JOURNEY TO MEXICO. 291 In January, 1803, the travellers embarked for Guayaquil, in the vicinity of which they found a splendid forest of palms, plumeria, tabernæ-montanæ, and scitaminæ. Here also they heard the incessant noises of the volcano of Cotopaxi, which had experienced a tremendous agitation on the 6th January. From Guayaquil they proceeded by sea to Acapulco in New-Spain. At first, Humboldt's intention was to remain only a few months in Mexico, and return as speedily as possible to Europe, more especially as his instruments, and in particular the chronometers, were getting out of order, while he found it impossible to procure others. But the attractions of so beautiful and diversified a country, the great hospitality of its inhabitants, and the dread of the yellow fever of Vera Cruz, which usually attacks those who descend from the mountains between June and October, induced him to remain until the middle of winter. After making numerous observations and experiments on the atmospherical phenomena, the horary variations of the barometer, magnetism, and the natural productions of the country, our travellers set out in the direction of Mexico; gradually ascending by the burning valleys of Mescala and Papagayo, where the thermometer rose to 89.6° in the shade, and where the river is crossed on fruits of Crescentia pinnata, attached to each other by ropes of agave. Reaching the elevated plains of Chilpantzuigo, Tehuilotepec, and Tasco, which are situated at a height varying from 3837 to 4476 feet above the sea, they entered a region blessed with a temperate climate, and producing oaks, cypresses, pines, tree-ferns, and the cultivated cereal plants of Europe. After visiting the silver-mines of Tasco, the oldest and formerly the richest of Mexico, they went up by Cuernaraca and Guachilaco to the capital. Here they spent some time in the agreeable occupation of examining numerous curiosities, antiquities, and institutions, in 292 EXCURSIONS TO THE PROVINCES. making astronomical observations, in studying the natural productions of the surrounding country, and in enjoying the society of enlightened individuals. The longitude of Mexico, which had been misplaced two degrees on the latest maps, was accurately determined by a long series of observations. Our travellers next visited the celebrated mines of Moran and Real del Monte, and examined the obsidians of Oyamel, which form layers in pearlstone and porphyry, and were employed by the ancient Mexicans for the manufacture of knives. The cascade of Regla, a representation of which forms the vignette to the present volume, is situated in the neighbourhood. The regularity of the basaltic columns is as remarkable as that of the deposites of Staffa. Most of them are perpendicular; though some are horizontal, and others have various degrees of inclination. They rest upon a bed of clay, beneath which basalt again occurs. Returning from this excursion in July, 1803, they made another to the northern part of the kingdom, in the course of which they inspected the aperture made in the mountain of Suicog for the purpose of draining the valley of Mexico. They next passed by Queretaro, Salamanca, and the fertile plains of Yrapuato, on the way to Guanaxuato, a large city placed in a narrow defile, and celebrated for its mines. There they remained two months, making researches into the geology and botany of the neighbouring country. From thence they proceeded by the valley of San Jago to Valladolid, the capital of the ancient kingdom of Mechoacan; and, notwithstanding a continuance of heavy autumnal rains, descended by Patzquaro, which is situated on the edge of an extensive lake towards the shores of the Pacific Ocean, to the plains of Jorullo. Here they entered the great crater, making their way over crevices exhaling ignited sulphuretted hydrogen, and VOLCANO OF JORULLO. 293 experiencing much danger from the brittleness of the lava. The formation of this volcano is one of the most extraordinary phenomena which have been observed on our globe. The plain of Malpais, covered with small cones from six to ten feet in height, is part of an elevated table-land bounded by hills of basalt, trachyte, and volcanic tufa. From the period of the discovery of America to the middle of the last century, this district had undergone no change of surface, and the seat of the crater was then covered with a plantation of indigo and sugar-cane; when, in June, 1759, hollow sounds were heard, and a succession of earthquakes continued for two months, to the great consternation of the inhabitants. From the beginning of September every thing seemed to announce the re-establishment of tranquillity; but in the night of the 28th the frightful subterranean noises again commenced. The Indians fled to the neighbouring mountains. A tract not less than from three to four square miles in extent rose up in the shape of a dome; and those who witnessed the phenomenon asserted, that flames were seen issuing from a space of more than six square miles, while fragments of burning rocks were projected to an immense height, and the surface of the ground undulated like an agitated sea. Two brooks which watered the plantations precipitated themselves into the burning chasms. Thousands of the small cones described above suddenly appeared, and in the midst of these eminences, called hornitos or ovens, six great masses, having an elevation of from 1312 to 1640 feet above the original level of the plain, sprang up from a gulf running from N.N.E. to S.S.W. The most elevated of these mounds is the great volcano of Jorullo, which is continually burning. The eruptions of this central volcano continued till February, 1760, when they became less frequent. The Indians, who had abandoned all the villages within thirty 294 VOLCANO OF JORULLO. miles of it, returned once more to their cottages, and advanced towards the mountains of Aguasarco and Santa Ines, to contemplate the streams of fire that issued from the numberless apertures. The roofs of the houses of Queretaro, more than 166 miles distant, were covered with volcanic dust. Mr. Lyell (Principles of Geology, vol. i. p. 379) states, on the authority of Captain Vetch, that another eruption happened in 1819, accompanied by an earthquake, during which ashes fell at the city of Guanaxuato, 140 miles distant from Jorullo, in such quantities as to lie six inches deep in the streets. When Humboldt visited this place, the natives assured him that the heat of the hornitos had formerly been much greater. The thermometer rose to 203° when placed in the fissures exhaling aqueous vapour. Each of the cones emitted a thick smoke, and in many of them a subterranean noise was heard, which seemed to indicate the proximity of a fluid in ebullition. Two streams were at that period seen bursting through the argillaceous vaults, and were found by the traveller to have a temperature of 126.9°. The Indians give them the names of the two rivers which had been ingulfed, because in several parts of the Malpais great masses of water are heard flowing in a direction from east to west. Our author considers all the district to be hollow; but Scrope and Lyell find it more suitable to their views of volcanic agency to represent the conical form of the ground as resulting from the flow of lava over the original surface of the plain. The Indians of this province are represented as being the most industrious of New-Spain. They have a remarkable talent for cutting out images in wood, and dressing them in clothes made of the pith of an aquatic plant, which being very porous imbibes the most vivid colours. Two figures of this kind, which Humboldt brought home for the Queen of Prussia, are here represented. They exhibit the INDIANS OF MECHOACAN. 295 characteristic traits of the American race, together with a strange mixture of the ancient costume with that which was introduced by the Spaniards. From Valladolid, the ancient kingdom of Mechoacan, the travellers returned to Mexico by the elevated plain of Tolucca, after examining the volcanic mountains in the vicinity. They also visited the celebrated cheiranthostæmon of Cervantes, a tree of which it was at one time supposed there did not exist more than a single specimen. At that city they remained several months, for the purpose of arranging their botanical and geological collections, calculating the barometrical and trigo |