But the interest yielded by the contemplation of such a picture must arise from a pure love of nature. No Oasis here reminds the traveller of former inhabitants, no hewn stone[[12]], no fruit-tree once cultivated and now growing wild, bears witness to the industry of past races. As if a stranger to the destinies of mankind, and bound to the present alone, this region of the earth presents a wild domain to the free manifestation of animal and vegetable life.
The Steppe extends from the littoral chain of Caracas to the forests of Guiana, and from the snow-covered mountains of Merida, on whose declivity lies the Natron lake of Urao,—the object of the religious superstition of the natives,—to the vast delta formed by the mouth of the Orinoco. To the south-west it stretches like an arm of the sea[[13]], beyond the banks of the Meta and of the Vichada, to the unexplored sources of the Guaviare, and to the solitary mountain group to which the vivid imagination of the Spanish warriors gave the name of Paramo de la Suma Paz, as though it were the beautiful seat of eternal repose.
This Steppe incloses an area of 256,000 square miles. Owing to inaccurate geographical data, it has often been described as extending in equal breadth to the Straits of Magellan, unmindful that it is intersected by the wooded plain of the Amazon, which is bounded to the north by the grassy Steppes of the Apure, and to the south by those of the Rio de la Plata. The Andes of Cochabamba and the Brazilian mountains approximate each other by means of separate transverse spurs, projecting between the province of Chiquitos and the isthmus of Villabella[[14]]. A narrow plain unites the Hylæa of the Amazon with the Pampas of Buenos Ayres. The area of the latter is three times larger than that of the Llanos of Venezuela; indeed so vast in extent, that it is bounded on the north by palms, while its southern extremity is almost covered with perpetual ice. The Tuyu, which resembles the Cassowary, (Struthio Rhea,) is peculiar to these Pampas, as are also those herds of wild dogs[[15]], which dwell in social community in subterranean caverns, and often ferociously attack man, for whose defence their progenitors fought.
Like the greater part of the desert of Sahara[[16]], the Llanos, the most northern plains of South America, lie within the torrid zone. Twice in every year they change their whole aspect, during one half of it appearing waste and barren like the Lybian desert; during the other, covered with verdure, like many of the elevated Steppes of Central Asia[[17]].
The attempt to compare the natural characteristics of remote regions, and to pourtray the results of this comparison in brief outline, though a gratifying, is a somewhat difficult branch of physical geography.
A number of causes, many of them still but little understood[[18]], diminish the dryness and heat of the New World. Among these are: the narrowness of this extensively indented continent in the northern part of the tropics, where the fluid basis on which the atmosphere rests, occasions the ascent of a less warm current of air; its wide extension towards both the icy poles; a broad ocean swept by cool tropical winds; the flatness of the eastern shores; currents of cold sea-water from the antarctic region, which, at first following a direction from south-west to north-east, strike the coast of Chili below the parallel of 35° south lat., and advance as far north on the coasts of Peru as Cape Pariña, where they suddenly diverge towards the west; the numerous mountains abounding in springs, whose snow-crowned summits soar above the strata of clouds, and cause the descent of currents of air down their declivities; the abundance of rivers of enormous breadth, which after many windings invariably seek the most distant coast; Steppes, devoid of sand, and therefore less readily acquiring heat; impenetrable forests, which, protecting the earth from the sun’s rays, or radiating heat from the surface of their leaves, cover the richly-watered plains of the Equator, and exhale into the interior of the country, most remote from mountains and the Ocean, prodigious quantities of moisture, partly absorbed and partly generated—all these causes produce in the flat portions of America a climate which presents a most striking contrast in point of humidity and coolness with that of Africa. On these alone depend the luxuriant and exuberant vegetation and that richness of foliage which are so peculiarly characteristic of the New Continent.
If, therefore, the atmosphere on one side of our planet be more humid than on the other, a consideration of the actual condition of things will be sufficient to solve the problem of this inequality. The natural philosopher need not shroud the explanation of such phenomena in the garb of geological myths. It is not necessary to assume that the destructive conflict of the elements raged at different epochs in the eastern and western hemispheres, during the early condition of our planet; or that America emerged subsequently to the other quarters of the world from the chaotic covering of waters, as a swampy island, the abode of crocodiles and serpents[[19]].
South America presents indeed a remarkable similarity to the south-western peninsula of the old continent, in the form of its outlines and the direction of its coast-line. But the internal structure of the soil, and its relative position with respect to the contiguous masses of land, occasion in Africa that remarkable aridity which over a vast area checks the development of organic life. Four-fifths of South America lie beyond the Equator, and therefore in a region which, on account of its abundant waters, as well as from many other causes, is cooler and moister than our northern hemisphere[[20]]. To this, nevertheless, the most considerable portion of Africa belongs.
The extent from east to west of the South American Steppes or Llanos, is only one third that of the African Desert. The former are refreshed by the tropical sea wind, while the latter, situated in the same parallel of latitude as Arabia and Southern Persia, are visited by currents of air which have passed over heat-radiating continents. The venerable father of history, Herodotus, so long insufficiently appreciated, has in the true spirit of a comprehensive observer of nature, described all the deserts of Northern Africa, Yemen, Kerman, and Mekran (the Gedrosia of the Greeks), as far even as Mooltan in Western India, as one sole connected sea of sand[[21]].
To the action of hot land winds, may be associated in Africa, as far as we know, a deficiency of large rivers, of forests that generate cold by exhaling aqueous vapour, and of lofty mountains. The only spot covered with perpetual snow is the western portion of Mount Atlas[[22]], whose narrow ridge, seen laterally, appeared to the ancient navigators when coasting the shore, as one solitary and aërial pillar of heaven. This mountain range extends eastward to Dakul, where the famed Carthage, once mistress of the seas, lies in crumbling ruins. This range forms a far extended coast-line or Gætulian rampart, which repels the cool north winds and with them the vapours rising from the Mediterranean.