are alone visited by the majority of those who take part in voyages of
circumnavigation, but also those portions of the interior of two vast
continents which present the most striking contrasts manifested in the
Alpine tropical landscapes of South America, and the dreary wastes of the
steppes in Northern Asia. Travels, undertaken in districts such as these,
could not fail to encourage the natural tendency of my mind toward a
generalization of views, and to encourage me to attempt, in a special work,
to treat of the knowledge which we at present possess, regarding the
sidereal and terrestrial phenomena of the Cosmos in their empirical
relations. The hitherto undefined idea of a physical geography has thus, by
an extended and perhaps too boldly imagined a plan, been comprehended under
the idea of a physical description of the universe, embracing all created
things in the regions of space and in the earth.

The very abundance of the materials which are presented to the mind for
arrangement and definition, necessarily impart no inconsiderable
difficulties in the choice of the form under
p 9
which such a work must be presented, if it would aspire to the honor of
being regarded as a literary composition. Descriptions of nature ought not
to be deficient in a tone of life-like truthfulness, while the mere
enumeration of a series of general results is productive of a no less
wearying impression than the elaborate accumulation of the individual data
of observation. I scarcely venture to hope that I have succeeded in
satisfying these various requirements of composition, or that I have myself
avoided the shoals and breakers which I have known how to indicate to
others. My faint hope of success rests upon the special indulgence which
the German public have bestowed upon a small work bearing the title of
'Ansichten der Natur', which I published soon after my return from Mexico.
This work treats, under general points of view, of separate branches of