The Tasco, Moran, and Guanajuato mines, which yield a profit of several million piastres per annum, first attracted the attention of Humboldt, who had early studied geology. He then examined the Jerullo volcano, which, although situated in the centre of an immense plain thirty-six leagues from the sea, and more than forty from any volcano, discharged earth on the 29th September, 1759, and formed a mountain of cinders and clay 1700 feet high.
In Mexico the travellers were able to obtain everything necessary to the arrangement of the immense collections they had accumulated, to classify and compare the observations each had taken, and to prepare their geographical map for publication.
Finally, in January, 1804, they left Acapulco to examine the eastern slopes of the Cordilleras, and to take the dimensions of the two lofty Puebla volcanoes.
"Popocatepetl," says Desborough Cooley, "is always active, although nothing but smoke and ashes have issued from its crater for centuries. It is not only 2000 feet higher than the loftiest mountains of Europe, but is also the loftiest mountain in Spanish America." In spite of the great quantity of snow which had recently fallen, Humboldt accomplished the ascent of the Cofre, 1300 feet higher than the peak of Teneriffe, obtaining from its summit, an extensive and varied view, embracing the Puebla plain and the eastern slopes of the Mexican Cordilleras, clothed with thick forests of "liquidambar," tree-ferns and sensitive plants. The travellers were able to make out the port of Vera Cruz, the castle of San Juan d'Ulloa and the sea-shore.
This mountain owes its name of Cofre to a naked rock of pyramidal form which rises like a tower from its summit at a height of 500 feet.
After this last trip Humboldt went down to Vera Cruz, and having fortunately escaped the yellow fever then decimating the population, he set sail for Cuba, where he had left the greater part of his collection, going thence to Philadelphia. There he remained a few weeks to make a cursory study of the political constitution of the United States, returning to Europe in August, 1804.
The results of Humboldt's travels were such, that he may be justly called the discoverer of Equinoctial America, which before his time had been explored without becoming really known, while many of its innumerable riches were absolutely ignored. It must be fully acknowledged that no traveller ever before did so much as Humboldt for physical geography and its kindred sciences. He was the very ideal of a traveller, and the world is indebted to him for important generalizations concerning magnetism and climate; whose results are plainly seen in the isothermal lines of modern maps. The writings of Humboldt mark an era in the science of geography, and have led to many further researches.
END OF THE GREAT NAVIGATORS OF THE EIGHTEENTH CENTURY.
LONDON:
GILBERT AND RIVINGTON, PRINTERS,
ST. JOHN'S SQUARE.