Lewis H. Lapham in Lapham's Quarterly:
Humboldt was a Prussian aristocrat educated as a young man in Jena and Weimar by Johann Wolfgang von Goethe, who directed his reading and lines of laboratory experiment. At the age of twenty-nine in 1799, accomplished as a botanist and zoologist, equipped with a knowledge of geology, history, and astronomy, Humboldt set forth on a five-year exploration of the Americas. Armed with reference books and intent upon perceiving “the connections between the physical and the intellectual worlds,” he brought with him “precise instruments” (barometer, hydrometer, artificial horizon) to measure, among other things, the variable intensity of magnetic forces, “the periodical oscillations of the aerial oceans,” the blueness of the sky. In the jungles and mountains of New Granada and Peru, the investigation’s mules were burdened with “forty-two boxes containing an herbal of six thousand equinoctial plants, seeds, shells, and insects, and geological specimens” gathered from the banks of the Amazon and on the ascent of Chimborazo, the volcano then regarded as the highest mountain in the world.
The climb in 1802 was arduous and slow; at seventeen thousand feet above sea level, the air is thin and no birds sing. Humboldt finds it hard to breathe, and his feet begin to bleed; but when he recalls the predicament ten years later in his Personal Narrative, he doesn’t dwell on the “unbelievable difficulties…quite unknown in the wildest parts of Europe.” He is surprised instead by joy, by the beauty of the landscape, and by the pleasure he takes in seeing how the vegetation changes with the topography—palms and bamboo forests at lower elevations, above them conifers and oaks, higher up lichens like those seen within the Arctic Circle. Although careful to mark the dots (the shape of a leaf, the layering of a rock), what delights him are the dots going together across otherwise unbridged distances in space and time. He draws upon his ferocious memory and love of learning to see the botanical specimen in his hand in the Andes similar to the one seen in his hand at the same altitude in the Alps. The scrupulously repeated making of similar connections—between the here and now with the there and then—leads him to a notion of the planet bound up in intertwining chains of being as fragile as they are beautiful, mortal and therefore analogous to the life and story of man:
The discovery of a new genus seemed to me far less interesting than an observation on the geographical relations of plants, or the migration of social plants, and the heights that different plants reach on the peaks of the cordilleras.
At the instigation of metaphor, Humboldt discovers a new way of looking at the earth, and over the course of the next fifty years he publishes a Promethean abundance of further notes, books, maps, letters, directing the thought not only of Goethe but also that of Henry David Thoreau and Charles Darwin, who says that without Humboldt, he never would have boarded the Beagle or written On the Origin of Species.