XVI PREFACE. 



The third section, which contains an account of his residence 

 in Paris, where for eighteen years he was closely occupied with 

 the preparation of his works and the arrangements necessary 

 for their publication, is also founded partly on information 

 derived from printed matter already before the public and 

 partly from manuscript letters and documents. 



In the preparation of the fourth section, which treats of 

 Humboldt's life at Berlin, from the year 1827, when he took 

 up his residence in his native city, till his death, a vast amount 

 of material has been at the disposal of the Author, enabling him 

 to introduce much new matter relating to this period, as well 

 as to correct many errors that have largely prevailed. 



The elaborate catalogue of all the works, treatises, and mis- 

 cellaneous writings of Humboldt, constituting the fifth section, 

 will, as a first attempt to reduce this literary chaos into any- 

 thing like system and order, be welcomed by all those who value 

 accuracy even in the most trivial facts in literature. 



It was found almost impossible in arranging for the compila- 

 tion of the sixth section, so to classify the various scientific 

 subjects that in the eight treatises, each of which was entrusted 

 to a different author, there should be on the one hand no 

 omissions of importance and on the other hand no unnecessary 

 repetitions. The names of the several authors are a sufficient 

 guarantee for the complete and accurate treatment of the sub- 

 jects they have taken in hand. 



Of the three portraits illustrating the work, that in the first 

 volume is engraved from a chalk drawing in the possession of 

 Fran von Biilow ; it was taken in the year 1796, and has never 

 before been published. The portrait in the second volume, 

 which also appears through the kind permission of Frau von 

 Biilow, was taken at Paris in 1814, and is interesting from the 

 fact that it is copied from a drawing made by Humboldt him- 

 self from the looking-glass. The third portrait is from an 

 oil-painting by Eduard Hildebrandt, with whom Humboldt was 

 on terms of intimate friendship ; and this picture, in the pos- 



