Tropical Americas

“ TRANSCONTINENTAL PROFILE OF MEXICO.
This steep formation accounts for absence of navigable streams and for the existence of climates verging from tropical to temperate, nearly side by side. The sharpness of contrasts in climate is scarcely to be appreciated by the hasty voyager. The really tropical vegetation is succeeded by a kind which to the eye of the American of the North is quite as exotic. ”

“ In the northern part of South America, where the land is bordered on every hand by vast tropical seas, which load the hot and thirsty air with vapor, and where the mighty Cordillera of the Andes rears its icy summits to chill and precipitate the vapors again, a quantity of rain amounting to more than ten feet in perpendicular height falls in a year. ”

“ As three quarters of South America lie within the tropics, the entire north coast, and the wider part of the continent including most of Brazil with the countries on the west as far down as the northern part of Chile, a tropical climate and productions might here be expected. ”

“ In like manner (§ 228) , extra-tropical New Holland and South Africa have each land — not water — to the windward of them in the trade-wind regions of the northern hemisphere, where, according to. this hypothesis, the vapor for their rains ought to be taken up: they are both countries of little rain; but extra-tropical South America has, in the trade-wind region to windward of it in the northern hemisphere, a great extent of ocean, and the amount of precipitation (§ 141) in extra-tropical South America is wonderful. ”

“ The loss of these barriers, combined with the narrowing of the space between the Atlantic and the Pacific waters, and its more southern position, increases the temperature and the rainfall; so that the fertility of the country augments in a rapid way as we go southwards, until finally in the isthmic part of the continent we have a tropical luxuriance of life. The lowland borders of the country gain upon the width of the table-land, until south of the Tehuantepec Isthmus the whole region is essentially unfit for the uses of our race. ”

“ Hardly less uncertain and irregular are the effects of climate. Hot countries usually differ widely from cold ones in all their organic forms; but the difference is by no means constant, nor does it bear any proportion to difference of temperature. Between frigid Canada and sub-tropical Florida there are less marked differences in the animal productions than between Florida and Cuba or Yucatan, so much more alike in climate and so much nearer together. ”

“ The northern plateau region of Mexico is without forests, except upon the higher ranges, while the southern and lower part of the country, with Central America, has a tropical profusion of fruit and vegetation. See Flora under Rocky Mountains; Canada; United States; Mexico; Nicaragua, etc.
South America.—The flora of South America ranges from that of the tropical to that of the temperate zone, and is controlled not only by latitude, but by altitude and rainfall. ”

“ In Central America the influence of mountains on the climate is much the same as in the West India islands; in fact, the narrow rugged belt of land connecting the two Americas may, from our present point of view, be considered as a great island situated mainly within the trade-wind belt, and similar to Jamaica, for example, in its influences on the winds blowing across it. ”

“ Farther north in the tropics are enormous expanses of high table-lands, stretching from the Atlantic to the foothills of the Andes, and lifted far above the tropical heats; the fertile valleys of the western cordilleras are cooled by perpetual snows even under the equator; vast forests grow untouched from a soil of incredible richness. The plains of Argentina, the great uplands of Brazil, the mountain valleys of Chile, Peru, Ecuador, Bolivia, and Colombia are suited to the habitation of any race, however far to the north its origin may have been ”

“ The intense heat and humidity of most tropical lands prevent any permanent occupation by a native-born population of pure whites. The catarrhal zone north of the fortieth parallel in America soon exterminates the negroes.50
The Indians of South America, though all fundamentally of the same ethnic stock, are variously acclimated to the warm, damp, forested plains of the Amazon; to the hot, dry, treeless coasts of Peru; and to the cold, arid heights of the Andes. The habitat that bred them tends to hold them, by restricting the range of climate which they can endure. ”

“ Climate, other things being equal, decides the flora of a country, and in this respect Mexico has many advantages. Were the country level from the Gulf to the ocean, it would have mostly a tropical climate, and produce only the vegetation of the tropics. But, rising in successive stages to a height of 19,720 feet, the temperature changes with the elevation, and a large portion enjoys the climate of the temperate zones. The low lying region near the coast, called the “hot country,” has a rich soil, a humid atmosphere, and abundant rains, that perpetually nourish a rank tropical vegetation. ”

“ We are led on various grounds to the conclusion that tropical shore-plants distributed by currents belong to two great regions, the American including the west coast of Africa, and the Asiatic, or Old World Region, which includes the African east coast. It is held that America is so placed with regard to the currents, that it is a distributor, and not a recipient of tropical shore-plants dispersed by that agency. From this it follows that all cosmopolitan tropical beach-plants that are dispersed by the currents have their homes in America. ”

“ Below Ecuador on the west coast, though still in the torrid zone, we find cooler weather, practically no rain, and for 1600 miles a desert region; beyond this there is a temperate climate with gradually increasing rainfall, and at last in southern Chile too much. On the east coast tropical weather and products continue till we pass Santos and the Tropic of Capricorn, followed by sub-tropical and temperate climates and production. The mountainous regions even at the equator have cooler weather, the temperature ever lowering with increase of altitude. ”

“ On the East Coast of South America this is the case, but not on the West after reaching Peru. Panama, Colombia, and Ecuador have ordinary tropical weather, continuous heat with plenty of rain and luxuriant vegetation. Peru is in striking contrast. From Paita, 5° south of the equator, throughout the journey of 1200 miles along the coast, all within the tropics, the weather is so cool at least half of the year that exercise is a pleasure, while wraps and steamer rugs are frequently desirable. ”

“ A more equable climate probably does not exist on the earth. (See Diagram, Plate III.)
On the Guiana side of the Amazon, in the islands of430 Mexiana and Marajo, the seasons are more strongly marked than even higher up the river. In the dry season, for about three months, no rain ever falls; and in the wet it is almost continual.
But it is in the country about the falls of the Rio Negro, that the most curious modifications of the seasons occur. Here the regular tropical dry season has almost disappeared, and a constant alternation of showers and sunshine occurs, almost all the year round. ”

“ A brief experience in the exploration of the Central American forests, however, soon removes any astonishment that one may feel at the little progress that has been hitherto made in ascertaining the conformation of the country. The difficulties thrown in the way of the explorer, by*the arid deserts of Africa or Australia, dwindle to insignificance in comparison with those presented by the inexhaustible fertility of Nature in the gorgeous lands of tropical America. ”

“ Central America and Southern Mexico lie within the tropics—their rains are tropical rains. The season is divided into wet and dry, as are the seasons of all tropical countries which are not rainless. During the rainy season it rains a portion of nearly every day, and during the dry season the sky is clear, the air is pure, and rain seldom falls.
All around the earth within the tropics, over the land and over the sea, there is a belt of almost daily rains, varying in width, north and south, in different sections, but averaging about five hundred miles. ”

“ The evidences of a Glacial period in South America are as conclusive as on our own continent; but it is difficult to conceive how barriers could, at that time, have been thrown across the great open oceans—the South Atlantic and South Pacific—in such a way as to confine the tropical currents to the central portions of these oceans.
We are, perhaps, not justified in saying that such barriers never did exist, but it will be conceded that the difficulties which oppose their erection there are much greater than in the northern hemisphere ”

“ In the mountainous portions of the West Indies and of Central America, on account of the more healthy conditions on the leeward or drier sides, as compared with the windward or humid slopes of the mountains, the towns and the principal portion of the white inhabitants are located on their western borders. Owing to the great humidity and the long-continued high temperature during the hotter portion of the year throughout the tropical province, much of the lowland to the eastward of the high mountains is swampy and unhealthy. ”

“ Among the changes which South America itself has undergone, perhaps the most important has been its separation into a group of large islands. Such a change is clearly indicated by the immense area and low elevation of the great alluvial plains of the Orinoko, Amazon, and La Plata, as well as by certain features in the distribution of the existing Neotropical fauna. A subsidence of less than 2,000 feet would convert the highlands of Guiana and Brazil into islands separated by a shallow strait from the chain of the Andes. ”

“ The boys made good progress down the coast of tropical South America. They had heard much of Peru, and were surprised to see only a great strip of sand, lying like a desert, between the Pacific and the mountains. Now and then a little stream, fed by the melting snows in the Andes, comes trailing out toward the sea, but it is usually smaller at its mouth than at its source for the reason that the precious water is utilized for irrigation purposes. Wherever there is water crops grow luxuriantly. ”

“ The climate we are seeking is not a tropical one. Whoever associates Mexico with the characteristics of heat, malaria, venomous reptiles, has received a wrong impression of it. Such places, with their drawbacks, exist within the geographical limits of the country, but it is wholly unnecessary to seek them; for the towns of historical and picturesque interest are above the reach of tropical dangers, for the most part, while there are seasons of the year when even the warmer portions can be visited with safety and delight. ”

“ On the tropical lowlands the heat of the torrid zone is experienced, but is not necessarily oppressive, although the European or American traveller who prefers a less enervating climate hastens to exchange that region for the more bracing air of the uplands. The night breezes, however, compensate largely for the heat of the sun, and render bearable, and indeed agreeable, the Vera Cruz littoral and the Yucatan peninsula, by the lowered temperature they afford. ”

“ On the verge of the tropics a greater quantity of rain falls annually than at the equator. Yet parts even of the tropical latitudes are entirely destitute of rain: Peru, for example, which owes its vegetation solely to rivers and nightly dews. In that country easterly winds prevail, blowing from the Pacific, and these being intercepted by the Andes, and cooled as they rise, are made to part with all their moisture before reaching the low region to the leeward. The desert zone of North Africa, between lat. ”

“ The monsoons of India, as I shall presently show, are examples of this; but the most striking instance with which I am personally acquainted occurs in the Pacific Ocean, between the Bay of Panama and the Peninsula of California, from latitude 8° to 22° north. If the huge continent of Mexico were taken away, and only sea left in its place, there can be no doubt but the ordinary phenomena of the Trade-winds would be observable in that part of the Pacific above mentioned. ”

“ The effort to account for South American civilization [Pg 169] by climate falls to pieces before the splendid and bracing altitudes of the Andes, the ideal conditions of Argentine, Uruguay, and Chile, and the delightful regions of the higher elevations of Central America. There is nothing inherently demoralizing in the climate of lands inhabited by the Latin peoples in America, but there is something distinctly vitiating in the moral miasma breathed by these peoples for three hundred years. ”

“ In North America, especially in the east, there are no transverse chains of mountains, there is no southern sea until the Gulf of Mexico is reached in lat. 30°, and even here Florida almost touches the tropic, and Mexico extends far beyond it. In this continent, therefore, the plants and animals, though driven far to the south, still found room to live and multiply, and had no great obstacle to cross either in their southward journey, or when they strove to re-annex their old territory as the cold conditions passed away again. ”

“ The trade-wind belt broadens in crossing the southern portion of the North American continent, and on the west coast and during its greatest northward migration reaches to southern California. As we have seen, the lowlands not adjacent to mountains in the Caribbean region receive little or no rain from the trade-winds, for the reason that the prevailing air-currents are moving from cooler to warmer regions, and therefore have their capacity for moisture increased as they advance more rapidly than their thirst can be satiated. ”