AUTHOll S PREFACE. 



present work, the whole of which, with the exception of a 

 portion of the Introduction, was written for the first time 

 in the years ]843 and 1844; the discourses in Berlin 

 having been delivered from November 1827 to April 1828, 

 previous to my departure for Northern Asia. A represen- 

 tation of the actual state of our knowledge, in which year 

 by year the acquisitions of new observations imperatively 

 demands the modification of previous opinions, must, as it 

 appears to me, gain in unity, freshness, and spirit, by being 

 definitely connected with some one determinate epoch. 



The first volume contains a general view of nature, from 

 the remotest nebulae and revolving double stars to the 

 terrestrial phenomena of the geographical distribution of 

 plants, of animals, and of races of men ; preceded by some 

 preliminary considerations on i^ie different degrees of enjoy- 

 ment offered by the study of nature and the knowledge of 

 her laws ; and on the limits and method of a scientific ex- 

 position of the physical description of the Universe. I 

 regard this as the most important and essential portion of 

 my undertaking, as manifesting the intimate connection of 

 the general with the special, and as exemplifying in form 

 and style of composition, and in the selection of the results 

 taken from the mass of our experimental knowledge, the 

 spirit of the method in which 1 have proposed to myself to 



conduct the whole work. In the two succeeding 

 VOL. i. c 



