in any single and extensive system of mountains we find, more or less distinctly represented, all the inorganic materials which form the solid carpentry of the globe, yet observations in distant regions are necessary in studying the composition the relative age, and the origin of rocks. Our knowledge of the structure and form of volcanoes was, till the end of the last century, drawn principally from Vesuvius and Ætna, though the basin of the Mediterranean afforded better means of studying the nature and action of these fiery cones. Among the Sporades trachytic rocks have been upraised, at three different times, in three centuries. Near Methone, in the Peloponnesus, "a monte nuovo," seen by Strabo and by Dodwell, is higher than the new volcano of Jorullo in Mexico, and Humboldt found it "surrounded with several thousand small basaltic cones, protruded from the earth, and still smoking." Volcanic fires also break out at Ischia, on the Monte Epomeo; and according to ancient relations, lavas have flowed from fissures, suddenly opened, in the Lelantine plain, near Chalcis. On the shores of the Mediterranean, too, on several parts of the mainland of Greece, in Asia Minor, and in Auvergne, and round the plain of Lombardy, there are numerous examples of volcanic action. From these facts our author has drawn the conclusion, "that the basin of the Mediterranean, with its series of islands, might have offered to an attentive observer much that has been recently discovered, under various forms, in South America, Teneriffe, and the Aleutian Islands, near the polar circle." "The objects to be observed," he continues, "were assembled within a moderate distance; yet distant voyages, and the comparison of extensive regions, in and out of Europe, have been required for the clear perception and recognition of the resemblance between volcanic phenomena and their dependence on each other." In different parts of the globe we find assemblages of volcanoes in various rounded groups, or in double lines, and we have thus the most conclusive evidence that their cause is deeply seated in the earth. All the American volcanoes are on the western coast opposite to Asia, nearly in a meridional direction, and extending 7200 geographical miles. Humboldt regards the whole plateau of Quito, whose summits are the volcanoes of Pinchincha, Cotapaxi, and Tunguragua, as a single volcanic furnace. The internal fire rushes out sometimes by one and sometimes by another vent; and in proof of the fact that there are subterranean communications between "fire emitting openings," at great distances from each other, he mentions the circumstance, that in 1797, the volcano of Pasto emitted a lofty column of smoke for three months continuously, and that it disappeared at the very instant, when, at the distance of 240 miles, "the great earthquake of Riobamba, and the immense eruption of mud called Moya' took place, causing the death of between thirty and forty thousand persons." In proof of the same fact, he adduces the sudden emergence from the sea near the Azores of the island of Sabrina, on the 30th of January, 1811, which was followed by those terrible internal commotions which, from May, 1811, to June, 1813, shook almost incessantly the West India islands, the plains of the Ohio and Mississippi, and the opposite coast of Venezuela or Caraccas. In the course of a month after this, the principal city of that province was destroyed. On the 30th April, 1811, the slumbering volcano of the island of St. Vincent broke forth, and at the very moment the explosion took place, a loud subterranean noise, like that of great pieces of ordnance, which spread terror over an area of 35,000 square miles, was heard at the distance of 628 miles from St. Vincent. The phenomena which accompanied the celebrated earthquake at Lisbon, on the 1st Nobember, 1755, lead to the same conclusion. At the very time it took place, the Lakes of Switzerland, and the sea upon the Swedish coast, were violently agitated; and at Martinique, Antigua, and Barbadoes, where the tide never exceeds thirty inches, the sea suddenly rose upward of twenty feet. In the remaining portion of this interesting chapter, our author directs our attention chiefly to the phenomena which accompanied the last great eruption of Vesuvius, on the night of the 22nd October, 1822. It had been supposed by several writers that the crater of Vesuvius had undergone an entire change from preceding eruptions; but our author has shown that this is not the case, and that the error had arisen from the observers having confounded "the outlines of the margin of the crater with those of the cones of eruption, accidentally formed in the middle of the crater, on its floor or bottom, which has been upheaved by vapors." During the period from 1816-1818, such a cone had gradually risen above the south-eastern margin of the crater, and the eruption of February, 1822, had raised it about 112 feet above the north-west margin. This singular cone, which from Naples appeared to be the true summit of the mountain, fell in with a dreadful noise on the eruption of the 22d October, 1822, "so that the floor of the crater, which had been constantly accessible since 1811, is now almost 800 feet lower than the northern, and 218 lower than the southern edge of the volcano." "In the last eruption, on the night of the 23d to the 24th October, 1822, twenty-four hours after the falling in of the great cone of scoria, which has been mentioned, and when the small but nu merous currents of lava had already flowed off, the fiery eruption of ashes and rapilli commenced; it continued without intermission for twelve days, but was greatest in the first four days. During this period the detonations in the interior of the volcano were so violent, that the mere concussion of the air (for no earthquake movement was perceived) rent the ceilings of the rooms in the palace of Portici. In the neighboring villages of Resina, Torre del Greco, Tor re del Annunziata, and Bosche tre Case, a remarkable phenomenon was witnessed. Throughout the whole of that part of the country the air was so filled with ashes as to cause in the middle of the day profound darkness, lasting for sev eral hours: lanterns were carried in the streets, as had often been done in Quito during the eruptions of Pinchincha. The flight of the inhabitants had never been more general. Lava currents are regarded by those who dwell near Vesuvius with less dread than an eruption of ashes, a phenomenon which had never been known to such a degree in modern times; and the ob scure tradition of the manner in which the de struction of Herculaneum, Pompeii, and Stabiæ, took place, filled the imaginations of men with appalling images.* The hot aqueous vapors which rose from the crater during the eruption, and spread themselves in the atmosphere, formed, in cooling, a dense cloud, surrounding the column of fire and ashes which rose to a height of between nine and ten thousand feet. Flashes of forked lightning issuing from the columns of ashes darted in every direction, and the rolling thunders were distinctly heard, and distinguished from the sounds which proceeded from the interior of the volcano. In no other eruption had the play of the electric forces formed so striking a feature. "On the morning of the 26th October, a surprising rumor prevailed that a torrent of boiling water was gushing from the crater, and pouring down the slope of the cone of ashes. Monticelli soon discovered that this was an optical illusion. It was in reality a flow of dry ashes, which, being loose and movable as shifting sand, issued in large quantities from a crevice in the upper margin of the crater."-Pp. 229, 230. Owing to the thunderstorm noticed in this extract, an abundant, and violent fall of rain took place, and as the rain is heaviest above the cone of ashes, torrents of mud descend from it in every direction; and when the summit of the volcano is in the region of perpetual snow, the melting of the snow produces very disastrous inundations. At the foot of volcanoes, too, and on their flanks, there are frequently vast cavities, which, having a communication by many channels with mountain torrents, become subterranean lakes or reservoirs of water. When earthquakes, as happens in the Andes, shake the entire mass of the volcano, these reservoirs are opened, discharging water, fishes, and mud. On the 19th feet high, fell in, an area of nearly thirty June, 1698, when the Carguairazo, to the north of Chimborazo, and upward of 19,000 square miles was covered with mud and fishes! Vesuvius, and other similar volcanoes, of their craters with the interior of the earth. have permanent communications by means They alternately break forth and slumber, and often " end by becoming solfataras, emitting There aqueous vapors, gases, and acids." is, however, another and a rarer class, which are closely connected with the earliest revolutions of our planet. Trachytic mountains open suddenly, emit lava and ashes, and close again perhaps for ever. The gigantic mountain of Antisana on the Andes, and Monte Epomeo in Ischia, in 1302, are examples of that phenomenon. Eruptions of this kind sometimes takes place in the plains, as happened in Quito, in Iceland, at a distance from Hecla, and in Euboea in the Lelantine fields. Many of the islands upheaved from the sea belong to the same class. The communication of the external opening with the interior of the earth is not permanent, and as soon as the cleft or opening closes, the volcanic action wholly ceases. Humboldt is of opinion that "veins or dykes of basalt, dolerite, and porphyry, which traverse almost all formations, and that masses of syenite, augitic porphyry, and amygdaloid, which characterize the recent transition and oldest sedimentary rocks, have probably been formed in a similar manner." The thickness of the bed of ashes which fell during the twelve days was little above three feet That the earth is a melted mass at no very on the slope of the cones, and only about eighteen inches on the planes. This is the greatest fall of great depth below its surface, is placed beashes since the eruption of Vesuvius, which occa-yond a doubt, not only by the preceding sioned the death of the elder Pliny. facts, but by a great mass of observations collected by Humboldt and Arago, on the increase of temperature as we descend into the bowels of the earth. "The primitive cause of this subterranean heat is, as in all planets, the process of formation itself, the separation of the spherically condensing mass from a cosmical gaseous fluid, and the cooling of the terrestrial strata at different depths by the loss of heat parted with by Elastic vapors press the molten oxydizing substances upward through deep fissures. Volcanoes might thus be termed intermitting springs or fountains of earthy substances; that is, of the fluid mixture of metals, alkalis, and earths, which solidify into lava currents, and flow softly and tranquilly, when being upheaved they find a passage by which to escape.' radiation. Our author concludes this instructive section with a speculation which he himself characterizes as bold; the object of which is to explain, by means of the internal heat of our globe, the existence, in a fossil state, of the tropical forms of animals and plants in the cold regions of the globe. This hitherto unexplained fact has been ascribed to various causes, to a change in the obliquity of the ecliptic by the approach of a comet, and to a change in the intensity of the sun's light and heat. We have been led to suppose that, as the two poles of maximum cold are nearly coincident with the magnetic poles, they may partake in their revolution, and thus make the warm and the cold meridians which are now proved to exist, occupy in succession every position on the earth's surface; and that variations in the forces or causes by which that cold is produced, may produce a still farther variation of temperature.* ern regions, it should be assumed that the longhaired species of elephant now found enclosed in ice, was originally indigenous in cold climates, and that forms resembling the same leading type may, as in the case of lions and lynxes, have been able to live in wholly different climates; still this solution of the difficulty presented by fossil remains cannot be extended so as to apply to vegetable productions. From reasons with which the study of physiology makes us acquainted, palms, musaceæ, and arborescent monocotyledones, are incapable of supporting the deprivation of their the present temperature of our northern regions; appendicular organs, which would be caused by and in the geological problem which we have to examine, it appears to me difficult to separate vegetable and animal remains from each other. The same mode of explanatiou ought to comprehend both."-Vol. ii. pp. 239, 241. The next chapter of the "Aspects of Nature" is one of seven pages, entitled, "The Vital Force, or the Rhodian Genius." It was first printed in Schiller's Hora for 1795, and contains " the development of a physiological idea in a semi-mythical garb." In an earlier work, our author had defined the vital force as "the unknown cause which prevents the elements from following their original affinities;" and he endeavors to illustrate this position by the following story :-A picture, called the Rhodian Genius, was brought to Syracuse from Greece, and was supposed to be the work of the same artist who cast the Colossus of Rhodes. It was placed in the Gallery of Paintings and Sculpture, and excited much difference of opinion, both respecting its author and its object. On the foreground were youths and maidens, handsome and graceful, but unclothed, and expressing in their features and movements, only the desires and sorrows of an earthly habitation. Their arms outstretched to each other, indicated "their desire of union;" but they turned their troubled looks toward a may be that, in the ancient world, exhala ions of halo-encircled Genius who stood in the midst heat issuing forth from the many openings of the of them. On his shoulder was a butterfly, deeply-fissured crust of the globe, may have favored, perhaps, for centuries, the growth of palms and in his hand a lighted torch. Though and tree-ferns, and the existence of animals rechildlike in his form and aspect, a celestial quiring a high temperature, over entire countries fire animated his glance, and he gazed as where now a very different climate prevails. Ac-with the eye of a master upon the gay throng cording to this view of things, the temperature of volcanoes would be that of the interior of the Earth; and the same cause, which, operating through volcanic eruptions, now produces devastating effects, might, in primeval ages, have clothed the deeply-fissured rocks of the newly oxydized Earth, in every zone, with the most luxuriant vegetation. "Everywhere," says our author, "the ancient world shows a distribution of organic forms at variance with our present elimate. It If, in order to explain the distribution of tropical forms, whose remains are now buried in north* Edinburgh Transactions, vol. ix. pp. 211, 212. at his feet. The object of the picture became a problem, which philosophers and connoisseurs strove to solve. "Some regarded the Genius as the personification of Spiritual Love forbidding the enjoyment of sensual pleasure: others said, that it was the assertion of the Empire of Reason over Desire.". A collection of pictures having arrived from Rhodes, there was found among them the companion or pendant of the Rhodian Genius. The Genius was still the central figure; but his head was now drooping. The butterfly was no longer on his shoulder; and his torch was inverted and extinguished. "The youths and maidens pressing around him had met and embraced. Their glance, no longer sad and subdued, announced, on the contrary, emancipation from restraint, and the fulfillment of long-cherished desires." The companion picture afforded no clue to the solution of the problem; and in this crisis of baffled ingenuity and disappointed curiosity, Dionysius ordered the picture, along with a faithful copy of the Rhodian Genius, to be carried to the house of Epicharmus, a Pythagorean philosopher, who fixed his eyes upon the picture, and thus addressed his disciples: them, without regard to their ancient rights, to obey his laws. the Tyrant has sent to me for explanation; turn Now view with me the new picture which your eyes from the image of life to that of death. The butterfly has left its former place and soars upward, the extinguished torch is reversed, the head of the youth has sunk, the spirit has fled to other spheres, and the vital force is dead. Now the youths and maidens joyfully join hands, the earthy substances resume their ancient rights; and follow impetuously after long restraint, the imthey are free from the chains that bound them, pulse to union. Thus inert matter, animated awhile by vital force, passes through an innumerable diversity of forms, and perhaps in the same substance which once enshrined the spirit of Pythagoras, a poor worm may have enjoyed a mopp. 255-257. mentary existence.”___Vol. ii. The closing chapter of Baron Humboldt's work contains an account of the Plateau "As living beings are compelled by natural de- of Caxamarca, the ancient capital of the sires to salutary and fruitful union, so the raw materials of inorganic matter are moved by simi- Inca Atahualpa, and describes the first lar impulses. Thus the fire of Heaven view of the Pacific Ocean as seen from follows metal,-iron obeys the attraction of the the crest of the Andes. After mentioning loadstone, amber rubbed takes up light sub- the Quina (or fever-bark)* producing forests stances, earth mixes with earth,-salt collects in the valleys of Loxa, and the alpine vegetogether from the water of the sea,-and the acid tation and mountain wildernesses of the Pamoisture of the Stypteria, as well as the flocculent salt of Trichitis, love the clay of Melos. In ramos, our author describes the gigantic reinanimate nature, all things hasten to unite with mains of the ancient artificial roads of the each other, according to their particular laws. Incas of Peru, which formed a line of comHence no terrestrial element is to be found any- munication through all the provinces of the where in its pure and primitive state. Each as empire, extending more than a thousand Ensoon as formed tends to enter into new combina-glish miles. The road itself is 21 feet wide, tions, and the art of man is needed to disjoin and present in a separated state substances which you would seek in vain in the interior of the Earth, and in the fluid ocean of air and water. In dead inorganic matter, entire inactivity and repose reign, so long as the bands of affinity continue undissolved, so long as no third substance comes to join itself to the others; but even then the action and disturbance produced are soon again succeeded by unfruitful repose. "It is otherwise, however, when the same substances are brought together in the bodies of plants and animals. In these the vital force of power reigns supreme, and regardless of the mutual amity or enmity of the atoms recognized by Democritus, commands the union of substances which, in inanimate nature, shun each other, and separates those which are ever seeking to enter into combination. "Now come nearer to me, my friends; look with me on the first of the pictures before us, and recognize in the Rhodian Genius, in the expression of youthful energy, in the butterfly on his shoulder, and in the commanding glance of his eye, the symbol of vital force animating each individual germ of the organic creation. At the feet are the earthy elements desiring to mix and unite conformably to their particular tendencies. The Genius, holding aloft his lighted torch with commanding gesture, controls and constrains and above a deep understructure was paved with well cut blocks of blackish trap porphyry. Station-houses, of hewn stone, are built at nearly equal distances, forming a kind of caravanserai. In the pass called the Paramo del Assuay, the road rises to the height of 15,526 feet, almost equal to that of Mon Blanc. Across the wide and arid plains between the Pacific and the Andes, and also over the ridges of the Cordilleras, these two great Peruvian roads, or systems of roads, are covered with flat stones, or "sometimes even with cemented gravel, (Macadamized.)" The roads crossed the rivers and ravines by three kinds of bridges," viz., those of stone, wood, and rope, and there were also aqueducts for bringing water to the caravanserais and to the fortresses." As wheel-carriages were not then used upon roads, they were occasionally interrupted by long flights of steps, provided with resting-places at suitable *The Cinchona Condaminia (officinalis). This beautiful tree, though only six inches in diameter, often attains a height of sixty feet. The bark was introduced into Europe in 1632 or 1640. 394 HUMBOLDT S ASPECTS OF NATURE. [March, intervals. Along with their grand artificial | tops or crowns, they have aspiring branches When the travelers approached the hot climate of the basin of the Amazons, they were delighted with the splendid orange trees, sweet and bitter, of the Huertas de “Laden with many thousands of ht of As night was closing upon our travelers, when they were ascending the eastern declivity of the Cordilleras, they arrived at an elevated plain where the argentiferous mouncelebrated Silver Mines of Chota, afforded tains of Gualgayoc, the chief locality of the Gualgayoc, an isolated mass of silicious rock, them a remarkable spectacle. The cerro of a deep ravine from the limestone mountains stands like an enchanted castle, separated by of Cormolatsche. It is traversed by innumerable veins of silver, and terminated on Besides being perforated to its sumthe N. W. by a nearly perpendicular precipice. mit by many hundred galleries driven in evnatural openings in the mass of the silicious ery direction, this mountain presents also rock, through which the intensely dark blue sky of those elevated regions is visible to a spectator standing at the foot of the mountain. These openings are popularly called windows," and "similar ones were pointed no of Pinchincha." out to us in the trachytic walls of the volca On their way to the ancient city of Cax- |