AUTHORS PREFACE. 1% 



which such a work must be presented, if it would aspire to 

 the honor of being regarded as a literary ccmposition. De* 

 Bcriptions of nature ought not to be deficient in a tone of hfe- 

 like truthfuhiess, while the mere enumeration of a series of 

 general results is productive of a no less wear)'ing impression 

 than the elaborate accumulation of the individual data of ob- 

 Rervation. 1 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 A?isich- 

 ten der Natur, which I published soon after my return from 

 Mexico. This work treats, under general points of view, of 

 separate branches of physical geography (such as the forms of 

 vegetation, grassy plains, and deserts). The effect produced 

 by this small volume has doubtlessly been more powerfully 

 manifested in the influence it has exercised on the sensitive 

 minds of the yonng, whose imaginative faculties are so strong- 

 ly manifested, than by means of any thing which it could it- 

 self impart. In the work on the Cosmos on which I am now 

 engaged, I have endeavored to show, as in that entitled A)i' 

 sichten der Natiir, that a certain degree of scientific com- 

 pleteness in the treatment of individual facts is not wholly 

 mcompatible with a picturesque animation of style. 



Since public lectures seemed to me to present an easy and 

 efficient means of testing the more or less successful manner 

 of connecting together the detached branches of any one sci- 

 ence, I undertook, for many months consecutively, first in the 

 French language, at Paris, iind aftervvard in my own native 

 German, at Berlin (almost simultaneously at two different 

 places of assembly), to deliver a course of lectures on the phys- 

 ical description of the universe, according to my conceptior 

 of the science. My lectures were given extemporaneously 

 both in French and German, and without the aid of wi'ittei 

 notes, nor have I, in any way, made use, in the present work 



