Xll PREFACE TO THE SECOND AND THIRD EDITIONS. 



advantages, the public have long regarded my imperfectly 

 executed undertaking with friendly partiality. 



The second edition of the " Ansichten der Natur" was 

 prepared by me in Paris in 1826 ; and at the same time two 

 fresh treatises were added, one an Essay on the Structure 

 and mode of Action of Volcanoes in different regions of the 

 earth ; and the other on the " Vital Power/' bearing the 

 title " Lebenskraft, oder der rhodische Genius." During 

 my long stay at Jena, Schiller, in the recollection of his 

 youthful medical studies, loved to converse with me on 

 physiological subjects; and the considerations in which I 

 was then engaged on the muscular and nervous fibres when 

 excited by contact with chemically different substances, often 

 gave a more specific and graver turn to our discourse. The 

 " Ehodian Genius" was written at this time : it appeared 

 first in Schiller's "Horen," a periodical journal; and it was 

 his partiality for this little work which encouraged me to 

 allow it to be reprinted. My brother, in a letter forming 

 part of a collection which has recently been given to the 

 public (Wilhelm von Humboldf s Briefe an eine Preundin, 

 Th. ii. S. 39), touches tenderly on the subject of the memoir 

 in question, but adds at the same time a very just remark : 



