 3. Two series of currents, of opposite character, pervade the sea iii high latitudes ; — the cold, flowing from the polar regions to- wan Is the equatorial ; and the warm, flowing in the opposite direction. In the middle latitudes, where the opposing currents meet, the cold, being heavier, sink beneath the warm and disappear, continu- ing their course in the deep waters. These under currents, having reached the inter-tropical seas, gradually rise again to the surface, where they become heated ; and, contributing their waters to the great equatorial current, which flows westward on each side of the equator, they finally return towards the poles. Hence the general currents of the sea are of three classes : the olar, the Equatorial, and the Return Currents. 3. Direction. The Polar and Return Currents, were they ted upon by no external force, would move in the line of the me- •idians, taking the shortest course between the poles and the equator. Both are, however, deflected from this course by the unceasing ion of the Earth's rotation, — the Polar Currents, as they advance, mding more ai!# more towards the west, and the Return Currents wards the east ; and their directions are still farther modified by ;e forms of the basins of the several oceans, and the influence of the 'evading winds in the different zones. Since the Earth performs one entire rotation on its axis every twenty-four mrs, the velocity of rotation at the equator, must be somewhat more than 1000 les an hour. As each successive parallel has a less circumference than the pre- leding, the velocity of rotation diminishes with increasing latitude, until at the poles it is zero. If, therefore, particles of water, or of air, move from the polar regions towards the equator, each s>tep in advance will bring them upon parallels where the rota- tion is more and more rapid. The new velocity cannot be instantaneously acquired, conseque^j^ at each successive parallel, the moving particles are left a little behind, or to the west of their previous position ; and when they reach the tropics they are many degrees west of the meridians upon which they laft the polar regions. A similar cause operates to give the Return Currents their eastward tendency. The particles moving towards the poles find, at each successive parallel, a rotary velocity less than at the preceding. Not acquiring the new and less rapid mo- tion instantaneously, they gain a little at each parallel, and find themselves slightly in advance, or to the east of their former position. This deflection from a direct north and south course, which appears in the at- mospheric as well as in the oceanic currents (see page 76, Topic 3), is, therefore, the result of a change of latitude of the moving particles. Were they to remain upon any given parallel, their westward, or eastward, motion would cease ; for the solid globe, the waters, and the atmosphere, all rotate together, in obedience to the same laws. In the northern hemisphere, the Polar and the Return Currents both preserve their normal course, the former flowing towards the southwest, the latter towards the northeast. In the southern hemi- sphere, the westerly winds which prevail beyond the tropics and sweep, without interruption, over the broad expanse of the southern sea, turn the Polar Current out of its normal, northwesterly, course, directing it towards the northeast. (See map, page 66.) II. Currents of the Pacific. 1. The Great Equatorial Current of this ocean occupies the entire breadth of the torrid zone, and consists of two parts, a north and a south current, which are separated by a narrow counter current, moving slowly eastward, in the immediate vicinity of the equator. Both branches begin near the American shores, and ad- vance westward at a nearly uniform rate of two or three miles an hour. The South Equatorial Current, starting from the South Ameri- can coast, off Pttnta Parina, moves on uninterruptedly across the eastern half of the ocean ; but it is broken up in the western part, where its path is obstructed by innumerable islands. The northern portions are lost among the numerous channels of the Indian Archi- pelago. The southern portions turn southward, forming the New Zealand and Australian Currents ; and finally, meeting the Antarc- tic Current, they return eastward with it. The North Equatorial Current, flowing through an unobstructed basin, advances unbroken to the Philippine Islands where it divides, the southern portion entering the Indian Archipelago. 2. Return Current. The principal part of the North Equa- torial Current turns northward, forming the warm and powerful Jap- anese Current, called by the natives the Kuro Sivo, or Black Water, on account of its dark blue color. This is the Return Current of the north Pacific, analogous to the Gulf Stream in the north Atlan- tic. South of the Aleutian Islands it is deflected from its northward course and crosses the ocean. Returning along the American shores to the Tropic of Cancer, it chiefly reenters the North Equatorial Cur- rent. A small branch of the Kuro Sivo continues along the Asiatic coast to Behring Strait. 3. Polar Currents are nearly wanting in the north Pacific, for the narrow and shallow passage of Behring Strait, connecting it with the Arctic Ocean, does not permit the free egress of the polar waters. Yet a small current, in each direction, passes through the strait, the warm on the eastern shore, towards the north, the cold on the western, towards the south. In the south Pacific, on the contrary, the polar waters advance northward in the form of the broad Antarctic Drift Current. MARINE CURRENTS. 120 Lougitude West SO ft-om Ore MKMiofa 40 CURRENTS. Entered "■— »i-rti,ii *A*- (MIm «/' «A* Librtu-ian of Cortprr-nr ut Wa.tfun^ton. CT- QUESTIONS ON THE MARINE CURRENTS. I. Pacific Ocean. Where does the South Equatorial Current commence? In what longitude does it first divide ? What shores are bathed by the southern branches of this current? What islands bathed by its northern branches? What is the position of the counter current in regard to the Equator? What are the eastern and western limits of this current ? In what longitude does the North Equatorial Current commence ? How does this current compare in breadth with the South Equatorial ? What name has the return current -of the North Pacific in the western half of its course? Where is the Kuro Sivo first apparent? What shores are bathed by this current? Near what islands does the Kuro Sivo divide ? Whither does the smaller branch go ? What name is given to the greater branch of the Kuro Sivo ? Describe the course of the North Pacific Current? What seems to be the most desirable route for vessels from California to China? From China or Japan to California? Why ? What current on the western coasts of South America ? Whence is this current derived ? Whither does it go ? What is the direction of the current east of northern Australia? What is the direction of the East Australian Current? Whence are these two currents derived ? What is the direction of the current east of New Zealand, and whither does it go? Whence come the currents on the west coast of North America? Whence are all the currents on the west coast of South America derived? What is their probable effect upon the climate? Why? Name the principal cold current, I of the Pacific. The warm currents. I. Atlantic Ocean. Trace the water of this ocean, from the Cape of Good Hope to North Cape, naming the cur- rents, and the coasts and islands bathed by each. Trace, in like manner, the currents from the Cape of Good Hope to Cape Horn. Where is the Gulf Stream first apparent? Whither does this current go ? What current bathes the southern shores of Iceland ? What current flows between Iceland and Greenland ? What is the position of the North Equatorial Current ? How does the Equatorial Counter Current, in the Atlantic, compare with that in the Pacific in position and extent ? Where does the South Equatorial Current originate ? Whither does the north branch of this current go ? Whither does the south branch mainly go ? Whence are all the currents on the eastern and northern coasts of South America derived? How does their influence on the climate of the coasts differ from that of the Peruvian Current? Why? Whence is the current on the western coast of south Africa derived ? Whence are the currents on the western coasts of north Africa and Europe ? What is their probable influence on the climate of those coasts? Why? Whence are the currents on the larger part of the eastern coast of North America ? How do the currents compare in direction on the opposite sides of the north Atlantic? What is the direction of the currents at the west of Greenland ? How do the polar currents of the north Atlantic compare in extent with those of the north Pacific? Why is this? Name all the warm currents of the Atlantic. Name the cold currents of the Atlantic. .^flfe. III. Indian Ocean. Trace the course of the currents from the Cape of Good Hope to Australia, and return. Whence is the South Australian Current derived ? What current flowing between India and Africa ? What is the direction of the currents in the northern part of the Indian Ocpan? (See page 67, Topic IV.) Which are the warm currents of this ocean? To what part of the Indian Ocean are the cold currents confined ? Why ? MARINE CURRENTS. 67 Bent out of its normal course by the strong westerly winds, this polar current turns eastward, and advances to the South American coast, where it divides. The principal branch flows northward, un- der the name of the Peruvian or Humboldt Current, bathing the coasts of Peru with its cool waters, and becoming the main feeder of the South Equatorial Current. The smaller branch, turning south- ward, rounds Cape Horn and enters the Atlantic. III. Currents of the Atlantic. 1. The Equatorial Current, in the Atlantic, owing to the narrowness of the basin and the projecting angle of South America, has neither the extent nor the regularity it shows in the Pacific. The northern branch is less marked, and the counter current is not well defined except near the African coasts. The south branch advances from the coast of Guinea to Cape St. Roque, the eastern point of South America, where it divides. The smaller division forms the Brazilian Current, flowing southward along the eastern coast of South America. Finally turning to the southeast, under the name of the Connecting Current, it joins the Antarctic waters, and returns with them to the Equatorial Current. The main portion of the south current continues westward, pass- ing the mouth of the Amazon and the coast of Guiana ; then, uniting with the North Equatorial Current, it traverses the Caribbean Sea and the Gulf of Mexico, and issues into the north Atlantic basin as the Gulf Stream. 2. The Gulp Stream, which first becomes apparent near the northeast coast of Cuba, advances gently eastward to the Bahama Banks ; then, turning northward, it follows the American coast, with an average velocity of four or five miles an hour, gradually expand- ing in breadth and diminishing in depth. In the latitude of New York it turns eastward and crosses to the Azores, where it divides. The main branch, bending south- ward, enters the tropical regions off the coast of Africa, and returns to the North Equatorial Current. The northern branch continues its northeast course to the British Isles and Norway, its advance in that direction being favored by the prevailing southwest winds. Near its origin this remarkable current has a breadth of 32 miles, and a depth of more than 2,000 feet ; off Cape Hatteras the breadth is at least 75 miles, and the depth about 700 feet. Its temperature, at its origin, is about 80° Fahr. ; and through the larger part of its course it is, on an average, from 10° to 15° Fahr., — in winter from 20° to 30°, — warmer than the adjacent waters. Its color is a deep blue, so strongly contrasting with the greenish color of the sea that the line of contact is distinctly traceable by the eye. Its boundaries are sharply denned, especially on the west, where the transition is immediate from the cold wall of adjacent waters to the warm waters of the Gulf Stream. In the middle and northern part of its course, alternate bands of cold and warm waters occur. This is due, perhaps, to the partial mingling of colder currents with 'the warm, or simply to the currents of warm water moving into the quiet colder waters of the sea. The comparatively high temperature and rapid motion, and the deep blue color of the Gulf Stream, distinguish it from other portions of the ocean. It was long supposed to be a phenomenon of an exceptional character, to account for which the most extravagant hypotheses were invented. A better knowledge of the ocean currents, ho\M||r, shows it to be simply a Return Current like the Japanese, the normal charfl^H which is intensified by the peculiarities of the Atlantic basin. This basin nWscarcely half the breadth of the Pacific basin ; hence the Gulf Stream retains, throughout its course, its original temperature in a much higher degree than the Kuro Sivo. Again, the open communication of the Atlantic basin with the Arctic, giving free entrance to the polar waters, while the north Pacific is closed against them, causes a much greater contrast between the Gulf Stream and the surrounding sea than is presented by the Japanese Current. The intermingling of the warm moist air, over the Gulf Stream, with the colder air over the surrounding sea, causes those frequent and violent storms which mark the course of this current across the Atlantic. The Gulf Stream transports not only the warm waters of the tropics, but car- ries with it large quantities of drift wood from the tropical forests. This, with debris from wrecked vessels, and weed from the vast Sargasso Sea, it throws upon the shores and islands of the Arctic regions whither it flows, the drift wood form- ing a valuable gift to the people of those inhospitable lands. 3. Two main Polar Currents, one on each side of Greenland, uniting off Cape Farewell, carry the icy waters and icebergs of the Arctic to the American shores, as the Gulf Stream and the superin- cumbent air transport the genial temperature of more southern lati- tudes to Europe. In the latitude of Newfoundland the Polar Cur- rent meets the Gulf Stream, and, condensing the vapors in the warm air which rests upon it, produces almost constant fogs. Thence as far as New York, the polar waters flow between the warmer waters and the shore, finally disappearing beneath them. IV. Currents of the Indian Ocean. The North Equatorial Current, in this basin, is overcome by the influence of the Monsoons ; and it flows alternately towards and from the southwest, its principal branch being known as the Mala- bar current. The South Equatorial Current is quite regular, extending from Australia to Madagascar, where it divides. The north branch forms the warm and powerful Mozambique current, west of Madagascar, and near the southern coast of Africa it is joined by the south branch. South of the Cape of Good Hope the united current meets the Antarctic Drift and turns backward with it to the shores of Aus- tralia, where it reenters the equatorial current. V. Conclusion. Thus is kept up, in each of the three great ocean basins, a con- stant circulation of the marine waters, which far surpasses in mag- nitude the greatest circulatory systems of the continents, and pro- duces important modifications in the climate of the adjacent lands. The north polar currents, transporting their icy waters into the middle latitudes, are, by the influence of the Earth's rotation, thrown upon the eastern shores of the continents, reducing their tempera- ture below that belonging to the latitudes. The return currents, on the contrary, carrying the warm waters, and accompanied by the warm air of the tropical regions, strike the western shores of the continents, and raise their temperature above that belonging to their latitudes. Thus on the opposite shores of the northern continents, there are great contrasts of temperature in the same latitude, due in a considerable degree to marine circulation. Again, the position of the warm waters on the surface of the sea, while the cold are beneath, doubtless augments, to an appreciable degree, the warmth of the entire temperate zone. ANALYSIS OP SECTION ni. I. General Currents. 1. Ocean Currents. a. Definition. b. Extent. o. Position relative to surface, d. Cause. 2 Shies or Currents. a. Cold currents. b. Warm currents. c. Results of meeting of cold and warm currents. d. Under current in equatorial regions. e. Classes of general currents. 3. Directions of Polar and Return Currents. a. Direction in absence of modifying influence. 68 MARINE CURRENTS. b. Influence modifying directions. Results. c. Explanation of direction of polar currents. d. Explanation of direction of return currents. e. Farther modifications of course of currents. II. Currents of Pacific Ocean. % 1. Equatorial Currents. a. Breadth. Subdivisions. Velocity. South Equatorial current. North Equatorial current. 2. Return Currents. a. How formed- b. Course. 3. Polar Currents. a. North Polar currents. b. South Polar current. Direction. Course of branches. III. Currents of the Atlantic. 1. Equatorial Currents. a. Effect of narrowness and form of basin. b. South branch and subdivisions. 2. Gulp Stream. a. Where first apparent. b. Course and velocity at first. c. Subdivisions and their courses. Characteristics of Gulf Stream. Peculiarities how accounted for. 3. Polar Currents. a. Position and character. b. Effect on meeting Gulf Stream. c. Latitude of disappearance. IV. Currents of Indian Ocean. a. North Equatorial current. b. South Equatorial current. V. Conclusion. a. Magnitude of marine circulations. b. Climatic effect of Polar currents. Of Return currents. ■ Resulting contrasts in coasts. REVIEW OF PART III. Introduction. (Page 47.) Enumerate the topics discussed in the introductory section. What is the effect of reducing the temperature of water ? What importance has this exception to a general law of nature ? Whence is the rain water which falls upon the continents, and what becomes of it V Continental Waters. I. (48.) Explain the formation of intermittent springs. Where are springs most numerous, and why in this position ? How are rivers combined into systems ? Upon what does the amount of water transported by a stream depend ? How does the erosion vary in different parts of the course of a stream ? (49.) What is the result of the lateral erosion in the middle course? Explain the sinuosity of the course of streams through the bottom land. How are the windings changed in high water ? Give examples of the amount of materials transported by streams. How is this transportation effected, and how do the materials vary in different parts of the course ? How does the deposit of the transported materials vary ? (50.) Describe the formation of deltas. What peculiarity of slope do deltas show, how is this occasioned, and what is the result of it? In what part of the course of a stream are the highest falls ? Why V Enumerate the topics discussed in Section I., with their primary divisions. II. (51.) What peculiarities of form distinguish mountain lakes ? What are the characteristics of lakes in plateaus and plains ? How is the formation of salt lakes to be accounted for ? Upon what does their size depend ? Examples. (52.) In what continents are lakes most numerous? Character of the lakes in each? Enumerate the topics and sub-topics discussed in Section II. III. What is the influence of the characteristic structure of North America upon its drainage ? What is the main water-shed, and what great streams flow from it ? (53.) Describe the formation of the Mississippi basin. What is the position of its three principal affluents, and what determines this position? How do the eastern affluents compare with the western in the amount of water transported ? Why this difference ? What especially characterizes the St. Lawrence basin? Name the other river systems, and the groups of smaller streams, in North America. (54.) How do the systems of the central plain compare with the others? Why is this? Enumerate the topics discussed in Section III. IV. How does the general plan of drainage in South America compire with that in North America ? What is the effect of the inequality of the continental slopes ? How is the absence of lakes in South America to be explained ? What is the structure of the Amazon basin, and the main source of its waters? How does the Amazon compare with other streams in its volume of water? Why? Name the remaining systems of South America, and the corresponding streams of ^cnh America. (55.) Enumerate the topics discussed in Section IV., and their primary divisions. Describe the general plan of drainage in eastern Asia. Why is it so different from the plan of the American continents? Enumerate the principal streams on each slope. Describe the drainage of western Asia. What are the hydrographical centres of Europe? Describe the drainage of High Europe. What governs the direction of the flowing waters of a continent? (56.) How does the course of the streams of High Europe illustrate this fact? Describe the drainage of Low Europe. How do its streams compare with those of High Europe ? Enumerate the topics discussed in Section V., with their several subdivisions. VI. (57.) What is the general plan of drainage in Africa ? Describe the course of the Nile, its valley, and its inundations. Describe the other river systems of Africa. From what part of the continent do these systems derive their waters? What peculiarity in regard to rivers is exhibited by Australia? Upon what does the plan of drainage in each continent depend ? What oceans receive the larger part of the flowing waters of the globe ? What is the reason of this ? Enumerate the topics discussed in Section VI., with their subdivisions. The Sea. I. (58.) What is the composition of sea water? How does the temperature of the surface vary ? What is the temperature of the deep waters ? Describe the bottom of the sea. Enumerate the topics discussed in Section I., with their se*ral subdivisions. II. (59.) Describe the forms of the several ocean basins. How are coast waters classified, and what class characterizes each ocean? How do the oceans compare in regard to islands? Describe the bed of the Atlantic Ocean. (60.) How does the bed of the oceans differ from the surface of the continents? Describe the bed of the Indian Ocean. What is the estimated depth of the Pacific? How do inland and border seas compare with the oceans in depth ? Examples. What is probably the greatest depth of the sea ? (61.) Enumerate the topics discussed in Section II., with their several divisions. III. What are the different classes of movement in the waters of the sea ? Describe the wave movement, and the advance of the wave. Describe the tides, their cause, the extent of the movement, and the several periods of the tides. How are the tidal waves produced on opposite sides of the globe ? (62.) Explain the spring tides and the neap tides. Upon what does the velocity of the movement of the tidal wave depend ? Describe the tidal wave of the Pacific. Why is the progress of the wave more rapid in mid-ocean than along the coasts? (63.) What is the normal height of the tide wave? Why is it higher along the coasts and in estuaries? Enumerate the topics discussed in Section III., with their several divisions. IV. (65.) Describe the general circulation of the oceanic waters. What are the three classes of ocean currents ? What is the normal direction of the polar, and of the return currents ?^| How is this direction caused ? How do the polar currents of the southern hemisphere vary from this direction? Describe the equatorial current of the Pacific. Describe the course of the Kuro Sivo. (67.) Describe the equatorial current of the Atlantic. Describe the Gulf Stream, its course, velocity, and temperature. How and why does it differ from the Kuro Sivo? What is the climatic influence of the ocean currents? What is the effect of the expansion of the warm currents on the surface of the sea, whii,, the cold are beneath ? PART IV THE ATMOSPHERE. I. — INTRODUCTION. I. Tlif Atmosphere a Geographical Element. 1. Its Relation to the other Elements. The Atmosphere, that vast ocean of air at the bottom of which we live, forms the third great geographical element of the Earth. Enveloping both the land and the water, it absorbs the heat and vapors caused by the action of the sun upon the surface of both ; and, through the medium of the winds, carries invis- ible moisture and fertilizing rains from the sea to the parched lands. 2. Composition. The atmosphere is a mechanical mix- ture of oxygen and nitrogen, in the pro- portion, by volume, of 21 parts of the former to 79 of the latter ; with a very small quantity of carbonic acid, and more or less of wa- tery vapor held in suspension. It is among the most elastic bodies in na- ture, expanding or contracting with the slightest in- crease or diminu- tion of temperature, or variation in the pressure which it supports. 3. Weight and Pressure. The weight of the atmosphere is measured by its pressure on the barometer. 1 This instrument is a slender glass tube about a yard in length, closed at one end, then filled with mercury and reversed, the open end being placed in a cup of the same fluid. The atmosphere, pressing upon the fluid in the cup, keeps within the tube a column of mercury exactly sufficient to balance its own weight. At the level of the sea this column, measured by a scale 1 From the Greek baros, weight, and metron, measure. .. \I:-. I .i I :!iir;i-ii-. < 1.. I ':..::.'■■ ■../ .. Iih. Dhawalagii i. 1- Kvcrcst. Or. OntV'l Lebanon Mts. M. B. Mont Biiuic. Po. Popocatepetl. By. Pyrenees. Sa. Soratu. 'Si W. Mt. Washington. Observers: G. Gerard. G. L. Gay Lussac. Gi. Glaisher. FIG 31. DENSITY AND PHESSUHE OF THE AIK AT DIFFERENT ALTITUDES. attached to the instrument, is about thirty inches in height. The weight of the entire atmosphere, therefore, is equivalent to that of a layer of mercury thirty inches deep, covering the globe, and exert- ing a pressure of fifteen pounds on every square inch of its surface. When, from any cause, the pressure of the air increases, the ba- rometer rises , when it decreases the barometer falls. 4. Density. The air, being a highly elastic body, the lower layers, which support the pressure of the entire atmosphere, are the most dense ; and the density diminishes upward with the decrease of pressure and the consequent increase of volume. The law of varia- tion is exhibited in the table below, in which the volume and density of a given weight of air at the sea level, un- der a barometric pressure of thirty inches, is taken as unity. It will be seen that one half of the entire atmosphere, by weight, is con- densed within 3$ miles — about 18,- 000 feet — of the sea level ; and fully two thirds are be- low the level of the summit of the highest mountains. This fact has an important bearing, both on the influence of mountains in directing or modifying the course of the winds, and on the general cli- matic phenomena of the globe. Figure 31 shows the diminution of barometric pressure, with increasing altitude, up to the highest points reached by observers, either upon mountains or by balloon, the highest being Glaisher's balloon ascent to 36,670 feet. I'k. Hi. Hindoo Koosh. K. Kilinwi Njaro. Scandinavian Mts. T. Torrcy's Pk. Gu. Green. II. Humboldt. Height of Barometer. Inches. Volume of a given weight. Density. Miles above sea level. 30.00 1 1 ' 15.00 2 \ 3.4 7.50 4 \ 6.8 .3.75 8 \ 10.2 1.81 16 A 18.6 .93 32 A 17.0 70 ASTRONOMICAL CLIMATE. 5. Height of the Atmosphere. In consequence of the above law of diminution, it is calculated that, at the height of from 45 to 50 miles above the sea, the atmosphere becomes so rarefied that the barometric pressure is nearly or quite insensible. If this be taken as practically its upper limit, the atmosphere appears as a thin film, measuring not much moi'e than the hundredth part of the radius of the Earth. 6. Its Relation to Organic Life. In the atmosphere alone the highest forms of vegetable and animal life, including man him- self, find the proportion of heat, of oxygen, and of watery vapor req- uisite for their vitality and development. It thus performs the part of universal mediator, not only between land and sea, but also be- tween organic and inorganic nature. II. Climate. 1. Definition. The physical agencies acting through the at- mosphere upon organic life, constitute climate, of which heat and moisture are the essential elements, the winds being the medium of circulation. Temperature, however, is the fundamental phenomenon of climate ; for the winds and the rains result from differences in the temperature of the air. 2. Astronomical Climate. The fundamental laws which gov- ern the climatic conditions of our globe are the result of astronomical causes, namely : the direct action of the Sun's rays upon the Earth's surface, the spherical form of the Earth, and the daily and yearly motions of the latter. These causes, operating constantly, establish permanent inequalities of temperature and rainfall in different lati- tudes ; and periodical variations, in the same latituda, in different parts of the year. The general climatic conditions belonging to a region, and de- pending upon its latitude, constitute its astronomical climate. 3. Physical Climate. The climate belonging to a place, by its latitude, is usually modified, to a greater or less extent, by sec- ondary physical agencies, — among which are the general atmos- pheric and marine currents, the differing power of land and water to absorb and radiate heat, and the altitude of the surface. The astronomical climate of a region thus modified, is its real, or physical climate. This depends not only upon its latitude, but also on its position in regard to the oceans, the direction of its prevailing winds, and its elevation above the level of the sea. analysis of SECriON I. I. The Atmosphere a Geographical Element. 1. Its Relation to other Elements. 2. Its Composition and Elasticity. 3. Its Weight and Pressure. 4. Its Density. 5. Its Height. 6. Its Relation to Organic Liu. II. Climate. 1. Definition. a. Essential elements. b. Fundamental phenomenon. 2. Astronomical Climate. a. General climatic conditions — how caused. b. Results of operation of astronomical causes. c. Astronomical climate defined. d. Astronomical climate depends on what. 8. Physical Climate. a. Subordinate agencies modifying climate b Physical climate defined. c. Physical climate depends on what. " II. — ASTRONOMICAL CLIMATE. I. Distribution of Temperature. 1. General Law. The amount of heat produced by the snn upon the Earth's surf ace, is greatest near the Equator, and diminishes gradually towards the Poles. 2. Causes of Variation. Three general causes, each referable to the spherical form of the Earth, combine to produce the gradua diminution of temperature from the Equator to the Poles. (1.) The angle at which the Sun's rays impinge upon the surface In the Equatorial regions they are perpendicular to the surface o the sphere, and there produce their maximum effect ; but, on ac- count of the curved outline of the globe, they fall more and more obliquely with increasing latitude, and the intensity of action dimin- ishes proportionately. At the Poles, they are tangent to the sur- face, and their effect is zero. (2.) The area on which a given amount of heating power is ex- pended, is least at the Equator, consequently the resulting heat is greatest. The area covered increases, and the effect diminishes with the increasing obliquity of the Sun's rays in higher latitudes which, as we have seen above, results from the spherical form of the Earth. (3.) The absorption of heat by the atmosphere, as the Sun's rays pass through it, is least where they fall perpendicularly, — that is, in the Equatorial regions, — and increases, with their increasing obliq- uity, towards the Poles. II. Influence of the Earth's Motions. 1. Motions of the Earth. The Earth revolves constantly around the Sun, and at the same time rotates upon an axis inclined 23 \° towards the plane of its orbit. In consequence of the inclina- tion of the axis, the declination of the Sun, or its angular distance from the Equator, varies with the advance of the Earth in its orbit, causing periodical variations in the length of day and night and, consequently, in temperature. 2. Positions of the Vertical Sun. Vernal Equinox. On the 20th of March, at mid-day, the Sun is vertical at the Equator. Rising directly in the east it ascends the heavens to the zenith, and, descending, sets directly in the west. The illuminated hemisphere extends from pole to pole, and em- braces half of every parallel of latitude ; hence every point on the Earth's surface is under the rays of the Sun during half of the diur- nal rotation ; the days and nights are equal all over the globe ; and the heating power of the Sun is the same in both the northern and the southern hemisphere. (See illustration Orbit of the Earth, page 5.) Summer Solstice. As the Earth advances in its orbit the vertical Sun declines northward ; and on the 21st of June, at the Summer Solstice, it is over the northern Tropic, 23£° from the Equator. The illuminated hemisphere, extending 90° on each side of the parallel of the vertical Sun, reaches 23£° beyond the north pole ; but, at the south, it barely touches the Antarctic circle. It embraces more than half of each parallel north of the Equator, hence throughout the northern hemisphere the day is longer than the night, the differ- ence in their duration increasing with the latitude ; and all points within the Arctic circle are in the light during the entire rotation. In the southern hemisphere, less than half of each parallel being illuminated, the night is longer than the day, and within the Ant- PHYSICAL CLIMATE. 71 arctic circle there is constant night. The heating power of the Sun is now at the maximum in the northern hemisphere, while in the southern it is at the minimum. At the Autumnal Equinox, on the 23d of September, the distri- bution of light and heat upon the two hemispheres is the same as at the Vernal ; and at the Winter Solstice, on the 22d of December, it is the reverse of that at the Summer Solstice. 3. Variations in Temperature. The inequality in the length of the days in different parts of the year, occasioned by the inclina- tion of the Earth's axis, is of itself sufficient to produce a marked variation in temperature. During the day the Earth receives from the Sun more heat than it radiates into space ; while during the night it radiates more than it receives. Hence a succession of long days and short nights re- sults in an accumulation of heat, raising the average temperature and producing summer ; while long nights and short days result in a temperature below the average, producing winter. Again, the heating power of the Sun in each hemisphere is greatest at the period of the longest days, because of its greater altitude in the heavens ; and least at the period of shortest days. Thus long days and a high sun operate together to produce the high temperature of rammer ; while long nights and a low sun cause the low temperature of winter. 4. Varying Inequality of Day and Night. Law of varia- tion. The inequality of day and night increases slowly in the trop- ical regions, but more and more rapidly towards the polar circles. Beyond these circles the Sun, in the hemisphere in which it is verti- cal, makes the entire circuit of the heavens, without sinking below the horizon, for a period varying from twenty-four hours to six months ; while in the opposite hemisphere there is a corresponding period of continuous night. The following table gives the length of the longest day, excluding the time of twilight, and of the shortest night, in the different latitudes, with the difference of duration in hours and minutes, thus exhibiting more clearly the above law. Latitude. Longest Day. Shortest Night. Difference. Latitude. Longest Day. Shortest Night. Difference. Equator 12.0 hours. 12.0 hours. 00.0 hours. 55° 17.3 hours. 6.7 hours. 10 6 hours. 10° 12.7 " 11.3 " 1.4 " 60° 18.7 " 5.3 ■ 13.4 " 20° 13 3 " 10.7 " 2.6 " Polar Circles 24.0 " 0.0 " 24.0 " Tropica 13.5 " 10.5 " 3.0 " 67J° 1 month. 0.0 " 30° 14.0 " 10.0 " 4.0 " 69J° 2 months. 0.0 " 36° 14.5 " 9.5 " 5.0 " 73.3° 3 0.0 " 40° 15.0 " 9.0 " 6.0 « 78.3° 4 " 0.0 " 45° 15.6 " 8.4 " 7.2 " 84° 5 " 0.0 " 60" 16.3 " 7.7 " 8.6 " North Pole 6 " 0.0 " Result of Varying Inequality. In the tropical regions, where the days and nights vary little in length, the temperature is nearly uni- form throughout the year ; while the increasing inequality of day and night towards the Poles, causes an increasing difference between the summer and the winter temperature. Again, the length of the day, in the summer of high latitudes, compensates for the diminished intensity of the Sun's influence ; so that the temperature, in the hottest part of the day, may equal, or even exceed, that within the tropics. A summer day in Labrador or St. Petersburg may be as warm as one under the Equator ; but in the former latitudes there are only a few days of extreme heat in the year, while with increasing nearness to the Equator the number of warm days constantly increases. 5. Seasons in Different Latitudes. The high latitudes have short, hot summers, and long, severe winters. The transition sea- sons, spring and autumn, on account of the very rapid change in the length of the days, are short and scarcely perceptible. In the middle latitudes the summer and winter are more nearly equal in length, with less difference in the extreme temperatures ; and the transition seasons are distinctly marked. Farther towards the Equator the summer increases in length, and the winter dimin- ishes, while the tropical latitudes have constant summer. Though in middle and polar latitudes, the intensity of the Sun's rays is greatest at the time of the Summer Solstice, yet the highest degree of heat, resulting from accumulation during the long days, does not occur until a month or more after that period. The lowest temperature, consequent upon successive losses during the short days, usually occurs a month or more after the Winter Solstice. A similar fact is apparent in the daily alternations of temperature. The highest degree of heat is not at noon, when the sun is highest, but about two o'clock ; and the lowest, a little before sunrise, at the end of the period of greatest radiation, instead of at midnight. ANALYSIS OF SECTION IT. I. Distribution of Heat on Globe. a. General law. b. Causes of unequal distribution. c. Operation of each. II. Effects of Earth's Motions. 1. Motions of the Earth. a. Result of inclination of axis. 2 Positions of Vertical Sun. a. Vernal equinox. When occurring. Daily course of Sun. Position of illuminated hemisphere. Length of day and night. Comparative heat of hemispheres. b. Summer solstice. When occurring. Position of illuminated hemisphere. Day and night in northern hemisphere. Day and night in southern hemisphere. Comparative heating of hemispheres. c. Autumnal equinox and winter solstice. S. Variations of Temperature. a. Variation in length of day. Effect of long days and short nights. Effect of long nights and short days. b. Variation in heating power of sun. 4. Varying Inequality op Day and Night. a. Law of variation. b. Result of variation. Summer day of high latitudes. 5. Seasons. In high latitudes. In middle latitudes. In tropical latitudes. Time of highest and of lowest temperature- Daily alternations of temperature. III. PHYSICAL CLIMATE. I. Contrasts in the same Latitude. 1. Contrasts Observed. According to the laws of astro- nomical climate, all places having the same latitude would have the same average annual temperature, and the same periodical changes. Thermometric observations, however, show quite a different state of things. In many cases the differences in average annual tempera- ture, in regions having the same latitude, and the resulting contrasts in the aspects of nature, are extreme ; while the differences in the character of the seasons are no less strongly marked. For example; — on the western shore of the Atlantic Ocean is Labrador, fro/..,r and treeless ; while opposite, in the same latitude, are the British Isles, with their mild climate, fertile soil, and rich verdure. New York, with a long icy winter, is in the same latitude with Naples, surrounded by orange groves and evergreen 72 WINDS. vegetation. Again, San Francisco, with mild winters and cool summers, is on the same parallel with Washington, where a burning sun in summer is succeeded by winters so cold as often to cover the Potomac with a thick coat of ice ; and the fruitful plains of southern China lie side by side with the frozen, and almost unin- habitable, wastes of Thibet. 2. Isothekmal lines. In order to illustrate the actual distri- bution of heat, irrespective of latitude, Humboldt devised a series of lines known as isothermals, 1 or lines of equal average temperature, as ascertained by thermometric observations. Each line connects places having the same mean temperature, either of the year, a season, or any one month. The annual isothermals show the aver- age temperature belonging to the places which they connect ; the monthly and season isothermals show the distribution of heat through- out the year. A correct delineation of the isothermal lines of the globe will, therefore, show most clearly the general deviations from the astro- nomical climates in all parts of the Earth. Where the isothermals bend from the parallels in the direction of the Poles, they indicate an average temperature higher than belongs to the latitude ; where they approach the Equator, they indicate a temperature lower than belongs to the latitude. II. Deviations from Astronomical Climates. 1. The general deviations from the astronomical climate occur chiefly in the middle latitudes, and may be distinguished as primary and secondary. The first are deviations from the mean annual tem- perature belonging to a given latitude, caused mainly by the influ- ence of the general winds and the marine currents. The second are departures from the average summer and ivinter temperatures belong- ing to a given latitude, occasioned chiefly by differences in the ab- sorbing and radiating power of land and water. 2. Local deviations, the result of elevation, occur in all lati- tudes. They consist in a reduction, proportionate to the altitude, of the mean temperature belonging to the latitude ; while the periodical changes remain very nearly the same. On an average, an increase of 330 feet in altitude diminishes the temperature 1° Fahr. ; hence the rate of diminution is about 3° to 1000 feet. In tracing the isothermals, according to Humboldt's example, the local influence of altitude is usually eliminated. This is done, as in the accompanying map, by adding, to the observed temperature of a place, 1° for every 333 feet of its eleva- tion, thus reducing the temperature to that which the place would have if situated at the level of the sea. 1 From the Greek isos, equal, and therme, heat. In large plateaus, however, the effect of altitude seems to be, in some measure, counteracted by the great extent of absorbing and radiating surface uplifted into the atmosphere. In general they are considerably warmer than the isolated summits of mountains of the same altitude. III. Influence of Winds and Marine Currents. 1. Mode of Operation. Winds from the equatorial regions carry into the middle latitudes some portion of the heat of the. tropical regions ; while polar winds bring the low temperature of the lati- tudes whence they come. If, therefore, either the polar or the equa- torial wind prevails throughout the year in a particular region, a large amount of heat is added to, or subtracted from, that which be- longs to the latitude. Marine currents produce a similar effect, and combine with the winds to cause the primary modifications of the astronomical cli- mates. 2. The observation op the isothermals traced upon the map, brings to light several important facts in regard to the distri- bution of temperature on the globe. (1.) The greatest modifications of the astronomical climates occur in the northern hemisphere, the isothermals of the southern hemi- sphere departing far less from the parallels of latitude. (2.) The extreme deviations occur on the coasts of the north Atlantic, western Europe being very much warmer than eastern America in corresponding latitudes. The difference in the temper- ature of the opposite coasts increases towards the pole. The isothermal of 50° Fahr., which passes near New York, on the 40th parallel of latitude, reaches London, on the opposite side of the Atlantic, eleven degrees farther north. The isothermal of 40° Fahr. passes through Canada and Nova Scotia, near the 46th parallel, but lies eighteen degrees farther north on the Euro- pean coast. The isothermal of 30° Fahr. connects central Labrador with North Cape in Europe, the two places differing in latitude by twenty-one degrees. Similar deviations take place in the north Pacific, but the differ- ences of temperature on the opposite coasts are only about one half as great as on the Atlantic coasts. In the northern hemisphere, the winds and marine currents from the equatorial regions, are directed towards the northeast, thus raising the temperature of the western coasts of the continents ; while the polar winds and currents strike the eastern coasts, lowering their temperature. The return-trades of the Atlantic, (see page 79, Top. II., 4,) moving northeast- ward over the warm surface of the Gulf Stream, absorb a portion of its heat, which QUESTIONS ON THE MAP OF TEMPERATURE. Explain the coloring of the map. (See margins, pages 74, 75.) Explain the lines of red and blue. Explain the figures near the isothermal lines, and those accompanying the names of places. Where are the regions of greatest heat ? What is the average temperature of these regiorts ? Near what cities in Asia, Africa, and North America does the isothermal of 70° pass? Where does this line have its nearest approach to the equator? What is indicated by this position of the line? (See text above.) How do you account for the comparatively low temperature of the eastern coast of Asia V (See Topic III., 1, below, and Map of Winds, pages 80, 81.) Where is the isothermal of 70" farthest from the equator? What places in Australia, Africa, and South America on the southern isothermal of 70°. Where does this line approach nearest to the equator? How do you account for the comparatively low temperature on the Pacific shores of South America? (See Map of Marine Currents, page 66.) Where does the southern isothermal of 70° depart farthest from the equator? How is tb ; - departure to be explained? (See page 67, IV.) Trace ,ne northern isothermal of 30° across Asia, Europe, and North America. iiow does its position in the interior of Asia, Europe, and North America compare with its position on the Atlantic and Pacific coasts? How do you explain this approach to the equator? (See Topic HI., 1, above, and Map of Winds.) How does the position of the isothermal of 30° compare on opposite sides of the Atlantic? Explain this northward deviation on the eastern coast. (See Topic III., (2), above.) How does the deviation of the isothermals between 70° and 30° vary from south to north? What important places in Asia, Europe, and North America lie on or near the isothermal of HP? Of 50°? Of 40°? Where are the regions of greatest cold found ? Wiiat isothermal forms the southern boundary of these regions? In which continent is this frigid region most extensive ? How do the isothermals of the southern hemisphere compare with the northern, in the amount of their deviation from the parallels? Near what parallel is the equatorial limit of drifting ice in the southern hemisphere? Where does the Antarctic ice advance nearest to the equator? Where, in the open seas, is the southern ice limit farthest from the equator? How far southward does the Arctic ice drift on the western shores of the Atlantic? How far on the eastern shores ? How do the temperatures of the ocean compare with those of the continents in summer ? (See small map of summer isothermals.) Why is this? (See page 73, Topic IV , 1.) How do the oceanic and continental temperatures compare in winter? Why? Where and what is the highest average summer temperature of the New World? Of the Old World? How do these averages compare? Why is the summer of northern Africa and Arabia so much warmer than the corresponding regions of the New World? (See page 73, Topic IV., 2.) PHYSICAL CLIMATE. 73 they spread, with their own, over western Europe ; but the return-trades of the Pacific derive little or no additional heat from the Japanese current, which, owing to the breadth of the basin it has to traverse, (see page 65, Topic II, 2,) becomes cool before reaching the American shores. Thus the western coast of North America has its temperature augmented by the equatorial winds alone, while western Europe has the heating influence of the winds and the Gulf Stream combined ; hence the higher temperature of the latter. In the southern hemisphere, branches of the equatorial current sweep along the eastern coasts, while the polar currents strike the western ; the former, therefore, are warmer, and the latter cooler, than the latitude would indicate. (3.) In both of the great land-masses of the northern hemisphere — Asia- Europe and North America — the western coasts are warmer than the eastern, while in the southern hemisphere, where the influ- ence of the marine currents from the Antarctic predominates, the eastern coasts are the warmer. (4.) Zones of physical climate are hounded by the isothermals, while the astronomical zones are limited by the tropics and the polar circles. The true torrid zone may be regarded as terminating, on each side of the equator, at the isothermal of 70° Fahr., beyond which the characteristic plants and animals of tropical regions disap- pear. The temperate zones lie between the isothermals of 70° and 30° Fahr. ; and the frigid, extend from the latter to the poles. Thus defined, the torrid zone is broadest in Africa, the temperate in Europe, the frigid in Asia. Hence it appears that, on an aver- age, Africa, the largest land mass within the tropics, is the hottest of the continents ; Europe, the smallest of the northern continents, is the warmest in the temperate zone ; while Asia, the largest of all, is the coldest. The two Americas, both in regard to size and tem- perature, occupy an intermediate grade. On the whole, therefore, we may conclude that, in the torrid zone, the greater the extent of the land the higher is its temperature, while in the temperate zone the reverse is true. IV. Influence of Continents and Oceans. 1. Absorption and Radiation. Water has a great capacity for absorbing heat, and but feeble conducting power ; hence the sea grows warm slowly under the rays of the sun and never attains a high temperature. It also radiates heat slowly, and as fast as the surface particles become cool, they sink and are replaced by warmer ones from beneath ; hence the cooling process is as gradual as the heating, and neither produces extremes of temperature. The land absorbs the solar heat rapidly, and the surface soon at- tains a high temperature. Especially is this the case where the soil is imperfectly covered with vegetation, as in treeless plains or des- erts. But when the sun is withdrawn heat radiates with rapidity, and a comparatively low temperature is soon reached. 2. Result. This inequality in the capacity of land and water for absorbing and radiating heat, gives rise to the secondary modifica- tions of the astronomical climates, affecting more especially the amount of heat in the various seasons. In summer, the land is warmer than the sea in the same latitude ; in winter, colder. Along the coasts the mingling of the air from the ocean with that over the land, moderates both the heat of summer and the cold of winter ; hence the coasts have more equable season temperatures than the interior. The. following table exhibits the rapid increase in the difference between the summer and the winter temperature, as the equalizing influence of the sea is lost by distance. It gives the average temperature of the coldest, and of the warmest month of the year, in places situated in the same latitudes but at different dis- tances from the sea. Names of Places. [.at. 62° Jan. Fahr. July. F'hr. Diff. Names of Places. Lat. Jan. Fahr. July. F'hr. 62.4 Diff. Faroe Islands, 39.0 61.7 22.7 Eastport, Maine, 45° 22.5 399 Bergen, Norway, 60° 34.9 60.3 25.4 Ft. Snelling, Minnesota, 45° 13.1 73.4 60.3 St. Petersburg, Russia, 60° 15.6 62.6 47.0 Bermuda, Atlantic, 32° 32.6 84.2 21.6 Yakutsk, Siberia, 62° -43.8 62.2 106.0 Natchez, Mississippi, 32° 62.2 81.3 29.1 Penzance, England, 50° 42.6 62.0 19.4 Madeira, Africa, 32* 636 73.8 10.8 Barnaul, Siberia, 63 s - 4.7 67.1 71.8 Cairo, Egypt, 30° 66.3 86.6 80.3 The extreme temperatures in summer and winter differ to a still greater degree. The highest temperature ever observed at the Faroe islands is only 65.3° Fahr, and the lowest is rarely below the freezing point. In St. Petersburg, 2° farther south, extremes of 92°, and — 40° Fahr. have been recorded. Nearer the tropics, though the difference between the seasons is less, the influence of the continents and the oceans is still apparent. The extremes of temperature in Madeira show a difference of only 20° to 27°, while in Egypt the difference is 56° Fahr. 3. Continental and Oceanic Climates. In general the climate of the oceans is characterized by uniformity, the difference between the summer and the winter temperature being comparatively slight. The continental climate, on the contrary, is characterized by sudden changes, and extremes, the difference between the summer and the winter temperature, in middle and high latitudes, being excessive. This difference in land and sea climates is sufficient to modify the average tem- perature of the entire globe. In consequence of the great preponderance of land in the middle latitudes of the northern hemisphere, and of water in the southern, the former has a hot summer, and the latter, at the same period, a mild winter. The two combined give, according to Prof. Dove, an average temperature of 62.4° Fahr. for the entire globe, in July, or during the northern summer. In like manner the winter of the northern hemisphere is colder because of the preponderance of land ; while the summer of the southern is less warm because of the excess of water. Hence in January, or during the southern summer, the average tempera- ture of the earth is but 54.3° Fahr. ; that is, 8.1° lower than in July. ANALYSIS OF SECTION III. I. Contrasts In the Same Latitude. 1. Contrasts Observed. a. Qeneral statement. b. Examples. 2. Isothermal Lines. a. Definition and use. b. Annual isothermals. c. Monthly and season isothermals. II. Deviations from Astronomical Climates. 1. General Deviations. a. Where occurring. b. How classed. c. Character and cause. 2. Local Deviations. a. How occasioned. b. Where occurring. c. In what consisting. d. Rate of diminution. e. How treated in tracing isothermals. f. Temperature of plateaus. III. Influence of Winds and Marine Currents. 1. Mode op Operation. ! Equatorial. Polar. Result of predominance of either, b. Marine currents. 2. Effects. Greatest modifications where. b. Extreme deviation where. Examples. Deviations on Pacific coast. Explanation. Heating influences in Atlantic. Heating influences in Pacific. Conditions in southern hemisphere. c. Coasts of land masses. d. Average temperature of oceans. e. Zones of physical climate. Limits. Extent in the several continents. Temperature of the continents compared. Effect of greater area of land. IV. Influence of land and Water Surface. 1. Absorption and Radiation of Heat. a. Water how affected. b. Land how affected. 2. Results. a. General character of seasons of continents. b. Modifying influence on coasts. c. Table. d. Comparison of extremes of temperature. 8. Continental and Oceanic Climates. a. Characteristic of oceanic climates. b. Characteristic of continental climates. c. Effects on average temperature of globe. *" "'1 Torrid Zone ; mean, temper-a - lure 70* degree.*- of ' I&Jirenheit and above • Temperate Zones,, tempera,, tttre between, 10 * an,/ SO * degrees- . ft-igld Zones temper-ature below 30' degrees- of' Rthrert- heit'. Hf./iort.s- cf greate.s-t heat Kegion-f of greatest cold The arrow .vhow the direr - tiorb? id* tht marine eurrenzt . Counter- Currents- J20 and the C< ANINPAL ISO 33: T/te figures' near the line*- in the main m thos'e hmv> t/te names- of p/aees- ttn.f net .vttsnmrr trmpwitttrrs' /•'■/'/■>:>•'■ nf**t fn rft> n t\T. &■, Stern.. JSngr.* 76 THE WINDS. IV. — THE WINDS. I. Equilibrium of the Atmosphere. 1, Conditions of Equilibrium. The atmosphere, under the influence of gravity, tends always so to adjust itself as to be in a state of equilibrium, the chief condition of which is a uniform density at any given altitude, the density diminishing upward with the de- creasing pressure (See page 69, Topic IV.) But the continuance of this equilibrium requires uniformity of temperature, as well as of pressure, in all parts of the same stratum of air. 2. Disturbance. If any given stratum, whether in the lower or the upper air, is unequally heated in different parts, the equilibrium is destroyed. The warmer portion expands and becomes lighter ; and, being pressed upon by the adjacent colder and heavier air, it rises, and its place is occupied by the latter. This process results in an ascending current, from the region of greatest heat, and horizontal currents flowing from all directions to- wards that region. This is exemplified in a heated stove, where the warm, light air, ascending through the pipe, is re- placed by a steady horizontal cur- rent from the surrounding cooler atmosphere. The ascending air, having reached a stratum of equal density with itself, ceases to move upward ; but, if still pressed upon by a current from beneath, it is diffused horizontally in all directions. At length, gradually sinking, it may help to feed the hori- zontal current flowing towards the region of greatest heat, thus completing a circuit which will be repeated as long as the inequality of tempera- ture continues. NORTH POLE EQUATOR It is evident that, if the in- equality of temperature be constant, the resulting circulation will be constant also ; but if the overheating of a given region be only temporary, the motion will cease as soon as the lighter air has all taken its position above the heavier, and the equilibrium is restored throughout the strata to which the disturbance extended. II. General Circulation of the Atmosphere. 1. Winds are movements of the atmosphere caused by a disturb- ance of the equilibrium of its particles, the tendency of the motion being to restore that equilibrium. The disturbances are mainly oc- casioned by differences in temperature, and in the amount of vapor held in suspension by the air. Winds may be grouped in three classes, namely : constant, peri- odical, and variable winds. The first class embraces the trade winds of tropical latitudes. The second includes the diurnal land and sea breezes, and the monsoons or season winds, occurring chiefly in trop- ical regions. The variable winds are more temporary and local, and characterize especially the temperate and high latitudes. SOUTH POLE WO. 32. NORMAL CIRCULATION OF THE ATMOSPHERE. Winds are named from the points of compass whence they come. 2. General Atmospheric Currents. In the vicinity of the equator, where the average annual temperature is highest, — reach- ing 82° Fahr. and upward, — the atmosphere is at its minimum density ; and the density gradually increases, with the diminishing temperature, front this region to the polar latitudes. Set in motion by the ascending movement of the lighter equato- rial atmosphere, the cooler and heavier air, all around the globe, flows towards this zone of maximum temperature. There, becom- ing, in its turn, rarefied by the intense heat, it ascends and finally returns, as an upper current, towards the poles. Cooled by its expansion in ascending and its advance into colder latitudes, and contracted laterally in its progress towards the poles, this upper return current gradually descends, reaching the surface of the Earth somewhat beyond the tropics. Thence a part returns towards the equator, the remainder con- tinuing towards the poles, partly in the upper air, and partly as a surface current. The latter is more or less in contact with, and opposed by, the current setting from the poles towards the zone of greatest heat. Hence from the permanent inequality in the distribution of heat in the tropical and polar regions, there results, in each hemisphere, a constant circulation of the atmosphere equator consisting of (1.) an ascend- ing current, in the zone of highest average temperature ; (2.) a polar current flowing upon the surface, from each pole towards the equator ; and (3.) a return current flowing from the equator to- wards each pole, partly in the upper air and partly on the surface, and supplying the constant drain of the polar current. The above diagram is designed to illustrate this normal circulation of the winds. The arrows parting from the circumference of the circle, on each side of the equator, represent the ascending current in the region of greatest heat. This region is designated, for reasons given below, the equatorial belt of calms. The polar current, which replaces the ascending air, is represented by the arrows pointing from the poles ; while those pointing towards the poles represent the return currents. The arrows within the circumference show the direction of the prevailing winds in the different zones, the figures indicating latitudes. Within the tropics the winds are directed westward and towards the equator. Beyond the tropics winds blow both towards and from the equator ; while near the poles the polar winds predominate. Belts of calms occur where the return-trade descends from the upper air. 3. Direction of Polar and Return Currents. Were the Earth at rest, and its surface uniform, these currents would doubt- less follow the meridians to and from the equator. But the rotary motion 1 common to both the terrestrial globe and its atmosphere, causes the polar currents, as they near the equator, to turn more and more towards the west ; hence they become northeasterly winds in the northern hemisphere and southeasterly winds in the southern. l See explanation of the direction of marine currents, page 65. THE WINDS. 77 The return currents, on the contrary, advancing from equatorial to polar latitudes, are deflected towards the east, becoming south- westerly winds in the northern hemisphere and northwesterly winds in the southern hemisphere. Again, the continental reliefs, and the relative positions of the land-masses and oceans, cause many local modifications in the direc- tion of these general currents. 4. Wind Zones. The general law of atmospheric circulation just noticed, gives rise to three distinctly marked wind zones, on each side of the Equator; namely: — (1.) the zone of constant winds, extending to latitude 25° or 30° ; (2.) the zone of variable winds, with alternate polar and equatorial currents dominating, ex- tending thence to latitude 60°, or near the polar circles ; and (3.) the zone of prevailing, though not constant, polar winds: (See Fig. 32, and the Map of the Winds, page 80, 81.) III. Trade Winds and Calms. 1. Trade Winds. The constant, gentle, northeasterly and south- easterly winds, occupying a belt of 25° or 30° of latitude on each side of the Equator, are designated the trade winds. It was this constant and gentle wind which carried the navigator Magellan across the Pacific, and gave this ocean the name it has since retained ; and which subsequently bore the Spanish treasure- ships, from the Mexican and Peruvian ports, to their destination in the Philippine Islands. The same unchanging westerly wind, ob- served in the Atlantic by the companions of Columbus, filled their minds with the fear that they could never accomplish a homeward voyage. The trades blow with entire regularity only upon the open sea, the course and character of the winds elsewhere being modified by the continental reliefs or other local influences. The continents, on account of the elevation of their surface, partially intercept the general atmospheric currents, and, being also more heated than the adjacent oceans, they modify, or even overcome, the trades in their immediate vicinity. Owing to this disturbing influence, the trades, both in the Atlan- tic and the Pacific, begin to blow regularly only at a considerable distance west of the continents. Thence they sweep, without inter- ruption, over the ocean basins, at a nearly uniform rate of from 15 to 18 miles per hour. In the northern half of the Indian Ocean the trades are suspended entirely during the northern summer, but resume their sway in winter. (See Monsoons, page 78.) 2. Equatorial Calms. The boundary between the northeast and southeast trades, is formed by the zone of the ascending cur- rent, frt "n 4° to 6° in breadth, adjacent to the thermal Equator. The mean position of this zone is, in the Atlantic, between 3° and 9° north latitude ; in the Pacific, between 4° and 8° north. In the continents it is usually found between 3° south, and 4° north lati- tude. Here the ascending current overpowers the horizontal ; and, as the upward motion is not perceptible to the observer, the atmosphere seems to be in a state of rest ; hence this belt is designated the Zone of Equatorial Calms. (See Fig. 32, and Map of the Winds, page 80.) The apparent equilibrium of the air, however, is very easily dis- turbed. Descending currents, sudden gusts of wind from any direc- tion, whirlwinds, and hurricanes, are of frequent occurrence. Hence this belt is sometimes called the Equatorial zone of variable winds. In each ocean this zone is considerably broader at the east than at the west. 3. Tropical Calms. At the tropical limits of the trades, also (see Map of the Winds'), there are zones of calms, designated the Calms of Cancer and the Calms of Capricorn. These, however, are less defined than the equatorial calms. They occupy a belt of a few degrees, in which the return current of the upper air, called the re- turn-trade, first appears at the surface of the Earth ; and where it divides, a part continuing towards the poles, and the remainder reen- tering the trade zone and returning to the Equatorial calm belt. 4. Oscillation op Trades and Calms. The position of the trades, and of the intervening and adjacent calms, changes with the seasons, all advancing northward, and retiring southward, with the apparent motion of the Sun. The extreme northward position of the trades is reached in August and September, and the southward in March and April. (See diagram, Limits of Trades, in Map of Winds.) In the oceans, the belt of Equatorial calms is north of the Equator in all seasons ; and the Calms of Cancer are farther from the Equa- tor than the Calms of Capricorn. These positions indicate a higher average temperature in the northern hemisphere than in the south- ern. 5. General Land Winds. The trades, as has been observed, lose their constancy of character under the influence of the continen- tal reliefs ; still prevailing easterly winds occur, so far as known, on the great plains within the zone of trades. They are felt in a part of the Sahara ; and in the basin of the Amazon they sweep, without . interruption, across almost the entire breadth of the continent. Though gentle, in the east, like the trades of the ocean, their force increases considerably near their western limit. Humboldt found at the base of the Andes, the east wind so strong that one could scarcely stand against it ; and it is said that, on account of the constant " east wind, the voyage up the Amazon, against the powerful current, is made quite as rapidly as that down the stream. ANALYSIS OP SECTION IV. I. Equilibrium of Atmosphere. 1. conditioks of equilibrium of alr. 2. Disturbance op Equilibrium. a. Effect of inequality of temperatuw. b. Resulting currents. . c. Course of ascending air. d. Effect if inequality be permanent. e. Effect if inequality be temporary. II. General Circulation of Atmosphere. 1. Winds. a. Definition. b. Classes. 2. General Currents. a. Zone of minimum density. b. Movement of air towards this zone. c. Movement of air from this zone. d. General currents resulting. e. Explanation of Fig. 32. 3. Directions of General Currents. a. Probable direction in absence of disturbing causes, b Effects of the rotation of the Earth. c. Direction of polar currents. d. Direction of return-currents. e. Other causes of modification. 4. Wind Zones. a. Number. b. Names and position. III. Zone of Trades and Calms. 1. Trade Winds. a. Definition. By whom first observed. b. Where occurring regularly. c. Place of beginning on oceans. d. Velocity. e. Trades of the Indian Ocean. 78 WINDS. 2. Equatorial Calms. a. Position in regard to trades. b. Breadth of calm belt. c. Cause of calm belt. d. Disturbance of equilibrium. 8. Tropical Calms. a. Position in regard to trades. b. Breadth and character of region. 4. Oscillations of Trades and Calms. a. Change of position caused how. b. When farthest northward. c. When farthest southward. d. Position of calm belt in regard to equator. 5. General Land Winds. a. Character of trades on land. b. Winds of Sahara, and Amazon basin. V. — WINDS. ( Continued.') I. Periodical Winds. 1. Monsoons. The name monsoon, from the Arabic word mous- sim, season, is applied to the periodical winds which replace the trades, in the northern half of the Indian Ocean, and in the adjacent portions of the Pacific. During the northern summer the wind blows from the southwest, during the opposite season from the north- east. The monsoons are due to the unequal heating, in different seasons, of the great land-masses which inclose the Indian Ocean. The extent of land within the tropics, and the position of vast' masses on opposite sides of the Equator, is such as to intensify to the greatest degree their disturbing influence upon the atmospheric cur- rents. Only in the interior of the Indian Ocean, south of the Equa- tor, does the trade wind blow regularly throughout the year. During the northern summer, southern Asia, under the rays of the vertical Sun, becomes intensely heated ; and the cooler and denser air of the adjacent ocean, and of southern Africa, flows towards it, producing the southwest monsoon, which lasts from April or May to September or October. The time of its beginning and its close varies in different latitudes, according to the time at which the sun is vertical in each. During the southern summer, southern Africa being under the vertical Sun and intensely heated, the cooler air of the surrounding seas, and of southern Asia, flows towards it. This produces the northeast monsoon, which lasts from October or November to April. This monsoon is, in fact, only the regular northeast trade wind somewhat intensified. A similar exchange takes place between Asia and Australia, but it is less marked, owing, perhaps, to the great islands lying between these continents. The period of transition of the monsoons, in spring and autumn, is marked by sudden and violent gales, and terrific thunder storms. Destructive hurricanes, also, are of frequent occurrence. Narrow monsoon belts occur in the Atlantic along the coast of Af- rica, and of Brazil ; also on the Pacific coasts of North and South America (See Map of the Winds) ; but the phenomena they exhibit are of a much less striking character. On the African coast, in gen- ' eral, the winds blow from sea to land in summer, from land to sea in • winter ; on the Brazilian, the wind is from the northeast in summer, while in winter the southeast trade resumes its sway. The mon- soons of the Pacific coast of America blow from the northwest and north during the southern summer ; from the southwest and south during the northern. 2. Diurnal Land and Sea Breezes occur along all coasts, whether in the zone of trades or of variable winds ; but the phe- nomenon is more strongly marked in the tropical regions, and in the summer of the temperate latitudes, because of the greater difference in the temperature of land and sea by day and by night. During the hottest part of the day the air over the land frequently reaches a temperature of 100° Fahr., and even more, while that over the sea rarely rises above 80°. During the night the land radiates its heat with such rapidity that, towards morning, its atmosphere may be from 10° to 15° colder than that of the sea. Soon after sunrise, the land being warmer than the sea, a sea breeze sets in, which increases in force until about three o'clock, when the difference of temperature is greatest. It then gradually diminishes until about sunset, when, the temperature of the land and sea having become equal, the atmosphere is at rest, the calm con- tinuing for an hour or more. Soon the land becomes cooler than the sea, and a gentle breeze from the former sets in. It increases in force as the night advances, becoming strongest a little before morning, when the temperature of the land is lowest ; after which it rapidly dies away, ?jid is suc- ceeded by a calm, to be soon replaced by the sea breeze. Similar diurnal breezes occur on the shores of all great lakes, and also at the foot of high mountains. The inclined surface of the mountain slopes has, while under the rays of the Sun, a higher temperature than the atmosphere, at corre- sponding altitudes, above the lowlands. Hence it becomes the natural channel for the ascending currents of warm air from the adjacent plains; and, consequently, a breeze ascends the valleys, towards the mountains, during the hottest part of the day. 3. Local Land Winds, of a peculiar character, occur more or less periodically, in different parts of the warm zones. The Sirocco of the Mediterranean shores, the Khamsin of Egypt, the Samiel or Simoom of Syria and Arabia, and the Harrnattan of Guinea, are local names for a violent, hot and dry wind from the adjacent deserts. In Guinea the desert wind blows from the northeast and east ; on QUESTIONS ON THE MAP OF THE WINDS. (See Map, pages 80, 81.) Explain the coloring of this map. (See bottom of map.) How is the direction of the winds indicated? (See explanation of arrows.) How are periodical winds represented ? In which ocean does the belt of trades extend farthest from the equator? On which shore of the Atlantic and the Pacific is the northeast trade belt broadest? Where is the southeast trade belt broadest? In what part of the oceans are the equatorial calm belts most extensive ? What name is given to the region of equatorial calms in the Atlantic? What (see diagram in left hand margin) is the summer limit of the northeast trades in the Atlantic ? The winter limit ? What are the summer and winter limits of the southeast trades? In what part of the Indian Ocean do the trades blow with regularity? Near what islands are the northeastern and southeastern limits of the Pacific monsoon region ? What are the directions of the monsoons in the seas adjacent to Australia? What are their directions in the Asiatic and African seas? In what part of the year does each current prevail ? Why? (See Monsoons, above.) What are the directions of the winds in the Brazilian monsoon belt? What winds prevail in the southern part of South America? What is the direction of the winds on the west coast of South America? When does each direction prevail ? What is the direction of the wind in the portion of the Pacific near the Isthmus of Panama? What is the usual direction of the winds on the Atlantic shores of Africa? What are the prevailing directions of the wind between the parallels of 30° and 60° ? How do these winds differ in character ? What is the direction of the polar winds in eastern North America and eastern Asia? In western Asia, Europe, and northwestern North America ? What causes this difference in direction? (See page 79, Topic II., 3.) What is the direction of the prevailing winds in the Arctic seas ? What is the position of the hurricane region of the New World ? Where are the hurricane regions of the Old World ? Where do the typhoons of the Asiatic seas originate ? What is their course ? Where do the Mauritius hurricanes start, and in what direction do they move ? What is the place of origin of the West India hurricanes ? What is their course ? What (see diagram in the right hand margin) are the intervening directions in a change of the wind, in the northern hemisphere, from northeast to southwest? What is the effect of this change on the thermometer and the barometer ? What is the order and effect of a change from southwest to northeast? What is the order and effect of a change, in the southern hemisphere, from a northwest to a southeast wind ? From a southeast to a northwest wind? WINDS. 79 the Mediterranean shores, from the southeast, south, and southwest ; in Syria, from the south and southeast ; and in Arabia, from the in- terior towards all points of the compass. The Sirocco, advancing across the Mediterranean, is felt in Sicily and Italy ; and is known in southern Spain as the Solano or Levanter. The name, Khamsin, meaning fifty, indicates the length of the season, — about fifty days, including the month of May and a part of April and June, — during which this wind may blow. Simoom means hot as well as poisonous. These desert winds are not continuous, but occur at intervals during the two or three months of greatest heat, lasting from one to fifteen days at a time. They usually blow in successive blasts, which differ in temperature, sometimes by more than 20° Fahr., and alternate with great rapidity. Dry, laden with the impalpable dust of the desert, and subject to such rapid alternations of temperature, they are exceedingly oppressive and exhausting to the human system, and not infrequently cause death by prostration. The Etesian Winds are northeasterly and easterly winds which blow, during the latter part of summer, over Greece, the Archipel- ago, and the Mediterranean, towards the continent of Africa. They commence near the middle of July, when the heat is greatest, and continue until September, blowing only in the day-time. The Northers of Texas are violent, cold, dry winds, which descend from the upper air, and occur chiefly in winter. They sweep over Texas, Lousiana, and the table-lands of Mexico, sometimes carrying their cold blasts even to the Antilles, where they present a striking contrast to the gentle and genial trade winds. II. Zone of \ariable, or Alternating Equatorial and Polar, Winds. 1. Prevailing Currents. Within this zone, which extends from the vicinity of the tropics to the polar circles, the winds are not periodical, but blow during the year from every quarter of the horizon, without apparent order. Two general currents, however, the polar winds and the return-trades, predominate to such an ex- tent that they may be considered the prevailing, or normal currents, of these latitudes. Differing in temperature, and flowing side by side, or one above the other, but in opposite directions, they constantly encounter each other and struggle for the mastery. Their conflicts produce the fre- quent storms which characterize these zones ; and the displacement of the one by the other always involves a marked change of weather. The return- trade brings heat, and clouds or rain ; but the polar winds bring cold, dry weather, a bracing air, and a clear sunny sky. The other winds blowing in these zones are either the transition winds, which occur during the displacement of one current by the other ; or are the result of the deflection of these normal currents, by mountain ranges or other peculiarities of the continental reliefs. 2. Succession op Winds. The return-trades and the polar winds usually displace each other in an order indicated by Prof. Dove, and called by him the law of the rotation of the winds. This order of succession must not be confounded with the veering of the wind from point to point in a revolving storm, which has a different origin. (See Revolving Storms, page 82.) In the northern hemisphere, generally, when the return-trade is dis- placed by the polar current, the wind blows successively from the west, the northwest, and the north, and settles in the northeast. In eastern North America, however, it settles in the northwest. (See Topic 3, below.) W,hen the polar wind is displaced by the return- trade, the successive changes are to the east, southeast, south, and finally to the southwest. (See diagram in Map of Winds.) In the southern hemisphere the order of transition is reversed, as is also the character of the currents. The northwest wind is the warm, moist return-trade ; while the southeast is the cold, dry polar wind. The transition is from the northwest by the west, southwest and south to the southeast ; and from the southeast by the east, northeast, and north, to the northwest. The effect of the transition of the winds is manifest, both in the density and the temperature of the air. When the return-trade blows, the air being warm, moist and light, the thermometer is high and the barometer low. When it is displaced by the polar current, the thermometer falls and the barometer rises. 3. The STARTING points OP the POLAR winds are in the centres of lowest temperature, on the Arctic shores of Asia and North America. (See Map of Temperature, pages 74, 75.) The expansion of these two continents at the north is such that a great extent of land lies in the immediate vicinity of the Arctic circle. This large area of Arctic land, combined with the long nights of a winter lasting nearly or quite half the year, converts the northern regions of Asia and North America into vast refrigerators, where the atmosphere, during the northern winter, is reduced to its minimum temperature and its greatest density. From here the cold, heavy air presses towards the oceans at the east and the west, and the more southerly warm lands. Hence East- ern Asia and North America, especially in high latitudes, receive their coldest winds from the northwest and north ; while Western Asia and Europe receive them from the northeast. As the cold air advances towards the equator, and falls increas- ingly under the influence of the Earth's rotary motion, it tends more and more to become everywhere a northeast wind. But in North America the great barrier of the Rocky Mountains, which is high- est in the middle latitudes, turns it out of its southwesterly course, and deflects it towards the southeast ; hence throughout our Atlantic seaboard, even to the sub-tropical regions, the cold, dry winds are from the northwest. This exceptional direction of the polar winds in eastern North America, is shown on the Map of the Winds. As the sun advances northward in the spring, his genial beams im- part a constantly growing warmth to the Arctic lands ; and the rap- idly increasing length of the days accelerates the change from a low to a high temperature. Thus the fountains of the cold winds are gradually dried up ; the pressure of the northern air is diminished ; and, during the summer, the warm gentle return-trades have almost undisputed sway nearly to the Arctic circle. 4. Range and Effects. The polar currents, having their ori- gin in the Arctic lands, take their course, in general, over the surface of the continents, while the return-trades prevail upon the oceans. This fact accounts for the low average temperature of the interior of the continents, in middle latitudes, in comparison with that of the oceans, as indicated by the isothermal lines. In the middle and northern portions of the zone of variable winds, the return-trades are the dominant winds during the summer, the polar winds during the winter. The period of transition, occupying several weeks following the equinoxes, is one of almost incessant conflict ; hence the severe storms, and frequent changes of wind and weather which characterize those seasons of the year. The final establishment of the return-trade, with its genial temper- ature and fertilizing showers, ushers in the summer ; its final retreat before the polar winds, toward the close of the year, opens the winter. The continuance of the return-trade beyond its average time of dis- placement produces a " late autumn," and that of the polar winds, a " late spring." JP.Sandoz <* XKr-u-mholz del . -Entered acoonimq to Act of CoHgp**** in-lheYea-r 1872 hy Scribncr, A itu.de 20 from Grt*?iiwiii O Spitsbergen PREVAILING N OR TH EASTERLY a. I list oil ^rSoFaru DArch.BLag'el ^ •O^v ^A r c/t^i Algiers /j Bokbar-iv ©Teheran ^C Sain i el ^^fclspak* 11 - t \r Laboi 0>" of "hot and) dry Wi6ds*\^ARA B I A Oljiotsk ' . A> V i La fPetropaulovsii r \ ,•/" P R E V A I LI NC ^>^W EST E R L Y WINDS \ ! W i n d s ^1 JAPAN ISi^ CHIN. 4£l„_ja ; . c K ■ 6 R T"H " E A" S"1f" • f O >« INO R T H E A : m~^~rw — r~ — DS Choline Jd* I '.; -'* . **■ '//' // f ■^S <0 tkCTK N Ss!&, /y> .•■■■• ... • •• Ons*,*** V\J\\ si.-** 3 v * 'A' '■■• """•<'■. ft .^->^ ^1 :.TJE alms X D S ^ t T r o p i ; c \c f L I N C M \\l *f Feejee • a / Svdney Tasmania \J ?New r Zealand \ STORMS ding to &U8. Kxplanalion of Arrows . The arrows show the direction of the Wrruls. The head marks the pouU ot' t/te compass towarxis which tJte Wind mrsves, the opposite end thszt from which it blows . Thtt.f "-_ mdebate* a fiartk Hr-.vr Wind hlouina towards South East . ^y indicates a South Wi'st Wind hlowiny towards Nor-tti J$a*t v North Lalitadc South I. attitude NEW ZEALAND n ■0 Xc Co. mthe OffjceofthjeZibra.ria.nof Con ores*. Wo* hi no ten .C.T.. W~.Sc A.K.Jbhn$lon .Edinburgh and London 100 VEGETABLE LIFE IN DIFFERENT LATITUDES. The vegetation consists of but a few species of plants, and these are mostly of low types, mosses, lichens, sedges, and ferns, being the characteristic forms. Mossy swamps, called tundras, frozen during the greater part of the year, occupy a considerable portion of the lowlands of this zone, in both Europe and Asia. The woody plants, — which include some varieties of willow and birch, azalea and rhododendron — in general trail along the ground, rising but a few inches above it ; while the main stem, sometimes several feet long, is hidden among the mosses. Stunted trees — dwarf willow, alder, birch, and pine — are, however, found near the southern limit of this zone. III. Cold-Temperate Zone. In the Cold-temperate Zone, or Zone of the Conifers, the mean annual temperature is from 30° to 40° Fahr. This zone is characterized especially by vast forests of cone-bearing trees, with evergreen, needle-shaped foliage ; among which the pine, spruce, and fir are the predominant forms. The willow, birch, and alder occur in greater numbers, and are of finer growth, than in the Arctic Zone ; and the ash, the aspen, and the larch are occasionally found. There are, also, extensive tree- less plains which are covered with meadow grasses and wild varieties of several useful plants, including flax, Indian rice, and oats. The indigenous fruits are mainly acid berries, among which are the currant, cranberry, raspberry, and strawberry. The most hardy of the cereals — oats, barley, and rye — and the potato, the turnip, and some other edible roots, can be cultivated with success, but only in the more favored localities. IV. The Temperate Zone. The Temperate Zone, or zone of Deciduous Trees, has a mean annual temperature varying from 40° to 60° Fahr. The forests — which cover vast areas in North America, eastern Europe, and the valleys and slopes of the Altai region and Manchu- ria, in Asia — display not only a large number of species of stately and beautiful trees, but also a rich and varied undergrowth. Among the most numerous trees are the oaks, elms, birches, ma- ples, beeches, walnuts, and chestnuts ; with the ash, larch, linden, alder, and sycamore — all of which lose their fobage in autumn. The undergrowth consists chiefly of the wild apple, yew, holly, hawthorn, wild rose, honeysuckle, clematis, azalea, and rhododen- dron ; varied by the wild grape, and some other climbing plants. The herbaceous vegetation embraces nearly all those families of plants which furnish the staple articles of food among civilized na- tions (see page 111, Topic II. 3) ; together with a great variety of meadow grasses, and the hemp, flax, and tobacco. The most numerous of the other characteristic orders, are the um- belliferous plants, as the parsnip, carrot, and caraway ; the cichora- ceae, as the lettuce and dandelion ; and the cruciferae, including the cabbage, turnip, radish, mustard, etc. The cruciferae, which are almost confined to the northern hemisphere, are so numerous and varied as to give a distinctive character to the herbaceous flora of the temperate zone, especially in Europe. Exceptions to the general abundance of vegetation in the temperate zone are found in the high barren plains and plateaus of western North America ; the steppes of southeastern Europe, and of western Asia ; and the deserts of Gobi and Shamo, in eastern Asia. (See pages 24, II. 3. and 25; also 101.) V. Warm-Temperate Zone. The Warm-temperate Zone, or Zone of Winter Foliage, situ- ated a little north of the Tropic of Cancer, has a mean annual tem- perature varying from 60° to 72° Fahr. Its characteristic vegetation consists of trees and shrubs which re- tain their foliage throughout the year, though their growth is inter- rupted during the winter. The leaves are in general tough, stiff, and glossy ; but lack the delicate tints which adorn the foliage of the deciduous trees in spring and summer, and the more gorgeous hues of autumn. Here are found the live-oak, myrtle, laurel, and oleander, and the box, invaluable in the arts ; with the cotton, the mulberry and the olive ; and tea, rice, and millet. Delicate fruits also abound, in- cluding the fig, orange, lemon, pomegranate, and almond — all char- acteristic of this region — and the choicest varieties of the vine. VI. Tropical Zone. The Tropical Zone, or Zone of Palms and Bananas, has a mean annual temperature varying from 72° to 82° Fahr. The veg- etation embraces an immense variety of species, in general remark- able for luxuriance of growth and great development of foliage. (See illustration, page 97.) The ferns, which in other zones are small herbaceous plants, here assume the proportion of trees, rivaling the palms in the beauty of their crown of foliage ; and the grasses far surpass those of middle latitudes in growth. To the latter class belongs the invaluable sugar-cane, and the gigantic bamboo which attains the height of 60 feet or more, while its hollow stalk furnishes the principal building material used in the East Indian Archipelago. One of the most striking characteristics of the tropical forests is the great variety of trees which are mingled together, without the preponderance of any one family ; while in temperate climes, ex- tensive forests of a single family — as of pine, oak, beech, etc. — are common. Another distinguishing feature is the number of large flowering trees. The plants are perpetually covered with verdure, and many yield a constant succession of fruits and flowers. The food producing plants, indigenous to this zone, include the date, the sago, and the cocoa palm ; the bread fruit and the cow- tree ; the plantain or banana ; rice, and the sweet potato, yam, arum, and manioc. The caoutchouch and gutta-percha, extensively employed in manufactures ; the rosewood, mahogany, and ebony, so valuable in the arts for their rich color and the fine polish they are capable of receiving ; with the cotton, coffee, and a multi- tude of other useful plants, are all natives of the tropical zone. VII. Southern Zones. 1. The Warm Temperate Zone resembles the corresponding zone north of the Equator, with the exception that it has few native food plants. The limited supply of moisture in Australia and South Africa, gives a peculiar meagreness to the general aspect of the veg- etable world in those regions, which is, however, relieved to a certain extent by the brilliancy of the flowers. (Pages 104, 105.) 2. The Temperate and Cold-Temperate Zones, though having a higher average temperature than the corresponding regions of the north, show less luxuriance and variety of vegetation. The former is characterized by forests of beech, and of the arau- caria, which takes the place of the northern pines ; but the latter has only the flora of the Arctic zone. VEGETATION IN THE NORTHERN CONTINENTS. 101 III. — VEGETATION IN THE NORTHERN CONTINENTS. I. Similarity. In the Arctic zone the vegetation is almost identical throughout the three continents, and they show a marked similarity in the cold- temperate zone. Advancing southward an increasing diversity is apparent, until, in the warm and tropical zones, the flora of each continent possesses a distinctive character. II. Xorth America. 1. Temperate and Warm Regions. In the temperate region, this continent is distinguished from Asia and Europe, especially by the greater variety of its forest trees ; and in the warm, by the number of large flowering trees. The most striking of these are the tulip-tree, the magnolias, the catalpas, and the locusts. The arid plateaus of the warm zone are covered with thickets of the cactus, a family of plants peculiar to America; the yucca, a plant of the lily family; the agave or American aloe (century plant) ; and the mesquite, a sort of locust. The distribution of forests, fertile prairies, and sterile plains, in the temperate and warm zones of this continent, is shown in the map, Vegetation of the United Slates, on page 1 20, which gives also the staple articles of culture in the latter zone. 2. The TROPICAL REGION is like South America in the luxuri- ance and variety of its flora, with nearly the same kinds both of trees and of herbaceous plants. (Page 104, II. 2.) III. Asia-Europe. 1. Western Asia and Europe are distinguished by the remark- able similarity of their flora, and the great variety of useful or beautiful plants which are indigenous. The cork-oak, and the box ; the mint, thyme, lavender, and other aromatic herbs ; the gladiolus, iris, narcissus, carnation, and migno- nette, are all indigenous to southern Europe. The oleander, syringa, almond, and fine varieties of the cherry, are natives of Asia Minor ; the peach, melon, cucumber, and hya- cinth, of Persia ; the choicest varieties of the vine and apricot, of Armenia j and the date-palm, fig, olive, mulberry, and damask-rose, of Syria. All of these are now naturalized in southern Europe. 2. The ARID table lands of Iran and Mongolia, produce only thorny bushes, or stunted and almost leafless trees, and a few species of herbaceous plants, which afford sustenance for the herds of the nomadic inhabitants. Thibet, being both dry and cold, has, except in certain favored spots, the flora of the cold-temperate and Arctic zones. Furze and other prickly shrubs, with the gooseberry, currant, hyssop, rhubarb, lucern, and assafoetida, are the most common plants ; but two or three species of wheat, of buckwheat, and of barley, are indigenous in this table-land. 3. China is the home of the camphor laurel and the paper mul- berry ; of the tea plant, which abounds both in that country and in Japan ; of some species of cotton ; and of the sugar-producing sor- ghum. 4. India, Indo-China, and the Indian Archipelago, disjxlay, in the lowlands, all the luxuriance and variety of vegetation which belongs to the tropical zone ; while in the more elevated regions the trees, shrubs, and herbaceous plants of the warm-temperate and tem- perate zones abound. (See page 102, Himalaya Mountains, .) (1.) Characteristics. Along the coasts are thickets of mangroves, and a matted vegetation of forest trees, bamboos, coarse grasses, and creeping and climbing plants. The trees are covered with parasites, or air plants, of almost infinite variety, one of which, the rafflesia, a yard in diameter, is the largest flower known. Palms are especially numerous, and occur in a great variety of spe- cies, some of which bear the largest leaves known. The banyan fig, and kindred species, abound, especially in India. These remarkable plants send down shoots from the branches, which take root and be- come new trunks, so that a single tree often produces a large grove. (2.) Useful Plants. The teak, one of the most valuable of tim- ber trees ; the gutta-percha, camphor, sandal-wood, and ebony ; the true indigo, now naturalized throughout the tropical zone ; and a great variety of trees yielding dyes, spices, gums, and resins, are na- tives of this region. The spices, which are more especially charac- teristic of the islands, include the nutmeg, clove, cinnamon, cassia, ginger, and black pepper, the last being peculiar to the hottest por- tions of the archipelago. No part of the earth surpasses this region in the number of its na- tive fruits and esculent vegetables. Among these are the bread- fruit, orange, mango, mangosteen, banana, cocoa-nut, sweet potato, arum, and yam ; and different varieties of the cucumber, melon, and gourd family. The sago palm is also a native of the Archipelago. 5. Arabia. In the vast deserts of the interior, mimosas, and stunted prickly bushes which appear here and there in the sand, form the only vegetation ; but the date palm abounds on the oases. In the mountains and valleys of the south and east are many varieties of the acacia, from one of which the gum arabic of com- merce is obtained. Several species of trees and shrubs also yield fragrant balsams or resins, the odoriferous plants giving the especial character to the Arabian flora. QUESTIONS ON THE MAP OF VEGETATION. (Pages 98, 99.) Name the several zones of vegetation. In what continent is the tropical zone broadest? What parts of the New World are included in this zone? What parts of the Old World? What plants ar« especially characteristic »f the tropical zone? What are the principal coffee districts of the New World? Of the Old World? In which of these is coffee native ? Where is the principal spice district ? Where is the chief district of rice cultivation? Where is the principal cotton region of the Old World? In what zone are the principal cotton and rice districts of North America? Are these plants native or introduced in this region ? What forme the characteristic vegetation of the warm-temperate zone? What part of the New World it included in the northern warm-temperate zone? What parts of the Old World ? What trees mark this zone in the eastern part of the United States? What plants are charac- teristic of the high western plateaus? Name the principal plants of this zone in Europe : in Africa; in western Asia; in eastern Asia. What plant is especially characteristic of the eastern portion of China? What part of North America is included in the temperate zone ? rn what part of the conti- nent is this zone broadest ? In which continent does it lie farthest north ? What is the characteristic vegetation of the temperate zone? What extensive desert lies in this zone? What is the vegetation of eastern Asia in this zone? Of central and western Asia ? Of Europe ? What trees characterize temperate America east of the Rocky Mountains? What trees grow on the Sierra Nevada and Cascade Mountains? Where are the only barren regions of North America? Where is the principal region of tobacco culture? Where is the cold-temperate zone situated farthest north? What part of North America is included in it? Of Europe? Of Asia? What is the characteristic vegetation of this zone ? What trees form the most extensive forests in this zone in North America? In Europe? In Asia ? What regions are included in the warm-temperate zone of the southern hemisphere? What is the characteristic vegetation of this zone? What lands are included in the south- em temperate zone? What are the characteristics of this zone? What lands are included in the southern cold-temperate zone? What is the characteristic vegetation of this zone? How do these southern zones compare in mean temperature with the northern ? How do they compare in luxuriance and variety of vegetation? In useful plants? )000 Eng.Feet. ANII.K8 HIMALAYA Nevada de Soram.Bolrwa. 15.000 Tt. I.aLJ5"4B'S. IIIimuiii.no I. 24,200 Ft.l.iO-4.0'.S. (himbornro, Ecuador. 21422 Ft.L.l' 2IS. Anli.sana,£cuador. 19,137 Ft.L.O'36'S. Lul.l9*N. Soda. Lichens Alpine Plants. Grasses. Shrubs. He/ana. jallorua. Oak. CineheatA Vvrrgreens\ irith ffrick JirtUTrfa. Mrrth ferns, figs . Hanarjas\ Palms Popocatepetl, 17,784 Fl. 0ri-/.«bu,17,0»4. Ft. Mt.Kverest,N?pa 1 .29.002 FLL2S J)um Huy,Cashmere.2.3,407 Ft. L.MH. njingH.. ','>',. Regions. Alpine Plants. Grasses. WkslfPuie.] Oak. Alder. Pines. Agave liuea live Oak. J.D Magnolia* Lrnwels. Mimosas. Tree firms. Jianaiws. Palms. 'Alpine Plants. Wwdadendnm Ash Juniper. Birch. Oak. P'nQ/J>eodaiu> \ Deezdruous Trees . ^Jhne, fNeozu) Lonu leaved Pine. Oak. Matfaolia. Laurels. Piys. I t~Hananas . K Palms, u'erai . Junglt UK WARM TEMPEHATK »OXK. IV. — VEGETATION AT DIFFERENT ALTITUDES. I. Vertical Zones of Vegetation. In consequence of the diminution of the temperature with in- creasing altitude (see page 72, Topic II., 2), vertical zones of veg- etation may be distinguished, with characteristics no less marked than those of the horizontal zones. The observer, passing from the base to the summit of high mountains, in any latitude, finds variations in the character of the plants similar to, though not iden- tical with, those observed in advancing to higher latitudes. The above diagram is designed to furnish a graphic representation of the verti- cal distribution of vegetation in the different latitudes. The Andes serve as the type for mountains in the tropical zone ; the Himalayas, for those in the warm- temperate ; the Alps, for those in the temperate proper ; and the Scandinavian Alps for the mountains of the cold-temperate zone. II. The Andes and Mexican Mountains. 1. Tropical Region. Below 4,000 feet of altitude, the vege- tation on the slopes of the Andes consists of families of plants belonging to the tropical zone ; and displays the luxuriance of growth, the abundance of foliage, and the immense variety of spe- cies which is especially characteristic of tropical America. In the lower half of this region, the palms and the various species of the banana are the dominant types ; in the upper half, the tree-ferns and the fig family, are the most numerous and characteristic trees. 2. Warm Region. Between 4,000 and 8,000 feet the vegeta- tion is that of the warm-temperate zone of the New World ; and is characterized by its thick, lustrous, evergreen foliage. The laurel, myrtle, evergreen-oak, and magnolia, among trees ; and the agave, yucca, and cactus, among herbaceous plants, give to this region its distinctive character. 3. Temperate Region. From 8,000 to 10,000 feet those fami- lies of trees occur which comnose the deciduous forests of the tem- VERTICAL DISTRIBUTION OF perate zone ; but the character of the species is modified by that uni- formity of temperature throughout the year which distinguishes the tropical zone at every altitude. In this region, and in the upper part of the preceding, grows the cinchona, so highly valued for the quinine and other remedies obtained from it. 4. Cold Region. Above 10,000 feet of altitude we find only the vegetation belonging to the .cold-temperate, arctic, and polar zones. Dwarf trees and shrubs, grasses, and alpine flowering plants, occur in succession ; and are followed by a region where only lich- ens grow upon the naked rock, above which are the fields of perpet- ual snow. In the Andes of Bolivia, where the snow fine is higher than under the Equator, these several zones each extend a little higher than in the Equatorial Andes. On the mountains of Mexico, the same succession of zones, and similar species of plants, are gen- erally found. There is, however, an exception in the third, or temperate region, where the western pine abounds ; and the Alpine vegetation reaches the snow line. III. The Himalayas. 1. Tropical Region. These mountains are situated on the southern boundary of the warm-temperate zone. On their southern slope, which is completely sheltered from polar winds, they have a narrow belt of tropical vegetation. It extends to the altitude of 2,000 feet in the northwest, and 4,000 feet in the southeast ; and is marked by the various species of plants belonging to the flora of India. The palms, bananas, figs, and bamboos grow here with scarcely less luxuriance than in the lowlands. At the foot of the mountains is a narrow belt of marshy jungle, known as the Terai, covered with an almost impenetrable tangle of tropical vegetation, and unin- habitable by reason of its malarious climate. 2. The warm region extends to the altitude of 7,000 or 8,000 feet, and is characterized by those families of plants which occur throughout the warm-temperate zone of the northern hemisphere. 30,000 English Feet. J66KU.ii8'n'7<. AIjPS and pvrknees. Mt.Hlunc.Savoy 15,780 Ft . I.. 45" 30'N. H>g/ons Mte.«osa,SwitzerH 15.223 Ft. L.45' OTN. * I!! tint Ptonfjr\ uvftKtrm/n'ri. Shrub a »*«/«/ IW/W Hinli A.tl, .ihmii. Cnnitrrs Spmtt'Ilinh ^flur.WUtm: VmtaJem/nn^ UfyinrHunts. ^\WlCtlottfudrflii. J ('fnt/pnf. ^/fcv/: fir. fyrutf yieriJ i*ous7rtv*\ TMiglmmlKuA ^HlrclUs/l.OilJt. Bamhra.,. U Chemnt. Palm* VPiTuwMyiilr Terai. Vhir. 'hkMagiioiw. Walnut, 'jliiret flitvntit ffnt/ijft*. Pic Anethou, Spain. 11.108 Ft. L. W38KT. Mt.Pwrdu, Sp 10,994 Ft. L.42'40'N. SCANDINAVIAN ALPS. YbUM, Norway. 8442 Ft.I.OIMON. Sneeliattiiii. Norway 1. TOT FtL62'20 r N. n/te/'lunts. ] fwurt'Jitaiiw. >1V Srolrfi fir. — ■, S/inirf/ir )J^llpine Hunt. — \ V\Thn/ifHirrfl. Yew. Jleenh OnkBea^ifr\ J (m/ifrix. (lirtmiil t-htr. fiirrli. (i'//i/ri I'iites . Fir.?. TKHPKHATK KO.VK fSsPfflii COI.I) TEMFER.VTK y.ONK. £M I 1 ' 4 ys In 1)6 yi4 In jio Sulifrlma, Lapland 6177 Ft . L.67*lu'N. _|8 wg^Hpinr limits. | fiirrh. —K Co/ii/fT*. \l NTS IN VARIOUS LATITUDES. The oaks, especially, of which twenty-five species grow here, attain great size. The long-leaved pine, which is characteristic of the Himalayas, also grows luxuriantly. 3. Temperate Region. Above the warm region, extending to an altitude of 11,000 or 12,000 feet, there is a belt of deciduous trees, mingled with pines, cedars, and other conifers. All the plants are closely allied to those which characterize the temperate zone of both Asia-Europe and North America. The poplar, willow, maple, alder, ash, and birch are all abundant here ; and rhododen- drons grow in great variety and beauty. 4. Cold Regions. Above the last, reaching, to the height of from 14,000 to 16,000 feet, is a region corresponding to the Arctic zone, where the vegetation consists of dwarf trees, stunted shrubs, and grasses. These are succeeded by small, bright flowering Alpine plants, which extend to the line of perpetual snows. IV. The Alps and Pyrenees. 1. Warm Region. These mountains, situated on the southern boundary of the temperate zone, have, upon their southern slopes, a narrow belt of vegetation belonging to the warm-temperate zone. It is characterized by the fig and the olive, which do not, however, extend above the altitude of 500 feet. 2. Temperate Region. In this region, extending to the alti- tude of 2,500 feet, there is a belt of deciduous trees, — character- ized by the chestnut and oak, and the vineyards, so numerous in Switzerland — succeeded by conifers, which extend to about 6,000 feet Both belts are more strongly marked than in the Himalayas, where the deciduous trees and conifers are largely intermingled. 3. Cold Region. The conifers are succeeded by rhododendrons, and diminutive Alpine plants, extending to the height of 9,000 feet ; beyond which are the perpetual snows. This Alpine flora is marked especially by very short stems, brilliant flowers, and large roots. to the warmth of the summer, these mountains and the Himalayas show, | rge of the perpetual snows, a much richer flora, both in number of species I ami beauty of forms and colors, than the corresponding region of the Anues, where the uniformity of temperature throughout the year limits the vegetation to a few varieties of plants which are mostly of low types. V. The Scandinavian Alps. These mountains, situated in the cold-temperate zone, show only a region of conifers and birches, succeeded by a belt of dwarf shrubs and Alpine plants, the characteristic flora of the Arctic zone. In the south the conifers extend to about 2,800 feet, the birches to 3,500 ; but the altitude to which they grow diminishes rapidly to- wards the north. VI. Cultivated Plants. The limits of the various species of cultivated plants, in the dif- ferent regions indicated above, are no less marked than those of the spontaneous vegetation. They furnish a striking illustration of the advantage of the varying seasons of the warm temperate zone over the uniformity of the tropical. On the Andes and the Mexican mountains, from latitude 16° south to 19° north, the average upper limit of the culture of the cereal grains and the potato, is about 10,000 feet ; but in the plateau of Bolivia, maize will mature somewhat higher, and barley as high as 13,000 feet above the sea level, k In the Himalayas, between 28° and 34° north latitude, lye and barley are successfully cultivated at the altitude of 14,000 feet, and wheat at 12,000 ; while turnips and some other edible roots succeed as high as 16,000 feet. In the Alps and the Pyrenees, latitudes 42° to 45° north, the cul- ture of the cereals terminates at from 4,000 to 6,000 feet of alti- titude. In the Scandinavian Alps, in latitudes 61° to 67°, barley and oats grow only near the sea level ; though rye may succeed as high as 600 feet above the sea. 104 VEGETATION OF THE SOUTHERN CONTINENTS. V.— VEGETATION OF THE SOUTHERN CONTINENTS. I. Africa. 1. Equatorial Africa. Africa, the dryest of the tropical con- tinents, and the hottest of all, has, in a large portion of its area, a comparatively meagre flora. Equatorial Africa, however, from about 15° north latitude to 20° south, has a luxuriant vegetation, with a general resemblance in types to those of India ; yet, even in this most favored zone of the continent, we nowhere find such dense, interminable forests, as char- acterize tropical America. The wooded lands, though extensive, are separated by large treeless tracts, which are covered with tall sedges, and gigantic grasses with branching stems. On the borders of this equatorial region, groves of acacias, mimo- sas and cassias, and stunted bushes, form a transition to the arid, treeless plateaus of South Africa and the deserts of Sahara. Palms are numerous, __^_^^_^^^^^^^^^^^^^^^^^^^^^^^^^^ but are of less varied species than in other tropical lands. The doom-palm, remarkable as being the only spe- cies with a branching stem (see illustration), is peculiar to the basin of the Nile, where it is accompanied by the wine-palm with its long flower clusters, and the deleb-palm with its sin- gularly swollen trunk. The oil-palm is found only on the coasts of the Gulf of Guinea. The musanga, kin- dred to the bread-fruit of the East Indies, and the yam tribe, are plentiful throughout equatorial Africa; and coffee is indigenous in the plateau of Abys- sinia. The alluvial plains on the western coast are covered with thick- ets of mangroves and other trees, intermingled with many poisonous plants. On the higher lands are groves of the baobab, a remarkable tree, which, though rarely more than fifty or sixty feet high, has a trunk sometimes over thirty feet in diame- ter. Solitary pandanus trees rise here and there ; and the butter tree, peculiar to Africa, abounds. The tamarind, a flowering tree similar to the locust, and valu- able for its timber, grows throughout equatorial Africa. 2. Northern Africa. The Mediterranean region of Africa bears a marked resemblance to southern Europe, more than half the plants which compose the flora of the former being found in the latter. South of the Atlas region, and upon the oases in the midst of the desert, are extensive groves of the date-palm which furnishes a large part of the food of the inhabitants of the country. The plants of the Sahara are few, and consist mainly of prickly and thorny bushes, and stunted shrubs, of the same general charac- ter as those of Arabia ; yet some portions yield a harsh, prickly grass, valuable as food for the camel. 3. South Africa. The flora of the high, arid, southern part of Africa differs entirely from that of other portions of the continent ; CHARACTERISTIC PLANTS OF AFRICA. and includes an immense number of species, many of which produce flowers of the most gorgeous hues. Thorny and prickly shrubs with meagre foliage, and fleshy and succulent plants, are the most numerous types. The latter include the house-leek tribe, the mesembryanthems, and the leafless euphor- bias which correspond to the cactus family of the New World. (See illustration below.) The flowering plants include 300 different species of heaths, and over 200 pro- teas, both of which are distinguished by their small, narrow, leathery, evergreen leaves, and their large clusters of brilliant flowers. Aloes, in great variety, grow in thickets which form the so-called " bush " of South Africa. Many beautiful plants of the oxalis or wood-sorrel tribe are found here ; with nearly every known species of gladiolus, and a great number of geraniums (Pelargonium). In the dry season the high interior plateaus have almost the aspect of a desert, bearing only a few stunted shrubs, with some succulent plants and mimosas along the borders of the streams. Immediately on the commencement of the rainy sea- son, however, the germs, bulbs, and roots, which have lain dormant in the parched soil, send forth their shoots, and the country is quickly covered with a brilliant and varied vegetation. II. South America. 1. General Character. The wealth of moisture which characterizes the continent of South America, to- gether with its tropical tempera- ture, secures to it a vegetation unsur- passed in luxuri- ance of growth. The e sp ecial characteristics of the South American llora are, its gfeat variety of species and remarkable de- velopment of foli- age ; and the bril- liancy of its blos- soms, with the great number of large flowering trees. 2. Forests within the Tropics. Among the most numerous plants are the palms and bananas, the tree ferns, the fig family — the kindred of the banyan tree — and the mimosas. Reeds and grasses of great height, and a multitude of herbaceous flowering plants, including the beautiful Victoria Regia (see illus- tration, page 97), enrich the flora, especially in the vicinity of the streams. Passion-flowers, and other slender creepers, twine round the lower plants ; while other vines, often as thick as cables, climb the trees, and stretch from bough to bough, intermixed with a mul- titude of parasitic plants, bearing the most brilliant flowers. This richness of vegetation, which finds its parallel nowhere, ex- cept in a comparatively small portion of Asia, extends over the larger part of the continent of South America, and the lowlands in the tropical portions of North America. It characterizes especially the plains of the Amazon basin, and the adjacent portions of the Orinoco and La Plata basins. Included in this tropical flora are the mahogany, rosewood, and other trees fur Date Palm. IXkb Palm. Euphorbia. Tamarind. Wine Palm. .Mcht-mbry anthem. ;c. ert VEGETATION OF THE SOUTHERN CONTINENTS. 105 nishing valuable timber or dyes ; the invaluable caoutchouc ; the coca of the Andes, whose leaf possesses powerful stimulant and narcotic properties ; the to- bacco, and the capsicum, or red pepper ; the cinchona, and many other medicinal plants ; and a great variety of plants yielding food, perfumes, balsams, gums, and resins. Among the esculent productions are the yam, whose large tuber replaces the Dotato in hot climates ; the cassava, from the root of the manioc : the fruits of the Bcrtholletia, — known in commerce as the "Brazil-nut"; the milky juice of the cow-tree ; the delicious cherimoya and pine-apple ; the fruit of the cacao tree, from which chocolate is prepared ; the vanilla, so valued for its perfume ; and the algaroba bean, the fruit of a kind of acacia. The yerba-mate, a species of holly, the leaves of which are used as tea, is a native of the Paraguay basin. 3. Exceptional Regions. In the dryer portions of the table- land of Brazil (see Map of the Mains'), the vegetation consists of stunted deciduous trees and extensive grassy plains, interspersed with myrtles and other shrubs. The agave and the cactus, — the latter peculiar to the New World, — also abound in these hot, arid plains. The Llanos, of the Orinoco basin, are covered with tall grasses, intermingled with lilies and other bulbous flowering plants in great vari- ety and beauty, with here and there groves of palms and mimosas. The Pampas, within and south of the La Plata ba- sin, are covered with tall grass, clo- ver, and thickets of gigantic thistles ; while the barren plains of Patagonia yield only coarse grass, growing in tufts, and the stunted, thorny bushes characteris- tic of desert lands. West of the An- des, throughout the zone of the trade winds, the scarcity of moisture is such as to render the soil, in general, barren, except where irrigation is resorted to. Chili, in the region of the return trades, is well supplied with moist- ure, and has a rich flora. Extensive forests clothe the mountain slopes, including majestic trees of many kinds, which support a beau- tiful growth of climbing and parasitical plants. The araucaria iinbricata, a species of fir tree with large cones inclosing edible seeds, growa in the Andes of Chili and Patagonia, and yields a large amount of nutriment invaluable to the native inhabitants. The potato, now cultivated so extensively in Europe and North America, is indigenous to southern Chili ; also the fuchsias, the much admired ornaments of our green-houses and gardens. III. Australia. 1. General Character. The flora of Australia, though in- cluding some species kindred to those of southern Africa and South America, is yet, in general, of a very exceptional character. Many entire orders of plants are known only in Australia; and the repre- Eucalyptus, CHARACTERISTIC VEGETATION OF AUSTRALIA. sentatives of those families which are found elsewhere, here appear in new and peculiar forms. Scarce an edible fruit, grain, or vege- table of any sort, is indigenous in this remarkable continent. The scantiness of foliage, and the sombre hues and stiff, lustreless leaves of the almost shadeless forests, unvarying in tint from season to season, — and composed of scattering trees, with little or no un- dergrowth, — give an aspect to the Australian landscape unlike that of any other quarter of the globe. 2. Forests. The myrtle tribe, including the eucalyptus (see illustration) and other trees with beautiful flowers of white, purple, yellow, and crimson, are the most numerous of Australian trees. They grow with rapidity, and frequently attain great size, some of the eucalypti being over 400 feet in height, the tallest of known trees. Their leaves are usually elongated and dispersed, and hang down vertically, thus presenting only the edge to the light, and casting but little shadow. Next in point of numbers are the acacias, of which there are nearly 10 species. The footstalks, placed with their edges to- wards the stem, re- place leaves in the larger number of these singular plants. They, chiefly, form those impenetrable thick- ets, called scrub, which cover vast tracts of the dry interior. The easuariimx, or marsh-oaks, pro- d u c i n g excellent timber, have long, slender, wiry branches, with scale-like sheaths instead of leaves ; and combine with the eucalyptus and acacia to give that singular aspect to the Australian landscape, remai'ked by travellers. 3. Local Flora. The epacris (a flowering shrub similar to the heaths), with scarlet, rose-colored, and white blossoms ; proteas in great variety and beauty ; a gigantic lily, with brilliant crimson flowers ; and the zamia, having the appearance of a dwarf palm — are all abundant in southeastern Australia. In the southwest the grass tree, with a tall trunk crowned with tufts of long, grassy leaves, grows on the sandy plains ; and plants with dry, everlasting blossoms are numerous. Reeds of great size often cover the moist lands along the streams ; and open grassy plains are frequent in all the Southern part of the continent. In the northeast some peculiar varieties of the fig family grow, the pandanus flourishes in the neighborhood of the sea, and a few species of palm are found along the eastern coasts. On the northern coasts are many species of plants belonging to the flora of the In- dian Archipelago, among others the cabbage palm, some species of nutmeg, and tin; sandal-wood. 0° Singapore 5° 10" Madras 15° 20" Calcutta 25" 30 "Cairo t?hounp. Ihtratwn of the longest tiay' in different latitudes M JlOUrS /J A 30 m. 14-hour.Y FaJirenlieii EF. CERENT LATITUDES. t le individuals less gigantic and powerful ; yet the antelopes, among most graceful of animals, and the camel, one of the most useful, e -pecially characterize this zone. 2. In the Temperate Zone, farther from the tropics, and re- ring the Sun's rays with greater obliquity, all the forms of wge- '' ible growth are more modest than in the preceding. The forests are 1' ;ss dense and varied, the foliage is less luxuriant, and flowers of b rilliant hues are confined to shrubs and herbaceous plants. Though useful plants are numerous, yet scarce a species is of value 11 1 its spontaneous growth ; and, above all, the long dormant season, v hen the trees and shrubs are bare and apparently lifeless, stamps tl le, vegetation of this zone with an aspect of inferiority. ■ The ^animal world still shows a large number of noble species ; there are some orders which, like the plants, are dormant during winter ; while many of the birds migrate to warmer climes. Here — associated with deciduous forests, boundless fertile prai- r ies, and arid steppes — are the bear, the wolf, the lynx, the bison, a nd many species of elk and deer. Here is the home of the horse, Hie ass, and many varieties of oxen, sheep, and goats, — those an- uJnals which, domesticated by man, have accompanied him to all nes, adapting themselves to all circumstances. j The American turkey, the European pheasant, and the Asiatic parents of many of our domestic fowls, also belong to the temperate z, )ne; toother with a multitude of song birds, whose sober plu- g so gloomily with the brilliant colors of their neigh- 's compensated by the sweetness of their notes, f the honey-bee, and of the silk-worm, tectly useful to man. n. r r b IV. 061(1 Regious. 1. General Aspect. In these regions, where the sun is always low, and in winter is above the horizon but a small part of the time, all nature becomes increasingly monotonous. The com. ts, with their stiff forms and sombre hues, impart a dreary aspect i to the summer landscape ; and, during the long winter, all life seems suspended. 2. . The animal WORLD, however, is more rich and varied thai) the vegetable. In the zone of the conifers we meet the great moose and the brown bear, the beaver and other rodents, in large numbers ; the sable, the mink, the ermine, and a host of other animals whose fine, soft furs form one of the main resources of this inhospitable- clime. In the Arctic Zone — where these forests give place to dwarf trees, stunted or creeping shrubs, mosses, and lichens — the reindeer, tho musk-ox, and the white bear are the only representatives of the larger land animals, though the smaller furry tribes are still nu- merous. The sea, however, more genial in its temperature than the laud, swarms with living creatures of innumerable species, among which are the largest representatives of the animal kingdom. The whale, the walrus, and the seal, inhabit the Arctic seas ; with every gr* - le of marine life, down to the animalcube, which are so numerous as to give their color to great areas of sea watefr and water-fowl, without number and of many varieties, enliven the icy shores. r - 108 ANIMAL LIFE IN THE NORTHERN CONTINENTS. —ANIMAL LIFE IN THE NORTHERN CONTINENTS. iieral Similarity. • . Extent of Resemblance. The three northern continents like in their general climatic conditions, and in their vegetation i ', in the main, inhabited by the same orders and genera of ani- i, though, as in the vegetation, few species are identical. In- . reptiles, birds, and mammals, all appear in kindred species, e, in mam' cases, that the superficial observer would declare to be idenical. • i 8g oiiMOX. Antelopes, of different kinds, are found in i he three continents ■ and the reindeers, the elks, and some • kinds of deer, are so similar that even zoologists are in doubt er they are really of distinct species. ■ bison and musk-ox of America, also, are closely related to the ta of Europe he yak and >xen of Asia ; e big-horn of the Rocky .aius finds its ndred in the moufflon of south- ern Europe, and the argali and other ep of western am! central As:.;. Goats of several eies, and the \vi! I boar, though g in Ainer- are common to i] c and Asia. The cat tribe aids in all three inents ; also rs, wolves, dogs, foxes. The ro- of gnawers vers, r a b b i ts , characteristic am.m rels, rats, mice, etc.) ; and the minks and ermines, with others of their tribe, are but slightly different in the several continents. II. ^ortli America. 4 1. Characteristic Animals. North America, with its wealth loisture and abundance of vegetation, and its vast rivers and : , is characterized by the predominance of the herbivorous over carnivorous animals ; by the great number of rodents, many of h are aquatic animals ; and by its innumerable water-fowls, jarly all the orders of the Old World, including both web-footed i and waders, are represented in North America, with many .liar to the New. Other birds are very numerous, among which ntinent; various kinds of pigi defy of oth move i 2. Other Species. The brown and the white bear inhabit the Arctic regions ; the grizzly bear, the largest and most ferocious of its kind, is found in the Rocky and Sierra Nevada Mountains ; and the black bear, in the forests of the east. Dogs are indigenous in the far north, where some varieties have been domesticated. The puma, or American lion — commonly called the panther — is the most powerful animal of the cat tribe belonging to North Amer- ica, and replaces in this continent the lion and tiger of Asia. III.- Asia-Europe. 1. Asia is especially characterized by the great number of animals capable. ^of domestication* which are found in every part of the continent. The horse, the ass, and the yak ; the valuable Cash- mef& and Angora goats ; several varieties of sheep ; and the Bactrian camel, with t\vt> fatH»£S, are all indigenous^ ^^,r. , : •.. 0"d aU were already the servants of man the dawn of his- tory. Southern Asia has the swine, and the gigantic ele- phant; the zebu and the buffalo, early domesticated by the native man, together with a number of other (ix en still wild. Western Asia lias the dromedary, or Arabia n camel, VI ith one hump ; the Syrian ox. and several sheep am! goats ; and north- ern Asia, has the reindeer. 2. Tbopical Asia, which in- cludes the Indian Archipelago and the adjacent peninsulas, is the home of the highest orders of animals, though their species are less numerous than in Africa. Here are found the orang-outang, so like to the human form that he is called by the Malays the man of the woods ; many species of apes and monkeys peculiar to Asia ; and the Indian elephant, the .rhinoceros, the tapir, and the wild boar. The carnivorous animals are numerous and powerful. The royal tiger, the handsomest and moflQ formidable of these, inhabits the jungles of Hindoostan ; leopards and panthers are common, and the lion is seen in some parts of Indo-China. Four species of bears are found in India, and wolves, foxes, hye- nas, and jackals occur nearly everywhere. the largest known speck- Iv of which TO, with man E I \LS OF NORTHERN CONTINENTS. White Bear. "Wild Turkey. Beaver. ANIMALS OF THE SOUTHERN CONTINENTS. 109 hues. This is the home of the great green parrot, so easily taught to speak, with a host of kindred species of eyery color ; of the pea- cock, and of the beautiful gold and silver pheasants. From here, also, our common domestic fowls are derived. The crocodile and other reptiles frequent the rivers, venomous snakes being especially numerous ; and insects of large size and bril- liant tints abound. 3. Europe, which forms the peninsular headland of the great double continent, has no family or order of animals peculiarly its own ; and a large number of its species are found in Asia or North America. Western Asia, Europe, and the Mediterranean region of Africa, so closely united, form but one zoological province, the prin- cipal types of animals, as of plants, being nearly identical. The European reindeer, goat, fallow-deer, red deer, swine and cat, have all been domesticated ; and it is possible that the moufflon of Corsica, and the wild cattle of Britain, may be the parents of the indispensable domestic sheep and kine. VIII. — ANIMALS OF THE SOUTHERN CONTINENTS. I. Africa. 1. General Character. The mammalia, the highest division of the animal kingdom, are especially characteristic of Africa, the highest orders occurring in greater numbers, both of species and of individuals, than in any other conti- nent. More than two-thirds of the species inhabiting this continent are peculiar to it, though many are represented by kin- dred species in trop- ical Asia. Since so large a part of Africa is either utterly bar- ren, or covered by temporary vegeta- tion and watered liy stream s that flow only during the rainy season, fleet animals, fitted to live on arid plains, and the carnivorous animals, which prey characteristic upon them, are particularly numerous. 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A i 1 Rf$ i- 114 RACES OF MEN. Zinc replaces tin in some of the antique bronzes, but it seems to have been pro- cured in the reduction of copper ores, with which it often occurs. No zinc mines were known until near the Christian era. Mercury, indispensable to modern civ- ilization, and platinum, invaluable to the chemist, were unknown to the ancients. 3. Ancient Mines. The following were the chief sources whence the ancients were supplied with the metals : — Copper — Nubia, and the Sinai peninsula; northern Syria, Armenia, and east- ern Asia Minor (Pontus) ; the island of Cyprus ; Greece, Italy, and Spain. Tin — The Hindoo Koosh, and the southern Caucasus, — apparently little worked ; Spain, the peninsula of Cornwall in England, and the adjacent Scilly Islands. The western mines alone supplied the merchants of ancient Sidon, Tyre, Phoenicia, and Egypt, with this metal, which they transported even into India. Tin, from its rarity and importance, was a most precious metal of the early ages. Silver and Gold — The Caucasus, Armenia, Pontus, northern Syria and India : Nubia and southeastern Africa ; Spain and the Pyrenees. Lead — Nubia, Asia Minor, the Island of Sardinia, Spain, and England. Zinc — Asia Minor. Iron — Nubia, Armenia, the Caucasus, Pontus, Syria, and Cyprus. 4. Ancient Commerce. The metals, gems from Spain and India, and amber from the shores of the Baltic, with spices and perfumes, were the earliest known objects of commerce. All the routes of ancient trade, and consequently of the spread of civilization from its earliest seats in western Asia and Egypt, were governed by the distribution of these articles. H. — THE HUMAN FAMILY. I. — RACES OF MEN. I. Introduction. Man, unlike the in- 1. Extent of Dispeksion of Mankind. dividual species of animals or of plants, is confined to ho cli- mate, to no fixed assemblage of physical conditions. Though the greater portion of the hu- man family inhabit the tem- perate latitudes, yet man is found in every zone ; adapting himself alike to the burning heat and continuous summer of the tropics, and the intense cold and almost unbroken winter of the polar regions. All climes furnish him materials for food, raiment, and shelter, suited to his needs in the circumstances which surround him. 2. Diversity. Under the influence of ever-varying ex- ternal conditions, the human family, — while preserving in all climes, and under all circum- stances, certain common fea- tures of body and mind, which mark them as one, — display an almost unlimited diversity of physical and mental qualities, and of social conditions. The form and features show every gradation, from the sym- metry, grace, and dignity of the ideal man, portrayed by the sculp- tors of ancient Greece, to the ugliness and deformity of the Hot- tentot and the Fuegian. The color of the skin varies from white tinted with rose, through brownish or yellowish hues, to an almost jet black. The temperament is here ardent and impulsive, the emotions re- sponding with the vivacity of childhood to every impression, whether joyous or sad ; there it is cold, passive, as in old age, almost in- sensible alike to pain or pleasure. The social condition varies from the refinement and culture of the European nations, to the degradation of the savage who roams the tropical forests, or burrows in the earth in the Arctic islands. 3. Races of Men. Notwithstanding this almost infinite diver- si i,y in the human family, certain physical features and mental char- acteristics, which have remained unchanged from a time anterior to all history, are common to great groups of men. These different groups, however, are not so sharply defined that they can be re- garded as specifically different ; hence they are denominated races, instead of species, like the distinct groups of the animal kingdom. The number of races recognized by different ethnologists, varies according to the number of common features which each regards as essential to constitute a distinct type. Those usually taken into account are the stature and proportions of the body ; the form of the head and of the features ; the color of the skin, and the appearance and relative abundance of the hair and beard. The races are often designated by the color, the most obvious distinction, though far from being a fundamental or a constant one ; — as the white race, the yellow race, the black, the red, etc. II. The Geographical Races. TYPICAL M.A.If. AMERICAN MALAY. • THE RACES OF MEN 1. Number. From a geo- graphical point of view, six dis- tinct races are recognizable, each connected with one of the grekt geographical regions of the earth. Each shows, through- out .all its branches, a common type, coinciding in all essential features with one of the types recognized as distinct by the most careful ethnologists. 2. Location and Name. The geographical races are as follows : — (1.) The Central, or White race, occupying western Asia and India, Europe, and the Mediterranean region of Africa, — the heart and centre of the great mass of the Old World. (2.) The Mongolic, or 1 race, occupying the who! eastern Asia, exclusive of India. (3.) The African, or I race (from the Latin n black), occupying all of A south of the Sahara. ( I.) The Australian, a,l> race, occupying Australia its islands. (5.) The Malayan, or Brown race, occupying the Malay Penin- sula, the Indian Archipelago, ami the islands of the Pacific and In- dian Oceans ; extending from Madagascar to the easternmost limits AUSTRALIAN. — " / of Polynesia, ai Zealand. (6.) The Am New World, i It will lie obset nents which form t!-. one at the north . an mote continents, 8. CHABAC tt» CIG8 their tall stati il t oval head and ruddy cheeks ; fchi ir abundant be* hair. The color I' ihc skin varii . irOJh white in the European, r swarthy in the Hindoos, Arabs, Eg thins, and Berb. is, who live on the borders of the tropical zone. This is fiii denominated the Caucasian race, the type being found in its greatest beauty in the Caucasus and the moun- tain lands of I .1 eapi tiallj in Armenia and Persia. (Portrait 4.) in. tingu. . i. form .i,riv defined ly more than .:tore, properly be dis- _m1', and the Malayan race, less strongly- uv-rs, may r be designated the secondary races. Of The A, marked thi these, the first tv Morigblic rather than either of the ABYSSINIA SOUTH DEC'CAN. WEST SOUDAN. 11 MOZAMBIQUE. 12 CAPE OK GOOD HOPE 13 IXUO-CIUNA CELEBES. 16 MODIFICATION OF TYPES. i'EE.IEE ISLANDS. SOUTH AUSTRALIA. (2.) The Mongolic peoples are characterized by their short stat- ure ; their broad form and high shoulders ; their round head, nar- rowing at the top, and wide, flat face ; their small chin, and prom- inent cheek bones, which give the face a triangular outline ; their small, deep-set, oblique eyes ; their coarse, straight hair, and scanty In 'tad ; and the yellowish color of their skin. (See portraits, 3, 19, 20, 21.) This type is found most clearly marked in the people of the great plateau of Mongolia. (3.) In the African race, the stature is usually of average height, but the figure is often ungainly, the hands and feet large and flat, and the gait awkward. The head is narrow, and elongated back- ward ; the forehead is low and retreating ; the nose broad and flat, tin' cheek bones very prominent, the jaws projecting, and the lips thick ; and the hair short and crisp, or woolly. (See portraits, 5, 11, 12.) (4.) The Australians show a general resemblance to the negro race, yet the form is still less symmetrical, often gaunt and meagre ; and the features more irregular. The color is a livid grayish black; the hair thick and waving, or bushy ; the beard abundant, and the eyes very deep-set, black, and piercing. (See portrait, 8.) ( 5.) The Malayan, race have, in general, the features of the Mon- other primary races, and may be distinguished as the Mongoloid types. The Australian is. Negroid, with scarce a feature; similar to either the White or the Yellow race. III. The White Race the Normal, or Typical, Race. 1. The typical MAN — as exhibited in the unrivaled works of the ancient sculptors (see the Apollo Belvedere, 1, 2) — is distin- guished by perfect regularity of features, and harmony in all the pro- portions of the figure, securing agility and strength in the highest degree, with the utmost beauty and grace. The head is oval, symmetrical, and well poised, its form showing the proper bal- iiiiic of all the faculties, with the just subordination of the lower to the higher. The face is a symmetrical oval, and is divided into three equal parts by the line of the eyes and the base of the nose. The ryes are large, well formed, and sepa- rated by a space equal to the length of the eye. The mouth is small and finely cut, the lips gracefully curving from the centre The stature is tall, lithe, and graceful, the shoulders not disproportionately wide nor narrow ; while the distance measured by the extended arms is equal to the entire height of the body. These ideal harmonies of proportion are realized in many indi- viduals among the nations inhabiting the mountain lands of Iran, in western Asia, — that region which revelation, the traditions of (he variatious fn,. derance of thf> io%> aud moral, they indie" 2. Gradual Modi depart from Iran, the geoj: >: . ilarity of features diminishes, and the ha isappears. This gradual transition of type is elearli .a- successive peoples met with in all directions from this centre. Passing southward we first meet the Arab, belonging unquestion- yet beautiful Hindoos, ,!), and the Siamese of le true White and Mon- ti i the more distant Ma- >> the peninsula and the differ materially in the the true Malay with the ing from New Guinea to the still possess some advantages true Australian type (8), we come to tlie so-.,, .. and Tasmanians (18), among the ugliest of mankind, with gaunt body, meagre members, bending knees, hump back, and projecting jaws. Passing northeastward to the extremity of Asia we observe almost insensible transitions, through the Tartars (19) and other Turanian people (see Map) — some of whom are hardly distinguishable from TURAN ciiiwa UTAH. 24 NEW MEXICO EASTERN BRAZIL n ANDES OV I'ERU. 27 T1ERRA DEL FUEGO. 28 MODIFICATION OF TYPES. ably to the white race, but his head is less symmetrical, while his complexion varies with the climate to tawny and even to black. Next are the transition types of Abyssinia (portrait 9) and Nubia (10), with features still comparatively regular ; but with a swarthy or black color, closely curling hair, and an increasing resemblance to the negro. The inhabitants of west Soudan (11), show the true negro type ; yet, while the skin is black and the features coarse, the expression of the face still indicates a lively intelligence. The same general characteristics are shared by the tribes of equatorial Africa and of Mozambique (12) ; but in the more southerly regions are the Hottentots and the Bushmen, who are among the most degraded types of humanity. the White race, — to the true Mongols of the plateau (20). Beyond, the Chinese (21) are still true Mongolians, but the Jap- anese are less strongly marked. The Kamchadale (22) is clearly a transition type through which we reach the Esquimaux (22), of the Aleutian Islands, and the Arctic lands of America. Passing southward through America, we meet, in the middle lati- tudes, the Indians of the Rocky Mountains (6, 24, 25), who are a comparatively noble type, often tall and symmetrical in form. In the tribes of South America (26, 27) we observe an increasing de- formity and ugliness ; while the Pecherays of Tierra del Fuego (28) are the most misshapen, the farthest from any culture, the most wretched of the inhabitants of the New World. QUESTIONS ON THE MAP OF THE RACES. What branches of the Mongolic race people the eastern shores and islands of Asia? What branches people the Arctic plains? What peoples intermediate between the latter and the Esquimaux of America? Where are the true Mongols found ? What branch of their race south of them ? What peoples are included in the Turanian family? What Turanian peoples in Europe and Asia Minor? Name the Asiatic branches of the Indo-European family; the European branches. What part of Europe does each of these great branches occupy ? Name the Semitic peoples of northern Africa. What portions of the New World are occupied by Indo-Europeans ? Of Africa ? Of Aus- tralia ? What are the three principal branches of the Malay race ? What are the eastern branches of the American race in North America? The western branches ? What are the principal branches of this race in South America ? What mixed races in South America and the southern part of North America? What race intermediate between the Malays and the Australians ? What races in North Africa intermediate between the whites and the true negro? What mixed races in eastern Africa? What part of Africa is peopled by Hottentots? , 118 CONCLUSION— THE TERRESTRIAL CONTRASTS. II.— UNITY AND CULTURE OF THE RACES. I. Unity of Mankind. 1. Evidences of Unity. A comparison of the different tribes and races of men, reveals the fact of ^gradual modification of types, on every side of the central or highest raceVuntil, by insensible de- grees, the lowest and most degraded forms of humanity are reached. Again : in the central race, — among the individuals of which there is greater diversity in form, features, temperament, and men- tal characteristics, than in any other, — there are persons of pure blood who show, in a less degree, almost every distinguishing feature of each of the lower races. These facts establish a bond of union among all the varieties of mankind, however remote they may appear to be from the most noble type. They also seem to indicate that the White is the nor- mal race, from which the others have gradually deviated. 2. The Law of Perfection of Type, in man, therefore, forms an exception to that observed in the lower orders of creation. (Page 106, Topic I.) The human family appears in its highest physical perfection, not within the Tropics, but in the Temperate Zone, in western Asia, the geographical centre of the Old World. The type degenerates gradually, with increasing distance, in all directions from this geographical centre ; until, in the remotest re- gions of the globe, are found the ugliest, and the most deformed specimens of the human family. The degree of perfection of the type is therefore proportioned, not to intensity of material agencies, but to distance from the central and highest race, irrespective of climatic conditions. The degree of culture of the races also varies in the same order. The central race is the race of culture and progress, both now and in all past ages. II. The White Race. 1. BRANCHES. This race is divided, on the basis of language and mental char- acteristics, into three great branches, designated the Hamitic, Semitic, and Japhetic, or Indo-European, families, each of which has had its especial function in history. The Hamitic family were the ancient people of Palestine, the Nile basin, and the shores of the Arabian Sea and Persian Gulf. They have either passed away or have so blended with their Semitic and Japhetic conquerors as to be scarcely disjinguishable. The Semitic family, who first appear on the upper Euphrates and in Syria, spread over the larger part of Arabia and, later, over northern Africa. The Indo-European family, whose original seats appear to have been on the northern borders of Iran, spread over this entire table-land, and westward, through Europe ; while a small branch went eastward into India. 2. Their Work. The Hamites and Semites were the earliest to gather into communities with organized governments, and to cultivate the arts and learning. The Hamites, a practical and inventive people, developed especially in the direc- tion of material civilization ; though they made comparatively high attainments in literature and in mathematical science. The Semites were the guardians of the ancient revelations. Though contrib- uting less than the Hamites to the material progress of the race, they gave to the world in succession -the simple religion of the patriarchs, the Mosaic ritual, and Christianity, the fundamental principle of modern civilization. Later, Moham- medanism had its origin among the same people. The Indo-Europeans, though later in entering upon their career, and deriving the germs of their civilization from the other two families, have shown themselves to be emphatically the people of progress. The Greco-Latin branch, in southern Europe, carried the heathen civilization of antiquity to its highest perfection ; and the Christian civilization of modern times finds its highest expression among the northern branches of the same family. They now possess the entire New World, the continent of Australia, and the great peninsula of India ; and have established themselves in various parts of Africa and upon the islands of the sea. (See map.) III. Mongolic and Negro Races. » 1. The Mongolic Race is more numerous than any other, and, including the various Mongoloid types, more widely dispersed than all others together. This race very anciently attained a comparatively high degree of civilization, and founded a powerful monarchy in China. They have, however, contributed little to the prog- ress of mankind in general, owing to their isolation, their jealousy of foreign nations, and the policy of non-intercourse so rigidly observed by them even to the present time. The Japanese, though less ancient as a nation than the Chinese, surpass them in culture ; and are now entering upon a new era of pi ogress in reorganizing theiz social system on the basis of modern ideas. 2. The Negro Race have, by themselves, made only the first steps in civili- zation, and the great mass are still "in the savage state. Where they have been brought under the influence of cultured nations, however, they have shown them- selves capable of a high degree of progress. A colony of American negroes have successfully organized the Republic of Li- beria, on the west coast of Africa, which gives promise of doing an important part in the work of Christianizing and civilizing this great and rich continent. IV. Secondary Races. 1. The Secondary Races have contributed nothing to the present condition of mankind ; and none of the existing branches have taken more than the first steps in civilization, except under the influence of the White or Mongolic races. 2. Ancient American Civilization. The inhabitants of the table-lands of Mexico, and of the high plateaus of the Andes, had, at the discovery of America, populous and rich cities, organized governments and religious systems, and great skill in some of the arts, especially in the working of gold, silver, and bronze. There are ruins of a still higher and more ancient civilization, both here and in the highlands of Central America ; but of the origin of these cultured peoples nothing is known definitely. Certain peculiarities in their customs, and in the works of art found in their tombs and ruins, point to an Asiatic origin for the Peruvian, and a Semitic or Egyptian for the Mexican civilization. III. — CONCLUSION. I. — THE TERRESTRIAL CONTRASTS. I. Introduction. The three grand contrasts observed in the arrangement of the land masses upon the globe (page 21), reappear in the climates, through which they exert a marked influence upon the character and distribution of every order of life. The continental and oceanic worlds present a contrast of geograph- ical elements, — the land, and the water, the most general and fun- damental of all. The contrast of the eastern and the western world is one of area and structure. The northern and the southern world show essentially a contrast of climate. II. Continental and Oceanic Worlds. 1. The Oceanic World, the world of uniformity, is also the world of inferiority. The life predominating by quantity is that of the sea, — vastly lower, both vegetable and animal, than that of the land. Australia and the oceanic islands, alike, lack all the higher types, whether of plants or of animals, and are peopled only by the lower races. 2. The Continental World, characterized by diversity in all its conditions, is the world of superiority both in the realm of nature and that of man. It is, however, not in the heart of the continents that the highest development is found ; but in the maritime zone, or zone of contact of the continental and oceanic worlds, along the coasts, and in the great continental islands. THE CONTINENTS OF HISTORY. 119 3. The Maritime Zone. Advantages. Here the vigor of the continents, their variety of reliefs, soil, and temperature, is blended ■ with the moisture of the seas ; and the extremes of the continental climate (page 73) are tempered, without being reduced to the same- ness of the oceanic. Here, too, the great highway of the seas permits that constant in- terchange, both of commodities and of ideas, which seems essential to the development of human society ; yet which, in the heart of the continents, is more difficult, sometimes almost impossible. Life. We have seen that the highest types of the animal world, and the most varied forms of the vegetable, with many of the most precious of vegetable productions, are found in the islands of the Indian archipelago, on the margin of the oceanic hemisphere. In the same zone of contact, we find the highest civilizations of eastern Asia, — in Japan, China, and India ; while the shores of the Mediterranean were the theatre of the most cultured nations of an- tiquity ; as those of the Atlantic are the scenes of the highest devel- opment and activity at the present day. III. Old and New Worlds. 1. The New World, — narrow, elongated, isolated between two great oceans ; with a preponderance in its structure of plains which are everywhere open to warm sea winds, — is, in the main, charac- terized by medium temperatures, abundant moisture, and the great- est luxuriance and power of vegetable life. In its fauna the lower types predominate ; and the native people are essentially the men of the forest, a race of hunters, without do- mestic animals, and with only the rudiments of agriculture here and there. 2. The Old World, — vast, compact, composed of the largest two land masses (Asia-Europe and Africa), closely crowded to- gether, from a large part of which the sea winds are almost excluded, — is characterized by the greatest extremes of temperature; and by a lack of moisture and poverty of vegetation over immense areas of the interior. It is the domain of the higher orders of animal life, especially of animals capable of domestication; and of the civilized and progressive races. IV. Northern and Southern Worlds. 1. The southern continents, — lying mainly in the tropical zone, where all the conditions that stimulate physical life are most powerful, and where, with few exceptions, man has remained at the bottom of the social scale, — may be designated the continents of nature. Each has its own especial character, wherein the influence of every distinguishing feature of the continent is seen. In South America, — the tropical continent of the Western World, and especially the continent of plains, — all the characteris- tics of the New World are exhibited in an exaggerated degree. It is preeminently the realm of vegetable life, where we find the largest, the most dense, and the most varied forests, and the greatest devel- opment of foliage on the face of the earth. Africa. — the tropical continent of the Eastern World, and the continent of plateaus, — has, in an extreme degree, the dry con- tinental climate of the Old World. It is, above all, the realm of the nobler animals, of the mammalia, — the highest division of the animal world, — which, by their number, their variety, their size and strength, give the African fauna its distinctive character. Australia, the only sub-tropical continent, and the most isolated, the smallest, and the least varied of all, is the only one which pre- serves to a great extent the ancient forms of plants and animals. Its isolation, size, and structure, as well as its fauna and flora, find their parallel in the other continents in the middle geological ages. 2. The Northern Continents, may properly be designated the continents of history. Less richly endowed with those elements which foster the life of nature, they possess all the conditions most favorable for the development and progress of the races inhabiting them ; and each was apparently designed, from the beginning, for the performance of a peculiar part in the education of mankind. II. — THE CONTINENTS OF HISTORY. I. Asia. 1. Characteristics. Asia is the largest of the continents, the most central, the only one with which all the others are closely con- nected ; and the one whose different physical regions show the strongest contrasts, and are separated by the greatest barriers. It has the loftiest mountains, the highest and most extended pla- teaus, the greatest plains, and the most numerous river systems ; with all climates, from the hottest to the coldest, from the dryest to the most moist. It has, also, a large number of useful plants, and of animals capable of domestication ; together with an abundance of both the useful and the precious metals. 2. Its Function. This great and strongly marked continent is the continent of origins. The human family, its races and civiliza- tions, and the systems of religion which rule the most enlightened nations, all had their beginning here. By the great diversity of its physical features and climate, and the strong barriers isolating them one from another, Asia was ad- mirably fitted to promote the formation of a diversity of races ; while its close connection with the other continents facilitated their disper- sion throughout the earth. Its alluvial plains, with their well-defined boundaries of moun- tains or deserts, and their rich soil, — covered annually by overflow- ing rivers with a fruitful loam, and so easily tilled that a plough was scarcely needed, — seem to have been especially adapted to foster the progress of a race still in its infancy. The abundance of their resources, developed by agriculture, allowed the congregation of great numbers of men upon the same area, and thus favored the formation of organized governments ; while the conflict with the overflowing rivers, the necessity of irri- gation, and the alternation of the seasons, incited forethought, and gave birth to the useful arts and the sciences of observation. 3. Centres of Culture. The four great alluvial plains of Asia, — those of China and of the Amoo Daria, in temperate re- gions ; of the Euphrates and Tigris in the warm-temperate ; and of the Indus and Ganges under the tropic, — with the Nile valley in Africa, were the theatres of the most ancient civilizations known to history or tradition. In the remotest antiquity each of these regions became the seat of a distinct nation, with a material and intellectual development, a re- ligion, and a social organization peculiar to itself ; and together they formed the five great centres of the primitive culture of the race. China and India, isolated from each other, and from the West, by almost impassable mountains and desert plateaus, have left scarce a trace upon the subsequent progress of mankind ; but the others, in greater proximity to Europe, became the parents of the higher cul- ture of ancient Greece and Rome, and, through them, of modern civilization. 120 THE CONTINENTS OF HISTORY- LangittU*. lOU Wktt At.//. II. Europe. 1. Characteristics. Europe shows a diversity of structure even greater than that of Asia ; but with smaller areas, more moderate forms of relief, less extreme contrasts of climate, a more generally fertile soil, and every- where an abundance of the most useful minerals ; while the relative extent of its coast line — its mari- time zone — is greater than that of any other continent. This continent is especially fitted, by its diversity, to foster the formation of distinct nationalities, each de- veloping in an especial direction. Moreover, the proximity of these nations one to another, the greater facility of communication be- tween them, and, above all, the com- mon highway of the sea, nowhere very dis- tant, facilitates mutual intercourse, the lack of which arrested the progress of the civilizations of Asia. 2. Centres op Progress. In Asia it is in the great inland plains, on the banks of the rivers, that civilization first shows itself. In Europe it is in the peninsulas and islands, on the margins of the seas — the regions most ac- cessible to influences from without — that the most ancient states are founded ; for not only her inhabitants, but the germs of her culture, were derived from Asia. 3. F UNCTIONS. Though not the conti- nent of origins, Eu- rope is emphatically the continent of de- velopment. The In- do-European race — the people of progress — find their . fullest expansion and activity, not in their original seat in Iran, but in Europe, whence they are spreading over all quarters of the globe. The arts and learning of antiquity attained their highest development, not in western Asia and Egypt, the places of their origir, but in Greece and Rome. Christianity, also, only germinated in western Asia. Trans- planted to Europe, it gradually attained its full development, and became the foundation on which is reared the vast and noble edifice of modern civilization. A Explanation. BW .o' • The ft'»wre;» ^ree in sqiutre ..miles, "the are* of fke river Slav n;^6£p< c „„,; d y,} ,? c -h oll.«r. HI. America. THE UNITED STATES. RIVER BASINS THE UNITED STATES. VEGETATION. 1. Character- istics. America, dif- ferent in position, structure, and climatic conditions, from both the other northern continents, seems des- tined to play a part in the history of man- kind unlike that of Europe and Asia, though not less noble than either. The structure of this continent (page 31) is characterized by a unity and sim- plicity as striking as is the diversity of Eu- rope. Few and vast phys- ical regions — the western highlands and the eastern plains, the northern and the southern slope — with comparatively slight barriers between them, present a marked contrast to the multiplicity of areas, with clearly defined natural bound- aries, which charac- terize Asia-Europe. Again, great river systems, whose basins, narrowed to a mere doorway near the sea (see Map of River Basins of U. mn'uiu Muisca, mu-Is'ka Mur, mur Muxinga, mHx-Tng'ga Narcondam, nar-con^dam Natron, na'tron Natupe, na-ti/pa Nevada, na-va/da Nevado, na-va'do Newfoundland, nu / ftlud-land , Ngai, n'ga/e Ngami, n'ga'me Nicaragua, nlc-a-rj/gwa Nicobar, ulc'o-bar^ Nieuweveld, nyuw'velt Niger, BfQgV N'ovaiaZemlia, no-vi'U zcui'le-a \yanza, ni-au'za Nyassa, nT-as/sa Obi, o'be Ofen, o-'fgn Ohiwao, o-he-wa'o Okhotsk, o-kotsk' Onega, o-ue'ga Orizaba, o-re-za/ba Pamir, pa-iner' Pampa, pam'pa Panama, pan-a-ma/ Papuan, pap'oo-an Paraguay, paVa-gwfi/ Parana, pa v ra-na/ Paumotu, pow^mo^tu Penas, p&n'yas Persian, p£r'sh6-an Peschawer, pfish-ow^r Petchora, peeb'o-ra Philippine, fiKip-in Pic Anethou, pek^ a-ua'too Pico de Teyde, pe'ko de ti'de Pilcomayo, pIPko-mi'o Pitcairn, pit-karn / Polynesian, pfin-nu'shi-an Popocatepetl, po-po kat x a-p6tl / Porto Rico, por'to rc r k6 Pruth, prooth Punta Parina, pooi/ta pa-r^'na Purus, poo'roos Pyrenees, pir'e-ues Quathlamba, kwat-liim'ba Quechua, kwa-ebU'a Quito, ke'to Radack, ra'dak Rainier, ra/ner Ralick, ra/llk Rauh, rau Reisen, re-sgn Reykjavik, r^kT-a-vIk* Rhenish, ran'Ish Rio Grande, ri'6 grand Rio Janeiro, n'S jan-e'ro Rilo Dagh, re'lo dah' Roumania, roo-ma'ne-a Samarang, sam-a-rang' Samiel, sa'ml-Cl Samoa, sa-mo'a Samoiedes, sa-moKeds Sampu, sam'poo Santorini, san-to-rt/ne Sadne, son Sarmiento, sar-nid-fin'to Saskatchewan, sas-kaek / e-wan'' Scandinavia, skanMI-na'vT-a Seathwaite, seth'wfit Seine, san Sereth, ser-eV Seychelles, sa-shfiK Shamo, sha'mo Shasta, shas'ta Shoshonee, sho-sho^ne Sidrj,sld'ra Sierra, se-eVrii Siestan, pOe^t&a Sikhota Alin, fl'-kc/t'& a/len Simoon, se moon' Sioux, so6s Sir Daria, ser da-'re-a Sir-i-kul, ser'e-kai' Siwa or Si wah, sS'vu Sneeuw, snC-oov' Socotora, so-ko'trii Somali, so-uia'le Sorata, sd-rii^ta Staubbach, staub'bak Soudan , soo-dau' Steppes, steps Stromboli, strOm-bo'le Suabo-Frauconian, swr/bo-frau^kyne-an Suaheli, su v a-ha^l« Sudetic, su-deVlk Sulltelma, sU-li-tel'ma Suliman, su-le-man' Sunda, sun'da Tahiti, ta-he'te Taiara, tl-a'ra Tanganyika, tan'gan-ye^kft Tanta, tai/ta Tapajos, ta-pa / zhos Tarawan, ta^ra-wan' Tarim ta/rem Ta Siue Shan, ta se v wa/shiLu Tchad, ebad Tchukchees, eJiook'^bes Tebu, ta/bu Tengri Nor, tfin^gre nor Tenuyan, ten-we'an Terai, ta-ra'e Tequendama, ta*kw6n-da'ma Teutoburg, toKto-boorg Theiss, tis Thian Shan, te^an' shau Thibet, tlb-et or tl-b6t' Thibetan, tlb-et'an Thuringian, thjj-rln'je-an Titicaca, te-te-ka'ka Tocantins, to^kan-tenz 7 Tolima, to-le'mii Tolmezzo, toi-mfit'zo Transylvania, tran^ll-va'ul-a Tristan da Cuiiha, trls'tan-da-kun'ya Tsien-tang, tse-gn'taug Tuareg, too-a-rgg' Tubuai, tu-bu'I Tufoa, tu-fo'il Tundra, toon'dra Tungusian, toon-gu'zhl-ftD Tupis, too-pes/ Tupungato, tu-pHDg-ga'tS Turooman, toor v ko-man , Turkestan, toor , kes-tan / Tzana, tza/nii Ucayali, oo^ki-fi'le Ugrian, oVgre-au Unalashka, oT/nii-la-li'kii Ural, yu'ral Uruguay, yoVroo-gwa Urumia, oo v roo-me/a Utah, yoVta Valdai, vaKdi Valdivia, vaTde / ve-a Vermejo, vfir-mS/ho Vesuvius, ve-soo^ve-tis Vindhya, vlud'ya Vistula, vls'too-la Volga, vdl'ga Vosges, vozh Wahsatch, wa-saek' Walachia, wU-la'ke-a Warasdin, wa % r^s-den' Wener, wa'ngr Weser, we-zgr Wetter, wgt'er Xingu, sheu-goo' Yablonoi, ya-blo-noi' Yakutsk, ya-ko3ts/k Yangtse Kiang, jangHse kt-aug' Yanteles, yan-ta'16s Yapura, ya-pu'rii Yenisei, yen-e-saf Yosemite, yS-sBm'i-tP Zambesi, zam-ba'ze Zermatt, z6r-maV 124 TABLES OF TEMPERATURE AND RAINFALL. TABLE OF MEAN TEMPERATURE AND RAINFALL IN THE UNITED STATES. NAMES OF PLACES. EAST OF MISSISSIPPI RIVER. Michipicoten, Lake Superior Fort Kent, Me Mackinac, Mich Eastport, Me Fort Snelling, near Bt. Paul, Min. . Potsdam, St. Lawrence Co., N. Y. . Fort Howard, Wis Burlington , Vt Sackett's Harbor, N. Y Hanover, Dartmouth College, N. H. Portland, Me Concord, N. H Rochester, N. Y Prairie du Chien, Wis Portsmouth, N. H Milwaukee, Wis Buffalo, N. Y Albany, N. Y Amherst College, Mass Boston, Mass Detroit, Mich Chicago, 111 Providence, R. I Cleveland, Fort Armstrong, Rock Island, 111. . West Point, N. Y New Haven, Conn Nantucket, Mass Logansport, Ind New York, N. Y... Pittsburg, Pa Philadelphia, Oirard College, Pa.. . Marietta, Baltimore, Md Cincinnati, Washington, D. C Fort Washington, Md Louisville, Ky Richmond, Va Fortress Monroe, Va Nashville, Tenn Knoxville, Tenn Chapel Hill, N. C Memphis, Tenn Huntsville, Ala Columbia, S. C Smithville, Fort Johnston, N. C. . . Augusta, Ga Charleston, S. Savannah , Ga Natchez, Miss Mobile, Ala Baton Rouge, La Pensacola, Fla New Orleans, La St. Augustine, Fla Cedar Keys, Fla Tampa Bay, Fla Fort Dallas, Fla Key West, Fla WEST OF MISSISSIPPI RIVER. Point Barrow, Alaska Fort Yukon, Alaska Sitka, Alaska Pembiua, Dak Fort Union, Dak Fort Benton, Mont Steilacoom, W. T Astoria, Or Fort Pierre, Dak Fort Orford, Or Dubuque, Iowa Fort Dodge (Clarke), Iowa F'ort Laramie, Wyo Des Moines, Iowa Council Bluffs, Iowa Salt Lake City, Utah Fort Kearney, Neb Fort Heading, Cal Denver, Col Fort Loavenworth, Kan Fort KUey, Kan St. Lvuis, Mo Sacramento, Cal San Francisco, Cal Fort Atkinson, Kan Fort Scott. Kan Fort Massachusetts, Col Fort MBcr, Cal Monterey, Cal 8antaFe, N. M Little Rock, Ark Fort Washita. Ind. T Los Angeles, Cal Fort Belknap, Tex Fort Webster, N. M Fort Yuma, Cal San Diego, Cal Fort Fillmore, N. M Fort Graham, Tex Natchitoches, La Austin, Texas Galveston, Tex Fort Clark, Tex Brownsville, Tex POSITION OF STATIONS. North Latitude 47 W 47 15 45 51 44 64 44 53 44 40 44 30 44 28 43 55 43 42 43 38 43 12 43 8 43 5 43 5 43 3 42 53 42 39 42 22 42 22 42 20 41 54 41 60 4142 41 30 41 24 41 18 41 17 40 4 40 42 40 27 39 58 39 25 39 18 39 6 38 53 38 43 38 10 37 32 37 36 10 35 59 35 54 35 8 34 43 33 59 33 55 33 28 32 47 32 5 31 34 30 41 30 26 30 24 29 57 29 54 29 7 28 25 55 24 34 71 21 66 57 3 49 48 47 50 47 10 46 11 44 23 42 44 42 30 42 28 42 12 41 35 41 30 40 46 40 38 40 30 39 44 39 21 39 3 38 37 38 34 37 48 37 47 37 45 37 32 37 36 36 35 41 34 42 34 14 32 48 32 44 32 42 32 14 31 56 31 33 30 15 29 19 29 17 25 54 W. Long. of Green- wich. 85 6 ' 68 35 84 33 66 59 93 10 75 1 88 6 73 11 75 57 72 17 70 15 71 29 77 51 91 70 46 87 65 78 65 73 45 72 34 71 4 83 87 38 71 23 81 36 90 40 73 67 72 55 70 6 86 1 74 1 79 59 75 10 81 31 76 36 84 28 77 1 77 2 85 40 77 27 76 18 86 49 83 54 79 17 90 86 46 81 2 78 1 81 68 79 56 81 5 91 28 88 2 91 18 87 13 90 4 81 19 833 82 28 80 20 8148 156 17 147 135 18 97 104 Alt. in Eng. feet above ocean. 110 36 122 25 123 49 100 12 124 29 90 40 94 3 104 31 93 37 95 48 112 6 98 57 122 5 104 57 94 48 96 35 90 16 121 28 122 27 100 14 94 45 105 23 119 40 121 62 106 2 92 15 96 38 118 12 98 40 108 5 114 36 117 14 106 16 97 26 93 32 97 47 94 47 100 25 97 26 675 728 40 620 346 266 . 530 20 374 500 642 50 591 600 75 267 60 562 591 150 625 628 167 50 30 625 23 850 133 630 30 582 40 60 450 172 8 533 1,000 570 262 600 315 20 600 25 42 264 30 41 18 20 8 85 20 20 10 700 2,022 2,663 300 60 1,456 50 4,519 830 1,260 4,320 2,360 674 6,000 896 1,300 481 82 130 2,330 1,000 8,365 402 140 6,846 150 645 457 1,600 6,350 200 150 3,937 900 100 200 1,000 50 TEMPERATURE IN DEGREES FUR January (Below ze ro-.) 10.6 11.1 19.4 22.4 13.7 18.4 18.9 20.6 15.8 22.8 21.2 26.9 19.4 24.9 25.2 24.3 23.7 27.8 27 23.6 27.5 22.8 28.3 34.9 15.1 30.2 29.1 32.1 32.6 30.9 30 28.3 36.5 35.8 33.7 36.5 38.2 30.5 41.5 41.7 42 49 46.7 48.1 54,4 52!3 67.6 53.5 53.6 55.3 67 55.6 61.5 66.4 69.6 -18.5 -26.6 21.3 16.5 38.7 48 19.2 48.1 19.8 19.6 31 27.4 19.4 27.1 21.1 44.2 82 28 27.1 31.4 45.3 49.6 33.4 32.9 19.7 47 62.2 31.4 40 42.9 52.8 42.3 40.6 56.4 61.9 44.5 47.9 50.6 46.4 48.1 47.2 60.4 July. 57 62.6 645 623 73.4 68.4 71.5 64.4 68.2 67.1 69.9 76.3 67.1 69.8 72.1 71 . 71.6 69.7 70.8 70.6 76.5 73.7 71 72.9 74.8 73 74.7 73.6 76.2 74.5 76.7 80 74.6 77.6 78.2 79.6 74.1 78.2 79.9 76.4 81.6 81.9 80.1 81.4 81.8 83.7 81.8 82.3 82.9 80.9 813 80.7 82.1 8&5 36.1 65.7 65.6 74.4 ,78.6 73.6 64.2 61.6 76.9 69.7 76.2 76.2 74.7 76.5 76.9 81.5 73.6 82.9 78 76.7 83.7 78.2 73.9 67.9 79.2 77.2 63.5 90.2 58.5 72.6 80 80.7 75 82.3 76.1 92.3 72.7 88.4 83.1 82.2 80.7 88 81 84.2 Year. 38.2 37 40.0 43 44.6 43.6 44.5 46 45.1 45.2 44.5 47 47.6 45.8 46.4 46.1 48.2 46.7 48.9 47.2 46.7 47.9 48.9 50.3 50.7 60.8 50.4 60.9 61.7 50.8 52.7 52.6 63.1 63.8 55.1 •57.8 64.9 56.2 59.9 68.5 65.7 59.7 60.8 59.1 57.1 65.7 64 659 67.4 67.1 70.3 68.1 68.7 69.9 69.6 70.6 71.9 74.7 76.4 7.1 16.8 43.2 48.2 60.8 52.2 61.9 53.6 49.4 47,4 50.1 49.7 49.3 47.7 62.1 48 52.8 66.6 64.5 69.9 64.9 64.6 64.5 41.1 66 66.3 50.6 62.3 62.2 62 64 54.8 73.6 62 64 65.7 66.3 66.7 69.4 67 73.7 Annual Rainfall in Eng. Inches. 27.81 36.45 23.96 40.09 25.82 28,133 34.62 34.15 30.73 40.32 43.63 40.99 82.56 35 29.88 30.40 33.84 40.52 43.90 39.40 30.05 33 41.38 37.61 38 47.65 44.43 41.10 37.34 44.59 47.68 35.55 42.55 40.84 44.87 41.05 45.02 48.12 38.29 47.04 52.02 39.76 42.71 45.46 54.88 47.17 46.01 24.20 41.92 48.32 63.55 64.42 60.16 59.27 61.05 48.16 45.77 61 69.04 36.23 83 16 11 12.60 43.98 86.36 13.51 70.59 33.47 26.82 1516 23.94 29 28.85 25.26 29.11 16 31.74 23.62 42.48 19.59 23.50 23 42.15 17.06 18.99 12.20 17 47 38.04 13 28.05 19.46 346 9.16 8.42 40.58 64 30.50 42 22.38 37 TABLE OF MEAN TEMPERATURE AND RAINFALL IN THE WORLD. NAMES OF PLACES. Hammeifest, Norway Archangel, Russia Reykjavik, Iceland Bergen , Norway St. Petersburg, Russia Christiauia, Norway Ekaterinburg, Russia Edinburgh, Scotland Moscow, Russia Bremen, German Empire Dublin, Ireland Berlin, Prussia Warsaw, Poland London, England Brussels, Belgium Paris, France Vienna, Austria Odessa, Russia Astrakhan, Russia Lyon, France -. Milan, Lombardy, Italy Bordeaux, France Belgrade, Turkey Florence, Italy Constantinople, Turkey Madrid, Spain Lisbon, Portugal Naples, Italy > Athens, Greece ^ . AFRICA. Algiers, Algeria Funchal, Madeira Cairo, Egypt Kuka, Bornu Christiansborg, Guinea , Gondokoro Zanzibar St. Helena Port D'Urban, Natal Cape Town, Cape Colony ASIA. Ust Yansk, Siberia Yakutsk, " Okhotsk, " Tobolsk, " Barnaul, M Petropaulovski, Kamchatka Irkutsk, Siberia Tiflis Peking, China Baghdad, Asiatic Turkey Nagasaki, Kiusiu, Japan Jerusalem, Syria Canton, China Calcutta, India j Bombay, Deccan ' Manila, Philippine Islauds Bangkok, Siam Aden, Yemen Trivandrum, Deccan Kandy, Ceylon Singapore Amboyna, Molucca Islands Batavia POLYNESIA AND AUSTRALIA. Honolulu, Sandwich Islands Raiatea, Society Islands Freemantle, West Australia Sydney, New South Wales. Adelaide, South AusUHia Auckland, New Zealand, Wellington, New Zealand NORTH AMERICA. Upernavik, Greenland Fort Simpson, British N. America. Assiniboine, Manitoba St. Johns, Newfoundland Montreal, Pr. Quebec Windsor, Nova Scotia St. George, Bermudas Matamoras, Mexico Havana, Cuba Mexico, Mexico Vera Cruz, Mexico St. Thomas, West Indies Balize, British Honduras Guatemala, Central America SOUTH AMERICA. Maracaibo, Venezuela Georgetown, British Guiana Bogota, United States of Columbia Quito, Ecuador Para, Brazil Lima, Peru Rio Janeiro, Brazil Asuncion, Paraguay Valparaiso, Chili Montevideo, Uruguay Falkland Islands POSITION OF STATIONS. Latitude. (South -) 70 4(V 64 33 64 8 60 24 59 67 59 55 56 60 55 58 65 45 63 6 52 21 62 30 62 13 61 30 60 51 48 80 48 12 46 25 46 21 45 45 45 28 44 51 44 60 43 47 41 7 40 25 38 43 38 11 87 58 36 47 32 38 30 2 13 10 6 24 4 44 - 6 28 -15 55 -29 40 -33 50 70 55 62 2 69 21 58 2 63 20 53 62 17 41 41 39 54 33 21 32 45 81 47 23 8 22 38 18 56 14 36 13 40 12 46 8 31 7 17 1 17 -3 41 -69 21 16 -16 40 -32 16 -33 40 -34 35 -86 60 -41 16 72 48 61 61 50 47 37 45 60 44 69 32 23 26 62 23 9 19 30 19 12 18 21 17 29 14 40 10 43 6 49 4 36 -0 14 - 1 28 -12 3 -22 24 -25 16 -33 2 -34 54 -62 Long, from Green- wich (West -.) 23 46' 40 34 -21 55 5 18 30 18 10 43 60 34 8 11 37 34 8 49 6 15 13 3 21 1 - 6 4 22 2 20 16 22 30 44 48 5 4 49 9 21 - 34 20 26 11 15 28 59 -3 41 -9 8 15 34 23 50 3 6 -16 56 31 15 14 30 10 81 40 39 30 - 5 43 31 18 29 138 24 129 45 143 11 88 16 103 27 158 42 104 11 44 60 116 26 44 22 129 52 35 14 113 16 88 20 72 64 129 10 1 45 15 77 80 49 103 50 128 15 106 63 -157 69 -160 116 30 151 138 45 174 61 174 47 -55 40 -120 25 -97 8 -52 43 -77 52 -64 7 -64 50 -97 27 -82 13 -99 1 -96 9 -64 56 -88 73 -90 28 -71 62 -58 12 -74 14 -78 40 -48 29 -77 8 -43 16 -57 41 -76 24 -56 13 -61 Alt. in Eng. feet above ocean. 852 864 490 19 19 153 825 193 121 637 167 392 42 266 234 160 1,327 321 222 06 1,760 299 13 378 300 1,270 1,487 28 2,610 199 1,790 300 .639 266 213 65 7,450 4,960 8,600 9,543 564 262 TEMPERATURE IN DEOREES F'HR. January. July. Year. Below ze- ro-.) 22.5 53.2 35.5 7 61.5 335 30 56.2 39.4 35 60.4 46.8 15.6 62.5 38.8 21.31 61 41.1 2.3 63.8 33.2 374 58.5 47.1 11.9 67.8 40.4 29.6 64.6 48.1 40.4 68.2 48.4 28.1 66.2 48.2 21.5 64.3 44.3 37.4 64.1 50.8 36 64.8 50.3 35.4 65.6 51.3 28.9 69.6 60.2 26.1 71.5 49.2 19.9 77.9 49.2 36.3 706 62.4 33.3 74.5 64.6 42.4 69.1 65.1 33.3 76.6 54.2 40.8 76.3 67 40.4 74.1 57.6 44.7 76.3 68 48.6 69.8 59.5 46.8 76.4 59.9 45.6 795 62.4 69.1 80.4 69.1 63.5 72.5 67.6 56.3 85:6 71.3 75.7 83.6 83.3 81.1 77.1 80.4 89.4 78.4 83.1 83.3 77.1 64 58 61.4 76.2 59 67.8 67.6 64.4 60.7 -38.6 52.6 2.8 -41.3 63.2 12.4 -11.6 54.6 23.1 - 2.9 63.4 83 -4.4 67.5 32.3 20.3 58.1 37 - 6.5 64.9 30.7 32.4 75.6 55 25.8 79.9 54.6 48.6 93.2 73.6 42.3 79.3 61 46.7 76.4 63.6 52.5 83 69.9 71.7 84.2 81.1 73.3 80.7 79.8 77.1 80.3 79.6 76.7 82 81.1 72.6 83.4 80.2 78 78 79.2 70.6 72.6 72.7 78.4 82.2 80.7 80.5 77 79-1 78.7 78 78.8 71.7 78.9 75.4 78.7 75.7 78.4 70.8 67 62.7 71.7 49.8 61.3 84.4 54.2 68.4 67.9 49 58.6 66.4 48.7 68.3 -12.3 385 12 -12.5 61 25.7 - 2.9 69.6 35.3 23.4 66 38.3 16 73.2 44.6 25.1 63.5 41.9 65.7 82.4 72.7 60.4 84.2 73.6 71.4 81.4 77.1 52.5 65.3 60.7 71 81.5 77.7 80.8 82.7 82.3 76 82 79.5 66 68.9 67.8 81.3 86.6 84.7 78.4 79 79.5 57 56.2 57.7 58.2 59.1 60.1 80.1 81.5 80.6 78.1 68.6 73.3 79.6 70.6 75.2 365 65.1 74.3 66 57.3 60.6 73 51.8 62.1 56 37.4 47.2 Note. — The altitudes given above refer to the position of the instruments used in observation. * J r T TTVRARY t T> "2lA-15m-4,'63 m VF 00704 9 „ i \ I Jm QkOf «;**EJ l , 1 ra F f -.V* I I ■