As a set-off against this jungle we have it intimated that, if proper search were made, gold would probably be found in this territory, as abundantly as in California. We sincerely hope no such discovery will be made. If there is a sure specific for demoralising a people, it is to involve them in the chase for gold, instead of that profitable industry which produces the veritable wealth for which gold has become the symbol and representative. The discovery of gold in one of our colonies would not only demoralise, it would impoverish. It would demoralise, by substituting for steady industry, with steady returns, a species of enterprise which has all the uncertainty and fluctuation of gambling; and it would finally impoverish by diverting labour from the creation of agricultural and manufacturing wealth, to the obtaining of the dry barren symbol of wealth, which, apart from its representative character, has but very little value whatever.
We will not look back towards Chimborazo and the Andes, as we should involve ourselves in long and tempting descriptions. In Africa, it is remarkable that we are little acquainted with the mountains. "No European has yet seen the Mountains of the Moon!" What a challenge to enterprising travellers! We know the level sands of Africa better than these elevations which have assumed so magnificent a title. What a terrific sterility does a large portion of this the most ill-fated of the great continents present! "On the interminable sands and rocks of these deserts no animal—no insect—breaks the dread silence; not a tree nor a shrub is to be seen in this land without a shadow. In the glare of noon the air quivers with the heat reflected from the red sand, and in the night it is chilled under a clear sky sparkling with its host of stars." The wind of heaven, which elsewhere breathes so refreshingly, is here a burning blast fatal to life; or else it drives the sand in clouds before it, obscuring the sun, and stifling and burying the hapless caravan.
In the new continent of America—if it still retains that title—the desert is comparatively rare. But its enormous forests have, in some regions, proved that excessive vegetation can assume almost as terrific an appearance as this interminable sterility.
"The forests of the Amazons not only cover the basin of that river, from the Cordillera of Chiquitos to the mountains of Parima, but also its limiting mountain-chains, the Sierra Dos Vertentes and Parima, so that the whole forms an area of woodland more than six times the size of France, lying between the 18th parallel of south latitude and the 7th of north, consequently inter-tropical and traversed by the equator. According to Baron Humboldt, the soil, enriched for ages by the spoils of the forest, consists of the richest mould. The heat is suffocating in the deep and dark recesses of these primeval woods, where not a breath of air penetrates, and where, after being drenched by the periodical rains, the damp is so excessive that a blue mist rises in the early morning among the huge stems of the trees, and envelops the entangled creepers stretching from bough to bough. A deathlike stillness prevails from sunrise to sunset, then the thousands of animals that inhabit these forests join in one loud discordant roar, not continuous, but in bursts. The beasts seem to be periodically and unanimously roused by some unknown impulse, till the forests ring in universal uproar. Profound silence prevails at midnight, which is broken at the dawn of morning by another general roar of the wild chorus. The whole forest often resounds when the animals, startled from their sleep, scream in terror at the noise made by bands of its inhabitants flying from some night-prowling foe. Their anxiety and terror before a thunder-storm is excessive, and all nature seems to partake in the dread. The tops of the lofty trees rustle ominously, though not a breath of air agitates them; a hollow whistling in the high regions of the atmosphere comes as a warning from the black floating vapour; midnight darkness envelops the ancient forests, which soon after groan and creak with the blast of the hurricane. The gloom is rendered still more hideous by the vivid lightning, and the stunning crash of thunder."
One of the most interesting subjects, of which mention is made in the work before us, is the gradual elevation and subsidence observed in some portions of these continents themselves. Just when the imagination had become somewhat familiar with the sudden but very partial upheaving of the earth by volcanic agencies, this new discovery came to light of the slow rising and sinking of vast areas of the land, and unaccompanied with any earthquakes or volcanic eruptions. In some parts the crust of the earth has sunk and risen again; in others, sort of see-saw movement on a most gigantic scale has been detected.
"There is a line crossing Sweden from east to west, in the parallel of 56° 3´ N. lat., along which the ground is perfectly stable, and has been so for centuries. To the north of it for 1000 miles, between Gottenburg and North Cape, the ground is rising; the maximum elevation, which takes place at North Cape, being at the rate of five feet in a century, from whence it gradually diminishes to three inches in a century at Stockholm. South of the line of stability, on the contrary, the land is sinking through part of Christianstad and Malmo; for the village of Stassten in Scania is now 380 feet nearer to the Baltic than it was in the time of Linnæus, by whom it was measured eighty-seven years ago."
It is evident that the elevation of the land, in relation to the level of the sea, may be produced either by an uprising of the continent or a depression of the bed of the ocean, permitting the waters to sink; as also the apparent depression of the land may be occasioned by an elevation in the bed of the ocean. This renders the problem somewhat more difficult to solve, because the causes we are seeking to discover may be sometimes operating at that part of the crust of the earth which is concealed from our view. Mr Lyell, who, in his Principles of Geology, has collected and investigated the facts bearing upon this subject, mentions the following as probable causes of the phenomena:—
1. "It is easy to conceive that the shattered rocks may assume an arched form during a convulsion, so that the country above may remain permanently upheaved. In other cases, gas may drive before it masses of liquid lava, which may thus be injected into newly opened fissures. The gas having then obtained more room, by the forcing up of the incumbent rocks, may remain at rest; while the lava, congealing in the rents, may afford a solid foundation for the newly raised district.
2. "Experiments have recently been made in America, by Colonel Patten, to ascertain the ratio according to which some of the stones commonly used in architecture expand with given increments of heat.... Now, according to the law of expansion thus ascertained, a mass of sandstone, a mile in thickness, which should have its temperature raised 200° F., would lift a super-imposed layer of rock to the height of ten feet above its former level. But, suppose a part of the earth's crust one hundred miles in thickness, and equally expansible, to have its temperature raised 600° or 800°, this might produce an elevation of between two and three thousand feet. The cooling of the same mass might afterwards cause the overlying rocks to sink down again, and resume their original position. By such agency, we might explain the gradual rise of Scandinavia, or the subsidence of Greenland, if this last phenomenon should also be established as a fact on further inquiry.
3. "It is also possible that, as the clay in Wedgwood's pyrometer contracts, by giving of its water, and then by incipient vitrification; so large masses of argillaceous strata, in the earth's interior, may shrink, when subjected to heat and chemical changes, and allow the incumbent rocks to subside gradually. It may frequently happen that fissures of great extent may be formed in rocks, simply by the unequal expansion of a continuous mass heated in one part, while in another it remains in a comparatively low temperature. The sudden subsidence of land may also be occasioned by subterranean caverns giving way, when gases are condensed, or when they escape through newly formed crevices. The subtraction, moreover, of matter from certain parts of the interior, by the flowing of lava and of mineral springs, must, in the course of ages, cause vacuities below, so that the undermined surface may at length fall in."[16]